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| author | nfenwick <nfenwick@pglaf.org> | 2025-01-27 23:47:20 -0800 |
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| committer | nfenwick <nfenwick@pglaf.org> | 2025-01-27 23:47:20 -0800 |
| commit | aff6f89854b8f73e6411b2c8154d531231e876ff (patch) | |
| tree | 6304e889151d06dd23f81f791b8835d89d20afa7 /old/61462-h | |
| parent | 6a64f54af7dfaace889e44bd3d86c84c9d88228c (diff) | |
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display: block;} } - .section { clear: both; page-break-before: always; } - .ol_1 li {font-size: .9em; } - @media handheld {.ol_1 li {padding-left: 1em; text-indent: 0em; } } - body {font-family: 'DejaVu Serif', Georgia, serif; text-align: justify; } - table {font-size: .9em; page-break-inside: avoid; margin: 1.5em 1em; } - .footnote {font-size: .9em; } - div.footnote p {text-indent: 2em; margin-bottom: .5em; } - .figcenter {font-size: .9em; page-break-inside: avoid; } - div.titlepage {text-align: center; page-break-before: always; - page-break-after: always; } - div.titlepage p {text-align: center; text-indent: 0em; font-weight: bold; - line-height: 1.5; margin-top: 3em; } - .ph2 { text-indent: 0em; font-weight: bold; font-size: x-large; margin: .75em auto; - page-break-before: always; } - .vincula{ text-decoration: overline; } - .fraction {display: inline-block; vertical-align: middle; text-align: center; - font-size: 75%;text-indent: 0; } - .center {text-align: center; } - nsc {font-variant: inherit; } - .tbl2 { margin: auto; border-collapse: collapse; } - .c12 { text-align: center; } - .c28 { text-indent: 1em; vertical-align: top; text-align: left; padding-left: .5em; - padding-right: .5em; } - </style> - </head> - <body> - - -<pre> - -The Project Gutenberg EBook of Standard methods for the examination of -water and sewage, by American Public Health Association - -This eBook is for the use of anyone anywhere at no cost and with -almost no restrictions whatsoever. You may copy it, give it away or -re-use it under the terms of the Project Gutenberg License included -with this eBook or online at www.gutenberg.org/license - - -Title: Standard methods for the examination of water and sewage - -Author: American Public Health Association - -Release Date: February 20, 2020 [EBook #61462] - -Language: English - -Character set encoding: UTF-8 - -*** START OF THIS PROJECT GUTENBERG EBOOK STANDARD METHODS FOR THE *** - - - - -Produced by Richard Tonsing and the Online Distributed -Proofreading Team at http://www.pgdp.net (This file was -produced from images generously made available by The -Internet Archive) - - - - - - -</pre> - - -<div class='tnotes covernote'> - -<p class='c000'><b>Transcriber’s Note:</b></p> - -<p class='c000'>The cover image was created by the transcriber and is placed in the public domain.</p> - -</div> - -<div class='titlepage'> - -<div> - <h1 class='c001'>STANDARD METHODS<br /> <span class='small'>FOR THE</span><br /> EXAMINATION<br /> <span class='small'>OF</span><br /> WATER AND SEWAGE</h1> -</div> - -<div class='nf-center-c0'> -<div class='nf-center c002'> - <div class='c003'><em>FOURTH EDITION</em></div> - <div class='c002'><span class='small'>Revised by committees of the American Public Health Association, American Chemical Society, and referees of the Association of Official Agricultural Chemists</span></div> - <div class='c003'>AMERICAN PUBLIC HEALTH ASSOCIATION</div> - <div><span class='sc'>169 Massachusetts Avenue</span></div> - <div>BOSTON</div> - <div>1920</div> - </div> -</div> - -</div> - -<div class='nf-center-c0'> -<div class='nf-center c004'> - <div><span class='small'><em>Copyright, 1917 and 1920</em></span></div> - <div class='c002'><span class='small'><em>By the American Public Health Association</em></span></div> - </div> -</div> - -<div class='pbb'> - <hr class='pb c002' /> -</div> -<div class='chapter'> - <span class='pageno' id='Page_iii'>iii</span> - <h2 class='c005'>CONTENTS.</h2> -</div> - -<table class='table0' summary='CONTENTS'> - <tr> - <th class='c006'></th> - <th class='c006'> </th> - <th class='c006'> </th> - <th class='c006'> </th> - <th class='c006'> </th> - <th class='c007'><span class='small'>PAGE</span></th> - </tr> - <tr> - <td class='c006' colspan='5'><span class='sc'>Preface to the Fourth Edition</span></td> - <td class='c007'><a href='#Page_vii'>vii</a></td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c006' colspan='5'><span class='sc'>Collection of Samples</span></td> - <td class='c007'><a href='#Page_1'>1</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Quantity of Water Required for Analysis</span></td> - <td class='c007'><a href='#Page_1'>1</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Bottles</span></td> - <td class='c007'><a href='#Page_1'>1</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Time Interval between Collection and Analysis</span></td> - <td class='c007'><a href='#Page_2'>2</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Representative Samples</span></td> - <td class='c007'><a href='#Page_3'>3</a></td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c006' colspan='5'><span class='sc'>Physical Examination</span></td> - <td class='c007'><a href='#Page_4'>4</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Temperature</span></td> - <td class='c007'><a href='#Page_4'>4</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Turbidity</span></td> - <td class='c007'><a href='#Page_4'>4</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Turbidity Standard</span></td> - <td class='c007'><a href='#Page_4'>4</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Platinum Wire Method</span></td> - <td class='c007'><a href='#Page_5'>5</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Turbidimetric Method</span></td> - <td class='c007'><a href='#Page_7'>7</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Coefficient of Fineness</span></td> - <td class='c007'><a href='#FINENESS'>8</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Color</span></td> - <td class='c007'><a href='#Page_9'>9</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Comparison with Platinum-Cobalt Standards</span></td> - <td class='c007'><a href='#Page_9'>9</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Comparison with Glass Disks</span></td> - <td class='c007'><a href='#Page_10'>10</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Comparison with Nessler Standards</span></td> - <td class='c007'><a href='#Page_10'>10</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Lovibond Tintometer</span></td> - <td class='c007'><a href='#Page_11'>11</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Odor</span></td> - <td class='c007'><a href='#Page_12'>12</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Cold Odor</span></td> - <td class='c007'><a href='#Page_12'>12</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Hot Odor</span></td> - <td class='c007'><a href='#Page_12'>12</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Expression of Results</span></td> - <td class='c007'><a href='#Page_12'>12</a></td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c006' colspan='5'><span class='sc'>Chemical Examination</span></td> - <td class='c007'><a href='#Page_14'>14</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Expression of Results</span></td> - <td class='c007'><a href='#Page_14'>14</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Forms of Nitrogen</span></td> - <td class='c007'><a href='#Page_15'>15</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Ammonia Nitrogen</span></td> - <td class='c007'><a href='#Page_15'>15</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Determination by Distillation</span></td> - <td class='c007'><a href='#Page_15'>15</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Measurement of Ammonia Nitrogen</span></td> - <td class='c007'><a href='#Page_16'>16</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'><span class='sc'>Comparison with Ammonia Standards</span></td> - <td class='c007'><a href='#Page_16'>16</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'><span class='sc'>Comparison with Permanent Standards</span></td> - <td class='c007'><a href='#Page_17'>17</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Modification for Sewage</span></td> - <td class='c007'><a href='#Page_18'>18</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Determination by Direct Nesslerization</span></td> - <td class='c007'><a href='#Page_19'>19</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Albuminoid Nitrogen</span></td> - <td class='c007'><a href='#Page_20'>20</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Organic Nitrogen</span></td> - <td class='c007'><a href='#Page_21'>21</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Nitrite Nitrogen</span></td> - <td class='c007'><a href='#Page_22'>22</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Nitrate Nitrogen</span></td> - <td class='c007'><a href='#Page_23'>23</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Phenoldisulfonic Acid Method</span></td> - <td class='c007'><a href='#Page_23'>23</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Reduction Method</span></td> - <td class='c007'><a href='#Page_24'>24</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Total Nitrogen</span></td> - <td class='c007'><a href='#Page_25'>25</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Oxygen Consumed</span></td> - <td class='c007'><a href='#Page_25'>25</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Recommended Method</span></td> - <td class='c007'><a href='#Page_26'>26</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Other Methods</span></td> - <td class='c007'><a href='#Page_27'>27</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Residue on Evaporation</span></td> - <td class='c007'><a href='#Page_29'>29</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Total Residue</span></td> - <td class='c007'><a href='#Page_29'>29</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Fixed Residue and Loss on Ignition</span></td> - <td class='c007'><a href='#Page_29'>29</a></td> - </tr> - <tr> - <td class='c006'><span class='pageno' id='Page_iv'>iv</span> </td> - <td class='c006' colspan='4'><span class='sc'>Suspended Matter</span></td> - <td class='c007'><a href='#Page_30'>30</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Determination with Gooch Crucible</span></td> - <td class='c007'><a href='#Page_30'>30</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Determination by Filtration</span></td> - <td class='c007'><a href='#Page_30'>30</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Determination of Volume</span></td> - <td class='c007'><a href='#Page_30'>30</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Fixed Residue and Loss on Ignition</span></td> - <td class='c007'><a href='#Page_30'>30</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Hardness</span></td> - <td class='c007'><a href='#Page_30'>30</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Total Hardness by Calculation</span></td> - <td class='c007'><a href='#Page_31'>31</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Total Hardness by Soap Method</span></td> - <td class='c007'><a href='#Page_31'>31</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Total Hardness by Soda Reagent Method</span></td> - <td class='c007'><a href='#Page_34'>34</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Temporary Hardness by Titration with Acid</span></td> - <td class='c007'><a href='#Page_34'>34</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Non-Carbonate Hardness by Soda Reagent Method</span></td> - <td class='c007'><a href='#Page_34'>34</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Non-Carbonate Hardness by Soap Method</span></td> - <td class='c007'><a href='#Page_35'>35</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Alkalinity</span></td> - <td class='c007'><a href='#Page_35'>35</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Procedure with Phenolphthalein</span></td> - <td class='c007'><a href='#Page_36'>36</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Procedure with Methyl Orange</span></td> - <td class='c007'><a href='#Page_37'>37</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Procedure with Lacmoid</span></td> - <td class='c007'><a href='#Page_37'>37</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Procedure with Erythrosine</span></td> - <td class='c007'><a href='#Page_37'>37</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Bicarbonate</span></td> - <td class='c007'><a href='#Page_37'>37</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Normal Carbonate</span></td> - <td class='c007'><a href='#Page_38'>38</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Hydroxide</span></td> - <td class='c007'><a href='#Page_38'>38</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Alkali Carbonates</span></td> - <td class='c007'><a href='#Page_39'>39</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Acidity</span></td> - <td class='c007'><a href='#Page_39'>39</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Total Acidity</span></td> - <td class='c007'><a href='#Page_40'>40</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Free Carbon Dioxide</span></td> - <td class='c007'><a href='#Page_40'>40</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Free Mineral Acids</span></td> - <td class='c007'><a href='#Page_41'>41</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Mineral Acids and Sulfates of Iron and Aluminium</span></td> - <td class='c007'><a href='#Page_41'>41</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Chloride</span></td> - <td class='c007'><a href='#Page_41'>41</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Iron</span></td> - <td class='c007'><a href='#Page_43'>43</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Total Iron</span></td> - <td class='c007'><a href='#Page_44'>44</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Colorimetric Method</span></td> - <td class='c007'><a href='#Page_44'>44</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'><span class='sc'>Comparison with Iron Standards</span></td> - <td class='c007'><a href='#Page_45'>45</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'><span class='sc'>Comparison with Permanent Standards</span></td> - <td class='c007'><a href='#Page_46'>46</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Volumetric Method</span></td> - <td class='c007'><a href='#Page_46'>46</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Dissolved Iron</span></td> - <td class='c007'><a href='#Page_47'>47</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Suspended Iron</span></td> - <td class='c007'><a href='#Page_47'>47</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Ferrous Iron</span></td> - <td class='c007'><a href='#Page_47'>47</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Ferric Iron</span></td> - <td class='c007'><a href='#Page_48'>48</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Manganese</span></td> - <td class='c007'><a href='#Page_48'>48</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Persulfate Method</span></td> - <td class='c007'><a href='#Page_48'>48</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Bismuthate Method</span></td> - <td class='c007'><a href='#Page_49'>49</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Lead, Zinc, Copper, and Tin</span></td> - <td class='c007'><a href='#Page_50'>50</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Lead</span></td> - <td class='c007'><a href='#Page_51'>51</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Zinc</span></td> - <td class='c007'><a href='#Page_52'>52</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Copper</span></td> - <td class='c007'><a href='#Page_53'>53</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Tin</span></td> - <td class='c007'><a href='#Page_54'>54</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Mineral Analysis</span></td> - <td class='c007'><a href='#Page_56'>56</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Residue on Evaporation</span></td> - <td class='c007'><a href='#Page_56'>56</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Alkalinity and Acidity</span></td> - <td class='c007'><a href='#Page_56'>56</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Chloride</span></td> - <td class='c007'><a href='#Page_56'>56</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Nitrate Nitrogen</span></td> - <td class='c007'><a href='#Page_56'>56</a></td> - </tr> - <tr> - <td class='c006'><span class='pageno' id='Page_v'>v</span> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Separation of Silica, Iron, Aluminium, Calcium, and Magnesium</span></td> - <td class='c007'><a href='#Page_56'>56</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Silica</span></td> - <td class='c007'><a href='#Page_56'>56</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Iron and Aluminium</span></td> - <td class='c007'><a href='#Page_57'>57</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Calcium</span></td> - <td class='c007'><a href='#Page_57'>57</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Magnesium</span></td> - <td class='c007'><a href='#Page_57'>57</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Separation of Sulfate, Sodium, and Potassium</span></td> - <td class='c007'><a href='#Page_58'>58</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Sulfate</span></td> - <td class='c007'><a href='#Page_58'>58</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Sodium, Potassium and Lithium</span></td> - <td class='c007'><a href='#Page_58'>58</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Potassium</span></td> - <td class='c007'><a href='#Page_59'>59</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Lithium</span></td> - <td class='c007'><a href='#Page_60'>60</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Bromine, Iodine, Arsenic, and Boric Acid</span></td> - <td class='c007'><a href='#Page_61'>61</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Bromine and Iodine</span></td> - <td class='c007'><a href='#Page_61'>61</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Arsenic</span></td> - <td class='c007'><a href='#Page_63'>63</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Boric Acid</span></td> - <td class='c007'><a href='#Page_63'>63</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Hydrogen Sulfide</span></td> - <td class='c007'><a href='#Page_63'>63</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Chlorine</span></td> - <td class='c007'><a href='#Page_64'>64</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Dissolved Oxygen</span></td> - <td class='c007'><a href='#Page_65'>65</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Ether-Soluble Matter</span></td> - <td class='c007'><a href='#Page_69'>69</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Relative Stability of Effluents</span></td> - <td class='c007'><a href='#Page_69'>69</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Biochemical Oxygen Demand of Sewages and Effluents</span></td> - <td class='c007'><a href='#Page_71'>71</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Relative Stability Method</span></td> - <td class='c007'><a href='#Page_71'>71</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Sodium Nitrate Method</span></td> - <td class='c007'><a href='#Page_72'>72</a></td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c006' colspan='5'><span class='sc'>Analysis of Sewage Sludge and Mud Deposits</span></td> - <td class='c007'><a href='#Page_73'>73</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Collection of Sample</span></td> - <td class='c007'><a href='#Page_73'>73</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Reaction</span></td> - <td class='c007'><a href='#Page_73'>73</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Specific Gravity</span></td> - <td class='c007'><a href='#Page_74'>74</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Moisture</span></td> - <td class='c007'><a href='#Page_74'>74</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Volatile and Fixed Matter</span></td> - <td class='c007'><a href='#Page_74'>74</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Total Organic Nitrogen</span></td> - <td class='c007'><a href='#Page_74'>74</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Ether-Soluble Matter</span></td> - <td class='c007'><a href='#Page_75'>75</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Ferrous Sulfide</span></td> - <td class='c007'><a href='#Page_76'>76</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Biochemical Oxygen Demand</span></td> - <td class='c007'><a href='#Page_76'>76</a></td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c006' colspan='5'><span class='sc'>Analysis of Chemicals</span></td> - <td class='c007'><a href='#Page_77'>77</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Reagents</span></td> - <td class='c007'><a href='#Page_77'>77</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Sulfate of Aluminium</span></td> - <td class='c007'><a href='#Page_78'>78</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Insoluble Matter</span></td> - <td class='c007'><a href='#Page_78'>78</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Oxides of Aluminium and Iron</span></td> - <td class='c007'><a href='#Page_78'>78</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Total Iron</span></td> - <td class='c007'><a href='#Page_79'>79</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Ferric Iron</span></td> - <td class='c007'><a href='#Page_79'>79</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Ferrous Iron</span></td> - <td class='c007'><a href='#Page_80'>80</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Basicity Ratio</span></td> - <td class='c007'><a href='#Page_80'>80</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Lime</span></td> - <td class='c007'><a href='#Page_80'>80</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Sulfate of Iron</span></td> - <td class='c007'><a href='#Page_81'>81</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Insoluble Matter</span></td> - <td class='c007'><a href='#Page_81'>81</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Iron as Ferrous Sulfate</span></td> - <td class='c007'><a href='#Page_81'>81</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Acidity</span></td> - <td class='c007'><a href='#Page_81'>81</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Soda Ash</span></td> - <td class='c007'><a href='#Page_82'>82</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Insoluble Matter</span></td> - <td class='c007'><a href='#Page_82'>82</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Available Alkali</span></td> - <td class='c007'><a href='#Page_82'>82</a></td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c006' colspan='5'><span class='sc'>Chemical Bibliography</span></td> - <td class='c007'><a href='#Page_82'>82</a></td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c006' colspan='5'><span class='pageno' id='Page_vi'>vi</span><span class='sc'>Microscopical Examination</span></td> - <td class='c007'><a href='#Page_89'>89</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Microscopical Bibliography</span></td> - <td class='c007'><a href='#MICROSCOPICAL'>91</a></td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c006' colspan='5'><span class='sc'>Bacteriological Examination</span></td> - <td class='c007'><a href='#Page_92'>92</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Apparatus</span></td> - <td class='c007'><a href='#Page_92'>92</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Sample Bottles</span></td> - <td class='c007'><a href='#Page_92'>92</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Pipettes</span></td> - <td class='c007'><a href='#Page_92'>92</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Dilution Bottles</span></td> - <td class='c007'><a href='#Page_92'>92</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Petri Dishes</span></td> - <td class='c007'><a href='#Page_92'>92</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Fermentation Tubes</span></td> - <td class='c007'><a href='#Page_92'>92</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Materials</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Water</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Meat Extract</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Peptone</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Sugars</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Agar</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Gelatin</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Litmus</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>General Chemicals</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Methods</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Preparation of Culture Media</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Titration</span></td> - <td class='c007'><a href='#Page_93'>93</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Sterilization</span></td> - <td class='c007'><a href='#Page_94'>94</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Nutrient Broth</span></td> - <td class='c007'><a href='#Page_95'>95</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Sugar Broths</span></td> - <td class='c007'><a href='#Page_95'>95</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Nutrient Gelatin</span></td> - <td class='c007'><a href='#Page_95'>95</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Nutrient Agar</span></td> - <td class='c007'><a href='#Page_96'>96</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Litmus or Azolitmin Solution</span></td> - <td class='c007'><a href='#Page_96'>96</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Litmus-Lactose-Agar</span></td> - <td class='c007'><a href='#Page_97'>97</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Endo’s Medium</span></td> - <td class='c007'><a href='#Page_97'>97</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Collection of Sample</span></td> - <td class='c007'><a href='#Page_98'>98</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Storage and Transportation of Sample</span></td> - <td class='c007'><a href='#Page_98'>98</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Dilutions</span></td> - <td class='c007'><a href='#Page_98'>98</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Plating</span></td> - <td class='c007'><a href='#Page_99'>99</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Incubation</span></td> - <td class='c007'><a href='#Page_99'>99</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Counting</span></td> - <td class='c007'><a href='#Page_99'>99</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>The Test for the Presence of Members of the B. Coli Group</span></td> - <td class='c007'><a href='#Page_100'>100</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Presumptive Test</span></td> - <td class='c007'><a href='#Page_100'>100</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Partially Confirmed Test</span></td> - <td class='c007'><a href='#Page_101'>101</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Completed Test</span></td> - <td class='c007'><a href='#Page_102'>102</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Application of these Tests</span></td> - <td class='c007'><a href='#Page_102'>102</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Expression of Results</span></td> - <td class='c007'><a href='#Page_103'>103</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Summary of these Tests</span></td> - <td class='c007'><a href='#Page_104'>104</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Interpretation of Results</span></td> - <td class='c007'><a href='#Page_106'>106</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Differentiation of Fecal from Non-fecal Members of the B. Coli Group</span></td> - <td class='c007'><a href='#Page_106'>106</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Methyl Red Test</span></td> - <td class='c007'><a href='#Page_107'>107</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='2'><span class='sc'>Voges-Proskauer Test</span></td> - <td class='c007'><a href='#Page_108'>108</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006'> </td> - <td class='c006' colspan='3'><span class='sc'>Routine Procedure for Bacteriological Examination</span></td> - <td class='c007'><a href='#PROCEDURE'>108</a></td> - </tr> - <tr> - <td class='c006'> </td> - <td class='c006' colspan='4'><span class='sc'>Bacteriological Bibliography</span></td> - <td class='c007'><a href='#Page_110'>110</a></td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c006' colspan='5'><span class='sc'>Index</span></td> - <td class='c007'><a href='#Page_113'>113</a></td> - </tr> -</table> - -<div class='chapter'> - <span class='pageno' id='Page_vii'>vii</span> - <h2 class='c005'>PREFACE TO FOURTH EDITION.</h2> -</div> - -<p class='c008'>The Committee on Standard Methods of Bacteriological Water Analysis was -reorganized in 1918 with the following membership: F. P. Gorham, chairman, -L. A. Rogers, W. G. Bissell, H. E. Hasseltine, H. W. Redfield, with M. Levine as -adjunct member. This committee made a report in 1918 which was not acted -on by the Laboratory Section, and in 1919 made a revised report, recommending -certain changes in Standard Methods, which were adopted by the section and -which are now incorporated in this present fourth edition.</p> - -<p class='c009'>Following are the more important changes:</p> - -<p class='c009'>New brands of peptone authorized.</p> - -<p class='c009'>Phenol Red Method of Hydrogen-ion Concentration.</p> - -<p class='c009'>Five-tenths per cent of sugar specified for broths instead of 1 per cent.</p> - -<p class='c009'>Sterilization of sugar is media specified in greater detail.</p> - -<p class='c009'>Preparation of Endo Medium.</p> - -<p class='c009'>Synthetic Medium for the Methyl Red Test.</p> - -<p class='c009'>There are no changes in the chemical methods in this edition.</p> - -<div class='chapter'> - <span class='pageno' id='Page_1'>1</span> - <h2 class='c005'>AMERICAN PUBLIC HEALTH ASSOCIATION.<br /> <span class='large'><em>LABORATORY SECTION.</em><br /> STANDARD METHODS FOR THE EXAMINATION OF WATER AND SEWAGE.</span></h2> -</div> - -<p class='c008'>Compiled and revised by committees of the American Public -Health Association and the American Chemical Society and -referees of the Association of Official Agricultural Chemists.</p> - -<div class='chapter'> - <h2 class='c005'>COLLECTION OF SAMPLES.</h2> -</div> - -<h3 class='c010'>QUANTITY REQUIRED FOR ANALYSIS.</h3> - -<p class='c011'>The minimum quantity necessary for making the ordinary physical, -chemical, and microscopical analyses of water or sewage is -2 liters; for the bacteriological examination, 100 cc. In special -analyses larger quantities may be required.</p> - -<h3 class='c010'>BOTTLES.</h3> - -<p class='c011'>The bottles for the collection of samples shall have glass stoppers, -except when physical, mineral, or microscopical examinations -only are to be made. Jugs or metal containers shall not be used.</p> - -<p class='c009'>Sample bottles shall be carefully cleansed each time before using. -This may be done by treating with sulfuric acid and potassium -bichromate, or with alkaline permanganate, followed by a mixture -of oxalic and sulfuric acids, and by thoroughly rinsing with water -and draining. The stoppers and necks of the bottles shall be protected -from dirt by tying cloth, thick paper or tin foil over them.</p> - -<p class='c009'>For shipment bottles shall be packed in cases with a separate -compartment for each bottle. Wooden boxes may be lined with -corrugated fibre paper, felt, or similar substance, or provided with -spring corner strips, to prevent breakage. Lined wicker baskets -also may be used.</p> - -<p class='c009'><span class='pageno' id='Page_2'>2</span>Bottles for bacteriological samples shall be sterilized as directed -on page <a href='#Page_98'>98</a>.</p> - -<h3 class='c010'>INTERVAL BEFORE ANALYSIS.</h3> - -<p class='c011'>In general, the shorter the time elapsing between the collection -and the analysis of a sample the more reliable will be the analytical -results. Under many conditions analyses made in the field are -to be commended, as data so obtained are frequently preferable -to data obtained in a distant laboratory after the composition -of the water has changed.</p> - -<p class='c009'>The time that may be allowed to elapse between the collection of -a sample and the beginning of its analysis cannot be stated definitely. -It depends on the character of the sample, the examinations -to be made, and other conditions. The following are suggested as -fairly reasonable maximum limits.</p> - -<table class='table1' summary=''> - <tr><td class='c012' colspan='2'><em>Physical and chemical analysis.</em></td></tr> - <tr><td> </td></tr> - <tr> - <td class='c013'>Ground waters</td> - <td class='c014'>72 hours</td> - </tr> - <tr> - <td class='c013'>Fairly pure surface waters</td> - <td class='c014'>48 〃</td> - </tr> - <tr> - <td class='c013'>Polluted surface waters</td> - <td class='c014'>12 〃</td> - </tr> - <tr> - <td class='c013'>Sewage effluents</td> - <td class='c014'> 6 〃</td> - </tr> - <tr> - <td class='c013'>Raw sewages</td> - <td class='c014'> 6 〃</td> - </tr> - <tr> - <td class='c013'> </td> - <td class='c014'> </td> - </tr> - <tr> - <td class='c013'><em>Microscopical examination.</em></td> - <td class='c014'> </td> - </tr> - <tr> - <td class='c013'> </td> - <td class='c014'> </td> - </tr> - <tr> - <td class='c013'>Ground waters</td> - <td class='c014'>72 hours</td> - </tr> - <tr> - <td class='c013'>Fairly pure surface waters</td> - <td class='c014'>24 〃</td> - </tr> - <tr> - <td class='c013'>Waters containing fragile organisms</td> - <td class='c014'>Immediate examination</td> - </tr> - <tr> - <td class='c013'> </td> - <td class='c014'> </td> - </tr> - <tr> - <td class='c013'><em>Bacteriological examination.</em></td> - <td class='c014'> </td> - </tr> - <tr> - <td class='c013'> </td> - <td class='c014'> </td> - </tr> - <tr> - <td class='c013'>Samples kept at less than 10°C</td> - <td class='c014'>24 hours</td> - </tr> -</table> - -<p class='c009'>If a longer period elapses between collection and examination -the time should be noted. If sterilized by the addition of chloroform, -formaldehyde, mercuric chloride, or some other germicide -samples for sanitary chemical examination may be allowed to -stand for longer periods than those indicated, but as this is a -matter which will vary according to circumstances, no definite -procedure is recommended. If unsterilized samples of sewage, -sewage effluents, and highly polluted surface waters are analyzed -after greater intervals than those suggested caution must be used -<span class='pageno' id='Page_3'>3</span>in interpreting analyses of the organic content, which frequently -changes materially upon standing.</p> - -<p class='c009'>Determinations of dissolved gases, especially oxygen, hydrogen -sulfide, and carbon dioxide, should be made at the time of collection -in order to be reasonably accurate, in accordance with the directions -given hereafter in connection with each determination.</p> - -<h3 class='c010'>REPRESENTATIVE SAMPLES.</h3> - -<p class='c011'>Care should be taken to obtain a sample that is truly representative -of the liquid to be analyzed. With sewages this is especially -important because marked variations in composition occur from -hour to hour. Satisfactory samples of some liquids can be obtained -only by mixing together several portions collected at different times -or at different places—the details as to collection and mixing -depending upon local conditions.</p> - -<div class='chapter'> - <span class='pageno' id='Page_4'>4</span> - <h2 class='c005'>PHYSICAL EXAMINATION.</h2> -</div> - -<h3 class='c010'>TEMPERATURE.</h3> - -<p class='c011'>The temperature of the sample, if taken, shall be taken at the time -of collection, and shall be expressed preferably in degrees Centigrade, -to the nearest degree, or closer if more precise data are required. -The thermophone<a id='r109' /><a href='#f109' class='c015'><sup>[109]</sup></a> is recommended for obtaining the temperature -of water at various depths below the surface.</p> - -<h3 class='c010'>TURBIDITY.</h3> - -<p class='c011'>The turbidity of water is due to suspended matter, such as clay, -silt, finely divided organic matter, microscopic organisms, and -similar material.</p> - -<h4 class='c016'>TURBIDITY STANDARD.<a id='r110' /><a href='#f110' class='c015'><sup>[110]</sup></a></h4> - -<p class='c011'>The standard of turbidity shall be that adopted by the United -States Geological Survey, namely, a water which contains 100 parts -per million of silica in such a state of fineness that a bright platinum -wire 1 millimeter in diameter can just be seen when the center -of the wire is 100 millimeters below the surface of the water and the -eye of the observer is 1.2 meters above the wire, the observation -being made in the middle of the day, in the open air, but not in -sunlight, and in a vessel so large that the sides do not shut out the -light so as to influence the results. The turbidity of such water is -arbitrarily fixed at 100 parts per million.</p> - -<p class='c009'>For preparation of the silica standard dry Pear’s “precipitated -fuller’s earth” and sift it through a 200–mesh sieve. One gram of this -preparation in 1 liter of distilled water makes a stock suspension -which contains 1,000 parts per million of silica and which should -have a turbidity of 1,000. Test this suspension, after diluting -a portion of it with nine times its volume of distilled water, by the -platinum wire method to ascertain if the silica has the necessary -degree of fineness and if the suspension has the necessary degree -of turbidity. If not, correct by adding more silica or more water as -the case demands.<a id='rA' /><a href='#fA' class='c015'><sup>[A]</sup></a></p> - -<div class='footnote' id='fA'> -<p class='c009'><a href='#rA'>A</a>. This method of correction very slightly alters the coefficient of fineness of the standard, but -does not noticeably affect its use.</p> -</div> - -<p class='c009'>Standards for comparison shall be prepared from this stock suspension -by dilution with distilled water. For turbidity readings -<span class='pageno' id='Page_5'>5</span>below 20, standards of 0, 5, 10, 15, and 20 shall be kept in clear glass -bottles of the same size as that containing the sample; for readings -above 20, standards of 20, 30, 40, 50, 60, 70, 80, 90, and 100 shall be -kept in 100 cc. Nessler tubes approximately 20 millimeters in -diameter.</p> - -<p class='c009'>Comparison with the standards shall be made by viewing both -standard and sample sidewise toward the light by looking at some -object and noting the distinctness with which the margins of the -object can be seen.</p> - -<p class='c009'>The standards shall be kept stoppered, and both sample and -standards shall be thoroughly shaken before making the comparison.</p> - -<p class='c009'>In order to prevent any bacterial or algal growths from developing -in the standards a small amount of mercury bichloride may be -added to them.</p> - -<h4 class='c016'>PLATINUM WIRE METHOD.<a id='r42' /><a href='#f42' class='c015'><sup>[42]</sup></a></h4> - -<p class='c011'>This method requires a rod with a platinum wire 1 mm. in -diameter inserted in it about 1 inch from one end of the rod and -projecting from it at a right angle at least 25 mm. Near the other -end of the rod, at a distance of 1.2 meters from the platinum wire, -a small ring shall be placed directly above the wire through which, -with his eye directly above the ring, the observer shall look when -making the examination.</p> - -<p class='c009'>The rod shall be graduated as follows: The graduation mark of -100 shall be placed on the rod at a distance of 100 mm. from the -center of the wire. Other graduations shall be made according to -Table 1, which is based on the best obtainable data. The distances -recorded in Table 1 are intended to be such that when the water -is diluted the turbidity readings will decrease in the same proportion -as the percentage of the original water in the mixture. These -graduations are those on what is known as the U. S. Geological -Survey Turbidity Rod of 1902.<a id='r105' /><a href='#f105' class='c015'><sup>[105]</sup></a></p> - -<table class='table2' summary=''> - <tr><td class='c012' colspan='2'><span class='pageno' id='Page_6'>6</span></td></tr> - <tr><th class='c012' colspan='2'>Table 1.—<span class='sc'>Graduation of turbidity rod.</span></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt c017'>Turbidity<br />(parts per million).</th> - <th class='btt blt c017'>Vanishing depth of wire (mm.).</th> - </tr> - <tr> - <td class='bbt c018'> </td> - <td class='bbt blt c018'> </td> - </tr> - <tr> - <td class='c018'>7</td> - <td class='blt c018'>1095  </td> - </tr> - <tr> - <td class='c018'>8</td> - <td class='blt c018'>971  </td> - </tr> - <tr> - <td class='c018'>9</td> - <td class='blt c018'>873  </td> - </tr> - <tr> - <td class='c018'>10</td> - <td class='blt c018'>794  </td> - </tr> - <tr> - <td class='c018'>11</td> - <td class='blt c018'>729  </td> - </tr> - <tr> - <td class='c018'>12</td> - <td class='blt c018'>674  </td> - </tr> - <tr> - <td class='c018'>13</td> - <td class='blt c018'>627  </td> - </tr> - <tr> - <td class='c018'>14</td> - <td class='blt c018'>587  </td> - </tr> - <tr> - <td class='c018'>15</td> - <td class='blt c018'>551  </td> - </tr> - <tr> - <td class='c018'>16</td> - <td class='blt c018'>520  </td> - </tr> - <tr> - <td class='c018'>17</td> - <td class='blt c018'>493  </td> - </tr> - <tr> - <td class='c018'>18</td> - <td class='blt c018'>468  </td> - </tr> - <tr> - <td class='c018'>19</td> - <td class='blt c018'>446  </td> - </tr> - <tr> - <td class='c018'>20</td> - <td class='blt c018'>426  </td> - </tr> - <tr> - <td class='c018'>22</td> - <td class='blt c018'>391  </td> - </tr> - <tr> - <td class='c018'>24</td> - <td class='blt c018'>361  </td> - </tr> - <tr> - <td class='c018'>26</td> - <td class='blt c018'>336  </td> - </tr> - <tr> - <td class='c018'>28</td> - <td class='blt c018'>314  </td> - </tr> - <tr> - <td class='c018'>30</td> - <td class='blt c018'>296  </td> - </tr> - <tr> - <td class='c018'>35</td> - <td class='blt c018'>257  </td> - </tr> - <tr> - <td class='c018'>40</td> - <td class='blt c018'>228  </td> - </tr> - <tr> - <td class='c018'>45</td> - <td class='blt c018'>205  </td> - </tr> - <tr> - <td class='c018'>50</td> - <td class='blt c018'>187  </td> - </tr> - <tr> - <td class='c018'>55</td> - <td class='blt c018'>171  </td> - </tr> - <tr> - <td class='c018'>60</td> - <td class='blt c018'>158  </td> - </tr> - <tr> - <td class='c018'>65</td> - <td class='blt c018'>147  </td> - </tr> - <tr> - <td class='c018'>70</td> - <td class='blt c018'>138  </td> - </tr> - <tr> - <td class='c018'>75</td> - <td class='blt c018'>130  </td> - </tr> - <tr> - <td class='c018'>80</td> - <td class='blt c018'>122  </td> - </tr> - <tr> - <td class='c018'>85</td> - <td class='blt c018'>116  </td> - </tr> - <tr> - <td class='c018'>90</td> - <td class='blt c018'>110  </td> - </tr> - <tr> - <td class='c018'>95</td> - <td class='blt c018'>105  </td> - </tr> - <tr> - <td class='c018'>100</td> - <td class='blt c018'>100  </td> - </tr> - <tr> - <td class='c018'>110</td> - <td class='blt c018'>93  </td> - </tr> - <tr> - <td class='c018'>120</td> - <td class='blt c018'>86  </td> - </tr> - <tr> - <td class='c018'>130</td> - <td class='blt c018'>81  </td> - </tr> - <tr> - <td class='c018'>140</td> - <td class='blt c018'>76  </td> - </tr> - <tr> - <td class='c018'>150</td> - <td class='blt c018'>72  </td> - </tr> - <tr> - <td class='c018'>160</td> - <td class='blt c018'>68.7</td> - </tr> - <tr> - <td class='c018'>180</td> - <td class='blt c018'>62.4</td> - </tr> - <tr> - <td class='c018'>200</td> - <td class='blt c018'>57.4</td> - </tr> - <tr> - <td class='c018'>250</td> - <td class='blt c018'>49.1</td> - </tr> - <tr> - <td class='c018'>300</td> - <td class='blt c018'>43.2</td> - </tr> - <tr> - <td class='c018'>350</td> - <td class='blt c018'>38.8</td> - </tr> - <tr> - <td class='c018'>400</td> - <td class='blt c018'>35.4</td> - </tr> - <tr> - <td class='c018'>500</td> - <td class='blt c018'>30.9</td> - </tr> - <tr> - <td class='c018'>600</td> - <td class='blt c018'>27.7</td> - </tr> - <tr> - <td class='c018'>800</td> - <td class='blt c018'>23.4</td> - </tr> - <tr> - <td class='c018'>1000</td> - <td class='blt c018'>20.9</td> - </tr> - <tr> - <td class='c018'>1500</td> - <td class='blt c018'>17.1</td> - </tr> - <tr> - <td class='c018'>2000</td> - <td class='blt c018'>14.8</td> - </tr> - <tr> - <td class='bbt c018'>3000</td> - <td class='bbt blt c018'>12.1</td> - </tr> -</table> - -<p class='c009'><em>Procedure.</em>—Lower the rod vertically into the water as far as the -wire can be seen and read the level of the surface of the water -on the graduated scale. This will indicate the turbidity.</p> - -<p class='c009'>The following precautions shall be taken to insure correct results:</p> - -<p class='c009'>Observations shall be made in the open air, preferably in the -middle of the day and not in direct sunlight. The wire shall be -kept bright and clean. If for any reason observations cannot be -made directly under natural conditions a pail or tank may be filled -with water and the observation taken in that, but if this is done care -shall be taken that the water is thoroughly stirred before the observation -is made, and no vessel shall be used for this purpose unless -its diameter is at least twice as great as the depth to which the wire -is immersed. Waters which have a turbidity greater than 500 -<span class='pageno' id='Page_7'>7</span>shall be diluted with clear water before the observations are made, -but if this is done the degree of dilution shall be reported.</p> - -<h4 class='c016'>TURBIDIMETRIC METHOD.</h4> - -<p class='c011'>Several forms of turbidimeter or diaphanometer<a id='r73' /><a href='#f73' class='c015'><sup>[73]</sup></a> have been -suggested for use. The simplest and most satisfactory form is -the candle turbidimeter.<a id='r116' /><a href='#f116' class='c015'><sup>[116]</sup></a> This consists of a graduated glass tube -with a flat polished bottom, enclosed in a metal case. This is -supported over an English standard candle and so arranged that -one may look vertically down through the tube at the flame of the -candle. The observation is made by pouring the sample of water -into the tube until the image of the flame of the candle just disappears -from view. Care shall be taken not to allow soot or moisture -to accumulate on the lower side of the glass bottom of the tube -so as to interfere with the accuracy of the observations. The -graduations on the tube correspond to turbidities produced in -distilled water by certain numbers of parts per million of silica -standard. In order to insure uniform results it is necessary to -have the distance between the top rim of the candle and the bottom -of the tube constant, and this distance shall be 7.6 cm. or 3 -inches. The observations shall be made in a darkened room or with -a black cloth over the head.</p> - -<p class='c009'>It is allowable to substitute for the candle an electric light. -Calibrate the apparatus to correspond with the United States -Geological Survey scale. The figures in Table 2 on page <a href='#Page_8'>8</a> are -believed to be approximately correct for the candle turbidimeter -but should be checked by the experimenter. It is allowable to -calibrate the tube of the instrument with waters of known turbidity -prepared by making a series of dilutions of the silica standard with -distilled water. From the figures obtained in calibrating plot a -curve from which the turbidity of a sample may be read when -the depth of water in the tube has been obtained.</p> - -<table class='table2' summary=''> - <tr><td class='c012' colspan='2'><span class='pageno' id='Page_8'>8</span></td></tr> - <tr><th class='c012' colspan='2'>Table 2.—<span class='sc'>Graduation of candle turbidimeter.</span></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017'>Depth of liquid<br />(cm.).</th> - <th class='btt bbt c017'>Turbidity<br />(parts per million of silica).</th> - </tr> - <tr> - <td class='brt c018'>2.3</td> - <td class='c018'>1000</td> - </tr> - <tr> - <td class='brt c018'>2.6</td> - <td class='c018'>900</td> - </tr> - <tr> - <td class='brt c018'>2.9</td> - <td class='c018'>800</td> - </tr> - <tr> - <td class='brt c018'>3.2</td> - <td class='c018'>700</td> - </tr> - <tr> - <td class='brt c018'>3.5</td> - <td class='c018'>650</td> - </tr> - <tr> - <td class='brt c018'>3.8</td> - <td class='c018'>600</td> - </tr> - <tr> - <td class='brt c018'>4.1</td> - <td class='c018'>550</td> - </tr> - <tr> - <td class='brt c018'>4.5</td> - <td class='c018'>500</td> - </tr> - <tr> - <td class='brt c018'>4.9</td> - <td class='c018'>450</td> - </tr> - <tr> - <td class='brt c018'>5.5</td> - <td class='c018'>400</td> - </tr> - <tr> - <td class='brt c018'>5.6</td> - <td class='c018'>390</td> - </tr> - <tr> - <td class='brt c018'>5.8</td> - <td class='c018'>380</td> - </tr> - <tr> - <td class='brt c018'>5.9</td> - <td class='c018'>370</td> - </tr> - <tr> - <td class='brt c018'>6.1</td> - <td class='c018'>360</td> - </tr> - <tr> - <td class='brt c018'>6.3</td> - <td class='c018'>350</td> - </tr> - <tr> - <td class='brt c018'>6.4</td> - <td class='c018'>340</td> - </tr> - <tr> - <td class='brt c018'>6.6</td> - <td class='c018'>330</td> - </tr> - <tr> - <td class='brt c018'>6.8</td> - <td class='c018'>320</td> - </tr> - <tr> - <td class='brt c018'>7.0</td> - <td class='c018'>310</td> - </tr> - <tr> - <td class='brt c018'>7.3</td> - <td class='c018'>300</td> - </tr> - <tr> - <td class='brt c018'>7.5</td> - <td class='c018'>290</td> - </tr> - <tr> - <td class='brt c018'>7.8</td> - <td class='c018'>280</td> - </tr> - <tr> - <td class='brt c018'>8.1</td> - <td class='c018'>270</td> - </tr> - <tr> - <td class='brt c018'>8.4</td> - <td class='c018'>260</td> - </tr> - <tr> - <td class='brt c018'>8.7</td> - <td class='c018'>250</td> - </tr> - <tr> - <td class='brt c018'>9.1</td> - <td class='c018'>240</td> - </tr> - <tr> - <td class='brt c018'>9.5</td> - <td class='c018'>230</td> - </tr> - <tr> - <td class='brt c018'>9.9</td> - <td class='c018'>220</td> - </tr> - <tr> - <td class='brt c018'>10.3</td> - <td class='c018'>210</td> - </tr> - <tr> - <td class='brt c018'>10.9</td> - <td class='c018'>200</td> - </tr> - <tr> - <td class='brt c018'>11.4</td> - <td class='c018'>190</td> - </tr> - <tr> - <td class='brt c018'>12.0</td> - <td class='c018'>180</td> - </tr> - <tr> - <td class='brt c018'>12.7</td> - <td class='c018'>170</td> - </tr> - <tr> - <td class='brt c018'>13.5</td> - <td class='c018'>160</td> - </tr> - <tr> - <td class='brt c018'>14.4</td> - <td class='c018'>150</td> - </tr> - <tr> - <td class='brt c018'>15.4</td> - <td class='c018'>140</td> - </tr> - <tr> - <td class='brt c018'>16.6</td> - <td class='c018'>130</td> - </tr> - <tr> - <td class='brt c018'>18.0</td> - <td class='c018'>120</td> - </tr> - <tr> - <td class='brt c018'>19.6</td> - <td class='c018'>110</td> - </tr> - <tr> - <td class='bbt brt c018'>21.5</td> - <td class='bbt c018'>100</td> - </tr> -</table> - -<p class='c009'>The results of turbidity observations shall be expressed in whole -numbers which correspond to parts per million of silica and recorded -as follows:</p> - -<table class='table2' summary=''> - <tr> - <td class='c017'>Turbidity between</td> - <td class='blt c018'>1</td> - <td class='blt c017'>and</td> - <td class='blt c018'>50</td> - <td class='blt c017'>recorded to nearest</td> - <td class='blt c018'>unit</td> - </tr> - <tr> - <td class='c017'>〃 〃</td> - <td class='blt c018'>51</td> - <td class='blt c017'>〃</td> - <td class='blt c018'>100</td> - <td class='blt c017'>〃 〃 〃</td> - <td class='blt c018'>5</td> - </tr> - <tr> - <td class='c017'>〃 〃</td> - <td class='blt c018'>101</td> - <td class='blt c017'>〃</td> - <td class='blt c018'>500</td> - <td class='blt c017'>〃 〃 〃</td> - <td class='blt c018'>10</td> - </tr> - <tr> - <td class='c017'>〃 〃</td> - <td class='blt c018'>501</td> - <td class='blt c017'>〃</td> - <td class='blt c018'>1000</td> - <td class='blt c017'>〃 〃 〃</td> - <td class='blt c018'>50</td> - </tr> - <tr> - <td class='c017'>〃 〃</td> - <td class='blt c018'>1001</td> - <td class='blt c017'>〃</td> - <td class='blt c018'>greater</td> - <td class='blt c017'>〃 〃 〃</td> - <td class='blt c018'>100</td> - </tr> -</table> - -<h4 id='FINENESS' class='c016'>COEFFICIENT OF FINENESS<a id='r80' /><a href='#f80' class='c015'><sup>[80]</sup></a></h4> - -<p class='c011'>The quotient obtained by dividing the weight of suspended -matter in the sample by the turbidity, both expressed in the same -unit, shall be called the coefficient of fineness. If the quotient is -greater than unity the matter in suspension is coarser and if it is -less than unity it is finer than the standard.</p> - -<div> - <span class='pageno' id='Page_9'>9</span> - <h3 class='c010'>COLOR.</h3> -</div> - -<p class='c011'>The “color,” or the “true color,” of water shall be considered -the color that is due only to substances in solution; that is, it is the -color of the water after the suspended matter has been removed. -In stating results the word “color” shall mean the “true color” -unless otherwise designated.</p> - -<p class='c009'>The “apparent color” shall be considered as including not only -the true color but also any color produced by substances in suspension. -It is the color of the original unfiltered sample.</p> - -<p class='c009'>The platinum-cobalt method of measuring color shall be considered -as the standard, and the unit of color shall be that produced -by 1 part per million of platinum.</p> - -<h4 class='c016'>COMPARISON WITH PLATINUM-COBALT STANDARDS.<a id='r43' /><a href='#f43' class='c015'><sup>[43]</sup></a></h4> - -<p class='c011'><em>Reagents.</em>—Dissolve 1.246 grams of potassium platinic chloride -(PtCl<sub>4</sub>2KCl), containing 0.5 gram platinum, and 1.00 gram crystallized -cobalt chloride (CoCl<sub>2</sub>.6H<sub>2</sub>O), containing 0.25 gram of cobalt, -in water with 100 cc. concentrated hydrochloric acid, and dilute to -1 liter with distilled water. This solution has a color of 500. -Dilute this solution with distilled water in 50 cc. Nessler tubes to -prepare standards having colors of 0, 5, 10, 15, 20, 25, 30, 35, 40, -50, 60, and 70. Keep these standards in Nessler tubes of such -diameter that the graduation mark is between 20 and 25 cm. above -the bottom and of such uniformity that they match within such limit -that the distance from the bottom to the graduation mark of the -longest tube shall not exceed that of the shortest tube by more than -6 mm. Protect the tubes from dust and light when not in use.</p> - -<p class='c009'><em>Procedure.</em>—The color of a sample shall be observed by filling a -standard Nessler tube to the height equal to that in the standard -tubes with the sample and by comparing it with the standards. -The observation shall be made by looking vertically downward -through the tubes upon a white or mirrored surface placed at -such angle that light is reflected upward through the column of -liquid.</p> - -<p class='c009'>Water that has a color greater than 70 shall be diluted before -making the comparison, in order that no difficulties may be encountered -in matching the hues.</p> - -<p class='c009'>Water containing matter in suspension shall be filtered, before -the color observation is made, until no visible turbidity remains. -<span class='pageno' id='Page_10'>10</span>If the suspended matter is coarse, filter paper may be used for this -purpose; if the suspended matter is fine, the use of a Berkefeld filter -is recommended. The Pasteur filter shall not be used as it exerts -a marked decolorizing action.</p> - -<p class='c009'>The apparent color, if determined, shall be determined on the -original sample without filtration. The true and the apparent -color of clear waters or waters with low turbidities are substantially -the same.</p> - -<p class='c009'>The results of color determinations shall be expressed in whole -numbers and recorded as follows:</p> - -<table class='table1' summary=''> - <tr> - <td class='c019'>Color between</td> - <td class='c020'>1</td> - <td class='c019'>and</td> - <td class='c020'>50</td> - <td class='c019'>recorded to nearest</td> - <td class='c021'>unit</td> - </tr> - <tr> - <td class='c019'>〃 〃</td> - <td class='c020'>51</td> - <td class='c019'>〃</td> - <td class='c020'>100</td> - <td class='c019'>〃 〃 〃</td> - <td class='c021'>5</td> - </tr> - <tr> - <td class='c019'>〃 〃</td> - <td class='c020'>101</td> - <td class='c019'>〃</td> - <td class='c020'>250</td> - <td class='c019'>〃 〃 〃</td> - <td class='c021'>10</td> - </tr> - <tr> - <td class='c019'>〃 〃</td> - <td class='c020'>251</td> - <td class='c019'>〃</td> - <td class='c020'>500</td> - <td class='c019'>〃 〃 〃</td> - <td class='c021'>20.</td> - </tr> -</table> - -<h4 class='c016'>COMPARISON WITH GLASS DISKS.<a href='#f105' class='c015'><sup>[105]</sup></a></h4> - -<p class='c011'>As the platinum-cobalt standard method is not well adapted for -field work, the color of the water to be tested may be compared -with that of glass disks held at the end of metallic tubes through -which they are viewed by looking toward a white surface. The -glass disks are individually calibrated to correspond with colors on -the platinum scale. Experience has shown that the glass disks -used by the U. S. Geological Survey give results in substantial -agreement with those obtained by the platinum determinations, -and their use is recognized as a standard procedure.</p> - -<h4 class='c016'>COMPARISON WITH NESSLER STANDARDS.</h4> - -<p class='c011'>Inasmuch as the Nessler scale<a id='r62' /><a href='#f62' class='c015'><sup>[62]</sup></a> and the natural water scale<a id='r22' /><a href='#f22' class='c015'><sup>[22]</sup></a><a id='r49' /><a href='#f49' class='c015'><sup>[49]</sup></a> -which agrees with it except for colors less than 20, have been largely -used in the past, the old results may be converted<a id='r117' /><a href='#f117' class='c015'><sup>[117]</sup></a> into terms of -the platinum standard by means of the ratios in Table 3, but they -must not be considered as universally applicable as the variable -sensitiveness of the Nessler solution introduces an uncertain factor.</p> - -<table class='table2' summary=''> - <tr><td class='c012' colspan='11'><span class='pageno' id='Page_11'>11</span></td></tr> - <tr><th class='c012' colspan='11'>Table 3.—<span class='sc'>Values for converting colors by the natural water scale into colors by the platinum standard in parts per million.</span><a id='rB' /><a href='#fB' class='c015'><sup>[B]</sup></a></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017'>Modified Nessler or natural water standard.</th> - <th class='btt bbt brt c018'>0.00.</th> - <th class='btt bbt brt c018'>0.01.</th> - <th class='btt bbt brt c018'>0.02.</th> - <th class='btt bbt brt c018'>0.03.</th> - <th class='btt bbt brt c018'>0.04.</th> - <th class='btt bbt brt c018'>0.05.</th> - <th class='btt bbt brt c018'>0.06.</th> - <th class='btt bbt brt c018'>0.07.</th> - <th class='btt bbt brt c018'>0.08.</th> - <th class='btt bbt c018'>0.09.</th> - </tr> - <tr><th class='c012' colspan='11'>Platinum-cobalt standard color.</th></tr> - <tr> - <td class='brt c018'>0.00</td> - <td class='brt c018'>0</td> - <td class='brt c018'>2</td> - <td class='brt c018'>4</td> - <td class='brt c018'>6</td> - <td class='brt c018'>8</td> - <td class='brt c018'>9</td> - <td class='brt c018'>11</td> - <td class='brt c018'>13</td> - <td class='brt c018'>15</td> - <td class='c018'>17</td> - </tr> - <tr> - <td class='brt c018'>.10</td> - <td class='brt c018'>18</td> - <td class='brt c018'>19</td> - <td class='brt c018'>20</td> - <td class='brt c018'>20</td> - <td class='brt c018'>21</td> - <td class='brt c018'>22</td> - <td class='brt c018'>23</td> - <td class='brt c018'>24</td> - <td class='brt c018'>24</td> - <td class='c018'>26</td> - </tr> - <tr> - <td class='brt c018'>.20</td> - <td class='brt c018'>26</td> - <td class='brt c018'>27</td> - <td class='brt c018'>27</td> - <td class='brt c018'>28</td> - <td class='brt c018'>29</td> - <td class='brt c018'>29</td> - <td class='brt c018'>30</td> - <td class='brt c018'>31</td> - <td class='brt c018'>32</td> - <td class='c018'>32</td> - </tr> - <tr> - <td class='brt c018'>.30</td> - <td class='brt c018'>33</td> - <td class='brt c018'>34</td> - <td class='brt c018'>34</td> - <td class='brt c018'>35</td> - <td class='brt c018'>35</td> - <td class='brt c018'>36</td> - <td class='brt c018'>37</td> - <td class='brt c018'>37</td> - <td class='brt c018'>38</td> - <td class='c018'>38</td> - </tr> - <tr> - <td class='brt c018'>.40</td> - <td class='brt c018'>39</td> - <td class='brt c018'>40</td> - <td class='brt c018'>40</td> - <td class='brt c018'>41</td> - <td class='brt c018'>42</td> - <td class='brt c018'>42</td> - <td class='brt c018'>43</td> - <td class='brt c018'>44</td> - <td class='brt c018'>45</td> - <td class='c018'>45</td> - </tr> - <tr> - <td class='brt c018'>.50</td> - <td class='brt c018'>46</td> - <td class='brt c018'>47</td> - <td class='brt c018'>47</td> - <td class='brt c018'>48</td> - <td class='brt c018'>48</td> - <td class='brt c018'>49</td> - <td class='brt c018'>50</td> - <td class='brt c018'>50</td> - <td class='brt c018'>51</td> - <td class='c018'>51</td> - </tr> - <tr> - <td class='brt c018'>.60</td> - <td class='brt c018'>52</td> - <td class='brt c018'>53</td> - <td class='brt c018'>53</td> - <td class='brt c018'>54</td> - <td class='brt c018'>54</td> - <td class='brt c018'>55</td> - <td class='brt c018'>56</td> - <td class='brt c018'>56</td> - <td class='brt c018'>57</td> - <td class='c018'>57</td> - </tr> - <tr> - <td class='brt c018'>.70</td> - <td class='brt c018'>58</td> - <td class='brt c018'>58</td> - <td class='brt c018'>59</td> - <td class='brt c018'>59</td> - <td class='brt c018'>60</td> - <td class='brt c018'>60</td> - <td class='brt c018'>61</td> - <td class='brt c018'>61</td> - <td class='brt c018'>62</td> - <td class='c018'>62</td> - </tr> - <tr> - <td class='brt c018'>.80</td> - <td class='brt c018'>63</td> - <td class='brt c018'>64</td> - <td class='brt c018'>64</td> - <td class='brt c018'>65</td> - <td class='brt c018'>66</td> - <td class='brt c018'>66</td> - <td class='brt c018'>67</td> - <td class='brt c018'>68</td> - <td class='brt c018'>69</td> - <td class='c018'>69</td> - </tr> - <tr> - <td class='brt c018'>.90</td> - <td class='brt c018'>70</td> - <td class='brt c018'>71</td> - <td class='brt c018'>72</td> - <td class='brt c018'>73</td> - <td class='brt c018'>74</td> - <td class='brt c018'>75</td> - <td class='brt c018'>77</td> - <td class='brt c018'>78</td> - <td class='brt c018'>79</td> - <td class='c018'>80</td> - </tr> - <tr> - <td class='brt c018'>1.00</td> - <td class='brt c018'>81</td> - <td class='brt c018'>82</td> - <td class='brt c018'>82</td> - <td class='brt c018'>83</td> - <td class='brt c018'>84</td> - <td class='brt c018'>84</td> - <td class='brt c018'>85</td> - <td class='brt c018'>86</td> - <td class='brt c018'>87</td> - <td class='c018'>87</td> - </tr> - <tr> - <td class='brt c018'>1.10</td> - <td class='brt c018'>88</td> - <td class='brt c018'>89</td> - <td class='brt c018'>89</td> - <td class='brt c018'>90</td> - <td class='brt c018'>91</td> - <td class='brt c018'>91</td> - <td class='brt c018'>92</td> - <td class='brt c018'>93</td> - <td class='brt c018'>94</td> - <td class='c018'>94</td> - </tr> - <tr> - <td class='brt c018'>1.20</td> - <td class='brt c018'>95</td> - <td class='brt c018'>96</td> - <td class='brt c018'>96</td> - <td class='brt c018'>97</td> - <td class='brt c018'>98</td> - <td class='brt c018'>98</td> - <td class='brt c018'>99</td> - <td class='brt c018'>100</td> - <td class='brt c018'>101</td> - <td class='c018'>101</td> - </tr> - <tr> - <td class='brt c018'>1.30</td> - <td class='brt c018'>102</td> - <td class='brt c018'>103</td> - <td class='brt c018'>103</td> - <td class='brt c018'>104</td> - <td class='brt c018'>105</td> - <td class='brt c018'>105</td> - <td class='brt c018'>106</td> - <td class='brt c018'>107</td> - <td class='brt c018'>108</td> - <td class='c018'>108</td> - </tr> - <tr> - <td class='brt c018'>1.40</td> - <td class='brt c018'>109</td> - <td class='brt c018'>110</td> - <td class='brt c018'>110</td> - <td class='brt c018'>111</td> - <td class='brt c018'>112</td> - <td class='brt c018'>112</td> - <td class='brt c018'>113</td> - <td class='brt c018'>114</td> - <td class='brt c018'>115</td> - <td class='c018'>115</td> - </tr> - <tr> - <td class='brt c018'>1.50</td> - <td class='brt c018'>116</td> - <td class='brt c018'>117</td> - <td class='brt c018'>117</td> - <td class='brt c018'>118</td> - <td class='brt c018'>118</td> - <td class='brt c018'>119</td> - <td class='brt c018'>120</td> - <td class='brt c018'>120</td> - <td class='brt c018'>121</td> - <td class='c018'>121</td> - </tr> - <tr> - <td class='brt c018'>1.60</td> - <td class='brt c018'>122</td> - <td class='brt c018'>123</td> - <td class='brt c018'>123</td> - <td class='brt c018'>124</td> - <td class='brt c018'>125</td> - <td class='brt c018'>125</td> - <td class='brt c018'>126</td> - <td class='brt c018'>127</td> - <td class='brt c018'>128</td> - <td class='c018'>128</td> - </tr> - <tr> - <td class='brt c018'>1.70</td> - <td class='brt c018'>129</td> - <td class='brt c018'>130</td> - <td class='brt c018'>130</td> - <td class='brt c018'>131</td> - <td class='brt c018'>132</td> - <td class='brt c018'>132</td> - <td class='brt c018'>133</td> - <td class='brt c018'>134</td> - <td class='brt c018'>135</td> - <td class='c018'>136</td> - </tr> - <tr> - <td class='brt c018'>1.80</td> - <td class='brt c018'>136</td> - <td class='brt c018'>137</td> - <td class='brt c018'>137</td> - <td class='brt c018'>138</td> - <td class='brt c018'>139</td> - <td class='brt c018'>139</td> - <td class='brt c018'>140</td> - <td class='brt c018'>141</td> - <td class='brt c018'>142</td> - <td class='c018'>142</td> - </tr> - <tr> - <td class='brt c018'>1.90</td> - <td class='brt c018'>143</td> - <td class='brt c018'>144</td> - <td class='brt c018'>144</td> - <td class='brt c018'>145</td> - <td class='brt c018'>146</td> - <td class='brt c018'>146</td> - <td class='brt c018'>147</td> - <td class='brt c018'>148</td> - <td class='brt c018'>149</td> - <td class='c018'>149</td> - </tr> - <tr> - <td class='bbt brt c018'>2.00</td> - <td class='bbt brt c018'>150</td> - <td class='bbt brt c018'> </td> - <td class='bbt brt c018'> </td> - <td class='bbt brt c018'> </td> - <td class='bbt brt c018'> </td> - <td class='bbt brt c018'> </td> - <td class='bbt brt c018'> </td> - <td class='bbt brt c018'> </td> - <td class='bbt brt c018'> </td> - <td class='bbt c018'> </td> - </tr> -</table> - -<div class='footnote' id='fB'> -<p class='c009'><a href='#rB'>B</a>. Zero on the true Nessler scale is about 15 on the platinum scale.</p> -</div> - -<h4 class='c016'>LOVIBOND TINTOMETER.</h4> - -<p class='c011'>The value of the readings of tint and shade by the Lovibond -tintometer<a id='r66' /><a href='#f66' class='c015'><sup>[66]</sup></a><a id='r82' /><a href='#f82' class='c015'><sup>[82]</sup></a><a id='r83' /><a href='#f83' class='c015'><sup>[83]</sup></a> has not been commensurate with the labor involved, -but it is necessary to make a record of the reflected tint and shade<a id='r50' /><a href='#f50' class='c015'><sup>[50]</sup></a> -of some waters. The standard color disks used in teaching optics -may be used for the purpose.</p> - -<p class='c009'><em>Procedure.</em>—The white disk supports three movable standard -color sectors, red, yellow, and blue, and one movable black sector. -All are mounted on a device which can be revolved rapidly, blending -the colors into a uniform tint or shade. A scale around the -circumference of the disk is used to indicate the percentage of each -color or white or black in the blend.</p> - -<p class='c009'>Place the sample in a battery jar on a white ground; adjust the -sectors so that when blended the tint or shade will match the reflected -tint or shade of the sample. Report the percentages of red, -yellow blue, white, and black in the blended tint or shade.</p> - -<div> - <span class='pageno' id='Page_12'>12</span> - <h3 class='c010'>ODOR.<a id='r4' /><a href='#f4' class='c015'><sup>[4]</sup></a><a id='r14' /><a href='#f14' class='c015'><sup>[14]</sup></a><a id='r53' /><a href='#f53' class='c015'><sup>[53]</sup></a><a id='r72' /><a href='#f72' class='c015'><sup>[72]</sup></a><a id='r92' /><a href='#f92' class='c015'><sup>[92]</sup></a><a id='r114' /><a href='#f114' class='c015'><sup>[114]</sup></a><a id='r115' /><a href='#f115' class='c015'><sup>[115]</sup></a><a id='r121c' /><a href='#f121c' class='c015'><sup>[121c]</sup></a><a id='r3'></a></h3> -</div> - -<p class='c011'>The observation of the odor, cold and hot, of samples of surface -water is important as the odors are usually indicative of organic -growths or sewage contamination or both. The odor of some -ground waters is caused by the earthy constituents of the water-bearing -strata. The odor of a contaminated well water is often -contributory evidence of its pollution. A study of the organisms -as directed under Microscopical Examination (p. <a href='#Page_90'>90</a>) is a valuable -adjunct to physical and chemical examination of water. Certain -odors distinguish or identify certain organisms, as, for example, the -“fishy” odor of <em>Uroglena</em>, the “aromatic” or “rose geranium” odor -of <em>Asterionella</em> and the “pig pen” odor of <em>Anabaena</em>. Observe and -record the odor, both at room temperature and at just below the -boiling point, as follows:</p> - -<h4 class='c016'>COLD ODOR.</h4> - -<p class='c011'>Shake the sample violently in one of the collecting bottles, when -it is half to two-thirds full and when the sample is at room temperature -(about 20° C.). Remove the stopper and smell the odor at -the mouth of the bottle.</p> - -<h4 class='c016'>HOT ODOR.</h4> - -<p class='c011'>Pour about 150 cc. of the sample into a 500 cc. Erlenmeyer flask. -Cover the flask with a well-fitting watch glass. Heat the water -almost to boiling on a hot plate. Remove the flask from the plate -and allow it to cool not more than five minutes. Then agitate -it with a rotary movement, slip the watch glass to one side, and -smell the odor.</p> - -<h4 class='c016'>EXPRESSION OF RESULTS.</h4> - -<p class='c011'>Express the quality of the odor by a descriptive epithet like the -following, which may be abbreviated in the record:</p> - -<div class='lg-container-b c022'> - <div class='linegroup'> - <div class='group'> - <div class='line'>a—aromatic</div> - <div class='line'>C—free chlorine</div> - <div class='line'>d—disagreeable</div> - <div class='line'>e—earthy</div> - <div class='line'>f—fishy</div> - <div class='line'>g—grassy</div> - <div class='line'>m—moldy</div> - <div class='line'>M—musty</div> - <div class='line'>P—peaty</div> - <div class='line'>s—sweetish</div> - <div class='line'>S—hydrogen sulfide</div> - <div class='line'>v—vegetable.</div> - </div> - </div> -</div> - -<p class='c009'>Express the intensity of the odor by a numeral prefixed to the -term expressing quality, which may be defined as follows:</p> - -<table class='table1' summary=''> - <tr><td class='c012' colspan='3'><span class='pageno' id='Page_13'>13</span></td></tr> - <tr> - <th class='c019'>Numerical value.</th> - <th class='c019'>Term.</th> - <th class='c023'>Definition.</th> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c019'>0</td> - <td class='c013'>None.</td> - <td class='c024'>No odor perceptible.</td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c019'>1</td> - <td class='c013'>Very faint.</td> - <td class='c024'>An odor that would not be detected ordinarily by the average consumer, but that could be detected in the laboratory by an experienced observer.</td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c019'>2</td> - <td class='c013'>Faint.</td> - <td class='c024'>An odor that the consumer might detect if his attention were called to it, but that would not attract attention otherwise.</td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c019'>3</td> - <td class='c013'>Distinct.</td> - <td class='c024'>An odor that would be detected readily and that might cause the water to be regarded with disfavor.</td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c019'>4</td> - <td class='c013'>Decided.</td> - <td class='c024'>An odor that would force itself upon the attention and that might make the water unpalatable.</td> - </tr> - <tr><td> </td></tr> - <tr> - <td class='c019'>5</td> - <td class='c013'>Very strong.</td> - <td class='c024'>An odor of such intensity that the water would be absolutely unfit to drink. (A term to be used only in extreme cases.)</td> - </tr> -</table> - -<div class='chapter'> - <span class='pageno' id='Page_14'>14</span> - <h2 class='c005'>CHEMICAL EXAMINATION.</h2> -</div> - -<h3 class='c010'>EXPRESSION OF RESULTS.</h3> - -<p class='c011'>The results of chemical analyses shall be expressed in parts per -million, which in most analyses is practically equivalent to milligrams -per liter. In some laboratories other forms of expression -have been used. Results expressed in parts per 100,000 or in grains -per gallon may be transformed to parts per million, or conversely, -by the use of the following table:</p> - -<table class='table2' summary=''> - <tr><th class='c012' colspan='5'>Table 4.—<span class='sc'>Factors for transforming results of analyses.</span></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt c017' rowspan='2'>Unit.</th> - <th class='btt bbt blt c017' colspan='4'>Equivalent.</th> - </tr> - <tr> - - <th class='bbt blt c017'>Grains per U.S. gallon.</th> - <th class='bbt blt c017'>Grains per Imperial gallon.</th> - <th class='bbt blt c017'>Parts per 100,000.</th> - <th class='bbt blt c017'>Parts per million.</th> - </tr> - <tr> - <td class='c025'>1 grain per U. S. gallon</td> - <td class='blt c018'>1.000</td> - <td class='blt c018'>1.20</td> - <td class='blt c018'>1.71</td> - <td class='blt c018'>17.1</td> - </tr> - <tr> - <td class='c025'>1 grain per Imperial gallon</td> - <td class='blt c018'>.835</td> - <td class='blt c018'>1.00</td> - <td class='blt c018'>1.43</td> - <td class='blt c018'>14.3</td> - </tr> - <tr> - <td class='c025'>1 part per 100,000</td> - <td class='blt c018'>.585</td> - <td class='blt c018'>.70</td> - <td class='blt c018'>1.00</td> - <td class='blt c018'>10.0</td> - </tr> - <tr> - <td class='bbt c025'>1 part per million</td> - <td class='bbt blt c018'>.058</td> - <td class='bbt blt c018'>.07</td> - <td class='bbt blt c018'>.10</td> - <td class='bbt blt c018'>1.0</td> - </tr> -</table> - -<p class='c009'>The following general rules shall govern the use of significant -figures in the expression of results:</p> - -<p class='c009'>1. If the results show quantities greater than 10 parts per -million use no decimals; record only whole numbers. If the quantities -reach hundreds and thousands of parts record only two significant -figures.</p> - -<p class='c009'>2. If the results are between 1 and 10 parts do not retain more -than one decimal place.</p> - -<p class='c009'>3. If the results are between 0.1 and 1 part do not retain more -than two decimal places.</p> - -<p class='c009'>4. Estimates of ammonia, albuminoid, and nitrite nitrogen alone -justify the use of three decimals.</p> - -<p class='c009'>5. If the results of analyses are tabulated ciphers should not -be added at the right of the decimal point to make the column -uniform.</p> - -<div> - <span class='pageno' id='Page_15'>15</span> - <h3 class='c010'>FORMS OF NITROGEN.</h3> -</div> - -<p class='c011'>Nitrogenous organic matter passes through several intermediate -compounds during its natural decomposition, and that which does -not gasify ultimately forms nitrate. Nitrogen in organic matter -is determined by the Kjeldahl process.<a id='r13' /><a href='#f13' class='c015'><sup>[13]</sup></a><a href='#f14' class='c015'><sup>[14]</sup></a><a id='r58' /><a href='#f58' class='c015'><sup>[58]</sup></a> An indication of the -amount present is obtained by the albuminoid nitrogen determination.<a href='#f14' class='c015'><sup>[14]</sup></a><a id='r15' /><a href='#f15' class='c015'><sup>[15]</sup></a><a id='r67' /><a href='#f67' class='c015'><sup>[67]</sup></a><a id='r106' /><a href='#f106' class='c015'><sup>[106]</sup></a><a id='r107' /><a href='#f107' class='c015'><sup>[107]</sup></a> -It has not been found possible to differentiate -the nitrogen in the organic matter that readily decomposes from -that in stable or non-putrescible compounds. Decomposition of -organic matter produces nitrogen combined in ammonia, which is -the first step between nitrogenous organic matter and the completely -mineralized nitrate. Ammonia nitrogen may be determined -by distillation and Nesslerization or by direct Nesslerization of the -clarified sample. The next step is oxidation to nitrite, and the -final step, oxidation to nitrate. It is recommended that all forms of -nitrogen be reported as the element nitrogen (N).</p> - -<h3 class='c010'>AMMONIA NITROGEN.</h3> - -<p class='c011'>There are two methods for estimating ammonia nitrogen—distillation -and direct Nesslerization. Distillation is recommended for -most waters and direct Nesslerization is recommended for sewages, -sewage effluents, and highly polluted surface waters.</p> - -<h4 class='c016'>DETERMINATION BY DISTILLATION.<a id='r38' /><a href='#f38' class='c015'><sup>[38]</sup></a><a id='r68b' /><a href='#f68b' class='c015'><sup>[68b]</sup></a><a id='r111' /><a href='#f111' class='c015'><sup>[111]</sup></a><a id='r121' /><a href='#f121' class='c015'><sup>[121]</sup></a></h4> - -<p class='c011'><em>Procedure.</em>—Use a metal or a glass flask connected with a condenser -so that the distillate may drop from the condenser tube -directly into a Nessler tube or a flask. Free the apparatus from -ammonia by boiling distilled water in it until the distillate shows -no trace of ammonia. After this has been done empty the distilling -flask and measure into it 500 cc. of the sample, or a smaller portion -diluted to 500 cc. with ammonia-free water. If the sample is acid -or if the presence of urea is suspected add about 0.5 gram of sodium -carbonate before distillation. Omit this if possible as it tends to -increase “bumping.” Apply heat so that the distillation may -proceed at the rate of not more than 10 cc. nor less than 6 cc. per -minute. Collect the distillate in four Nessler tubes, 50 cc. to each -tube, or if the nitrogen is high in a 200 cc. graduated flask. These -receptacles contain the ammonia nitrogen to be measured as hereafter -described.</p> - -<p class='c009'><span class='pageno' id='Page_16'>16</span>Use Nessler tubes of such diameter that the graduation mark is -between 20 and 25 cm. above the bottom and of such uniformity -of diameter that the distance from the bottom to the -graduation mark of the longest tube shall not exceed that of the -shortest tube by more than 6 mm. The tubes must be of clear -white glass with polished bottoms.</p> - -<h5 class='c016'>MEASUREMENT OF AMMONIA NITROGEN.</h5> - -<p class='c011'>The amount of ammonia in the distillates may be measured -either by (1) comparison of the Nesslerized distillates with Nesslerized -solutions containing known quantities of nitrogen as ammonium -chloride, or by (2) comparison of the Nesslerized distillates with -permanent standard solutions in which the colors of Nesslerized -standard ammonia solutions are duplicated by solutions of platinum -and cobalt chlorides.</p> - -<h6 class='c016'><span class='sc'>Comparison with ammonia standards.</span></h6> - -<p class='c011'><em>Reagents.</em>—1. Ammonia-free water.</p> - -<p class='c009'>2. Standard ammonium chloride solution. Dissolve 3.82 grams of -ammonium chloride in ammonia-free water and dilute to 1 liter; -dilute 10 cc. of this to 1 liter with ammonia-free water. One cc. -equals 0.00001 gram of nitrogen.</p> - -<p class='c009'>3. Nessler reagent.<a id='r8' /><a href='#f8' class='c015'><sup>[8]</sup></a> Dissolve 50 grams of potassium iodide in -a minimum quantity of cold water. Add a saturated solution of -mercuric chloride until a slight precipitate persists permanently. -Add 400 cc. of 50 per cent solution of potassium hydroxide, made -by dissolving the potassium hydroxide and allowing it to clarify by -sedimentation before using. Dilute to 1 liter, allow to settle, -and decant. This solution should give the required color with -ammonia within five minutes after addition and should not produce -a precipitate with small amounts of ammonia within two hours.</p> - -<p class='c009'><em>Procedure.</em>—Prepare a series of 16 Nessler tubes containing the -following amounts of the standard ammonium chloride solution, -diluted to 50 cc. with ammonia-free water, namely: 0.0, 0.1, 0.3, -0.5, 0.7, 1.0, 1.4, 1.7, 2.0, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, and 6.0 cc. -These solutions will contain 0.00001 gram of nitrogen for each cubic -centimeter of the standard solution.</p> - -<p class='c009'>Nesslerize the standards and the distillates by adding approximately -1 cc. of Nessler reagent to each tube. Do not stir the -contents of the tubes. The temperature of the tubes should be -<span class='pageno' id='Page_17'>17</span>practically the same as that of the standards; otherwise the colors -will not be directly comparable.<a id='r45' /><a href='#f45' class='c015'><sup>[45]</sup></a> Allow the tubes to stand at least -10 minutes after Nesslerizing. Compare the color produced in the -tubes with that in the standards by looking vertically downward -through them at a white or mirrored surface placed at an angle in -front of a window so as to reflect the light upward.</p> - -<p class='c009'>If the color obtained by Nesslerizing the distillates is greater than -that of the darkest tube of the standards, mix the contents of the -tube thoroughly, pour out half of the liquid, and dilute the remainder -to the original volume with ammonia-free water; then make the -color comparison and multiply the result by two. If the color is -still too dark after pouring out half the liquid, repeat this process -of division until a reading can be made. The process of dilution -may be shortened by mixing together the distillates from one sample -before making the comparison and comparing an aliquot portion -with the standards.</p> - -<p class='c009'>After the readings have been recorded add the results obtained -by Nesslerizing each portion of the entire distillate. If 500 cc. -of the sample is distilled this sum, expressed in cubic centimeters -and multiplied by 0.02, will give the number of parts per million -of ammonia nitrogen in the sample. If x cc. of sample is used -multiply the sum of the readings by 10/x.</p> - -<p class='c009'>If the ammonia is known to be high the distillate may be collected -in 200 cc. flasks and an aliquot part Nesslerized.</p> - -<h6 class='c016'><span class='sc'>Comparison with permanent standards.</span><a href='#f62' class='c015'><sup>[62]</sup></a><a id='r65' /><a href='#f65' class='c015'><sup>[65]</sup></a></h6> - -<p class='c011'><em>Reagents.</em>—Platinum solution. Dissolve 2.00 grams of potassium -platinic chloride (PtCl<sub>4</sub>.2KCl) in a small amount of distilled water, -add 100 cc. of strong hydrochloric acid, and dilute to 1 liter.</p> - -<p class='c009'>Cobalt solution. Dissolve 12 grams of cobaltous chloride -(CoCl<sub>2</sub>.6H<sub>2</sub>O) in distilled water, add 100 cc. of strong hydrochloric -acid, and dilute to 1 liter.</p> - -<p class='c009'>Prepare standards by putting various amounts of these two solutions -into Nessler tubes and diluting to the 50 cc. mark with distilled -water as indicated in Table 5. These standards may be kept for -several months if protected from dust.</p> - -<table class='table2' summary=''> - <tr><td class='c012' colspan='3'><span class='pageno' id='Page_18'>18</span></td></tr> - <tr><th class='c012' colspan='3'>Table 5.—<span class='sc'>Preparation of permanent standards for the determination of Ammonia.</span></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017'>Value in standard ammonium chloride.</th> - <th class='btt bbt brt c017'>Solution of platinum.</th> - <th class='btt bbt c017'>Solution of cobalt.</th> - </tr> - <tr> - <td class='brt c018'><em>cc.</em></td> - <td class='brt c018'><em>cc.</em></td> - <td class='c018'><em>cc.</em></td> - </tr> - <tr> - <td class='brt c018'>0.0</td> - <td class='brt c018'>1.2</td> - <td class='c018'>0.0</td> - </tr> - <tr> - <td class='brt c018'>.1</td> - <td class='brt c018'>1.8</td> - <td class='c018'>.0</td> - </tr> - <tr> - <td class='brt c018'>.2</td> - <td class='brt c018'>2.8</td> - <td class='c018'>.0</td> - </tr> - <tr> - <td class='brt c018'>.4</td> - <td class='brt c018'>4.7</td> - <td class='c018'>.1</td> - </tr> - <tr> - <td class='brt c018'>.7</td> - <td class='brt c018'>5.9</td> - <td class='c018'>.2</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>1.0</td> - <td class='brt c018'>7.7</td> - <td class='c018'>.5</td> - </tr> - <tr> - <td class='brt c018'>1.4</td> - <td class='brt c018'>9.9</td> - <td class='c018'>1.1</td> - </tr> - <tr> - <td class='brt c018'>1.7</td> - <td class='brt c018'>11.4</td> - <td class='c018'>1.7</td> - </tr> - <tr> - <td class='brt c018'>2.0</td> - <td class='brt c018'>12.7</td> - <td class='c018'>2.2</td> - </tr> - <tr> - <td class='brt c018'>2.5</td> - <td class='brt c018'>15.0</td> - <td class='c018'>3.3</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>3.0</td> - <td class='brt c018'>17.3</td> - <td class='c018'>4.5</td> - </tr> - <tr> - <td class='brt c018'>3.5</td> - <td class='brt c018'>19.0</td> - <td class='c018'>5.7</td> - </tr> - <tr> - <td class='brt c018'>4.0</td> - <td class='brt c018'>19.7</td> - <td class='c018'>7.1</td> - </tr> - <tr> - <td class='brt c018'>4.5</td> - <td class='brt c018'>19.9</td> - <td class='c018'>8.7</td> - </tr> - <tr> - <td class='brt c018'>5.0</td> - <td class='brt c018'>20.0</td> - <td class='c018'>10.4</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>6.0</td> - <td class='brt c018'>20.0</td> - <td class='c018'>15.0</td> - </tr> - <tr> - <td class='bbt brt c018'>7.0</td> - <td class='bbt brt c018'>20.0</td> - <td class='bbt c018'>22.0</td> - </tr> -</table> - -<p class='c009'>The amounts in Table 5 are approximate, and the actual amount -necessary will differ with the character of the Nessler solution, the -color sensitiveness of the analyst’s eye, and other conditions. The -final test of the standard is best obtained by comparing it with -Nesslerized standards and modifying the tint accordingly. Such -comparison should be made for each new batch of Nessler solution -and should be checked by each analyst.</p> - -<p class='c009'><em>Procedure.</em>—In comparison with permanent standards, Nesslerize -the distillates in the manner above described and compare the -resulting colors at the end of about 10 minutes with the permanent -standards. The method of calculating results is precisely the same -as with the ammonia standards.</p> - -<h5 class='c016'>MODIFICATION FOR SEWAGE.</h5> - -<p class='c011'>Ammonia nitrogen and albuminoid nitrogen in sewages, soils, and -other materials of high nitrogen content may be satisfactorily determined -by diluting the sample with ammonia-free distilled water and -proceeding as described in the preceding sections, but it is permissible -to distill with steam.<a id='r40' /><a href='#f40' class='c015'><sup>[40]</sup></a></p> - -<p class='c009'><span class='pageno' id='Page_19'>19</span><em>Procedure.</em>—Use a 200 cc. long-necked Kjeldahl flask connected -with a condenser so that the distillate may drop from the condenser -tube directly into a Nessler tube or a flask. Connect the Kjeldahl -flask with a steam generator by a tube reaching almost to the -bottom of the flask.</p> - -<p class='c009'>After the apparatus is freed from ammonia put the sample to be -tested into the flask. Use 10 to 100 cc. of the sample according to -its ammonia content. Pass ammonia-free steam through the liquid -in the Kjeldahl flask and collect the distillate in the usual way. It -is usually convenient to collect the distillate in a 200 cc. flask and -to take an aliquot part of it for Nesslerization. Compare with -standards and calculate the nitrogen content in the usual manner.</p> - -<p class='c009'>This method has the advantage, when the sample is treated with -an alkaline solution of potassium permanganate, of avoiding bumping, -permitting the assay of solid matter, and yielding the ammonia -more rapidly than by the ordinary process of distillation.</p> - -<h4 class='c016'>DETERMINATION BY DIRECT NESSLERIZATION.<a id='r21' /><a href='#f21' class='c015'><sup>[21]</sup></a><a id='r75' /><a href='#f75' class='c015'><sup>[75]</sup></a></h4> - - <dl class='dl_1 c002'> - <dt><em>Reagents.</em>—</dt> - <dd>1. Ten per cent solution of copper sulfate (CuSO<sub>4</sub>.5H<sub>2</sub>O). - </dd> - <dt> 2.</dt> - <dd>Ten per cent solution of lead acetate (Pb(C<sub>2</sub>H<sub>3</sub>O<sub>2</sub>)<sub>2</sub>.3H<sub>2</sub>O). - </dd> - <dt> 3.</dt> - <dd>Fifty per cent solution of sodium hydroxide (NaOH) or potassium hydroxide (KOH). - </dd> - </dl> - -<p class='c009'><em>Procedure.</em>—To 50 cc. of the sample to be tested, diluted if necessary -with an equal volume of ammonia-free water, in a short -tube, add a few drops of the copper sulfate solution. After thoroughly -mixing, add 1 cc. of the alkali hydroxide solution and -again thoroughly mix. Allow the tube to stand for a few minutes, -when a heavy precipitate should fall to the bottom, leaving a colorless -supernatant liquid. Nesslerize an aliquot part. Compare -with standards and compute the ammonia nitrogen in the same -manner as in the distillation procedure.</p> - -<p class='c009'>Samples containing hydrogen sulfide may require the use of lead -acetate in addition to the copper sulfate. Some samples may require -a few trials before the right combination of the three solutions -to bring about the best results can be found.</p> - -<p class='c009'>Instead of adding copper sulfate to sewages of high magnesium -content satisfactory clarification of the sample can be obtained by -mixing it with the alkali hydroxide alone.<a id='r54' /><a href='#f54' class='c015'><sup>[54]</sup></a></p> - -<div> - <span class='pageno' id='Page_20'>20</span> - <h3 class='c010'>ALBUMINOID NITROGEN.</h3> -</div> - -<p class='c011'>The addition of an alkaline permanganate solution to liquids containing -nitrogenous organic matter causes the formation of ammonia, -which can be distilled and determined by Nesslerization of the -distillate. The nitrogen of the ammonia, thus obtained, is called -albuminoid nitrogen. As the ratio of nitrogenous organic matter to -the ammonia obtained by distillation is decidedly variable<a id='r6' /><a href='#f6' class='c015'><sup>[6]</sup></a><a id='r30' /><a href='#f30' class='c015'><sup>[30]</sup></a><a href='#f75' class='c015'><sup>[75]</sup></a> in -sewages and other substances containing much nitrogenous organic -matter albuminoid nitrogen results on such substances are less -accurate<a id='r29' /><a href='#f29' class='c015'><sup>[29]</sup></a> than organic (Kjeldahl) nitrogen. Therefore in sewage -work, including analysis of influents and effluents of purification -plants and the water of highly polluted streams, it is recommended -that determinations of organic nitrogen be substituted for determinations -of albuminoid nitrogen. For ground waters and surface -waters containing but little pollution, the albuminoid nitrogen is -approximately one-half the organic nitrogen; accordingly the continuance -of albuminoid nitrogen determinations for this class of -work is approved.</p> - -<p class='c009'><em>Reagents.</em>—Alkaline potassium permanganate. Pour 1,200 cc. of -distilled water into a porcelain dish holding 2,500 cc., boil 10 -minutes, and turn off the gas. Add 16 grams of C. P. potassium -permanganate and stir until solution is complete. Then add 800 -cc. of 50 per cent clarified solution of potassium hydroxide or an -equivalent amount of sodium hydroxide and enough distilled water -to fill the dish. Boil down to 2,000 cc. Test this solution for -ammonia by making a blank determination. Correct determinations -by the amount of this blank.</p> - -<p class='c009'><em>Procedure.</em>—After the collection of the distillate for ammonia -nitrogen described on page <a href='#Page_15'>15</a> add 50 cc. (or more if necessary to -insure the complete oxidation of the organic matter) of alkaline -potassium permanganate and continue the distillation until at least -four portions, and preferably five portions, of 50 cc. each, of distillate -have been collected in separate tubes. Determine the -albuminoid nitrogen in the distillate by Nesslerization. If the albuminoid -nitrogen is known to be high it is convenient to collect the -distillate in a 200 cc. flask and to Nesslerize an aliquot part of it.</p> - -<p class='c009'>Dissolved albuminoid nitrogen may be determined in a sample -from which suspended matter has been removed by filtration either -through filter paper or through a Berkefeld filter. Suspended -<span class='pageno' id='Page_21'>21</span>albuminoid nitrogen is the difference between the total and the -dissolved albuminoid nitrogen.</p> - -<h3 class='c010'>ORGANIC NITROGEN.<a id='r24b' /><a href='#f24b' class='c015'><sup>[24b]</sup></a><a id='r69' /><a href='#f69' class='c015'><sup>[69]</sup></a><a id='r71' /><a href='#f71' class='c015'><sup>[71]</sup></a><a id='r76' /><a href='#f76' class='c015'><sup>[76]</sup></a><a id='r84' /><a href='#f84' class='c015'><sup>[84]</sup></a></h3> - -<p class='c011'><em>Procedure for water.</em>—Boil 500 cc. of the sample in a round-bottomed -flask to remove ammonia nitrogen. This usually causes -the loss of 200 cc. of the sample, which may be collected for the -determination of ammonia nitrogen. Add 5 cc. of nitrogen-free -concentrated sulfuric acid and a small piece of ignited pumice. -Mix by shaking and place over a flame under a hood. Digest until -copious fumes of sulfuric acid are given off and the liquid finally -becomes colorless or pale straw color. Remove from the flame, -and add potassium permanganate crystals in small portions until a -heavy green precipitate persists in the liquid. Cool. Dilute to -about 300 cc. with ammonia-free water. Make alkaline with -10 per cent ammonia-free sodium hydroxide. Distill the ammonia, -collect the distillate in Nessler tubes, Nesslerize, and compare with -standards as described (pp. <a href='#Page_16'>16</a>–18).</p> - -<p class='c009'><em>First procedure for sewage</em><a href='#f76' class='c015'><sup>[76]</sup></a>.—Distill the ammonia nitrogen -directly from 100 cc. or less of the sample, diluted to 500 cc. with -nitrogen-free water. Collect the distillate and determine the -ammonia nitrogen in it. Add 5 cc. of nitrogen-free sulfuric acid -and 1 cc. of 10 per cent nitrogen-free copper sulfate, and digest -the liquid for half an hour after it has become colorless or pale -straw color. Add 0.5 gram of potassium permanganate crystals -to the hot acid solution, and dilute to 500 cc. with ammonia-free -water. Dilute 10 cc. or more of this liquid, in a Kjeldahl distilling -flask, to about 300 cc. with ammonia-free water. Make alkaline -with 10 per cent sodium hydroxide, distill, and Nesslerize. With -some samples direct Nesslerization may be used. (See p. <a href='#Page_19'>19</a>.)</p> - -<p class='c009'>In this determination care must be taken to digest thoroughly, -to add potassium permanganate to the point of precipitation, to -sample carefully after dilution, and to add enough sodium hydroxide -to insure the separation of the ammonia from the precipitated -manganese hydroxide. Potassium permanganate should not be -added during digestion because it causes loss of nitrogen.</p> - -<p class='c009'><em>Second procedure for sewage.</em>—Omit the separation of ammonia -nitrogen and determine the ammonia nitrogen and organic nitrogen -together. Determine the ammonia nitrogen in a separate sample -<span class='pageno' id='Page_22'>22</span>by direct Nesslerization as described on page <a href='#Page_19'>19</a>. The organic -nitrogen is equal to the difference.</p> - -<h3 class='c010'>NITRITE NITROGEN.<a id='r51' /><a href='#f51' class='c015'><sup>[51]</sup></a><a id='r63a' /><a href='#f63a' class='c015'><sup>[63a]</sup></a><a id='r64' /><a href='#f64' class='c015'><sup>[64]</sup></a><a id='r94c' /><a href='#f94c' class='c015'><sup>[94c]</sup></a><a id='r108' /><a href='#f108' class='c015'><sup>[108]</sup></a></h3> - -<p class='c011'><em>Reagents.</em>—1. Sulfanilic acid solution. Dissolve 8.00 grams of -the purest sulfanilic acid in 1,000 cc. of 5 N acetic acid (sp. gr. -1.041) or in 1,000 cc. of water containing 50 cc. of concentrated -hydrochloric acid. This is practically a saturated solution.</p> - -<p class='c009'>2. α-naphthylamine acetate or chloride solution. Dissolve 5.00 -grams solid α-naphthylamine in 1,000 cc. of 5 N acetic acid or in -1,000 cc. of water containing 8 cc. of concentrated hydrochloric acid. -Filter the solution through washed absorbent cotton or an alundum -filter.</p> - -<p class='c009'>3. Sodium nitrite stock solution. Dissolve 1.1 gram silver nitrite -in nitrite-free water; precipitate the silver with sodium chloride -solution and dilute the whole to 1 liter.</p> - -<p class='c009'>4. Standard sodium nitrite solution. Dilute 100 cc. of solution -3 to 1 liter, then dilute 50 cc. of this solution to 1 liter with -sterilized nitrite-free water, add 1 cc. of chloroform, and preserve -in a sterilized bottle. One cc. = 0.0005 mg. nitrogen.</p> - -<p class='c009'>5. Fuchsine solution. 0.1 gram per liter.</p> - -<p class='c009'><em>Procedure.</em>—Place in a standard Nessler tube 50 cc. of the -sample, decolorized if necessary with nitrite-free aluminium hydroxide -(see p. <a href='#Page_42'>42</a>) or a smaller amount diluted to 50 cc. At the -same time prepare in Nessler tubes a set of standards, by diluting -to 50 cc. with nitrite-free water, various amounts of the standard -nitrite solution. The following amounts of standard solution are -suggested: 0.0, 0.1, 0.2, 0.4, 0.7, 1.0, 1.4, 1.7, 2.0, and 2.5 cc. Add -1 cc. of the sulfanilic acid solution and 1 cc. of the α-naphthylamine -acetate or hydrochloride solution to the sample and to -each standard. Mix thoroughly and allow to stand 10 minutes; -then compare the sample with the standards. Do not allow the -sample to stand more than one-half hour before making the comparison. -If the color of the sample is deeper than that of the -highest standard repeat the test on a diluted sample. If 50 cc. -of the sample is used 0.01 times the number of cc. of the standard -matched equals parts per million of nitrite nitrogen. Satisfactory -results can be obtained by using either hydrochloric or acetic acid -in preparing the test solutions, but the speed of the reaction is -more rapid if acetic acid is used.<a id='r112' /><a href='#f112' class='c015'><sup>[112]</sup></a></p> - -<p class='c009'><span class='pageno' id='Page_23'>23</span>Permanent standards may be prepared by matching the nitrite -standards with dilutions of the fuchsine solution. Fuchsine -standards have been found to be sufficiently accurate for waters -high in nitrite and for sewage. The standards should be checked -once a month and kept out of bright sunlight.</p> - -<h3 class='c010'>NITRATE NITROGEN.<a id='r16' /><a href='#f16' class='c015'><sup>[16]</sup></a><a id='r36' /><a href='#f36' class='c015'><sup>[36]</sup></a><a id='r90' /><a href='#f90' class='c015'><sup>[90]</sup></a><a id='r100' /><a href='#f100' class='c015'><sup>[100]</sup></a><a id='r91'></a></h3> - -<p class='c011'>Two methods are recommended for the determination of nitrate -nitrogen in water, sewage, and sewage effluents.</p> - -<h4 class='c016'>PHENOLDISULFONIC ACID METHOD.<a id='r1' /><a href='#f1' class='c015'><sup>[1]</sup></a><a id='r5' /><a href='#f5' class='c015'><sup>[5]</sup></a><a id='r32' /><a href='#f32' class='c015'><sup>[32]</sup></a></h4> - -<p class='c011'><em>Reagents.</em>—1. Phenoldisulfonic acid. Dissolve 25 grams of pure -white phenol in 150 cc. of pure concentrated sulfuric acid. Add -75 cc. of fuming sulfuric acid (15 per cent SO<sub>3</sub>), stir well, and heat -for 2 hours at about 100°C.</p> - -<p class='c009'>2. Potassium hydroxide solution. Prepare an approximately -12 N solution, 10 cc. of which will neutralize about 4 cc. of the -phenoldisulfonic acid.</p> - -<p class='c009'>3. Standard nitrate solution. Dissolve 0.72 gram of pure -recrystallized potassium nitrate in 1 liter of distilled water. Evaporate -cautiously to dryness 10 cc. of the solution on the water bath. -Moisten residue quickly and thoroughly with 2 cc. of phenoldisulfonic -acid and dilute to 1 liter. This is the standard solution, -1 cc. of which equals 0.001 mg. of nitrate nitrogen.</p> - -<p class='c009'>4. Standard silver sulfate solution. Dissolve 4.4 grams of silver -sulfate free from nitrate in 1 liter of water. One cc. of this solution -is equal to 1 mg. of chloride.</p> - -<p class='c009'><em>Procedure.</em>—The alkalinity, chloride, and nitrite content, and color -of the sample must first be determined. If the sample is highly -colored decolorize it with freshly precipitated aluminium hydroxide. -Measure into an evaporating dish 100 cc. of the sample, or if nitrate -is very high such volume as will contain about 0.01 mg. of nitrate -nitrogen. Add sufficient N/50 sulfuric acid nearly to neutralize -the alkalinity. Then add sufficient standard silver sulfate to -precipitate all but about 0.1 mg. of chloride. The removal of -chloride may be omitted if the sample contains less than 30 parts -per million of chloride. Heat the mixture to boiling, add a little -aluminium hydroxide, stir, filter, and wash with small amounts -of hot water. Evaporate the filtrate to dryness, and add 2 cc. of the -phenoldisulfonic acid, rubbing with a glass rod to insure intimate -<span class='pageno' id='Page_24'>24</span>contact. If the residue becomes packed or appears vitreous -because of the presence of much iron, heat the dish on the water -bath for a few minutes. Dilute the mixture with distilled water, -and add slowly a strong solution of potassium hydroxide or ammonium -hydroxide until the maximum color is developed. Transfer -the solution to a Nessler tube, filtering if necessary. If nitrate -is present a yellow color will be formed. Compare the color with -that of standards<a id='r52' /><a href='#f52' class='c015'><sup>[52]</sup></a><a id='r55' /><a href='#f55' class='c015'><sup>[55]</sup></a> made by adding 2 cc. of strong potassium -hydroxide or ammonium hydroxide to various amounts of standard -nitrate solution and diluting them to 50 cc. in Nessler tubes. -The following amounts of standard nitrate solution are suggested: -0, 0.5, 1.0, 1.5, 2.0, 4.0, 6.0, 8.0, 10.0, 15.0, 20.0, and 40.0 cc. These -standards may be kept several weeks without deterioration. If 100 -cc. of water is used the number of cubic centimeters of the standard -multiplied by 0.01 is equal to parts per million of nitrate nitrogen.</p> - -<p class='c009'>Standards that will remain permanent for several years if stored in -the dark may be prepared from tripotassium nitrophenoldisulfonate.<a href='#f5' class='c015'><sup>[5]</sup></a></p> - -<p class='c009'>If nitrite nitrogen is present in excess of 1 part per million it -should be oxidized by heating the samples a few minutes with a -few drops of hydrogen peroxide free from nitrate repeatedly added<a id='r95' /><a href='#f95' class='c015'><sup>[95]</sup></a> -or by adding dilute potassium permanganate in the cold until a faint -pink coloration appears; the nitrogen equivalent of the nitrite thus -oxidized to nitrate is then subtracted from the final nitrate nitrogen -reading.</p> - -<h4 class='c016'>REDUCTION METHOD.<a id='r2' /><a href='#f2' class='c015'><sup>[2]</sup></a><a id='r46' /><a href='#f46' class='c015'><sup>[46]</sup></a></h4> - -<p class='c011'><em>Reagents.</em>—1. Sodium or potassium hydroxide solution. Dissolve -250 grams of the hydroxide in 1.25 liters of distilled water. -Add several strips of aluminium foil and allow the evolution of -hydrogen to continue over night. Concentrate the solution to 1 liter -by boiling.</p> - -<p class='c009'>2. Aluminium foil. Use strips of pure aluminium about 10 cm. -long, 6 mm. wide, and 0.33 mm. thick and weighing about 0.5 gram.</p> - -<p class='c009'><em>Procedure.</em>—To 100 cc. of the sample in a 300 cc. casserole add -2 cc. of the hydroxide solution and concentrate by boiling to about -20 cc. Pour the contents of the casserole into a test tube about -16 cm. long and 3 cm. in diameter, or of approximately 100 cc. -capacity. Rinse the casserole several times with nitrogen-free -water and add the rinse water to the liquid already in the tube, -<span class='pageno' id='Page_25'>25</span>thus making the contents of the tube approximately 75 cc. Add a -strip of aluminium foil. Close the tube by means of a rubber -stopper through which passes a bent glass tube about 5 mm. in -diameter. Put the shorter arm of the tube flush with the lower -side of the rubber stopper and let the longer arm extend below -the surface of distilled water in another test tube. This apparatus -serves as a trap through which the evolved hydrogen escapes freely. -The small amount of ammonia escaping into the trap may be -neglected. Allow the action to proceed for a minimum period of -four hours or over night. Pour the contents of the tube into a -distilling flask, dilute with 250 cc. of ammonia-free water, distill, -collect the distillate in Nessler tubes, and Nesslerize. If the nitrate -content is high collect the distillate in a 200 cc. flask and Nesslerize -an aliquot part. If the supernatant liquid in the reduction tube is -clear and colorless the solution may be diluted to a definite volume -and an aliquot part Nesslerized without distillation.</p> - -<h3 class='c010'>TOTAL NITROGEN.<a id='r93' /><a href='#f93' class='c015'><sup>[93]</sup></a></h3> - -<p class='c011'>In sewage work it is frequently of assistance to know the total -nitrogen content. This is ordinarily computed by adding together -the organic, ammonia, nitrite, and nitrate nitrogen, each of which -is determined as already described.</p> - -<h3 class='c010'>OXYGEN CONSUMED.<a id='r24' /><a href='#f24' class='c015'><sup>[24]</sup></a><a href='#f67' class='c015'><sup>[67]</sup></a><a id='r84a' /><a href='#f84a' class='c015'><sup>[84a]</sup></a><a id='r85' /><a href='#f85' class='c015'><sup>[85]</sup></a><a id='r94f' /><a href='#f94f' class='c015'><sup>[94f]</sup></a><a id='r101' /><a href='#f101' class='c015'><sup>[101]</sup></a><a id='r102' /><a href='#f102' class='c015'><sup>[102]</sup></a></h3> - -<p class='c011'>Oxygen consumed means the oxygen that the oxidizable compounds -of sewage and water consume when treated in an acid -solution with potassium permanganate. The expression is synonymous -with oxygen required, oxygen absorbed, and oxygen-consuming -capacity. It should not be confused with biochemical oxygen -demand.</p> - -<p class='c009'>As the carbon, not the nitrogen, in organic matter is oxidized -by potassium permanganate, oxygen consumed is considered by -some an indication of the amount of carbonaceous organic matter -present. The determination indicates, however, only part of -the carbon, the proportion varying in different samples because -the carbon in nitrogenous matter is not so readily oxidized as that -in carbonaceous organic matter. Furthermore, it does not directly -differentiate the carbon present in unstable organic matter from -that in fairly stable organic matter, such as is sometimes referred -<span class='pageno' id='Page_26'>26</span>to as residual humus matter. As nitrite nitrogen, ferrous iron, -sulfide, and other oxidizable mineral substances reduce potassium -permanganate, corrections for them should be made in the determination.</p> - -<h4 class='c016'>RECOMMENDED METHOD.</h4> - -<p class='c011'><em>Reagents.</em>—1. Dilute sulfuric acid. Dilute 1 part of concentrated -sulfuric acid with 3 parts of distilled water and free the -solution from oxidizable matter by adding potassium permanganate -until a faint pink color persists after the solution has stood several -hours.</p> - -<p class='c009'>2. Standard ammonium oxalate. Dissolve 0.888 gram of the pure -salt in 1 liter of distilled water. One cc. is equivalent to 0.1 mg. -of oxygen. An equivalent quantity of oxalic acid or sodium -oxalate may be used.</p> - -<p class='c009'>3. Standard potassium permanganate. Dissolve 0.4 gram of -the crystallized salt in 1 liter of distilled water. Add 10 cc. of the -dilute sulfuric acid and 10 cc. of this solution of potassium permanganate -to 100 cc. of distilled water, and digest 30 minutes. Add -10 cc. of the ammonium oxalate solution, and then add potassium -permanganate till a pink coloration appears. This destroys the -oxygen-consuming capacity of the water used. Now add another -10 cc. of ammonium oxalate solution and titrate with potassium -permanganate. Adjust the potassium permanganate solution so -that 1 cc. is equivalent to 1 cc. of ammonium oxalate solution or -0.1 mg. of available oxygen.</p> - -<p class='c009'><em>Acid digestion.</em>—Place in a flask 100 cc. of the water, or, if the -water is of high organic content, a smaller portion diluted to 100 cc. -Add 10 cc. of sulfuric acid solution and 10 cc. of standard potassium -permanganate and digest the liquid exactly 30 minutes in a bath -of boiling water the level of which is kept above the level of the -contents of the flask.<a id='r70' /><a href='#f70' class='c015'><sup>[70]</sup></a><a id='r71a' /><a href='#f71a' class='c015'><sup>[71a]</sup></a> If the quantity of permanganate is insufficient -for complete oxidation repeat the digestion with a larger -quantity; at least 5 cc. excess of the standard permanganate should -be present when the ammonium oxalate solution is added. Remove -the flask, add 10 cc. of the ammonium oxalate solution, and -titrate with the standard permanganate until a faint but distinct -color is obtained. If 100 cc. of water is used the number of cubic -centimeters of potassium permanganate solution in excess of the -<span class='pageno' id='Page_27'>27</span>number of cubic centimeters of ammonium oxalate solution is -equal to parts per million of oxygen consumed.</p> - -<p class='c009'>If oxidizable mineral substances, such as ferrous iron, sulfide, -or nitrite, are present in the sample corrections should be applied -as accurately as possible by suitable procedures. Direct titration -of the acidified sample in the cold, using a three-minute period -of digestion, serves this purpose quite well for polluted surface -waters and fairly well for purified sewage effluents. Few raw -sewages containing no trade wastes need such a correction, but -raw sewages containing “pickling” liquors do need it. If the sample -contains both oxidizable mineral compounds and gaseous -organic substances the latter should be driven off by heat and the -sample allowed to cool before applying this test for the correction -factor. If such corrections are made the fact should be stated -with the amount of correction.</p> - -<p class='c009'><em>Period and temperature of digestion.</em>—As the practice in regard -to the period and temperature of digestion has varied widely it is -difficult to compare the results obtained at one laboratory with -those obtained at another. None of the methods gives absolute -results. They are all relative<a id='r26' /><a href='#f26' class='c015'><sup>[26]</sup></a><a href='#f29' class='c015'><sup>[29]</sup></a><a id='r57' /><a href='#f57' class='c015'><sup>[57]</sup></a> at best. Digesting 30 minutes -at the boiling temperature is herein designated the recommended -method. If samples are analyzed by any other method the method -should be noted, and, representative results by the standard -method should be placed on record for purposes of comparison.</p> - -<h4 class='c016'>OTHER METHODS.</h4> - -<p class='c011'><em>Additional reagents.</em>—1. Potassium iodide solution. Ten per cent -solution, free from iodate.</p> - -<p class='c009'>2. Standard sodium thiosulfate. Dissolve 1.0 gram of the pure -crystallized salt in 1 liter of distilled water. Standardize this -solution against the standard potassium permanganate. As the -thiosulfate solution does not keep well determine its actual -strength at frequent intervals.</p> - -<p class='c009'>3. Starch indicator. Prepare as directed in the section on -dissolved oxygen (pp. <a href='#Page_65'>65</a>–66).</p> - -<p class='c009'>4. Sodium hydroxide solution. Dissolve 1 part of pure sodium -hydroxide in 2 parts of distilled water.</p> - -<p class='c009'>Certain widely practiced deviations from the standard procedure -just described are noted in the following paragraphs.</p> - -<p class='c009'>1. Heat the acidified sample to boiling, add the permanganate -<span class='pageno' id='Page_28'>28</span>solution, and digest for two minutes<a href='#f16' class='c015'><sup>[16]</sup></a> at boiling temperature. -This procedure is facilitated by agitating the liquid constantly -with a small current of air to guard against bumping.</p> - -<p class='c009'>2. Same method as No. 1 except that the period of digestion is -five minutes.<a id='r121a' /><a href='#f121a' class='c015'><sup>[121a]</sup></a></p> - -<p class='c009'>3. Same method as No. 2 except that the permanganate solution -is added to the acidified sample when cold, and digestion is -continued five minutes after the sample reaches the boiling point. -The advantage of this method is that there is included the oxygen-consuming -power of the volatile matter present in some sewages -and sewage effluents, which is driven off by heat and thus escapes -when the test is made in accordance with procedures 1 and 2.</p> - -<p class='c009'>4. Same method as No. 3 except that the period of digestion is -10 minutes.<a id='r63' /><a href='#f63' class='c015'><sup>[63]</sup></a><a id='r68c' /><a href='#f68c' class='c015'><sup>[68c]</sup></a></p> - -<p class='c009'>5. Digestion of the sample after the acid and permanganate solutions -are added is carried out abroad, especially in England, at approximately -the room temperature,<a id='r24a' /><a href='#f24a' class='c015'><sup>[24a]</sup></a><a id='r69a' /><a href='#f69a' class='c015'><sup>[69a]</sup></a><a href='#f94f' class='c015'><sup>[94f]</sup></a><a id='r100a' /><a href='#f100a' class='c015'><sup>[100a]</sup></a> apparently to guard -against decomposition<a id='r17' /><a href='#f17' class='c015'><sup>[17]</sup></a> of permanganate in the presence of high -chloride, for periods of three minutes, fifteen minutes, and four -hours; many observers record the oxygen consumed after all -three periods, while some record the result only for the four-hour -period. At the end of the period of digestion, add 0.5 cc. -of potassium iodide solution to discharge the pink color; mix; -titrate the liberated iodine with thiosulfate until the yellow -color is nearly destroyed, then add a few drops of starch solution -and continue titration until the blue color is just discharged. -The number of cubic centimeters of potassium permanganate solution -in excess of the number of cubic centimeters of sodium thiosulfate -solution is equal to parts per million of oxygen consumed.</p> - -<p class='c009'>6. Digestion in alkaline solution<a id='r104' /><a href='#f104' class='c015'><sup>[104]</sup></a> is preferable to digestion in -acid solution for brines or waters high in chlorine. Place in a -flask 100 cc. of the sample, or if it is of high organic content a -smaller portion diluted to 100 cc. Add 0.5 cc. of sodium hydroxide -solution and 10 cc. of standard potassium permanganate and -digest exactly 30 minutes. Remove the flask, add 5 cc. of sulfuric -acid and 10 cc. of the standard ammonium oxalate, and titrate with -the standard potassium permanganate as in the acid digestion.</p> - -<div> - <span class='pageno' id='Page_29'>29</span> - <h3 class='c010'>RESIDUE ON EVAPORATION.</h3> -</div> - -<h4 class='c016'>TOTAL RESIDUE.<a href='#f16' class='c015'><sup>[16]</sup></a></h4> - -<p class='c011'>Ignite and weigh a clean platinum dish, and measure into it -100 cc. of the thoroughly shaken sample. Evaporate to dryness -on a water bath. Then heat the dish in an oven at 103° C. or -180° C. for one hour. Cool in a desiccator and weigh. The temperature -of drying should be mentioned in the report. The increase -in weight gives the total solids or residue on evaporation. If 100 cc. -of the sample was taken this weight expressed in milligrams and -multiplied by 10 is equal to parts per million of residue on evaporation. -The residue from waters low in organic matter but relatively -high in iron may be used, as a matter of convenience, for the -determination of iron.</p> - -<h4 class='c016'>FIXED RESIDUE AND LOSS ON IGNITION.<a href='#f13' class='c015'><sup>[13]</sup></a><a id='r96' /><a href='#f96' class='c015'><sup>[96]</sup></a></h4> - -<p class='c011'>The residue from sewages and waters high in organic matter may -be ignited to burn off the organic matter, which, with some volatile -inorganic matter, constitutes the loss on ignition.</p> - -<p class='c009'><em>Procedure.</em>—Ignite the residue in the platinum dish at a low red -heat. If great accuracy is desired this should be done in an electric -muffle furnace or in a radiator, which consists of a platinum or a nickel -dish large enough to allow an air space of about half an inch between -it and the dish within it, the inner dish being supported by a -triangle of platinum wire laid on the bottom of the outer dish. -A disc of platinum or nickel foil large enough to cover the outer -dish is suspended over the inner dish to radiate the heat into it. -The larger dish is heated to bright redness until the residue is white -or nearly so. Allow the dish to cool, and moisten the residue with -a few drops of distilled water. Dry the residue in the oven, cool -in a desiccator, and weigh. The fixed residue on evaporation -is the difference between this weight and the weight of the dish.</p> - -<p class='c009'>The loss on ignition is the difference between the total residue -on evaporation and the fixed residue on evaporation.</p> - -<p class='c009'>If the odor and color on ignition of some residues give helpful -clues to the character of the organic matter record them.</p> - -<div> - <span class='pageno' id='Page_30'>30</span> - <h3 class='c010'>SUSPENDED MATTER.<a id='r56' /><a href='#f56' class='c015'><sup>[56]</sup></a><a href='#f110' class='c015'><sup>[110]</sup></a></h3> -</div> - -<h4 class='c016'>DETERMINATION WITH GOOCH CRUCIBLE.</h4> - -<p class='c011'><em>Reagent.</em>—Prepare a dilute cream of asbestos fibre which has been -finely shredded, thoroughly ignited, treated with strong hydrochloric -acid for at least 12 hours, and washed with distilled water till free -from acid.</p> - -<p class='c009'><em>Procedure.</em>—1. Prepare a mat of the asbestos fibre 1/16 inch thick -in a Gooch crucible. Dry it in an oven at 103 or 180° C., cool and -weigh. Filter 1,000 cc. of samples having a turbidity of 50 parts -per million or less. If the turbidity is higher use sufficient water -to obtain 50 to 100 mg. of suspended matter. Dry for one hour at -103 or 180° C., cool and weigh. Report the temperature at which -the residue was dried. If 1,000 cc. is filtered the increase in weight -expressed in milligrams is equal to parts per million of suspended -matter.</p> - -<h4 class='c016'>DETERMINATION BY FILTRATION.</h4> - -<p class='c011'>The difference between the total solids in filtered and unfiltered -portions of a sample may be used as a basis for calculating suspended -matter.</p> - -<h4 class='c016'>DETERMINATION OF VOLUME.</h4> - -<p class='c011'>The determination of the volume<a id='r9' /><a href='#f9' class='c015'><sup>[9]</sup></a><a id='r69b' /><a href='#f69b' class='c015'><sup>[69b]</sup></a> of suspended matter in -sewages has received considerable attention abroad. Imhoff recommends -the use of conical glass vessels holding 1 liter with the -lower portions graduated in cubic centimeters. Others recommend -centrifuges with sediment tubes.</p> - -<h4 class='c016'>FIXED RESIDUE AND LOSS ON IGNITION.</h4> - -<p class='c011'>Treat the total residue from a filtered sample in the same manner -as described for the total residue, and obtain the loss on ignition -due to dissolved matter, and by difference the loss on ignition due -to suspended matter.</p> - -<h3 class='c010'>HARDNESS.<a id='r94e' /><a href='#f94e' class='c015'><sup>[94e]</sup></a></h3> - -<p class='c011'>A water containing certain mineral constituents in solution, -chiefly calcium and magnesium, which form insoluble compounds -with soap, is said to be hard. Carbon dioxide in water increases -the solubility of calcium and magnesium carbonates, forming -<span class='pageno' id='Page_31'>31</span>bicarbonate. If carbon dioxide is removed from the water by -boiling the bicarbonate is decomposed and calcium and magnesium -are partly precipitated. The proportion of calcium or magnesium -carbonate that a water can hold in solution depends on the concentration -of carbon dioxide, which in turn depends on the temperature -of the water and the proportion of carbon dioxide in the -atmosphere with which the water has been in contact. Consequently, -when the carbon dioxide is removed from the water by -boiling or otherwise the carbonates of calcium and magnesium are -partly, but not completely, precipitated, and the hardness of the -water is thus diminished and the water is softened to the extent to -which these substances are precipitated. The hardness thus removed -is called temporary hardness. The hardness which still remains -after boiling is due mainly to calcium and magnesium in -equilibrium with sulfate, chloride, and nitrate, and residual carbonate, -and it is called permanent hardness. Non-carbonate hardness -is the hardness caused by sulfates, chlorides, and nitrates of -calcium, magnesium, iron, and other metals that form insoluble -soaps.</p> - -<h4 class='c016'>TOTAL HARDNESS BY CALCULATION.</h4> - -<p class='c011'>The most accurate method of ascertaining total hardness is to -compute it from the results of determinations of calcium and -magnesium in the sample. (See methods, pp. <a href='#Page_57'>57</a>–58.) Iron and -other metals must be included in the calculation if they are present -in significant amounts. Total hardness as CaCO<sub>3</sub> equals 2.5 Ca -plus 4.1 Mg.</p> - -<h4 class='c016'>TOTAL HARDNESS BY SOAP METHOD.<a id='r121b' /><a href='#f121b' class='c015'><sup>[121b]</sup></a></h4> - -<p class='c011'>The determination of hardness by the soap method roughly -approximates the amount of calcium and magnesium in a water, -though it actually measures the soap-consuming power of the water.</p> - -<p class='c009'><em>Reagents.</em>—1. Standard calcium chloride solution. Dissolve 0.2 -gram of pure calcite (calcium carbonate) in a little dilute hydrochloric -acid, being careful to avoid loss of solution by spattering. -Evaporate the solution to dryness several times with distilled -water to expel excess of acid. Dissolve the residue in distilled -water and dilute the solution to 1 liter. One cc. of this dilution is -equivalent to 0.2 mg. of calcium carbonate.</p> - -<p class='c009'>2. Standard soap solution. Dissolve 100 grams of dry white -Castile soap in 1 liter of 80 per cent alcohol, and allow this -<span class='pageno' id='Page_32'>32</span>solution to stand several days before standardizing. Pure potassium -oleate made from lead plaster and potassium carbonate may -be used in place of Castile soap.</p> - -<p class='c009'><em>First method of standardization.</em>—Dilute 20 cc. of the calcium -chloride solution in a 250 cc. glass-stoppered bottle to 50 cc. with -distilled water which has been recently boiled and cooled. Add -soap solution from a burette, 0.2 or 0.3 cc. at a time, shaking the -bottle vigorously after each addition until a lather remains unbroken -for five minutes over the entire surface of the water while the -bottle lies on its side. Then adjust the strength of the stock solution -with 70 per cent alcohol so that the resulting diluted soap solution -will give a permanent lather when 6.40 cc. of it is properly added to -20 cc. of standard calcium chloride solution diluted to 50 cc. Usually -75 to 100 cc. of the stock soap solution is required to make 1 liter -of the standard soap solution. The quantity of calcium carbonate -equivalent to each cubic centimeter of the standard soap solution -consumed in the titration is indicated in Table 6.</p> - -<table class='table2' summary=''> - <tr><th class='c012' colspan='11'>Table 6.—<span class='sc'>Total hardness in parts per million of CaCO<sub>3</sub> for each tenth of a cubic centimeter of soap solution when 50 cc. of the sample is titrated</span>.</th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017'>Cubic centimeters of soap solution.</th> - <th class='btt bbt brt c018'>0.0.</th> - <th class='btt bbt brt c018'>0.1.</th> - <th class='btt bbt brt c018'>0.2.</th> - <th class='btt bbt brt c018'>0.3.</th> - <th class='btt bbt brt c018'>0.4.</th> - <th class='btt bbt brt c018'>0.5.</th> - <th class='btt bbt brt c018'>0.6.</th> - <th class='btt bbt brt c018'>0.7.</th> - <th class='btt bbt brt c018'>0.8.</th> - <th class='btt bbt c018'>0.9.</th> - </tr> - <tr> - <td class='brt c018'>0.0</td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'>0.0</td> - <td class='brt c018'>1.6</td> - <td class='c018'>3.2</td> - </tr> - <tr> - <td class='brt c018'>1.0</td> - <td class='brt c018'>4.8</td> - <td class='brt c018'>6.3</td> - <td class='brt c018'>7.9</td> - <td class='brt c018'>9.5</td> - <td class='brt c018'>11.1</td> - <td class='brt c018'>12.7</td> - <td class='brt c018'>14.3</td> - <td class='brt c018'>15.6</td> - <td class='brt c018'>16.9</td> - <td class='c018'>18.2</td> - </tr> - <tr> - <td class='brt c018'>2.0</td> - <td class='brt c018'>19.5</td> - <td class='brt c018'>20.8</td> - <td class='brt c018'>22.1</td> - <td class='brt c018'>23.4</td> - <td class='brt c018'>24.7</td> - <td class='brt c018'>26.0</td> - <td class='brt c018'>27.3</td> - <td class='brt c018'>28.6</td> - <td class='brt c018'>29.9</td> - <td class='c018'>31.2</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>3.0</td> - <td class='brt c018'>32.5</td> - <td class='brt c018'>33.8</td> - <td class='brt c018'>35.1</td> - <td class='brt c018'>36.4</td> - <td class='brt c018'>37.7</td> - <td class='brt c018'>38.0</td> - <td class='brt c018'>40.3</td> - <td class='brt c018'>41.6</td> - <td class='brt c018'>42.9</td> - <td class='c018'>44.3</td> - </tr> - <tr> - <td class='brt c018'>4.0</td> - <td class='brt c018'>45.7</td> - <td class='brt c018'>47.1</td> - <td class='brt c018'>48.6</td> - <td class='brt c018'>50.0</td> - <td class='brt c018'>51.4</td> - <td class='brt c018'>52.9</td> - <td class='brt c018'>54.3</td> - <td class='brt c018'>55.7</td> - <td class='brt c018'>57.1</td> - <td class='c018'>58.6</td> - </tr> - <tr> - <td class='brt c018'>5.0</td> - <td class='brt c018'>60.0</td> - <td class='brt c018'>61.4</td> - <td class='brt c018'>62.9</td> - <td class='brt c018'>64.3</td> - <td class='brt c018'>65.7</td> - <td class='brt c018'>67.1</td> - <td class='brt c018'>68.6</td> - <td class='brt c018'>70.0</td> - <td class='brt c018'>71.4</td> - <td class='c018'>72.9</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>6.0</td> - <td class='brt c018'>74.3</td> - <td class='brt c018'>75.7</td> - <td class='brt c018'>77.1</td> - <td class='brt c018'>78.6</td> - <td class='brt c018'>80.0</td> - <td class='brt c018'>81.4</td> - <td class='brt c018'>82.9</td> - <td class='brt c018'>84.3</td> - <td class='brt c018'>85.7</td> - <td class='c018'>87.1</td> - </tr> - <tr> - <td class='bbt brt c018'>7.0</td> - <td class='bbt brt c018'>88.6</td> - <td class='bbt brt c018'>90.0</td> - <td class='bbt brt c018'>91.4</td> - <td class='bbt brt c018'>92.9</td> - <td class='bbt brt c018'>94.3</td> - <td class='bbt brt c018'>95.7</td> - <td class='bbt brt c018'>97.1</td> - <td class='bbt brt c018'>98.6</td> - <td class='bbt brt c018'>100.0</td> - <td class='bbt c018'>101.5</td> - </tr> -</table> - -<p class='c009'>This table does not provide for the use of so large volume of -soap solution for a single determination as former ones because the -end-point becomes somewhat obscured in the presence of magnesium -if more than 7 cc. is used.</p> - -<p class='c009'><em>Second method of standardization.</em>—Dilute 100 cc. of the stock -soap solution to 1 liter with 70 per cent alcohol. This dilute solution -should be of such strength that approximately 6.4 cc. of it will -give a permanent lather when 20 cc. of standard calcium chloride -<span class='pageno' id='Page_33'>33</span>solution diluted to 50 cc. with distilled water is titrated with it. -Determine the amount of soap solution required to give a permanent -lather with 50 cc. of distilled water and with 5, 10, 15, and 20 cc. -of standard calcium chloride solution diluted to 50 cc. with distilled -water. Finally plot on cross-section paper a curve showing the -relation of various quantities of soap solution to corresponding -quantities of standard calcium carbonate solution and therefore to -parts per million of hardness.</p> - -<p class='c009'><em>Procedure.</em>—Measure 50 cc. of the water into a 250 cc. bottle -and add to it soap solution in small quantities in precisely the same -manner as described under the standardization of the soap solution. -From the number of cubic centimeters of soap solution used obtain -from Table 6 or from the plotted curve the total hardness of the -water in parts per million of calcium carbonate.</p> - -<p class='c009'>To avoid mistaking the false or magnesium end-point for the true -one<a id='r35' /><a href='#f35' class='c015'><sup>[35]</sup></a> when adding the soap solution to waters containing magnesium -salts, read the burette after the titration is apparently finished, and -add about 0.5 cc. more of soap solution. If the end-point was due -to magnesium the lather will disappear. Soap solution must then -be added until the true end-point is reached. Usually the false -lather persists for less than five minutes.</p> - -<p class='c009'>If more than 7 cc. of soap solution is required for 50 cc. of the -water take less of the sample and dilute it to 50 cc. with distilled -water which has been recently boiled and cooled. This step reduces -somewhat the disturbing influence of magnesium,<a id='r107a' /><a href='#f107a' class='c015'><sup>[107a]</sup></a> which consumes -more soap than an equivalent weight of calcium.</p> - -<p class='c009'>At best the soap method is not a precise test on account of the -different relative amounts of calcium and magnesium in different -waters. For hard waters, especially in connection with processes -for purification and softening, it is advised that this method be not -exclusively used. If the same water is frequently analyzed it may -be of assistance to standardize the soap solution against a mixture -of calcium and magnesium salts, the relative proportions of which -approximate those found in the water.</p> - -<p class='c009'>The strength of the soap solution should be determined from -time to time, to make sure that it has not materially changed. -Record all results in parts per million of calcium carbonate.</p> - -<p class='c009'>One English degree of hardness, Clark’s scale, is equivalent to 1 -grain per Imperial gallon of calcium carbonate. One French degree -of hardness is equivalent to 1 part per 100,000 of calcium carbonate. -<span class='pageno' id='Page_34'>34</span>One German degree of hardness is equivalent to 1 part per 100,000 -of calcium oxide, and multiplied by 17.9 gives parts per million of -calcium carbonate. The relations of these various scales are -indicated in Table 7.</p> - -<table class='table2' summary=''> - <tr><th class='c012' colspan='5'>Table 7.—<span class='sc'>Conversion table for hardness.</span></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017' rowspan='2'>Unit.</th> - <th class='btt bbt c017' colspan='4'>Equivalent.</th> - </tr> - <tr> - - <th class='bbt brt c017'>Parts per million.</th> - <th class='bbt brt c017'>Clark degrees.</th> - <th class='bbt brt c017'>French degrees.</th> - <th class='bbt c017'>German degrees.</th> - </tr> - <tr> - <td class='brt c026'>One part per million</td> - <td class='brt c018'>1.00</td> - <td class='brt c018'>0.07</td> - <td class='brt c018'>0.10</td> - <td class='c018'>0.056</td> - </tr> - <tr> - <td class='brt c026'>One Clark degree</td> - <td class='brt c018'>14.3</td> - <td class='brt c018'>1.00</td> - <td class='brt c018'>1.43</td> - <td class='c018'>.80</td> - </tr> - <tr> - <td class='brt c026'>One French degree</td> - <td class='brt c018'>10.0</td> - <td class='brt c018'>.70</td> - <td class='brt c018'>1.00</td> - <td class='c018'>.56</td> - </tr> - <tr> - <td class='bbt brt c026'>One German degree</td> - <td class='bbt brt c018'>17.9</td> - <td class='bbt brt c018'>1.24</td> - <td class='bbt brt c018'>1.78</td> - <td class='bbt c018'>1.00</td> - </tr> -</table> - -<h4 class='c016'>TOTAL HARDNESS BY SODA REAGENT METHOD.<a id='r47' /><a href='#f47' class='c015'><sup>[47]</sup></a><a id='r74' /><a href='#f74' class='c015'><sup>[74]</sup></a><a id='r81' /><a href='#f81' class='c015'><sup>[81]</sup></a><a id='r94d' /><a href='#f94d' class='c015'><sup>[94d]</sup></a></h4> - -<p class='c011'>Add standard sulfuric acid to 200 cc. of the sample until the -alkalinity is neutralized. (See Procedure with methyl orange, p. <a href='#Page_37'>37</a>.) -Then apply the non-carbonate hardness method (pp. <a href='#Page_34'>34</a>–35). This -method gives fairly satisfactory estimates of total hardness of hard -waters.</p> - -<h4 class='c016'>TEMPORARY HARDNESS BY TITRATION WITH ACID.</h4> - -<p class='c011'>Determine the alkalinity in presence of methyl orange (see p. <a href='#Page_37'>37</a>) -in the original sample and also in the sample after boiling, cooling, -restoring to the original volume with boiled distilled water, and -filtering. The difference between the two, if any, is the temporary -hardness. This is the most accurate method of determining -the temporary hardness of ordinary waters. Iron bicarbonate is -included as a part of the temporary hardness.</p> - -<h4 class='c016'>NON-CARBONATE HARDNESS BY SODA REAGENT METHOD.<a href='#f47' class='c015'><sup>[47]</sup></a><a href='#f74' class='c015'><sup>[74]</sup></a><a href='#f81' class='c015'><sup>[81]</sup></a><a href='#f94d' class='c015'><sup>[94d]</sup></a></h4> - -<p class='c011'>The use of soda reagent does not avoid entirely the error due to -solubility of the salts of calcium and magnesium; consequently, if -much depends on the results, as in water softening, gravimetric -determinations of the calcium and magnesium that remain in solution -should be made and a correction should be applied for those -amounts.</p> - -<p class='c009'><em>Reagent.</em>—Prepare soda reagent from equal parts of sodium -<span class='pageno' id='Page_35'>35</span>hydroxide and sodium carbonate. It should be approximately tenth -normal.</p> - -<p class='c009'><em>Procedure.</em>—Measure 200 cc. of the sample and 200 cc. of distilled -water into 500 cc. Jena or similar glass Erlenmeyer flasks. Treat -the contents of each flask in the following manner. Boil 15 minutes -to expel free carbon dioxide. Add 25 cc. of soda reagent. Boil 10 -minutes, cool, rinse into 200 cc. graduated flasks, and dilute to 200 -cc. with boiled distilled water. Filter, rejecting the first 50 cc., and -titrate 50 cc. of each filtrate with N/50 sulfuric acid in the presence -of methyl orange or erythrosine indicator. The non-carbonate -hardness in parts per million of calcium carbonate is equal to 20 -times the difference between the number of cubic centimeters of -sulfuric acid required for the soda reagent in distilled water and the -number of cubic centimeters of N/50 sulfuric acid required for the -soda reagent in the sample.</p> - -<p class='c009'>Water naturally containing bicarbonate and carbonate in excess -of calcium and magnesium requires a larger amount of acid to neutralize -the sample after it has been treated than is required to neutralize -the volume of soda reagent originally added. (See p. <a href='#Page_39'>39</a>.)</p> - -<h4 class='c016'>NON-CARBONATE HARDNESS BY SOAP METHOD.</h4> - -<p class='c011'>Non-carbonate hardness may be calculated for waters which are -soft or moderately hard in a fairly satisfactory manner by deducting -the total alkalinity from the total hardness by the soap method -(pp. <a href='#Page_31'>31</a>–34). For waters that are very hard, and particularly those -that contain much magnesium, this method is not advised.</p> - -<h3 class='c010'>ALKALINITY.<a id='r11' /><a href='#f11' class='c015'><sup>[11]</sup></a><a id='r18' /><a href='#f18' class='c015'><sup>[18]</sup></a><a href='#f47' class='c015'><sup>[47]</sup></a><a id='r97' /><a href='#f97' class='c015'><sup>[97]</sup></a></h3> - -<p class='c011'>The alkalinity of a natural water represents its content of carbonate, -bicarbonate, borate, silicate, phosphate, and hydroxide. -Alkalinity is determined by neutralization with standard sulfuric -acid or potassium bisulfate in the presence of phenolphthalein and -either methyl orange, erythrosine, or lacmoid as indicators. Methyl -orange may be used except in waters containing aluminium sulfate -or iron sulfate. The relations between estimates in presence of -these indicators and the carbonate, bicarbonate, and hydroxide -radicles are indicated in Table 8. The alkalinity of carbonates in -the presence of phenolphthalein is different from that in the presence -of methyl orange, partly because of loss of carbon dioxide -<span class='pageno' id='Page_36'>36</span>and partly because of defects in phenolphthalein as an indicator -in such conditions.</p> - -<table class='table2' summary=''> - <tr><th class='c012' colspan='4'>Table 8.—<span class='sc'>Relations between alkalinity to phenolphthalein and that to methyl orange, erythrosine, or lacmoid, in presence of bicarbonate, carbonate, and hydroxide.</span></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017' rowspan='2'>Result of titration.<a id='rC' /><a href='#fC' class='c015'><sup>[C]</sup></a></th> - <th class='btt bbt c017' colspan='3'>Value of radicle expressed in terms of calcium carbonate.</th> - </tr> - <tr> - - <th class='bbt c017'>Bicarbonate.</th> - <th class='bbt blt c017'>Carbonate.</th> - <th class='bbt blt c017'>Hydroxide.</th> - </tr> - <tr> - <td class='brt c027'>P = 0</td> - <td class='c017'>T</td> - <td class='blt c017'>0</td> - <td class='blt c017'>0</td> - </tr> - <tr> - <td class='brt c027'>P &lt; 1/2T</td> - <td class='c017'>T − 2P</td> - <td class='blt c017'>2P</td> - <td class='blt c017'>0</td> - </tr> - <tr> - <td class='brt c027'>P = 1/2T</td> - <td class='c017'>0</td> - <td class='blt c017'>2P</td> - <td class='blt c017'>0</td> - </tr> - <tr> - <td class='brt c027'>P > 1/2T</td> - <td class='c017'>0</td> - <td class='blt c017'>2(T − P)</td> - <td class='blt c017'>2P − T</td> - </tr> - <tr> - <td class='bbt brt c027'>P = T</td> - <td class='bbt c017'>0</td> - <td class='bbt blt c017'>0</td> - <td class='bbt blt c017'>T</td> - </tr> -</table> - -<div class='footnote' id='fC'> -<p class='c009'><a href='#rC'>C</a>. T = Total alkalinity in presence of methyl orange, erythrosine, or lacmoid. -P = Alkalinity in presence of phenolphthalein.</p> -</div> - -<p class='c009'><em>Reagents.</em>—1. Sulfuric acid or potassium bisulfate. A N/50 solution.</p> - -<p class='c009'>2. Phenolphthalein indicator. Dissolve 5 grams of a good quality -of phenolphthalein in 1 liter of 50 per cent alcohol. Neutralize -with N/10 potassium hydroxide. The alcohol should be diluted -with boiled distilled water.</p> - -<p class='c009'>3. Methyl orange indicator. Dissolve 0.5 gram of a good grade of -methyl orange in 1 liter of distilled water. Keep the solution in the -dark.</p> - -<p class='c009'>4. Lacmoid indicator. Dissolve 2.0 grams of lacmoid in 1 liter of -50 per cent alcohol. Dilute the alcohol with freshly boiled distilled -water.</p> - -<p class='c009'>5. Erythrosine indicator. Dissolve 0.5 gram of erythrosine (the -sodium salt) in 1 liter of freshly boiled distilled water.</p> - -<h4 class='c016'>PROCEDURE WITH PHENOLPHTHALEIN.</h4> - -<p class='c011'>Add 4 drops of phenolphthalein indicator to 50 or 100 cc. of the -sample in a white porcelain casserole or an Erlenmeyer flask over a -white surface. If the solution becomes colored, hydroxide or normal -carbonate is present. Add N/50 sulfuric acid from a burette until -the coloration disappears.</p> - -<p class='c009'>The phenolphthalein alkalinity in parts per million of calcium -carbonate is equal to the number of cubic centimeters of N/50 -<span class='pageno' id='Page_37'>37</span>sulfuric acid used multiplied by 20 if 50 cc. of the sample was used, -or by 10 if 100 cc. was used.</p> - -<h4 class='c016'>PROCEDURE WITH METHYL ORANGE.</h4> - -<p class='c011'>Add 2 drops of methyl orange indicator to 50 or 100 cc. of the -sample, or to the solution to which phenolphthalein has been added, -in a white porcelain casserole or an Erlenmeyer flask over a white -surface. If the solution becomes yellow, hydroxide, normal carbonate, -or bicarbonate is present. Add N/50 sulfuric acid from a -burette until the faintest pink coloration appears. The methyl -orange alkalinity in parts per million of calcium carbonate is equal -to the total number of cubic centimeters of N/50 sulfuric acid used -multiplied by 20 if 50 cc. of the sample was used, or by 10 if 100 cc. -was used.</p> - -<h4 class='c016'>PROCEDURE WITH LACMOID.</h4> - -<p class='c011'>Add 4 drops of lacmoid indicator to 50 or 100 cc. of the sample in -a porcelain casserole or an Erlenmeyer flask. Add N/50 sulfuric -acid from a burette until within 1 or 2 cc. of the amount necessary -for neutralization has been added. Heat the solution until bubbles -of steam begin to break at the surface. Remove the dish from the -source of heat and continue the titration until a drop of the acid -striking the surface of the liquid and sinking to the bottom of the -vessel produces no change in the uniform reddish or purple color -of the solution. The calculation is the same as for phenolphthalein -alkalinity.</p> - -<h4 class='c016'>PROCEDURE WITH ERYTHROSINE.</h4> - -<p class='c011'>Add 5 cc. of neutral chloroform and 1 cc. of erythrosine indicator -to 50 or 100 cc. of the sample in a 250 cc. clear glass-stoppered bottle. -If the chloroform becomes rose colored on shaking, hydroxide, bicarbonate, -or normal carbonate is present. Add N/50 sulfuric acid -from a burette until the chloroform becomes colorless. A white -surface behind the bottle facilitates detection of a trace of color as -the end-point is approached. The calculation is the same as with -phenolphthalein alkalinity.</p> - -<h4 class='c016'>BICARBONATE.</h4> - -<p class='c011'>Bicarbonate is present if the alkalinity to phenolphthalein is less -than one-half the alkalinity to methyl orange, erythrosine, or lacmoid. -<span class='pageno' id='Page_38'>38</span>The alkalinity to methyl orange, erythrosine, or lacmoid is -due entirely to bicarbonate if there is no phenolphthalein alkalinity. -If there is phenolphthalein alkalinity the bicarbonate, in terms of -calcium carbonate, is equal to the methyl orange, erythrosine, or -lacmoid alkalinity minus twice the phenolphthalein alkalinity. -Bicarbonate, carbon dioxide as bicarbonate, and half-bound carbon -dioxide can be calculated as follows:</p> - -<p class='c009'>Bicarbonate (HCO<sub>3</sub>) = 1.22 times the bicarbonate expressed in -terms of calcium carbonate.</p> - -<p class='c009'>Carbon dioxide (CO<sub>2</sub>) as bicarbonate = 0.88 times the bicarbonate -expressed in terms of calcium carbonate.</p> - -<p class='c009'>Half-bound carbon dioxide (CO<sub>2</sub>) = 0.44 times the bicarbonate -expressed in terms of calcium carbonate.</p> - -<h4 class='c016'>NORMAL CARBONATE.<a id='r20' /><a href='#f20' class='c015'><sup>[20]</sup></a><a id='r94' /><a href='#f94' class='c015'><sup>[94]</sup></a></h4> - -<p class='c011'>Normal carbonate is present if the alkalinity to phenolphthalein -is greater than zero but less than the alkalinity to methyl orange, -erythrosine, or lacmoid. If the phenolphthalein alkalinity is exactly -equal to one-half the methyl orange, erythrosine, or lacmoid alkalinity -the alkalinity is due entirely to normal carbonate. If the -phenolphthalein alkalinity is less than one-half the methyl orange, -erythrosine, or lacmoid alkalinity normal carbonate expressed in -terms of calcium carbonate is equal to twice the phenolphthalein -alkalinity. If the phenolphthalein alkalinity is greater than one-half -the methyl orange, erythrosine, or lacmoid alkalinity the -normal carbonate is equal to twice the difference between the -methyl orange, erythrosine, or lacmoid alkalinity and the phenolphthalein -alkalinity. The carbonate, carbon dioxide as carbonate, -and bound carbon dioxide can be calculated as follows:</p> - -<p class='c009'>Carbonate (CO<sub>3</sub>) = 0.6 times the normal carbonate expressed in -terms of calcium carbonate.</p> - -<p class='c009'>Carbon dioxide as carbonate (CO<sub>2</sub>) = 0.44 times the normal -carbonate expressed in terms of calcium carbonate.</p> - -<p class='c009'>Bound carbon dioxide (CO<sub>2</sub>) is the sum of the carbon dioxide as -carbonate and one-half that as bicarbonate.</p> - -<h4 class='c016'>HYDROXIDE.<a href='#f20' class='c015'><sup>[20]</sup></a><a href='#f94' class='c015'><sup>[94]</sup></a></h4> - -<p class='c011'>If hydroxide, or caustic alkalinity, is present the alkalinity to -phenolphthalein is greater than one-half the alkalinity to methyl -<span class='pageno' id='Page_39'>39</span>orange, erythrosine, or lacmoid; the alkalinity is due entirely to -hydroxide if the phenolphthalein alkalinity is equal to the methyl -orange, erythrosine, or lacmoid alkalinity. If the phenolphthalein -alkalinity is more than half and less than all the methyl orange, -erythrosine, or lacmoid alkalinity, hydroxide, expressed in terms of -calcium carbonate, is equal to twice the phenolphthalein alkalinity -minus the methyl orange, erythrosine, or lacmoid alkalinity.</p> - -<h4 class='c016'>ALKALI CARBONATES.</h4> - -<p class='c011'>Waters which contain sodium or potassium carbonates or bicarbonates -contain all of their calcium and magnesium as carbonates -or bicarbonates. That is, they possess no non-carbonate hardness -(sulfates, nitrates or chlorides of calcium and magnesium).</p> - -<p class='c009'>The most accurate method is to determine the total alkalinity by -titration with N/50 sulfuric acid, using methyl orange, erythrosine, -or lacmoid as an indicator; then determine the calcium and magnesium -content; and subtract from the total alkalinity the computed -alkalinity due to the calcium and magnesium expressed in terms of -calcium carbonate. The remainder is the alkalinity due to carbonates -and bicarbonates of sodium and potassium.</p> - -<p class='c009'>This determination may also be made by applying the method, -for non-carbonate hardness with soda reagent (see p. <a href='#Page_35'>35</a>), and -by noting the excess of acid required to neutralize the alkaline carbonates -originally present.</p> - -<p class='c009'>With present information as to solubilities of the normal carbonates -of calcium and magnesium, it is difficult in their presence -to measure slight quantities of carbonates of sodium or potassium.</p> - -<h3 class='c010'>ACIDITY.<a id='r24d' /><a href='#f24d' class='c015'><sup>[24d]</sup></a><a id='r37' /><a href='#f37' class='c015'><sup>[37]</sup></a></h3> - -<p class='c011'>Waters may have an acid reaction because of the presence of free -carbon dioxide, mineral acids, or some of their salts, especially those -of iron and aluminium.</p> - -<p class='c009'><em>Reagents.</em>—1. N/50 sodium carbonate. Dissolve 1.06 grams of -anhydrous sodium carbonate in 1 liter of boiled distilled water that -has been cooled in an atmosphere free from carbon dioxide. -Preserve this solution in bottles of resistant glass protected from -the air by tubes filled with soda-lime. One cc. is equivalent to 1 mg. -of CaCO<sub>3</sub>.</p> - -<p class='c009'><span class='pageno' id='Page_40'>40</span>2. N/22 sodium carbonate. Dissolve 2.41 grams of anhydrous -sodium carbonate in 1 liter of boiled distilled water that has been -cooled in an atmosphere free from carbon dioxide. Preserve this -solution in bottles of resistant glass protected from the air by tubes -filled with soda-lime. One cc. is equivalent to 1 mg. of CO<sub>2</sub>.</p> - -<p class='c009'>3. Phenolphthalein indicator (see p. <a href='#Page_36'>36</a>).</p> - -<p class='c009'>4. Methyl orange indicator (see p. <a href='#Page_36'>36</a>).</p> - -<h4 class='c016'>TOTAL ACIDITY.</h4> - -<p class='c011'><em>Procedure.</em>—Add 4 drops of phenolphthalein indicator to 50 or -100 cc. of the sample in a white porcelain casserole or an Erlenmeyer -flask over a white surface. Add N/50 sodium carbonate -until the solution turns pink. The total acidity in parts per million -of calcium carbonate is equal to the number of cubic centimeters of -N/50 sodium carbonate used multiplied by 20 if 50 cc. of the -sample was used, or by 10 if 100 cc. was used.</p> - -<h4 class='c016'>FREE CARBON DIOXIDE.<a href='#f20' class='c015'><sup>[20]</sup></a><a id='r23' /><a href='#f23' class='c015'><sup>[23]</sup></a><a id='r61' /><a href='#f61' class='c015'><sup>[61]</sup></a><a id='r87' /><a href='#f87' class='c015'><sup>[87]</sup></a><a id='r88' /><a href='#f88' class='c015'><sup>[88]</sup></a><a id='r94a' /><a href='#f94a' class='c015'><sup>[94a]</sup></a><a id='r118' /><a href='#f118' class='c015'><sup>[118]</sup></a><a id='r89'></a><a id='r89a'></a></h4> - -<p class='c011'>Carbon dioxide may exist in water in three forms—free carbon -dioxide, bicarbonate (pp. <a href='#Page_37'>37</a>–38), and carbonate (p. <a href='#Page_38'>38</a>). One-half the -carbon dioxide as bicarbonate is known as the half-bound carbon -dioxide. The carbon dioxide as carbonate plus one-half that as -bicarbonate is known as the bound carbon dioxide.</p> - -<p class='c009'><em>Procedure.</em>—Pour 100 cc. of the sample into a tall narrow vessel, -preferably a 100 cc. Nessler tube. Add 10 drops of phenolphthalein -indicator, and titrate rapidly with N/22 sodium carbonate, stirring -gently, until a faint but permanent pink color is produced. The -free carbon dioxide (CO<sub>2</sub>) in parts per million is equal to 10 times -the number of cubic centimeters of N/22 sodium carbonate used.</p> - -<p class='c009'>Because of the ease with which free carbon dioxide escapes from -water, particularly when the gas is present in large amount, a special -sample should be collected for this determination, which should -preferably be made at the time of collection. If the analysis cannot -be made at the time of collection approximate results with water -not too high in free carbon dioxide may be obtained on samples -collected in bottles completely filled so as to leave no air space -under the stopper. Bottled samples should be kept, until tested, at -a temperature lower than that of the water when collected. If -mineral acids or certain salts are present correction must be made. -<span class='pageno' id='Page_41'>41</span>At best, the results of the titration are uncertain because the -proper end-point for correct results differs in color with different -types of water.</p> - -<h4 class='c016'>FREE MINERAL ACIDS.</h4> - -<p class='c011'><em>Procedure.</em>—Add 2 drops of methyl orange indicator to 50 or 100 -cc. of the sample in a white porcelain casserole or an Erlenmeyer -flask over a white surface. Add N/50 sodium carbonate from a -burette until the pink coloration of the solution disappears. The -acidity due to free mineral acids, expressed in terms of calcium -carbonate, is equal to the number of cubic centimeters of N/50 -sodium carbonate used multiplied by 20 if 50 cc. of the sample -was used, or by 10 if 100 cc. was used.</p> - -<h4 class='c016'>MINERAL ACIDS AND SULFATES OF IRON AND ALUMINIUM.<a href='#f24d' class='c015'><sup>[24d]</sup></a><a href='#f37' class='c015'><sup>[37]</sup></a></h4> - -<p class='c011'><em>Procedure.</em>—Modify the method for free mineral acids by titrating -the water at boiling temperature in the presence of phenolphthalein -indicator. The acidity due to free mineral acids and sulfates of -iron and aluminium, expressed in terms of calcium carbonate, is -equal to the number of cubic centimeters of N/50 sodium carbonate -used multiplied by 20 if 50 cc. of the sample was used, or by 10 if -100 cc. was used.</p> - -<p class='c009'>The acidity due to sulfates of iron and aluminium is equal to the -acidity due to mineral acids and sulfates minus the acidity due to -mineral acids. The acidity due to ferrous and ferric sulfate can -be calculated from the determined amount of these salts (pp. <a href='#Page_43'>43</a>–48). -The acidity due to aluminium sulfate is equal to the acidity due to -total acid sulfates minus that due to iron sulfates.</p> - -<p class='c009'>Acidity shall be reported in parts per million of calcium carbonate -(CaCO<sub>3</sub>). Sulfate (SO<sub>4</sub>) equals parts per million of calcium -carbonate multiplied by 0.96.</p> - -<p class='c009'>Carbon dioxide (CO<sub>2</sub>) equals parts per million of calcium carbonate -multiplied by 0.44.</p> - -<h3 class='c010'>CHLORIDE.<a href='#f16' class='c015'><sup>[16]</sup></a></h3> - -<p class='c011'>Chloride in water and sewage has its origin in common salt, from -mineral deposits in the earth, from ocean vapors carried inland by -the wind, or from polluting materials like sewage and trade wastes, -which contain the salt used in the household and in manufacturing. -<span class='pageno' id='Page_42'>42</span>Comparison of the chloride content of a water with that of other -waters in the vicinity known to be unpolluted frequently affords -useful information as to its sanitary quality. If, however, the -chloride normally exceeds 20 parts per million because of chloride-bearing -mineral deposits the chloride content of a water has little -sanitary significance.</p> - -<p class='c009'><em>Reagents.</em>—1. Standard sodium chloride solution. Dissolve 16.48 -grams of pure fused sodium chloride in 1 liter of distilled water. -Dilute 100 cc. of this stock solution to 1 liter in order to obtain a -standard solution each cubic centimeter of which contains 0.001 -gram of chloride.</p> - -<p class='c009'>2. Standard silver nitrate solution. Dissolve about 2.40 grams -of silver nitrate crystals in 1 liter of distilled water. Standardize -this with the standard salt solution, and adjust, correcting for -volume (see p. <a href='#Page_43'>43</a>), so that 1 cc. will be exactly equivalent to -0.0005 gram of chloride.</p> - -<p class='c009'>3. Potassium chromate indicator. Dissolve 50 grams of neutral -potassium chromate in a little distilled water. Add enough silver -nitrate to produce a slight red precipitate. Filter and dilute the -filtrate to 1 liter with distilled water.</p> - -<p class='c009'>4. Aluminium hydroxide. Electrolyze ammonia-free water, using -aluminium electrodes. Wash the precipitate until it is free from -chloride, ammonia, and nitrite. Or dissolve 125 grams of potassium -or ammonium alum in 1 liter of distilled water. Precipitate the -aluminium by adding cautiously ammonium hydroxide. Wash -the precipitate in a large jar by successive additions and decantations -of distilled water until free from chloride, nitrite, and ammonia.</p> - -<p class='c009'><em>Procedure.</em>—Add 1 cc. of potassium chromate indicator to 50 cc. -of the sample in a 6–inch white porcelain evaporating dish or a -150 cc. Erlenmeyer flask over a white surface. Titrate with the -silver nitrate solution under similar conditions of volume, light, and -temperature as were used in standardizing the silver nitrate until -a faint reddish coloration is perceptible. The detection of the end-point -is facilitated by comparison of the contents of the porcelain -dish with those of another dish containing the same quantity of -potassium chromate indicator in 50 cc. of distilled water. Some -analysts prefer to make the titration in a dark-room provided with -a yellow light. The end-point is very sharp by electric light and -also by daylight with photographic yellow glass. The titration may -<span class='pageno' id='Page_43'>43</span>be made in Nessler tubes<a id='r68a' /><a href='#f68a' class='c015'><sup>[68a]</sup></a> if the solutions are standardized under -similar conditions.</p> - -<p class='c009'>If the amount of chloride is very high use 25 cc., or even a smaller -quantity, dilute the volume taken to 50 cc. with distilled water. -If the amount of chloride is very low concentrate 250 cc. of the -sample to 50 cc. by evaporation. Rotate the liquid to make sure -that no residue remains undissolved on the walls of the dish, and, -if necessary, use a rubber-tipped glass rod to assist in this operation.</p> - -<p class='c009'>Chloride is determined by some observers by extracting with -hot distilled water the residue in the platinum dish in the determination -of the residue on evaporation and proceeding as just -described. This is permissible if a little sodium carbonate is added -before evaporation to prevent loss of chloride through decomposition -of magnesium chloride in the residue.</p> - -<p class='c009'>If the sample has a color greater than 30 it should be decolorized -by shaking it thoroughly with washed aluminium hydroxide (3 cc. -to 500 cc. of the sample) and allowing the precipitate to settle. -Make the determination on a portion of the clarified sample, filtered -if necessary. If the sample is acid, neutralize it with sodium carbonate; -if hydroxide is present, add dilute sulfuric acid until the -cold liquid will just discharge the color of phenolphthalein. If the -presence of sulfide and sulfocyanate renders it necessary, make -proper corrections<a id='r24c' /><a href='#f24c' class='c015'><sup>[24c]</sup></a><a id='r100b' /><a href='#f100b' class='c015'><sup>[100b]</sup></a> or modifications in treatment.</p> - -<p class='c009'>Make correction for the error due to variations in the volume of -the liquid and precipitate by means of the formula<a id='r39' /><a href='#f39' class='c015'><sup>[39]</sup></a> X = 0.003V + 0.02, -in which X = the correction in cubic centimeters of silver -nitrate solution and V = cubic centimeters of liquid at the end of -the titration. If 50 cc. of the sample is titrated chloride (Cl) in -parts per million is equal to the number of cubic centimeters of -silver nitrate solution multiplied by 10. The correction to be applied -is 0.2 cc. unless unusual accuracy is required.</p> - -<h3 class='c010'>IRON.<a id='r94b' /><a href='#f94b' class='c015'><sup>[94b]</sup></a><a id='r98' /><a href='#f98' class='c015'><sup>[98]</sup></a></h3> - -<p class='c011'>Iron occurs in natural waters in both ferrous and ferric condition, -depending on the source of the sample. In ground waters the iron -is usually in an unoxidized and soluble condition, sometimes combined -with carbonic or sulfuric acid, and also in combination with -organic matter. Many waters, especially those that have been -<span class='pageno' id='Page_44'>44</span>exposed to the air, contain the iron in the form of a colloidal hydroxide. -Silt-bearing waters often contain much iron in suspension, -usually in an oxidized form. Sewages and sewage effluents, -particularly those receiving manufacturing wastes, contain various -forms of iron of different degrees of solubility, oxidation, and coagulation.</p> - -<h4 class='c016'>TOTAL IRON.<a id='r59' /><a href='#f59' class='c015'><sup>[59]</sup></a><a id='r63b' /><a href='#f63b' class='c015'><sup>[63b]</sup></a></h4> - -<h5 class='c016'>COLORIMETRIC METHOD.</h5> - -<p class='c011'><em>Reagents.</em>—1. Standard iron solution. Dissolve 0.7 gram of crystallized -ferrous ammonium sulfate in 50 cc. of distilled water to -which 20 cc. of dilute sulfuric acid has been added. Warm the -solution slightly and add potassium permanganate until the iron -is completely oxidized. Dilute the solution to 1 liter. One cc. of -the standard solution equals 0.1 mg. Fe.</p> - -<p class='c009'>2. Potassium sulfocyanide solution. Dissolve 20 grams of the -salt in 1 liter of distilled water.</p> - -<p class='c009'>3. Dilute hydrochloric acid. One volume of acid (Sp. gr. 1.2) and -one volume of distilled water. This shall be free from nitric acid.</p> - -<p class='c009'>4. N/5 potassium permanganate. Dissolve 6.30 grams of the -salt in distilled water and dilute to 1 liter.</p> - -<p class='c009'>5. Hydrochloric acid. Concentrated, free from iron.</p> - -<p class='c009'>6. Nitric acid. Concentrated, free from iron.</p> - -<p class='c009'>7. Nitric acid. 5N, free from iron.</p> - -<p class='c009'><em>First procedure.</em>—Evaporate 100 cc. of the water to dryness, or -use the residue left after the determination of residue on evaporation -(p. <a href='#Page_29'>29</a>). Ignite the residue at a low red heat taking care not -to heat it hot enough to make the iron difficultly soluble. Cool the -dish and add 5 cc. of concentrated hydrochloric acid. Moisten the -inner surface of the dish. Warm the solution for two or three -minutes, and again moisten the inner surface of the dish by permitting -the hot acid to flow over it. Wash the hot solution from -the dish into a 50 cc. Nessler tube, filtering if necessary through -paper that has been washed with hot water. Dilute to 50 cc., and -add 3 drops of potassium permanganate solution. Add 5 cc. of -potassium sulfocyanide solution, mix, and compare with standards.</p> - -<p class='c009'>If it is not convenient to use the residue on evaporation and if -the sample is relatively free from organic matter, boil 50 cc. of the -sample with 5 cc. of 5N nitric acid for five minutes. Add a few -drops of permanganate and 5 cc. of potassium sulfocyanide and -<span class='pageno' id='Page_45'>45</span>compare with standards, using nitric acid in place of hydrochloric -acid in the standards. This method is excellent for ground waters. -The permanganate and acid liberate chlorine in water high in chloride, -and produce a permanent yellow color which interferes with the -determination, unless the sample is first diluted to 50 cc. An excess -of permanganate, reacting with hydrochloric acid, causes similar -trouble. The amounts of hydrochloric acid, 5 cc., and of sulfocyanide, -5 cc., should be approximately measured because more acid -lightens the color whereas more sulfocyanide deepens it. This is -especially important if permanent standards are used.</p> - -<p class='c009'><em>Second procedure.</em>—For surface waters containing small amounts -of organic matter, the method of Klut<a href='#f59' class='c015'><sup>[59]</sup></a> is recommended. Samples -containing small amounts of iron should be concentrated, if possible, -until at least 0.5 mg. of iron is present in the volume tested. Boil -the sample in a beaker with 2 to 3 cc. of concentrated nitric acid -free from iron, adding permanganate if necessary to destroy the -organic matter. To the hot liquid add ammonia in slight excess -and warm until the smell of ammonia is hardly discernible. Filter -and wash with water at 70° to 80° C. containing a little ammonia. -Dissolve the iron in the beaker and on the filter paper in 5 cc. of -concentrated hydrochloric acid, and wash with hot water until the -iron is all dissolved, collecting the filtrate in a 50 cc. Nessler tube. -Dilute to 50 cc. Add potassium sulfocyanide and determine the -iron by comparison with standards.</p> - -<h6 class='c016'><span class='sc'>Comparison with iron standards.</span></h6> - -<p class='c011'><em>First procedure.</em>—Prepare standards containing amounts of standard -iron solution ranging from 0.05 to 4 cc. according to the quantity -of iron in the sample. Dilute these amounts with water to about -40 cc. Add 5 cc. of dilute hydrochloric acid and 3 drops of potassium -permanganate to each tube and dilute to 50 cc. Add 5 cc. of the -potassium sulfocyanide to each of the standard solutions at the -same time that it is added to the samples of water under examination, -and compare immediately after mixing. If 100 cc. of the sample -is used the iron in parts per million is equal to the number of cubic -centimeters of the standard iron solution in the standard that the -sample matches.</p> - -<p class='c009'><em>Second procedure.</em>—For a small number of determinations it is -more convenient to run the standard iron solution into a Nessler -<span class='pageno' id='Page_46'>46</span>tube containing the acid, distilled water, and potassium sulfocyanide -until the color matches that of the sample tested. When -determining iron in three or four samples the colors may be matched -in the order of their intensity and the volumes of standard iron -solution required for each tube may be read from the burette.</p> - -<h6 class='c016'><span class='sc'>Comparison with permanent standards.</span></h6> - -<p class='c011'><em>Reagents.</em>—1. Platinum solution. Dissolve 2 grams of potassium -platinic chloride (PtCl<sub>4</sub>.2KCl) in distilled water, add 100 cc. of -concentrated hydrochloric acid, and dilute to 1 liter with distilled -water.</p> - -<p class='c009'>2. Cobalt solution. Dissolve 24 grams of dry cobaltous chloride -crystals (CoCl<sub>2</sub>.6H<sub>2</sub>O) in a small amount of distilled water, add 100 -cc. of strong hydrochloric acid, and dilute to 1 liter with distilled -water.</p> - -<p class='c009'><em>Procedure.</em>—Prepare a series of permanent standards by diluting -to 50 cc. with distilled water the amounts of platinum and cobalt -solutions, in 50 cc. Nessler tubes, indicated in Table 9. Compare -the sample with these standards, and calculate the parts per million -of iron.</p> - -<table class='table2' summary=''> - <tr><th class='c012' colspan='3'>Table 9.—<span class='sc'>Preparation of permanent standards for the determination of iron.</span></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017'>Value in standard iron solution.</th> - <th class='btt bbt brt c017'>Platinum solution.</th> - <th class='btt bbt c017'>Cobalt solution.</th> - </tr> - <tr> - <th class='brt c017'><i>cc.</i></th> - <th class='brt c017'><i>cc.</i></th> - <th class='c017'><i>cc.</i></th> - </tr> - <tr> - <td class='brt c018'>0.0</td> - <td class='brt c018'>0</td> - <td class='c018'>0.0</td> - </tr> - <tr> - <td class='brt c018'>.1</td> - <td class='brt c018'>2</td> - <td class='c018'>1.0</td> - </tr> - <tr> - <td class='brt c018'>.3</td> - <td class='brt c018'>6</td> - <td class='c018'>3.0</td> - </tr> - <tr> - <td class='brt c018'>.5</td> - <td class='brt c018'>10</td> - <td class='c018'>5.0</td> - </tr> - <tr> - <td class='brt c018'>.7</td> - <td class='brt c018'>14</td> - <td class='c018'>7.5</td> - </tr> - <tr> - <td class='brt c018'>1.0</td> - <td class='brt c018'>20</td> - <td class='c018'>11.0</td> - </tr> - <tr> - <td class='brt c018'>1.5</td> - <td class='brt c018'>28</td> - <td class='c018'>17.0</td> - </tr> - <tr> - <td class='brt c018'>2.0</td> - <td class='brt c018'>35</td> - <td class='c018'>24.0</td> - </tr> - <tr> - <td class='brt c018'>2.5</td> - <td class='brt c018'>39</td> - <td class='c018'>32.0</td> - </tr> - <tr> - <td class='brt c018'>3.0</td> - <td class='brt c018'>39</td> - <td class='c018'>43.0</td> - </tr> - <tr> - <td class='bbt brt c018'>3.5</td> - <td class='bbt brt c018'>40</td> - <td class='bbt c018'>55.0</td> - </tr> -</table> - -<h5 class='c016'>VOLUMETRIC METHOD.<a id='r24f' /><a href='#f24f' class='c015'><sup>[24f]</sup></a></h5> - -<p class='c011'>Some samples of sewage and water mixed with trade wastes and -mine drainage contain so much iron that it is preferable to use the -volumetric method described on page <a href='#Page_57'>57</a> for the determination of -<span class='pageno' id='Page_47'>47</span>both total and dissolved iron, rather than to work with quantities -small enough to permit application of the colorimetric methods just -described. If iron is present in large quantities in suspension, as in -some sewages and septic tank effluents, it may be filtered off and -the residue washed, ignited, and fused with potassium and sodium -carbonate. The fusion is then extracted with hydrochloric acid -and the iron determined as on page <a href='#Page_57'>57</a>.</p> - -<p class='c009'>Samples containing much organic matter should be evaporated -to dryness with 0.5 cc. of concentrated sulfuric acid and the residue -then ignited before estimation of iron.</p> - -<h4 class='c016'>DISSOLVED IRON.</h4> - -<p class='c011'>Determine, by the method described for total iron, the iron in -the sample after filtration. Iron may precipitate from some samples -during filtration.</p> - -<h4 class='c016'>SUSPENDED IRON.</h4> - -<p class='c011'>The suspended iron is the difference between total iron in the -unfiltered sample and dissolved iron in the filtered sample.</p> - -<h4 class='c016'>FERROUS IRON.<a id='r24e' /><a href='#f24e' class='c015'><sup>[24e]</sup></a></h4> - -<p class='c011'>Determine the total ferrous iron in an unfiltered sample and the -dissolved ferrous iron in a filtered sample.</p> - -<p class='c009'><em>Reagents.</em>—1. Standard iron solution. Dissolve 0.7 gram of -crystallized ferrous ammonium sulfate in a large volume of freshly -boiled distilled water to which 10 cc. of dilute sulfuric acid has -been added and dilute to 1 liter. This solution should be freshly -prepared when needed. One cc. of this standard solution contains -0.1 mg. of Fe.</p> - -<p class='c009'>2. Potassium ferricyanide solution. Dissolve 5 grams of the salt -in 1 liter of distilled water. Use a freshly prepared solution.</p> - -<p class='c009'>3. Dilute sulfuric acid. Dilute 1 part of sulfuric acid, specific -gravity 1.84, with 5 parts of distilled water.</p> - -<p class='c009'><em>Procedure.</em>—Add 10 cc. of dilute sulfuric acid to 50 cc. of the -sample, remove the suspended matter by filtration if necessary, -and add 15 cc. of potassium ferricyanide solution. Dilute the solution -to 100 cc. with distilled water. Compare the color developed -in the sample with that in standards made at the same time from -the ferrous iron solution. Place in 100 cc. Nessler tubes, in the -following order, 75 cc. of distilled water, 10 cc. of dilute sulfuric -<span class='pageno' id='Page_48'>48</span>acid, and 15 cc. of potassium ferricyanide solution, and mix well -the contents of each tube. Prepare as many tubes in this way as -are needed. Add various quantities of standard ferrous iron solution -to several tubes, mix well, and compare the resulting colors -with the samples <em>immediately</em>.</p> - -<h4 class='c016'>FERRIC IRON.</h4> - -<p class='c011'>The amount of ferric iron in solution and suspension is equal to -the difference between the total iron and the ferrous iron obtained -by the methods described.</p> - -<h3 class='c010'>MANGANESE.</h3> - -<p class='c011'>If the sample contains less than 10 parts per million of manganese, -use a colorimetric method in which the manganous salt is oxidized -to permanganate and the color produced thereby is compared with -that of a standard solution similarly treated. The persulfate -method and the bismuthate method are suitable. If the sample -contains more than 10 parts per million of manganese it is sometimes -preferable to use a volumetric or gravimetric method.</p> - -<h4 class='c016'>PERSULFATE METHOD.</h4> - -<p class='c011'><em>Reagents.</em>—1. Nitric acid. Dilute concentrated nitric acid with -an equal volume of distilled water. Free the diluted acid from -brown oxides of nitrogen by aeration.</p> - -<p class='c009'>2. Silver nitrate. Dissolve 20 grams of silver nitrate in 1 liter -of distilled water.</p> - -<p class='c009'>3. Standard manganous sulfate. Dissolve 0.288 gram of purest -potassium permanganate in about 100 cc. of distilled water. Acidify -the solution with sulfuric acid and heat to boiling. Add slowly a -sufficient quantity of dilute solution of oxalic acid to discharge the -color. Cool and dilute to 1 liter. One cc. of this solution contains -0.1 mg. of manganese.</p> - -<p class='c009'>4. Ammonium persulfate. Crystals, free from chloride.</p> - -<p class='c009'><em>Procedure.</em>—Use an amount of the sample that contains not -more than 0.2 mg. of manganese. Add 2 cc. of nitric acid and -boil down to about 50 cc. Precipitate the chloride with silver -nitrate solution, adding at least 1 cc. in excess. Shake and heat to -coagulate the precipitate, and filter. A sample that contains much -chloride should be evaporated with a few drops of sulfuric acid until -<span class='pageno' id='Page_49'>49</span>white fumes appear and then diluted before the nitric acid and -silver nitrate are added as directed above. If the sample is highly -colored by organic matter it should be evaporated with sulfuric -acid, and the residue ignited and dissolved in dilute nitric acid. -Add about 0.5 gram of ammonium persulfate crystals and warm -the solution until the maximum permanganate color is developed. -This usually takes about ten minutes. At the same time prepare -standards by diluting portions of 0.2, 0.4, 0.6 cc., etc. of the standard -manganous sulfate solution to about 50 cc. and treating them exactly -as the sample was treated. Transfer the sample and the standards -to 50 cc. Nessler tubes, and compare the colors immediately. -Manganese in parts per million is equal to the number of cubic -centimeters of standard manganous sulfate solution in the tube -that the sample matches multiplied by 100, divided by the number -of cubic centimeters of the sample used.</p> - -<h4 class='c016'>BISMUTHATE METHOD.<a id='r2a' /><a href='#f2a' class='c015'><sup>[2a]</sup></a><a id='r113' /><a href='#f113' class='c015'><sup>[113]</sup></a></h4> - -<p class='c011'><em>Reagents.</em>—1. Nitric acid. Dilute 1 part of concentrated nitric -acid with 4 parts of distilled water. Free the dilute acid from brown -oxides of nitrogen by aeration.</p> - -<p class='c009'>2. Sulfuric acid. Dilute 1 part of concentrated sulfuric acid with -3 parts of distilled water.</p> - -<p class='c009'>3. Dilute sulfuric acid. Dilute 25 cc. of concentrated acid to 1 -liter with distilled water. Add enough permanganate solution to -color faintly the dilute acid.</p> - -<p class='c009'>4. Standard manganous sulfate. The standard solution of -manganous sulfate prepared as described under persulfate -method (p. <a href='#Page_48'>48</a>) should be used and the standards should be prepared -by following the same procedure as is used for the sample. -This solution is more permanent than a solution of potassium -permanganate, which may, however, be used. To prepare it dissolve -0.288 gram of potassium permanganate in distilled water and -dilute the solution to 1 liter.</p> - -<p class='c009'>5. Sodium bismuthate. Purest dry salt.</p> - -<p class='c009'><em>Procedure.</em>—Use an amount of the sample that contains not -more than 0.2 mg. of manganese. Add 0.5 cc. of sulfuric acid -and evaporate to dryness. Heat until the sulfuric acid is volatilized -and ignite the residue. Dissolve in 40 cc. of nitric acid, add about -0.5 gram of sodium bismuthate, and heat until the permanganate -color disappears. Add a few drops of a solution of ammonium or -<span class='pageno' id='Page_50'>50</span>sodium bisulfate to clear the solution and again boil to expel oxides -of nitrogen. Remove from the source of heat, cool to 20° C., again -add 0.5 gram of sodium bismuthate, and stir. When the maximum -permanganate color has developed, filter through an alundum or -Gooch crucible containing an asbestos mat ignited and washed -with potassium permanganate. Wash the precipitate with dilute -sulfuric acid until the washings are colorless. Transfer the filtrate -to a 50 cc. Nessler tube and compare the color of it with that of -standards prepared from the potassium permanganate solution. To -prepare the standards, dilute portions of 0.2, 0.4, 0.6 cc., etc. of the -permanganate solution to 50 cc. with dilute sulfuric acid. The -content of manganese is calculated as described under persulfate -method (p. <a href='#Page_49'>49</a>).</p> - -<h3 class='c010'>LEAD, ZINC, COPPER, AND TIN.<a id='r7' /><a href='#f7' class='c015'><sup>[7]</sup></a><a id='r60' /><a href='#f60' class='c015'><sup>[60]</sup></a></h3> - -<p class='c011'>Determinations of lead, zinc, copper, and tin are important in -certain mining regions and in places where the water has a solvent -action on pipes and other containers. The use of certain “germicides” -also makes it necessary to test for some of these metals.</p> - -<p class='c009'>Lead, zinc, and copper may be determined colorimetrically or -electrolytically. The colorimetric methods are not so accurate as -a combination of both, and are chiefly of value as qualitative tests.</p> - -<p class='c009'>It is possible to make a rough estimation of the amount of lead -in clear waters by acidifying with acetic acid, saturating with -hydrogen sulfide, and comparing the color produced with that -produced by standard lead solutions in Nessler tubes, treated in -similar manner. This method, however, is not applicable if the -water is colored or contains iron.</p> - -<p class='c009'><em>Reagents.</em>—1. Standard lead solution. Dissolve 1.60 grams of -lead nitrate (Pb(NO<sub>3</sub>)<sub>2</sub>) in 1 liter of distilled water. One cc. of this -solution contains 1 mg. of lead (Pb). As a check it is desirable to -determine lead as sulfate in a measured portion of this solution.</p> - -<p class='c009'>2. Standard copper solution. Dissolve about 0.8 gram of copper -sulfate crystals (CuSO<sub>4</sub>.5H<sub>2</sub>O) in water and, after the addition of -1 cc. of concentrated sulfuric acid, dilute the solution to 1 liter. -Determine the copper in 100 cc. of this solution in the usual way -by electrolytic deposition. Dilute the solution so that 1 cc. contains -0.2 milligram copper (Cu). This solution is permanent.</p> - -<p class='c009'>3. Ammonium chloride. Twenty-five per cent solution.</p> - -<p class='c009'>4. Ammonium acetate. Fifty per cent solution.</p> - -<p class='c009'><span class='pageno' id='Page_51'>51</span>5. Ammonium hydroxide. (Sp. gr. 0.96.)</p> - -<p class='c009'>6. Hydrogen sulfide. Saturated solution.</p> - -<p class='c009'>7. Potassium sulfide. An alkaline solution of potassium sulfide -made by mixing equal volumes of 10 per cent potassium hydroxide -and a saturated aqueous solution of hydrogen sulfide.</p> - -<p class='c009'>8. Potassium oxalate. Crystals.</p> - -<p class='c009'>9. Potassium sulfate. Crystals.</p> - -<p class='c009'>10. Alcohol. Ninety-five per cent.</p> - -<p class='c009'>11. Alcohol. Fifty per cent.</p> - -<p class='c009'>12. Acetic acid. Fifty per cent.</p> - -<p class='c009'>13. Nitric acid. Concentrated acid (Sp. gr. 1.42).</p> - -<p class='c009'>14. Nitric acid. Dilute 1 part of the concentrated acid to 10 -parts with distilled water.</p> - -<p class='c009'>15. Hydrochloric acid. (Sp. gr. 1.20.)</p> - -<p class='c009'>16. Sulfuric acid. Concentrated acid (Sp. gr. 1.84).</p> - -<p class='c009'>17. Sulfuric acid. Dilute the concentrated acid with an equal -volume of distilled water.</p> - -<p class='c009'>18. Urea. Crystals.</p> - -<h4 class='c016'>LEAD.</h4> - -<p class='c011'>Concentrate (1)<a id='rD' /><a href='#fD' class='c015'><sup>[D]</sup></a> rapidly by boiling in a 7–inch porcelain dish -over a free flame 3 or 4 liters of the sample to be tested, or more if -very small amounts of the metals are present, to a volume of about -30 cc. Add 10 or 15 cc. of ammonium chloride solution to assist in -the separation of the sulfides, then add a few drops of concentrated -ammonium hydroxide, and saturate with hydrogen sulfide. Allow -to stand some time, preferably over night, add a little more ammonium -hydroxide and hydrogen sulfide, boil the contents of the -dish a few minutes, and filter. The precipitate (2) may consist -of lead, zinc, copper, and iron sulfides and the suspended organic -matter. The soluble coloring matter is in the filtrate (3). Wash -the precipitate a few times with hot water, place the precipitate -and the filter paper in the original dish and boil with dilute nitric -acid, rubbing down the sides of the dish, if necessary, to detach -any adhering sulfide precipitate. After again filtering and washing -several times with hot water, evaporate the filtrate and washings -in the original dish to a bulk of 10 to 15 cc., cool, add 5 cc. of concentrated -sulfuric acid, and heat until copious fumes of sulfuric -acid are evolved.</p> - -<div class='footnote' id='fD'> -<p class='c009'><a href='#rD'>D</a>. The numbers in parentheses refer to tables 10–12, pages <a href='#Page_55'>55</a>–56.</p> -</div> - -<p class='c009'><span class='pageno' id='Page_52'>52</span>If lead is present dilute the contents of the dish slightly with -water, and treat them with 150 cc. of 50 per cent alcohol, in which -the lead sulfate is insoluble. Allow to stand some time, preferably -over night, filter off the lead sulfate, and wash it with 50 per cent -alcohol. Save the filtrate for the determination of zinc.</p> - -<p class='c009'>Dissolve the precipitate of lead sulfate by boiling the filter containing -it in ammonium acetate solution in a porcelain dish. (4). -Filter into a 50 cc. Nessler tube and wash the filter with boiling -water containing a little ammonium acetate. Divide this filtrate -in halves and treat one-half with saturated hydrogen sulfide water -in order to get an approximation of the amount of lead present. -To the other half, or an aliquot portion, if a large amount of lead is -present, add a few drops of acetic acid, then an excess of saturated -hydrogen sulfide solution, and compare the color with that of -standards made by treating known amounts of the standard lead -solution with a little acetic acid, ammonium acetate, and hydrogen -sulfide.</p> - -<h4 class='c016'>ZINC.</h4> - -<p class='c011'>If zinc is present and copper is absent concentrate the filtrate -from the lead sulfate to expel the alcohol, and remove the iron by -adding an excess of ammonium hydroxide. Filter, wash, and acidify -the filtrate with sulfuric acid. Concentrate the filtrate to about -150 cc. and transfer to a weighed platinum dish. Add 2 grams of -potassium oxalate and 1.5 grams of potassium sulfate. Deposit the -zinc electrolytically by means of a current of about 0.3 ampere for -three hours. After deposition is complete and while the current -is on, siphon off the solution and at the same time run into the dish -a stream of distilled water in order to expel the free sulfuric acid, -which might dissolve some of the zinc if the circuit were broken. -After the acid has been removed break the circuit, wash the dish -with water, then with 95 per cent alcohol, dry at 70° C., cool, and -weigh it. The difference between this weight (10) and the weight -of the platinum dish equals the amount of metallic zinc. Some -difficulty has been experienced in this determination in obtaining -pure reagents. It is therefore advisable to make blank determinations -with each new lot of reagents and to correct the results if -necessary.</p> - -<p class='c009'>If copper also is present (5) concentrate the filtrate from the -lead sulfate until the alcohol is expelled, and add an excess of -<span class='pageno' id='Page_53'>53</span>ammonium hydroxide. (6) Remove any iron precipitate by filtration. -Neutralize the filtrate (7) with sulfuric acid, and add 2 cc. of -concentrated sulfuric acid and 1 gram of urea. Electrolyze the -solution and determine copper colorimetrically as described in the -procedure for copper (p. <a href='#Page_54'>54</a>). After the copper has been deposited -add ammonium hydroxide to the solution containing the zinc until -nearly all the sulfuric acid has been neutralized, concentrate to -slightly less than the capacity of the platinum dish, add 1.5 grams -of potassium sulfate and 2 grams of potassium oxalate, and electrolyze -for zinc. As this solution is usually saturated with ammonium -salts due to neutralizing the large quantity of sulfuric acid, -it is frequently impossible to get the zinc deposited firmly on the -dish before the salts interfere by crystallization. To avoid this -difficulty, dilute half the solution and electrolyze it for zinc; or, if -the amount of zinc is very small, precipitate the zinc as sulfide in -acetic acid solution, wash, ignite to oxide, and weigh the precipitate. -This difficulty will not be encountered if copper is absent as there -will then be no excess of ammonium salts.</p> - -<p class='c009'>If lead and copper are known to be absent and zinc alone is to be -determined (13), after treating with sulfuric acid for separation -of lead, slightly dilute the contents of the dish. Add an excess of -ammonium hydroxide to precipitate iron and filter. Make the -filtrate slightly acid with sulfuric acid, concentrate to about 150 -cc., transfer to a weighed platinum dish, add potassium oxalate and -sulfate, and electrolyze the solution as described for deposition of -zinc.</p> - -<h4 class='c016'>COPPER.<a id='r77' /><a href='#f77' class='c015'><sup>[77]</sup></a></h4> - -<p class='c011'>Use 1 liter of a sample containing 0.1 to 1.0 part per million of -copper, and proportionate amounts for other concentrations. -Evaporate to about 75 cc., and wash into a 100 cc. platinum dish. -Add 2 cc. of dilute sulfuric acid for clear and soft waters; add more -acid to very alkaline waters to offset the alkalinity; add 5 cc. of -acid to waters carrying much organic matter or clay to insure the -formation of a soluble copper salt. Then place the dish as the -anode in a direct current circuit, suspend a spiral wire cathode in -the solution so that it is parallel to and about half an inch from the -bottom of the dish, and close the circuit.</p> - -<p class='c009'>Electrolyze for about four hours with occasional stirring, or over -night, if convenient. The current may be supplied by two gravity -<span class='pageno' id='Page_54'>54</span>cells in series, yielding a current through the solution of about 0.02 -ampere. Lift out the cathode without previously opening the circuit, -and immerse the spiral in a small amount of dilute nitric acid -previously heated to boiling. Wash off the wire and evaporate the -nitric acid solution to dryness on the water bath. If the presence -of silver is suspected add a few drops of hydrochloric acid before -evaporation. Dissolve the residue in water and wash it into a -50 cc. Nessler tube. Dilute to 50 cc. and add 10 cc. of the potassium -sulfide solution. The color of the copper sulfide develops at once -and is fairly permanent, lasting at least several hours. Add 10 cc. -of the potassium sulfide solution to a similar tube containing 50 cc. -of distilled water, and then add to it standard copper solution in -0.2 cc. portions until the colors of the two tubes match. If 1 liter -of the sample is used copper in parts per million is equal to the -number of cubic centimeters of standard copper solution required -to match the color of the sample multiplied by 0.2.</p> - -<h4 class='c016'>TIN.</h4> - -<p class='c011'>Small quantities of tin are occasionally found in waters that have -passed through tin or tin-lined pipes. This metal, if present, is -precipitated with the iron by ammonia in the lead, zinc, and copper -separations. In the method for copper alone, it is removed in the -same way and may be further avoided by dissolving the sulfides in -concentrated nitric acid. Any tin present will then separate as an -insoluble compound, which may be ignited and weighed as the oxide -(SnO<sub>2</sub>).</p> - -<p class='c009'>The following schematic tables illustrate the procedures given.</p> - -<div><span class='pageno' id='Page_55'>55</span></div> -<table class='tbl2' summary=''> - <tr><th class='c12' colspan='4'>Table 10.—<span class='sc'>Scheme for the separation of lead, zinc, and copper.</span></th></tr> - <tr><td> </td></tr> - <tr> - <td class='btt bbt c28' colspan='4'>1. Concentrate sample. Add 10 cc. NH<sub>4</sub>Cl, a few drops NH<sub>4</sub>OH and saturate with H<sub>2</sub>S. Allow to stand, add more NH<sub>4</sub>OH and H<sub>2</sub>S. Boil, filter, and wash.</td> - </tr> - <tr> - <td class='bbt brt c28' colspan='3'>2. Dissolve the precipitate in dilute HNO<sub>3</sub>. Filter and wash. Evaporate to 10 or 15 cc. Cool. Add 5 cc. concentrated H<sub>2</sub>SO<sub>4</sub>, and heat until white fumes are given off. Dilute slightly and treat with 150 cc. of 50 per cent alcohol. Allow to stand; filter, and wash with 50 per cent alcohol.</td> - <td class='bbt c28' rowspan='2'>3. Reject the filtrate which contains the coloring matter.</td> - </tr> - <tr> - <td class='brt bbt c28' rowspan='2'>4. The precipitate contains the Pb. Dissolve in NH<sub>4</sub>C<sub>2</sub>H<sub>3</sub>O<sub>2</sub> solution. Filter into a 50 cc. Nessler tube and wash with water containing NH<sub>4</sub>C<sub>2</sub>H<sub>3</sub>O<sub>2</sub>. Divide filtrate in halves. Saturate one-half with H<sub>2</sub>S. Determine the Pb in the other half by adding HC<sub>2</sub>H<sub>3</sub>O<sub>2</sub> and H<sub>2</sub>S and comparing with standards containing known amounts of Pb.</td> - <td class='brt bbt c28' colspan='2'>5. The filtrate contains the Zn and Cu. Concentrate to expel alcohol. Add excess of NH<sub>4</sub>OH, filter and wash precipitate.</td> - </tr> - <tr> - <td class='bbt brt c28'>6. Reject the precipitate which contains the Fe.</td> - <td class='bbt c28' colspan='2'>7. The filtrate contains the Zn and Cu. Neutralize with H<sub>2</sub>SO<sub>4</sub>. Add 10 cc. concentrated H<sub>2</sub>SO<sub>4</sub> and 1 g. urea. Electrolyze for two hours with a current of 0.5 ampere. Break circuit, empty dish and wash.</td> - </tr> - <tr> - <td class='brt bbt c28' rowspan='2'>8. The deposit is Cu. Immerse the cathode in a small amount of hot, dilute HNO<sub>3</sub>; wash off and evaporate to dryness. Take up in water and wash into a Nessler tube. Make up to mark, and add 10 cc. of potassium sulfide solution. Compare with standard. If large amount is present, dry and weigh as Cu.</td> - <td class='c28 bbt' colspan='3'>9. The solution contains the Zn. Nearly neutralize with NH<sub>4</sub>OH. Concentrate to less than the capacity of the dish. Add 2 g. K<sub>2</sub>C<sub>2</sub>O<sub>4</sub> and 1.5 g. K<sub>2</sub>SO<sub>4</sub>. Electrolyze for 3 hours with a current of 0.3 ampere. Siphon off solution, break circuit, wash with water, then alcohol, dry at 70° C., cool and weigh.</td> - </tr> - <tr> - <td class='bbt c28' colspan='3'>10. The weighed residue is metallic Zn.</td> - </tr> - <tr><td> </td></tr> - <tr><th class='c12' colspan='4'>Table 11.—<span class='sc'>Scheme for determination of copper only.</span></th></tr> - <tr><td> </td></tr> - <tr> - <td class='btt bbt c28' colspan='4'>11. Concentrate sample to 75 cc. Add 2 cc. conc. H<sub>2</sub>SO<sub>4</sub> for clear, soft waters and 5 cc. for alkaline or turbid waters. Electrolyze following procedure in 7 and 8.</td> - </tr> - <tr><td> </td></tr> - <tr><th class='c12' colspan='4'>Table 12.—<span class='sc'>Scheme for determination of zinc only.</span></th></tr> - <tr><td> </td></tr> - <tr> - <td class='btt bbt c28' colspan='4'>13. Follow scheme for all three metals as given in Table 10 through section 5. Nearly neutralize the filtrate with H<sub>2</sub>SO<sub>4</sub>, concentrate to less than the capacity of the dish and electrolyze as directed in section 9.</td> - </tr> -</table> - -<div> - <span class='pageno' id='Page_56'>56</span> - <h3 class='c010'>MINERAL ANALYSIS.</h3> -</div> - -<h4 class='c016'>RESIDUE ON EVAPORATION.</h4> - -<p class='c011'>See description of method (p. <a href='#Page_29'>29</a>). The residue should be dried -one hour at 180° C. Turbid waters should be filtered, and the -composition of the suspended matter should be determined separately -or the amount of it reported as suspended matter.</p> - -<h4 class='c016'>ALKALINITY AND ACIDITY.</h4> - -<div class='nf-center-c0'> -<div class='nf-center c002'> - <div>See description of method (pp. <a href='#Page_35'>35</a>–41).</div> - </div> -</div> - -<h4 class='c016'>CHLORIDE.</h4> - -<div class='nf-center-c0'> -<div class='nf-center c002'> - <div>See description of method (pp. <a href='#Page_41'>41</a>–43).</div> - </div> -</div> - -<h4 class='c016'>NITRATE NITROGEN.</h4> - -<div class='nf-center-c0'> -<div class='nf-center c002'> - <div>See description of method (pp. <a href='#Page_23'>23</a>–25).</div> - </div> -</div> - -<h4 class='c016'>SEPARATION OF SILICA, IRON, ALUMINIUM, CALCIUM, AND MAGNESIUM.<a id='r10' /><a href='#f10' class='c015'><sup>[10]</sup></a><a id='r48' /><a href='#f48' class='c015'><sup>[48]</sup></a></h4> - -<h5 class='c016'>SILICA.</h5> - -<p class='c011'>Evaporate in platinum 100 to 1,000 cc. of the sample or sufficient -if possible to form a residue weighing 0.4 to 0.6 gram, and preferably -containing 0.1 to 0.2 gram of calcium. When the residue is -nearly dry add 1 cc. of hydrochloric acid (1 to 1) and, after moistening -the sides of the dish, evaporate to dryness. Dry at 180° -C. and if much organic matter is present char it in a radiator. -Moisten the residue with dilute hydrochloric acid and expel the excess -of acid by heating on the water bath. Add a few drops of -hydrochloric acid, dissolve in hot water, and filter. Wash the -residue with hot water. Evaporate the filtrate to dryness, repeat -the filtration, and combine the two residues. If great accuracy -is not required the second evaporation with hydrochloric acid may -be omitted. Ignite and weigh the insoluble residue. Add 2 drops -of concentrated sulfuric acid and a little hydrofluoric acid, volatilize -the acids, ignite, and weigh again. Report the loss in weight -<span class='pageno' id='Page_57'>57</span>as silica (SiO<sub>2</sub>). A weight of non-volatile matter exceeding 0.5 mg. -should be analyzed.</p> - -<h5 class='c016'>IRON AND ALUMINIUM.</h5> - -<p class='c011'>Heat to boiling the filtrate from the insoluble residue, oxidize with -concentrated nitric acid or bromine, and concentrate to about 25 cc. -Add ammonium hydroxide in slight excess, boil one minute, and -filter. Dissolve the precipitate on the filter in a small amount -of hot dilute hydrochloric acid. Reprecipitate with ammonium -hydroxide, filter, and wash. Unless very accurate results are -necessary this solution and reprecipitation may be omitted. Unite -the two filtrates for determination of calcium. Ignite and weigh -the precipitate. It will comprise oxides of iron and aluminium -and phosphate. If much phosphate is present it should be determined -in a separate sample and a correction for the amount -applied; otherwise it may be neglected. Determine the iron in -the ignited precipitate by fusion with sodium or potassium pyrosulfate, -reduction with zinc, and titration with potassium permanganate. -Aluminium (Al) is calculated as follows:</p> - -<div class='nf-center-c0'> - <div class='nf-center'> - <div>Al = 0.53[(Fe<sub>2</sub>O<sub>3</sub> + Al<sub>2</sub>O<sub>3</sub>) − 1.43 Fe]</div> - </div> -</div> - -<h5 class='c016'>CALCIUM.</h5> - -<p class='c011'>Concentrate the filtrate from the separation of iron and aluminium -to about 100 cc., and add an excess of concentrated solution of ammonium -oxalate, little by little, to the hot ammoniacal solution. -Keep the solution warm and stir at intervals till the precipitate -settles readily and leaves a clear supernatant liquid. Filter, -dissolve the precipitate in a little hot dilute hydrochloric acid, -and reprecipitate with ammonium hydroxide and ammonium -oxalate. If great accuracy is not required this solution and reprecipitation -may be omitted, and the first precipitate may be -washed clean with hot water<a id='r64a' /><a href='#f64a' class='c015'><sup>[64a]</sup></a>. Save the filtrate for determination -of magnesium. Ignite the precipitate and weigh it as calcium -oxide, 71.5 per cent of which is the equivalent of calcium (Ca); or -dissolve the precipitate in hot 2 per cent sulfuric acid and titrate -with a standard solution of potassium permanganate.</p> - -<h5 class='c016'>MAGNESIUM.</h5> - -<p class='c011'>Acidify with hydrochloric acid the filtrate from the separation of -calcium and concentrate it to about 100 cc. Add 20 cc. of a -saturated solution of microcosmic salt, cool, and make slightly but -<span class='pageno' id='Page_58'>58</span>distinctly alkaline by adding ammonium hydroxide, drop by drop. -Allow the solution to stand four hours, then filter and wash with -3 per cent ammonium hydroxide. Dissolve the precipitate, -especially in the presence of large amounts of sodium or potassium, -in a slight excess of dilute hydrochloric acid and reprecipitate the -magnesium with ammonium hydroxide and a few drops of microcosmic -salt solution. If great accuracy is not required this solution -and reprecipitation may be omitted. Ignite the precipitate and -weigh it as magnesium pyrophosphate (Mg<sub>2</sub>P<sub>2</sub>O<sub>7</sub>), 21.9 per cent of -which is the equivalent of magnesium (Mg.). If manganese is -present<a href='#f64a' class='c015'><sup>[64a]</sup></a> it is precipitated with the magnesium and a correction -for it should be applied after having determined manganese in -a separate sample. The weight of manganese pyrophosphate -(Mn<sub>2</sub>P<sub>2</sub>O<sub>7</sub>) is 2.58 times the weight of manganese.</p> - -<h4 class='c016'>SEPARATION OF SULFATE, SODIUM, AND POTASSIUM.</h4> - -<h5 class='c016'>SULFATE.</h5> - -<p class='c011'>Evaporate to dryness 100 to 1,000 cc. of the sample, or sufficient -to obtain a residue weighing 0.4 to 0.6 gram and containing preferably -0.05 to 0.2 gram of sodium. Acidify the residue with hydrochloric -acid and remove the silica, iron, and aluminium (pp. <a href='#Page_56'>56</a>–57). -Make acid and add a hot solution of barium chloride in slight excess -to the hot filtrate, and warm it, stirring at intervals -for one-half hour, until the precipitate settles readily and leaves a -clear supernatant liquid. Dry, ignite, and weigh the precipitate of -barium sulfate, 41.1 per cent of which is equal to the content of -sulfate (SO<sub>4</sub>).</p> - -<h5 class='c016'>SODIUM, POTASSIUM, AND LITHIUM.</h5> - -<p class='c011'>Evaporate to dryness the filtrate from the precipitation of -barium sulfate. Add a few cubic centimeters of hot water and -then a saturated solution of barium hydroxide until a slight film -collects on the top of the solution. Filter and wash the precipitate -with hot water. Add to the filtrate an excess of ammonium hydroxide -and ammonium carbonate solution. Filter, evaporate the -filtrate to dryness, dry, and ignite at low red heat to expel ammonium -salts. Repeat the operations including the addition of barium -hydroxide until no precipitate is obtained by barium hydroxide or -by ammonium hydroxide and ammonium carbonate. Evaporate -the final filtrate to dryness in a weighed platinum dish, dry, cool, -<span class='pageno' id='Page_59'>59</span>and weigh the residue. Dissolve the residue in a few cubic centimeters -of water, filter, wash the filter paper twice with hot water, -then ignite the filter paper in the platinum dish. Cool and weigh -the residue. Subtract this weight from the first weight including -the residue. The difference is the weight of the chlorides of sodium -and potassium and lithium. If it is not desired to separate -sodium and potassium the weight of sodium and potassium as -sodium may be calculated from this difference by multiplying it by -0.394.</p> - -<h5 class='c016'>POTASSIUM.</h5> - -<p class='c011'><em>First procedure.</em>—Add to the solution of the chlorides of sodium -and potassium a few drops of dilute hydrochloric acid (1 to 3) and -1 cc. of 10 per cent platinic chloride (PtCl<sub>4</sub>) for each 30 mg. of the -combined chlorides. Evaporate to a thick syrup on the water -bath, then remove dish and allow it to come to dryness at laboratory -temperature. Treat the residue cold with 80 per cent alcohol and -filter. Wash the precipitate with 80 per cent alcohol until the -filtrate is no longer colored. Dry the precipitate and dissolve it -in hot water. Evaporate the solution to dryness in a platinum -dish and weigh it as potassium platinic chloride (K<sub>2</sub>PtCl<sub>6</sub>). The -weight of potassium (K) is 16.1 per cent of this weight and the -equivalent of potassium chloride (KCl) is 30.7 per cent of this -weight. Subtract the equivalent weight of potassium chloride -from the weight of the combined chlorides. The weight of the -sodium is 39.4 per cent of the difference.</p> - -<p class='c009'><em>Second procedure.</em><a id='r86' /><a href='#f86' class='c015'><sup>[86]</sup></a><a id='r103a' /><a href='#f103a' class='c015'><sup>[103a]</sup></a>—Add to the hot solution of the combined -chlorides 20 per cent perchloric acid (HClO<sub>4</sub>) slightly in excess of -the amount required to combine with the bases. One cubic centimeter -of 20 per cent perchloric acid is equivalent to 90 mg. of -potassium. Evaporate the solution to dryness, dissolve the residue -in 10 cc. of hot water and a small amount of perchloric acid, and -again evaporate to dryness. Repeat the addition of water, perchloric -acid, and evaporation until white fumes appear on evaporating -to dryness. Add to the residue 25 cc. of 96 per cent alcohol containing -0.2 per cent of perchloric acid (1 cc. of 20 per cent perchloric -acid in 100 cc. of 98 per cent alcohol). Break up the residue with -a stirring rod. Decant the supernatant liquid through a weighed -Gooch crucible that has been washed with 0.2 per cent perchloric -acid in alcohol. If the precipitate is unusually large dissolve it in -hot water and repeat the evaporation with perchloric acid. Wash -<span class='pageno' id='Page_60'>60</span>the precipitate once by decantation with the 0.2 per cent perchloric -acid in alcohol, transfer the precipitate to the crucible, and wash it -several times with a 0.2 per cent perchloric acid in alcohol. Dry -the crucible at 120–130° C. for one hour, cool, and weigh it. The -increase in weight is potassium perchlorate (KClO<sub>4</sub>). The equivalent -weight of potassium is 28.2 per cent and the equivalent weight -of potassium chloride is 53.8 per cent of the potassium perchlorate. -Calculate the content of sodium by difference.</p> - -<h4 class='c016'>LITHIUM.<a id='r34' /><a href='#f34' class='c015'><sup>[34]</sup></a></h4> - -<p class='c011'>Use a large quantity of the sample. Obtain the combined -chlorides of sodium, potassium, and lithium (see pp. <a href='#Page_58'>58</a>–59). -Transfer the combined chlorides to a small Erlenmeyer flask (50 -or 100 cc. capacity) and evaporate the solution nearly, but not -quite, to dryness. Add about 30 cc. of redistilled amyl alcohol. -Connect the flask, the stopper of which carries a thermometer, with -a condenser<a id='rE' /><a href='#fE' class='c015'><sup>[E]</sup></a> and boil until the temperature rises approximately to -the boiling point of amyl alcohol (130° C.), showing that all the -water has been driven off. Cool slightly and add a drop of hydrochloric -acid to convert small amounts of lithium hydroxide to -lithium chloride. Connect with the condenser and continue the -boiling to drive off again all water and until the temperature reaches -the boiling point of amyl alcohol. The content of the flask at this -time is usually 15 to 20 cc. Filter through a small paper or a -Gooch crucible into a graduated cylinder and note exact quantity -of filtrate, which determines the subsequent correction. Wash -the precipitate with small quantities of dehydrated amyl alcohol. -Evaporate the filtrate and washings in a platinum dish to dryness -on the steam bath, dissolve the residue in water, and add a few -drops of sulfuric acid. Evaporate on a steam bath and expel the -excess of sulfuric acid by gentle heat over a flame. Repeat until -carbonaceous matter is completely burned off. Cool and weigh -the dish and contents. Dissolve in a small quantity of hot water, -filter through a small filter, wash, and return filter to dish, ignite, -and weigh. The difference between the original weight of dish -and contents and the weight of the dish and small amount of -residue equals the weight of impure lithium sulfate. The purity -of the lithium sulfate should be tested by adding small amounts of -<span class='pageno' id='Page_61'>61</span>ammonium phosphate and ammonium hydroxide, which will precipitate -any magnesium present with the lithium sulfate. Any -precipitate appearing after standing over night should be collected -on a small filter and weighed as magnesium pyrophosphate, calculated -to sulfate, and subtracted from the weight of impure -lithium sulfate. From this weight subtract 0.00113 gram for -every 10 cc. of amyl alcohol filtrate exclusive of the amyl alcohol -used in washing residue because of the slight solubility of solid -mixed chlorides in amyl alcohol. Calculate lithium from the corrected -weight of lithium sulfate. Dissolve the mixed chlorides -from flask and filter with hot water, evaporate to dryness, ignite -gently to remove amyl alcohol, filter and thoroughly wash; concentrate -the filtrates and washings to 25 to 50 cc.</p> - -<div class='footnote' id='fE'> -<p class='c009'><a href='#rE'>E</a>. The amyl alcohol may be boiled off without the use of a condenser, but the vapors are very disagreeable.</p> -</div> - -<p class='c009'>To the weight of potassium chloride add 0.00051 gram for every -10 cc. of amyl alcohol used in the extraction of the lithium chloride, -which corrects for the solubility of the potassium chloride in -amyl alcohol. Calculate to potassium.</p> - -<p class='c009'>The weight of sodium chloride is found by subtracting the -combined weights of lithium chloride and potassium chloride -(corrected) from the total weight of the three chlorides. Calculate -sodium chloride to sodium.</p> - -<h4 class='c016'>BROMINE, IODINE, ARSENIC, AND BORIC ACID.</h4> - -<p class='c011'>Evaporate to dryness a large quantity of the sample to which -a small amount of sodium carbonate has been added. Boil the -residue with distilled water, transfer it to a filter, and thoroughly -wash it with hot water. Dilute the alkaline filtrate to a definite -volume, and determine bromine and iodine, arsenic, and boric -acid in aliquot portions of it.</p> - -<h5 class='c016'>BROMINE AND IODINE.<a href='#f10' class='c015'><sup>[10]</sup></a></h5> - -<p class='c011'><em>Reagents.</em>—1. Sulfuric acid. 1 to 5.</p> - -<p class='c009'>2. Potassium nitrite or sodium nitrite. Two per cent solution.</p> - -<p class='c009'>3. Carbon bisulfide. Freshly purified by distillation.</p> - -<p class='c009'>4. Iodine standards. Acidify with dilute sulfuric acid measured -quantities of a standard solution of potassium iodide in small tubes. -Add 3 or 4 drops of the potassium nitrite solution and extract -with carbon bisulfide as in the actual determination. Transfer to -small flasks the standards from which the iodine has been removed.</p> - -<p class='c009'>5. Chlorine water. Saturated solution.</p> - -<p class='c009'><span class='pageno' id='Page_62'>62</span>6. Bromine standards. Add measured quantities of a standard -solution of a bromide to the liquid in each of the small flasks from -which the iodine has been removed. Add to each 5 cc. of purified -carbon bisulfide, and proceed exactly as with the sample.</p> - -<p class='c009'><em>Procedure.</em>—Evaporate to dryness an aliquot portion of the -alkaline filtrate. Dissolve the residue in 2 or 3 cc. of water, and -add enough absolute alcohol to make the percentage of alcohol -about 90. Boil and filter and repeat the extraction of the residue -with alcohol once or twice. Add 2 or 3 drops of sodium hydroxide -to the combined alcoholic filtrates and evaporate to dryness. -Dissolve the residue in 2 or 3 cc. of water and repeat the extraction -with alcohol and the filtration. Add a drop of sodium hydroxide -to the filtrate and evaporate it to dryness. Dissolve the residue in -a little water. Acidify this solution with dilute sulfuric acid, -adding 3 or 4 drops excess, and transfer it to a small flask. Add -4 drops of the solution of potassium nitrite or sodium nitrite and -about 5 cc. of carbon bisulfide. Shake the mixture until all the -iodine is extracted. Separate the acid solution from the carbon -bisulfide by filtration. Wash the flask, filter, and contents with -cold distilled water, and transfer the carbon bisulfide containing -the iodine in solution to Nessler tubes by means of about 5 cc. of -pure carbon bisulfide. In washing the filter, dilute the contents -of the tube to a definite volume, usually 12 or 15 cc., and compare -the color with that of known amounts of iodine dissolved in carbon -bisulfide in other tubes.</p> - -<p class='c009'>Transfer to a small flask the sample from which the iodine -has been removed. Add saturated chlorine water, 1 cc. at a time, -shaking after each addition until all the bromine is freed. Care -must be taken not to add much more chlorine than that necessary -to free the bromine, since an excess of reagent may form a bromochloride -that spoils the color reaction. Separate the water solution -from the carbon bisulfide by filtration through a moistened filter, -wash the contents of the filter two or three times with water, and -then transfer them to a Nessler tube by means of about 1 cc. of -carbon bisulfide. Repeat this extraction of the filtrate twice, -using 3 cc. of carbon bisulfide each time. The combined carbon -bisulfide extracts usually amount to 11.5 to 12 cc. Add enough -carbon bisulfide to the tubes to bring them to a definite volume, -usually 12 to 15 cc., and compare the sample with the standards. -If much bromine is present it is not always completely extracted -<span class='pageno' id='Page_63'>63</span>by the amounts of carbon bisulfide recommended. If the extraction -is incomplete, therefore, make one or two extra extractions with -carbon bisulfide, transfer the extracts to another tube, and compare -the color with that of the standards.</p> - -<h5 class='c016'>ARSENIC.<a id='r31' /><a href='#f31' class='c015'><sup>[31]</sup></a></h5> - -<p class='c011'>Evaporate to dryness an aliquot portion of the alkaline filtrate -(p. <a href='#Page_61'>61</a>). Acidify the residue with arsenic-free sulfuric acid, and -subject it to the action of arsenic-free zinc and sulfuric acid in a -Marsh-Berzelius apparatus. Compare the mirror obtained with -a mirror obtained from an arsenious oxide solution of known -strength.</p> - -<h5 class='c016'>BORIC ACID.</h5> - -<p class='c011'>Evaporate to dryness an aliquot portion of the alkaline filtrate -(p. <a href='#Page_61'>61</a>), treat the residue with 1 or 2 cc. of water, and slightly -acidify the solution with hydrochloric acid. Add about 25 cc. of -absolute alcohol, boil, filter, and repeat the extraction of the -residue. Make the filtrate slightly alkaline with sodium hydroxide, -and evaporate it to dryness. Add a little water, slightly acidify -with hydrochloric acid, and place a strip of turmeric paper in the -liquid. Evaporate to dryness on the steam bath, and continue -the heating until the turmeric paper is dry. If boric acid is present -the turmeric paper becomes cherry red. It is not usually necessary -to determine quantitatively boric acid; the quantitative method -devised by Gooch<a id='r33' /><a href='#f33' class='c015'><sup>[33]</sup></a> is recommended.</p> - -<h3 class='c010'>HYDROGEN SULFIDE.<a id='r103' /><a href='#f103' class='c015'><sup>[103]</sup></a></h3> - -<p class='c011'>Hydrogen sulfide should be determined preferably in the field; -the procedure as far as the final titration with sodium thiosulfate -must be carried out in the field.</p> - -<p class='c009'><em>Reagents.</em>—1. N/100 sodium thiosulfate.</p> - -<p class='c009'>2. Standard iodine. A N/100 solution containing potassium -iodide standardized against the N/100 sodium thiosulfate. To -standardize, add 10 cc. of the iodine solution to 500 cc. of boiled -distilled water. Add about 1 gram of potassium iodide, and titrate -with N/100 sodium thiosulfate in the presence of starch indicator. -One cc. of N/100 iodine is equivalent to 0.17 mg. H<sub>2</sub>S.</p> - -<p class='c009'>3. Potassium iodide. Crystals.</p> - -<p class='c009'>4. Starch. A freshly prepared solution for use as indicator.</p> - -<p class='c009'><span class='pageno' id='Page_64'>64</span><em>Procedure.</em>—Add 500 cc. of the sample to 10 cc. of the standard -iodine solution and 1 gram of potassium iodide in a large glass-stoppered -bottle or flask. If the sample is to be collected from -a tap lead the water into the bottle through a rubber tube extending -to the bottom of the bottle so as to eliminate errors due to -aeration. Shake the bottle, allow it to stand for a few minutes, -and then titrate the excess of iodine with sodium thiosulfate in the -presence of starch indicator. Hydrogen sulfide (H<sub>2</sub>S) in parts per -million is equal to 0.34 times the difference in cubic centimeters -between the amount of iodine solution added and the amount of -N/100 thiosulfate used in the titration.</p> - -<h3 class='c010'>CHLORINE.</h3> - -<p class='c011'>In waters that have been treated with calcium hypochlorite or -liquid chlorine it is frequently advisable to ascertain the presence -or absence of chlorine. As the reagents which have been proposed -for its detection are not specific for chlorine but give -similar or identical reactions with oxidizing agents or reducible -substances care must be exercised in interpreting the results of -such tests: nitrites and ferric salts are of common occurrence, and -chlorates also may lead to misinterpretation in waters treated with -calcium hypochlorite.</p> - -<p class='c009'><em>Reagents.</em>—1. Tolidin solution. One gram of o-tolidin, purified -by being recrystallized from alcohol, is dissolved in 1 liter of 10 per -cent hydrochloric acid.</p> - -<p class='c009'>2. Copper sulfate solution. Dissolve 1.5 grams of copper sulfate -and 1 cc. of concentrated sulfuric acid in distilled water and dilute -the solution to 100 cc.</p> - -<p class='c009'>3. Potassium bichromate solution. Dissolve 0.025 gram of -potassium bichromate and 0.1 cc. of concentrated sulfuric acid in -distilled water and dilute the solution to 100 cc.</p> - -<p class='c009'><em>Procedure.</em>—Mix 1 cc. of the tolidin reagent with 100 cc. of the -sample in a Nessler tube and allow the solution to stand at least -5 minutes. Small amounts of free chlorine give a yellow and -larger amounts an orange color.</p> - -<p class='c009'>For quantitative determination compare the color with that -of standards in similar tubes prepared from the solutions of copper -sulfate and potassium bichromate. The amounts of solution for -various standards are indicated in Table 13.</p> - -<table class='table2' summary=''> - <tr><td class='c012' colspan='3'><span class='pageno' id='Page_65'>65</span></td></tr> - <tr><th class='c012' colspan='3'>Table 13.—<span class='sc'>Preparation of permanent standards for content of chlorine.</span></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017'>Chlorine.</th> - <th class='btt bbt brt c017'>Solution of copper sulfate.</th> - <th class='btt bbt c017'>Solution of potassium bichromate.</th> - </tr> - <tr> - <th class='brt c017'><em>Parts per million.</em></th> - <th class='brt c017'><em>cc.</em></th> - <th class='c017'><em>cc.</em></th> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>0.01</td> - <td class='brt c018'>0.0</td> - <td class='c018'>0.8</td> - </tr> - <tr> - <td class='brt c018'>.02</td> - <td class='brt c018'>.0</td> - <td class='c018'>2.1</td> - </tr> - <tr> - <td class='brt c018'>.03</td> - <td class='brt c018'>.0</td> - <td class='c018'>3.2</td> - </tr> - <tr> - <td class='brt c018'>.04</td> - <td class='brt c018'>.0</td> - <td class='c018'>4.3</td> - </tr> - <tr> - <td class='brt c018'>.05</td> - <td class='brt c018'>.4</td> - <td class='c018'>5.5</td> - </tr> - <tr> - <td class='brt c018'>.06</td> - <td class='brt c018'>.8</td> - <td class='c018'>6.6</td> - </tr> - <tr> - <td class='brt c018'>.07</td> - <td class='brt c018'>1.2</td> - <td class='c018'>7.5</td> - </tr> - <tr> - <td class='brt c018'>.08</td> - <td class='brt c018'>1.5</td> - <td class='c018'>8.7</td> - </tr> - <tr> - <td class='brt c018'>.09</td> - <td class='brt c018'>1.7</td> - <td class='c018'>9.0</td> - </tr> - <tr> - <td class='brt c018'>.10</td> - <td class='brt c018'>1.8</td> - <td class='c018'>10.0</td> - </tr> - <tr> - <td class='brt c018'>.20</td> - <td class='brt c018'>1.9</td> - <td class='c018'>20.0</td> - </tr> - <tr> - <td class='brt c018'>.30</td> - <td class='brt c018'>1.9</td> - <td class='c018'>30.0</td> - </tr> - <tr> - <td class='brt c018'>.40</td> - <td class='brt c018'>2.0</td> - <td class='c018'>38.0</td> - </tr> - <tr> - <td class='bbt brt c018'>.50</td> - <td class='bbt brt c018'>2.0</td> - <td class='bbt c018'>45.0</td> - </tr> -</table> - -<h3 class='c010'>DISSOLVED OXYGEN.<a href='#f16' class='c015'><sup>[16]</sup></a><a href='#f65' class='c015'><sup>[65]</sup></a><a id='r68' /><a href='#f68' class='c015'><sup>[68]</sup></a><a id='r71b' /><a href='#f71b' class='c015'><sup>[71b]</sup></a><a id='r99' /><a href='#f99' class='c015'><sup>[99]</sup></a><a id='r100c' /><a href='#f100c' class='c015'><sup>[100c]</sup></a><a id='r120' /><a href='#f120' class='c015'><sup>[120]</sup></a></h3> - -<p class='c011'><em>Reagents.</em>—1. Sulfuric acid, concentrated. (Sp. gr. 1.83–1.84.)</p> - -<p class='c009'>2. Potassium permanganate. Dissolve 6.32 grams of the salt -in water and dilute the solution to 1 liter.</p> - -<p class='c009'>3. Potassium oxalate. A 2 per cent solution.</p> - -<p class='c009'>4. Manganous sulfate. Dissolve 480 grams of the salt in water -and dilute the solution to 1 liter.</p> - -<p class='c009'>5. Alkaline potassium iodide. Dissolve 700 grams of potassium -hydroxide and 150 grams of potassium iodide in water and dilute -the solution to 1 liter.</p> - -<p class='c009'>6. Hydrochloric acid. Concentrated (Sp. gr. 1.18–1.19).</p> - -<p class='c009'>7. Sodium thiosulfate. A N/40 solution. Dissolve 6.2 grams -of chemically pure recrystallized sodium thiosulfate in water and -dilute the solution to 1 liter with freshly boiled distilled water. -Each cc. is equivalent to 0.2 mg. of oxygen or to 0.1395 cc. of oxygen -at 0°C. and 760 mm. pressure. Inasmuch as this solution is -not permanent it should be standardized occasionally against a -N/40 solution of potassium bichromate. The keeping qualities of -the thiosulfate solution are improved by adding to each liter 5 cc. -of chloroform and 1.5 grams of ammonium carbonate before diluting -to the prescribed volume.</p> - -<p class='c009'>8. Starch solution. Mix a small amount of clean starch with -cold water until it becomes a thin paste and stir this mass into 150 -to 200 times its weight of boiling water. Boil for a few minutes, -<span class='pageno' id='Page_66'>66</span>then sterilize. It may be preserved by adding a few drops of -chloroform.</p> - -<p class='c009'><em>Collection of sample.</em>—Collect the sample in a narrow-necked -glass-stoppered bottle of 250 to 270 cc. capacity. The following -procedure should be followed in order to avoid entrainment or -absorption of atmospheric oxygen. In collecting from a tap fill -the bottle through a glass or rubber tube extending well into the -tap and to the bottom of the bottle. To avoid air bubbles allow -the bottle to overflow for several minutes, and then carefully replace -the glass stopper so that no air bubble is entrained. In collecting -from the surface of a pond or tank connect the sample bottle to -a bottle of 1 liter capacity. Provide each bottle with a two-hole -rubber stopper having one glass tube extending to the bottom and -another glass tube entering but not projecting into the bottle. -Connect the short tube of the sample bottle with the long tube -of the liter bottle. Immerse the sample bottle in the water and -apply suction to the outlet of the liter bottle. To collect a sample -at any depth arrange the two bottles so that the outlet tube of -the liter bottle is at a higher elevation then the inlet tube of the -sample bottle. Lower the two bottles, in any convenient form -of cage properly weighted, to the desired depth. Water entering -during the descent will be flushed through into the liter bottle. -When air bubbles cease rising to the surface raise the bottles. -Finally replace the perforated stopper of the sample bottle with -a glass stopper in such manner as to avoid entraining bubbles of air.</p> - -<p class='c009'><em>Procedure.</em>—Remove the stopper from the bottle and add, first, -0.7 cc. of the concentrated sulfuric acid, and then 1 cc. of the potassium -permanganate solution. These and all other reagents should -be introduced by pipette under the surface of the liquid. Insert -the stopper and mix by inverting the bottle several times. After -20 minutes have elapsed destroy the excess of permanganate by -adding 1 cc. of the potassium oxalate solution, the bottle being -at once restoppered and its contents mixed. If a noticeable excess -of potassium permanganate is not present at the end of 20 minutes, -again add 1 cc. of the potassium permanganate solution. If this is -still insufficient use a stronger potassium permanganate solution. -After the liquid has been decolorized by the addition of potassium -oxalate add 1 cc. of the manganous sulfate solution and 3 cc. -of the alkaline potassium iodide solution. Allow the precipitate -to settle. Add 2 cc. of the hydrochloric acid and mix by shaking.</p> - -<p class='c009'>The procedure to this point must be carried out in the field, but -<span class='pageno' id='Page_67'>67</span>after the acid has been added and the stopper replaced there is no -further change, and the rest of the test may be performed within -a few hours, as convenient. Transfer 200 cc. of the contents of -the bottle to a flask and titrate with N/40 sodium thiosulfate, -using a few cubic centimeters of the starch solution as indicator -toward the end of the titration. Do not add the starch solution -until the color has become faint yellow, and titrate until the blue -color disappears.</p> - -<p class='c009'>The use of potassium permanganate is made necessary by high -nitrite or organic matter. The procedure outlined must be followed -in all work on sewage and partly purified effluents or seriously -polluted streams or samples whose nitrite nitrogen exceeds 0.1 -part per million. In testing other samples the procedure may be -shortened by beginning with the addition of the manganous sulfate -solution and proceeding from that point as outlined, except that -only 1 cc. of alkaline potassium iodide need be added.</p> - -<p class='c009'><em>Calculation of Results.</em>—Oxygen shall be reported in parts per -million by weight. It is sometimes convenient to know the number -of cubic centimeters per liter of the gas at 0°C. temperature and -760 mm. pressure and also to know the percentage which the -amount of gas present is of the maximum amount capable of -being dissolved by distilled water at the same temperature and -pressure. If 200 cc. of the sample is taken the number of cubic -centimeters of N/40 thiosulfate used is equal to parts per million -of oxygen. Corrections for volume of reagents added amount to -less than 3 per cent and are not justified except in work of unusual -precision. To obtain the result in cubic centimeters per liter -multiply the number of cubic centimeters of thiosulfate used by -0.698. To obtain the result in percentage of saturation divide -the number of cubic centimeters of thiosulfate by the figure in -Table 14 opposite the temperature of the water and under the -proper chlorine figure. The last column of Table 14 permits -interpolation for intermediate chlorine values. At elevations -differing considerably from mean sea level and for accurate work -attention must be given to barometric pressure, the normal pressure -in the region being preferable to the specific pressure at the time -of sampling. The term “saturation” refers to a condition of -equilibrium between the solution and an oxygen pressure in the -atmosphere corresponding to 158.8 millimeters, or approximately -one-fifth atmosphere. The true saturation or equilibrium between -the solution and pure oxygen is nearly five times this value, and -<span class='pageno' id='Page_68'>68</span>consequently values in excess of 100 per cent saturation frequently -occur in the presence of oxygen-forming plants.</p> - -<table class='table2' summary=''> - <tr><th class='c012' colspan='7'>Table 14.—<span class='sc'>Solubility of oxygen in fresh water and in sea water of stated degrees of salinity at various temperatures when exposed to an atmosphere containing 20.9 per cent of oxygen under a pressure of 760 mm.</span><a id='rF' /><a href='#fF' class='c015'><sup>[F]</sup></a></th></tr> - <tr><td> </td></tr> - <tr><th class='c012' colspan='7'>(Calculated by G. C. Whipple and M. C. Whipple from measurements of C. J. Fox.)<a id='r27' /><a href='#f27' class='c015'><sup>[27]</sup></a><a id='r119' /><a href='#f119' class='c015'><sup>[119]</sup></a></th></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017' rowspan='2'>Temperature.</th> - <th class='btt bbt brt c017' colspan='5'>Chloride in sea water (milligrams per liter).</th> - <th class='btt bbt c017' rowspan='2'>Difference per 100 parts of chloride.</th> - </tr> - <tr> - - <th class='bbt brt c017'>0.</th> - <th class='bbt brt c017'>5000.</th> - <th class='bbt brt c017'>10000.</th> - <th class='bbt brt c017'>15000.</th> - <th class='bbt brt c017'>20000.</th> - - </tr> - <tr> - <th class='brt c017'><em>°C.</em></th> - <th class='brt c017' colspan='5'><em>Dissolved oxygen in milligrams per liter.</em></th> - <th class='c017'><em>Parts per million.</em></th> - </tr> - <tr> - <td class='brt c018'>0</td> - <td class='brt c018'>14.62</td> - <td class='brt c018'>13.79</td> - <td class='brt c018'>12.97</td> - <td class='brt c018'>12.14</td> - <td class='brt c018'>11.32</td> - <td class='c018'>0.0165</td> - </tr> - <tr> - <td class='brt c018'>1</td> - <td class='brt c018'>14.23</td> - <td class='brt c018'>13.41</td> - <td class='brt c018'>12.61</td> - <td class='brt c018'>11.82</td> - <td class='brt c018'>11.03</td> - <td class='c018'>.0160</td> - </tr> - <tr> - <td class='brt c018'>2</td> - <td class='brt c018'>13.84</td> - <td class='brt c018'>13.05</td> - <td class='brt c018'>12.28</td> - <td class='brt c018'>11.52</td> - <td class='brt c018'>10.76</td> - <td class='c018'>.0154</td> - </tr> - <tr> - <td class='brt c018'>3</td> - <td class='brt c018'>13.48</td> - <td class='brt c018'>12.72</td> - <td class='brt c018'>11.98</td> - <td class='brt c018'>11.24</td> - <td class='brt c018'>10.50</td> - <td class='c018'>.0149</td> - </tr> - <tr> - <td class='brt c018'>4</td> - <td class='brt c018'>13.13</td> - <td class='brt c018'>12.41</td> - <td class='brt c018'>11.69</td> - <td class='brt c018'>10.97</td> - <td class='brt c018'>10.25</td> - <td class='c018'>.0144</td> - </tr> - <tr> - <td class='brt c018'>5</td> - <td class='brt c018'>12.80</td> - <td class='brt c018'>12.09</td> - <td class='brt c018'>11.39</td> - <td class='brt c018'>10.70</td> - <td class='brt c018'>10.01</td> - <td class='c018'>.0140</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>6</td> - <td class='brt c018'>12.48</td> - <td class='brt c018'>11.79</td> - <td class='brt c018'>11.12</td> - <td class='brt c018'>10.45</td> - <td class='brt c018'>9.78</td> - <td class='c018'>.0135</td> - </tr> - <tr> - <td class='brt c018'>7</td> - <td class='brt c018'>12.17</td> - <td class='brt c018'>11.51</td> - <td class='brt c018'>10.85</td> - <td class='brt c018'>10.21</td> - <td class='brt c018'>9.57</td> - <td class='c018'>.0130</td> - </tr> - <tr> - <td class='brt c018'>8</td> - <td class='brt c018'>11.87</td> - <td class='brt c018'>11.24</td> - <td class='brt c018'>10.61</td> - <td class='brt c018'>9.98</td> - <td class='brt c018'>9.36</td> - <td class='c018'>.0125</td> - </tr> - <tr> - <td class='brt c018'>9</td> - <td class='brt c018'>11.59</td> - <td class='brt c018'>10.97</td> - <td class='brt c018'>10.36</td> - <td class='brt c018'>9.76</td> - <td class='brt c018'>9.17</td> - <td class='c018'>.0121</td> - </tr> - <tr> - <td class='brt c018'>10</td> - <td class='brt c018'>11.33</td> - <td class='brt c018'>10.73</td> - <td class='brt c018'>10.13</td> - <td class='brt c018'>9.55</td> - <td class='brt c018'>8.98</td> - <td class='c018'>.0118</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>11</td> - <td class='brt c018'>11.08</td> - <td class='brt c018'>10.49</td> - <td class='brt c018'>9.92</td> - <td class='brt c018'>9.35</td> - <td class='brt c018'>8.80</td> - <td class='c018'>.0114</td> - </tr> - <tr> - <td class='brt c018'>12</td> - <td class='brt c018'>10.83</td> - <td class='brt c018'>10.28</td> - <td class='brt c018'>9.72</td> - <td class='brt c018'>9.17</td> - <td class='brt c018'>8.62</td> - <td class='c018'>.0110</td> - </tr> - <tr> - <td class='brt c018'>13</td> - <td class='brt c018'>10.60</td> - <td class='brt c018'>10.05</td> - <td class='brt c018'>9.52</td> - <td class='brt c018'>8.98</td> - <td class='brt c018'>8.46</td> - <td class='c018'>.0107</td> - </tr> - <tr> - <td class='brt c018'>14</td> - <td class='brt c018'>10.37</td> - <td class='brt c018'>9.85</td> - <td class='brt c018'>9.32</td> - <td class='brt c018'>8.80</td> - <td class='brt c018'>8.30</td> - <td class='c018'>.0104</td> - </tr> - <tr> - <td class='brt c018'>15</td> - <td class='brt c018'>10.15</td> - <td class='brt c018'>9.65</td> - <td class='brt c018'>9.14</td> - <td class='brt c018'>8.63</td> - <td class='brt c018'>8.14</td> - <td class='c018'>.0100</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>16</td> - <td class='brt c018'>9.95</td> - <td class='brt c018'>9.46</td> - <td class='brt c018'>8.96</td> - <td class='brt c018'>8.47</td> - <td class='brt c018'>7.99</td> - <td class='c018'>.0098</td> - </tr> - <tr> - <td class='brt c018'>17</td> - <td class='brt c018'>9.74</td> - <td class='brt c018'>9.26</td> - <td class='brt c018'>8.78</td> - <td class='brt c018'>8.30</td> - <td class='brt c018'>7.84</td> - <td class='c018'>.0095</td> - </tr> - <tr> - <td class='brt c018'>18</td> - <td class='brt c018'>9.54</td> - <td class='brt c018'>9.07</td> - <td class='brt c018'>8.62</td> - <td class='brt c018'>8.15</td> - <td class='brt c018'>7.70</td> - <td class='c018'>.0092</td> - </tr> - <tr> - <td class='brt c018'>19</td> - <td class='brt c018'>9.35</td> - <td class='brt c018'>8.89</td> - <td class='brt c018'>8.45</td> - <td class='brt c018'>8.00</td> - <td class='brt c018'>7.56</td> - <td class='c018'>.0089</td> - </tr> - <tr> - <td class='brt c018'>20</td> - <td class='brt c018'>9.17</td> - <td class='brt c018'>8.73</td> - <td class='brt c018'>8.30</td> - <td class='brt c018'>7.86</td> - <td class='brt c018'>7.42</td> - <td class='c018'>.0088</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>21</td> - <td class='brt c018'>8.99</td> - <td class='brt c018'>8.57</td> - <td class='brt c018'>8.14</td> - <td class='brt c018'>7.71</td> - <td class='brt c018'>7.28</td> - <td class='c018'>.0086</td> - </tr> - <tr> - <td class='brt c018'>22</td> - <td class='brt c018'>8.83</td> - <td class='brt c018'>8.42</td> - <td class='brt c018'>7.99</td> - <td class='brt c018'>7.57</td> - <td class='brt c018'>7.14</td> - <td class='c018'>.0085</td> - </tr> - <tr> - <td class='brt c018'>23</td> - <td class='brt c018'>8.68</td> - <td class='brt c018'>8.27</td> - <td class='brt c018'>7.85</td> - <td class='brt c018'>7.43</td> - <td class='brt c018'>7.00</td> - <td class='c018'>.0083</td> - </tr> - <tr> - <td class='brt c018'>24</td> - <td class='brt c018'>8.53</td> - <td class='brt c018'>8.12</td> - <td class='brt c018'>7.71</td> - <td class='brt c018'>7.30</td> - <td class='brt c018'>6.87</td> - <td class='c018'>.0083</td> - </tr> - <tr> - <td class='brt c018'>25</td> - <td class='brt c018'>8.38</td> - <td class='brt c018'>7.96</td> - <td class='brt c018'>7.56</td> - <td class='brt c018'>7.15</td> - <td class='brt c018'>6.74</td> - <td class='c018'>.0082</td> - </tr> - <tr> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='brt c018'> </td> - <td class='c018'> </td> - </tr> - <tr> - <td class='brt c018'>26</td> - <td class='brt c018'>8.22</td> - <td class='brt c018'>7.81</td> - <td class='brt c018'>7.42</td> - <td class='brt c018'>7.02</td> - <td class='brt c018'>6.61</td> - <td class='c018'>.0080</td> - </tr> - <tr> - <td class='brt c018'>27</td> - <td class='brt c018'>8.07</td> - <td class='brt c018'>7.67</td> - <td class='brt c018'>7.28</td> - <td class='brt c018'>6.88</td> - <td class='brt c018'>6.49</td> - <td class='c018'>.0079</td> - </tr> - <tr> - <td class='brt c018'>28</td> - <td class='brt c018'>7.92</td> - <td class='brt c018'>7.53</td> - <td class='brt c018'>7.14</td> - <td class='brt c018'>6.75</td> - <td class='brt c018'>6.37</td> - <td class='c018'>.0078</td> - </tr> - <tr> - <td class='brt c018'>29</td> - <td class='brt c018'>7.77</td> - <td class='brt c018'>7.39</td> - <td class='brt c018'>7.00</td> - <td class='brt c018'>6.62</td> - <td class='brt c018'>6.25</td> - <td class='c018'>.0076</td> - </tr> - <tr> - <td class='bbt brt c018'>30</td> - <td class='bbt brt c018'>7.63</td> - <td class='bbt brt c018'>7.25</td> - <td class='bbt brt c018'>6.86</td> - <td class='bbt brt c018'>6.49</td> - <td class='bbt brt c018'>6.13</td> - <td class='bbt c018'>.0075</td> - </tr> -</table> - -<div class='footnote' id='fF'> -<p class='c009'><a href='#rF'>F</a>. Under any other barometric pressure, B, the solubility can be obtained from the corresponding -value in the table by the formula:</p> - -<table class='table1' summary=''> - <tr> - <td class='c020'>S´ = S<span class='fraction'>B<br /><span class='vincula'>760</span></span> = S<span class='fraction'>B´<br /><span class='vincula'>29.92</span></span> in which</td> - <td class='c024'>S´ = Solubility at B or B´,</td> - </tr> - <tr> - <td class='c020'> </td> - <td class='c024'>S = Solubility at 760 mm. or 29.92 inches,</td> - </tr> - <tr> - <td class='c020'> </td> - <td class='c024'>B = Barometric pressure in mm.,</td> - </tr> - <tr> - <td class='c020'>and</td> - <td class='c024'>B´ = Barometric pressure in inches.</td> - </tr> -</table> - -</div> - -<div> - <span class='pageno' id='Page_69'>69</span> - <h3 class='c010'>ETHER-SOLUBLE MATTER.<a id='r44' /><a href='#f44' class='c015'><sup>[44]</sup></a></h3> -</div> - -<p class='c011'>Evaporate 500 cc. of the sample in a porcelain evaporating -dish to a volume of about 50 cc. By means of a rubber-tipped -glass rod remove to the bottom of the dish the solid matter -attached to the sides, and add normal sulfuric acid to neutralize -the alkalinity. Do not use an excess of acid. Then evaporate -the contents of the dish to dryness. Treat the dry residue with -boiling ether, rubbing the bottom and sides of the dish to insure -complete solution of fat. Three extractions with ether are required. -Filter the ether solution through a 5 cm. filter into a weighed -flask having a wide mouth. Evaporate the ether slowly, and dry -the flask at 100° C. for 30 minutes. The increase in weight of the -flask gives the amount of fats, or, in more precise language, the -ether-soluble matter.</p> - -<p class='c009'>An excess of acid gives too high results because of the formation -of fatty-acid residues.</p> - -<h3 class='c010'>RELATIVE STABILITY OF EFFLUENTS.<a id='r78' /><a href='#f78' class='c015'><sup>[78]</sup></a><a id='r79'></a></h3> - -<p class='c011'><em>Reagent.</em>—Methylene blue solution. A 0.05 per cent aqueous -solution of methylene blue, preferably the double zinc salt or -commercial variety.<a id='r60b' /><a href='#f60b' class='c015'><sup>[60b]</sup></a></p> - -<p class='c009'><em>Collection of sample.</em>—Collect the sample in a glass-stoppered -bottle holding approximately 150 cc. If the dissolved oxygen is -low observe precautions similar to those used in collecting samples -for dissolved oxygen (p. <a href='#Page_66'>66</a>).</p> - -<p class='c009'><em>Procedure.</em>—Add 0.4 cc. of the methylene blue solution to the -sample in the 150 cc. bottle. As methylene blue has a slightly -antiseptic property be careful to add exactly 0.4 cc. Add the -methylene blue solution preferably below the surface of the liquid -after filling the bottle with the sample. If the methylene blue -is added first do not allow the liquid to overflow as coloring matter -will thus be lost. Incubate the sample at 20° C. for ten days. -Four days’ incubation may be considered sufficient for all practical -purposes in routine plant-control work. If quick results are -desired incubate the sample at 37° C. for five days using suitable -stoppers<a id='r1a' /><a href='#f1a' class='c015'><sup>[1a]</sup></a><a href='#f2a' class='c015'><sup>[2a]</sup></a> to prevent the loss and reabsorption of dissolved -oxygen. The bacterial flora at 37° C. is different from that -at 20° C. The lower temperature is more nearly the average -temperature of surface waters and therefore the higher temperature -should be used only when quick approximate results are essential. -<span class='pageno' id='Page_70'>70</span>Observe the sample at least twice a day during incubation. Give -a sample in which the methylene blue becomes decolorized a -relative stability corresponding to the time required for reduction -(see Table 15). For routine filter control ordinary room or cellar -temperature gives fairly satisfactory results. For accurate studies, -room temperature incubation is very undesirable, as the fluctuations -in temperature which are ordinarily not noticed are -responsible for appreciable deviations from the true values of -relative stability. If the samples are incubated less than 10 days -at 20° C. and are not decolorized place a plus sign after the stability -value in order to indicate that the stability might have been higher -if more time had been allowed. In applying this test to river waters -it often happens that the blue coloring matter is removed either -partly or completely through absorption by the clay which many -rivers carry in suspension. True relative stabilities cannot be -obtained for such waters except by determining the initial available -oxygen at the start and the biochemical oxygen demand on -incubation at 20° C. for 10 days (pp. <a href='#Page_71'>71</a>–73). Germicides, such as -hypochlorite of lime, if present in sufficient quantity, vitiate the -results. If a sample contains free chlorine, therefore, store it -about 2 hours, or until the chlorine is gone, and then add methylene -blue.</p> - -<p class='c009'>Table 15<a href='#f78' class='c015'><sup>[78]</sup></a> gives the relation between the time in days to decolorize -methylene blue at 20° C. (<em>t</em><sub>20</sub>) and the relative stability -number or ratio of available oxygen to oxygen required for equilibrium, -expressed in percentage (S).</p> - -<table class='table2' summary=''> - <tr><td class='c012' colspan='2'>Table 15.—<span class='sc'>Relative stability numbers.</span></td></tr> - <tr><td> </td></tr> - <tr> - <th class='btt bbt brt c017'>Time required for decolorization at 20° C.</th> - <th class='btt bbt c017'>Relative stability.</th> - </tr> - <tr> - <th class='brt c017'><em>Days.</em></th> - <th class='c017'><em>Percentage.</em></th> - </tr> - <tr> - <td class='brt c018'>0.5</td> - <td class='c018'>11</td> - </tr> - <tr> - <td class='brt c018'>1.0</td> - <td class='c018'>21</td> - </tr> - <tr> - <td class='brt c018'>1.5</td> - <td class='c018'>30</td> - </tr> - <tr> - <td class='brt c018'>2.0</td> - <td class='c018'>37</td> - </tr> - <tr> - <td class='brt c018'>2.5</td> - <td class='c018'>44</td> - </tr> - <tr> - <td class='brt c018'>3.0</td> - <td class='c018'>50</td> - </tr> - <tr> - <td class='brt c018'>4.0</td> - <td class='c018'>60</td> - </tr> - <tr> - <td class='brt c018'>5.0</td> - <td class='c018'>68</td> - </tr> - <tr> - <td class='brt c018'>6.0</td> - <td class='c018'>75</td> - </tr> - <tr> - <td class='brt c018'>7.0</td> - <td class='c018'>80</td> - </tr> - <tr> - <td class='brt c018'>8.0</td> - <td class='c018'>84</td> - </tr> - <tr> - <td class='brt c018'>9.0</td> - <td class='c018'>87</td> - </tr> - <tr> - <td class='brt c018'>10.0</td> - <td class='c018'>90</td> - </tr> - <tr> - <td class='brt c018'>11.0</td> - <td class='c018'>92</td> - </tr> - <tr> - <td class='brt c018'>12.0</td> - <td class='c018'>94</td> - </tr> - <tr> - <td class='brt c018'>13.0</td> - <td class='c018'>95</td> - </tr> - <tr> - <td class='brt c018'>14.0</td> - <td class='c018'>96</td> - </tr> - <tr> - <td class='brt c018'>16.0</td> - <td class='c018'>97</td> - </tr> - <tr> - <td class='brt c018'>18.0</td> - <td class='c018'>98</td> - </tr> - <tr> - <td class='bbt brt c018'>20.0</td> - <td class='bbt c018'>99</td> - </tr> -</table> - -<p class='c009'><span class='pageno' id='Page_71'>71</span>The theoretical relation is, S = 100 (1 − 0.794<em>t</em><sub>20</sub>)</p> - -<p class='c009'>The relation between the time of reduction at 20° C. and that at -37° C. is approximately two to one, but if an observer incubates -at 37° C. he should work out his own comparative 37° C. table or -factor.</p> - -<p class='c009'>A relative stability of 75 signifies that the sample examined -contains a supply of available oxygen equal to 75 per cent of the -amount of oxygen which it requires in order to become perfectly -stable. The available oxygen is approximately equivalent to the -dissolved oxygen plus the available oxygen of nitrate and nitrite. -Nitrite in sewage is usually so low as to be negligible.</p> - -<h3 class='c010'>BIOCHEMICAL OXYGEN DEMAND OF SEWAGE AND EFFLUENTS.<a id='r60a' /><a href='#f60a' class='c015'><sup>[60a]</sup></a><a id='r60c' /><a href='#f60c' class='c015'><sup>[60c]</sup></a><a id='r60d' /><a href='#f60d' class='c015'><sup>[60d]</sup></a></h3> - -<h4 class='c016'>RELATIVE STABILITY METHOD.</h4> - -<p class='c011'>The relative stability method may be employed to obtain a -measure of the putrescible material in sewages and effluents in -terms of oxygen demand.</p> - -<p class='c009'><em>Procedure for effluents.</em>—Divide the total available oxygen, -including the oxygen of nitrite and nitrate, by the relative stability -expressed as a decimal.</p> - -<p class='c009'><em>Procedure for sewages.</em>—Make one or two dilutions with fully -aerated distilled water of known dissolved oxygen content. Tap -water may be employed if it is free from nitrates. Vary the relative -proportions of sewage and water to be employed to give a relative -stability of 50 to 75. Unless seals<a id='r1b' /><a href='#f1b' class='c015'><sup>[1b]</sup></a><a id='r2b' /><a href='#f2b' class='c015'><sup>[2b]</sup></a><a id='r52a' /><a href='#f52a' class='c015'><sup>[52a]</sup></a> are used bring the water -as well as the sewage to the temperature at which the mixtures -are to be incubated before preparing the dilutions. During -the manipulation avoid aeration. Having made the proper dilutions, -determine the relative stability of each.</p> - -<p class='c009'>Calculate the oxygen demand in parts per million by the formula:</p> - -<div class='nf-center-c0'> - <div class='nf-center'> - <div>Oxygen demand = O(1 − p)/Rp</div> - </div> -</div> - -<p class='c009'>In this formula, O is the initial dissolved oxygen of the diluting -water, p is the proportion of sewage; and R is the relative stability -of the mixture. Ordinarily the available oxygen in crude sewages, -septic tank effluents, settling tank effluents, and trade wastes can -be neglected.</p> - -<div> - <span class='pageno' id='Page_72'>72</span> - <h4 class='c016'>SODIUM NITRATE METHOD.</h4> -</div> - -<p class='c011'>For the determination of the biochemical oxygen demand the -sodium nitrate method may be used<a href='#f60a' class='c015'><sup>[60a]</sup></a><a href='#f60c' class='c015'><sup>[60c]</sup></a><a href='#f60d' class='c015'><sup>[60d]</sup></a><a href='#f52a' class='c015'><sup>[52a]</sup></a>. The method -is based on the biochemical consumption of oxygen from sodium -nitrate by a sewage or polluted water during an incubation period -of ten days at 20° C. A reasonable excess of sodium nitrate does -not give a higher oxygen demand, as do higher dilutions with -aerated water. The oxygen absorbed from the air in applying the -method to sewages is negligible.</p> - -<p class='c009'><em>Reagent.</em>—Sodium nitrate solution. Dissolve 26.56 grams of -pure sodium nitrate in 1 liter of distilled water. One cc. of this -solution in 250 cc. of sewage represents 50 parts per million of -available oxygen. The strength of the sodium nitrate solution -may be varied to suit conditions.</p> - -<p class='c009'><em>Procedure for sewages.</em>—Ordinarily disregard the initial available -oxygen as it is very small compared with the total biochemical -oxygen demand. Add measured amounts of the sodium nitrate -solution to the sewage in bottles holding approximately 250 cc. -which have been completely filled and stoppered. Incubate for -10 days at 20° C. A seal is not required during incubation. The -appearance of a black sediment and the development of a putrid -odor during incubation indicates that too little sodium nitrate has -been added. Methylene blue solution in proper proportion may -be added at the start to serve as an indicator during the incubation. -Domestic sewage usually varies in its oxygen demand from 100 to -300 parts per million, approximately 30 per cent of which is used -up at 20° C. in the first 24 hours. At the end of the incubation -period determine the residual nitrite and nitrate. Determine -the nitrate by the aluminium reduction method and direct -Nesslerization. To convert the nitrogen into oxygen equivalents, -multiply the nitrite nitrogen by 1.7 and the nitrate nitrogen by 2.9. -The difference between the available oxygen added as sodium nitrate -and that found as nitrite and nitrate at the end of the incubation -period is the biochemical oxygen demand.</p> - -<p class='c009'><em>Procedure for industrial wastes.</em>—Employ the same procedure -using larger quantities of the sodium nitrate solution. Make the -reaction alkaline to methyl orange and acid to phenolphthalein. -Adjust an acid reaction with sodium bicarbonate and a caustic -alkaline reaction with weak hydrochloric acid. If the liquid is -<span class='pageno' id='Page_73'>73</span>devoid of sewage bacteria seed it with sewage after adjusting the -reaction.</p> - -<p class='c009'><em>Procedure for polluted river waters.</em>—Determine the initial available -oxygen. Unless the river water is badly polluted add 10 parts -per million of sodium nitrate oxygen. Collect carefully, avoiding -aeration, three samples in 250 cc. bottles. To one sample add a -definite quantity of sodium nitrate solution and incubate. Incubate -the other two samples for the determination of the residual -free oxygen, nitrite, and nitrate. If there is free oxygen left, the -bottle containing the sodium nitrate solution may be discarded. -If there is no free oxygen determine residual nitrite and nitrate -as directed under the procedure for sewage (p. <a href='#Page_72'>72</a>) and calculate -the oxygen demand.</p> - -<div class='chapter'> - <h2 class='c005'>ANALYSIS OF SEWAGE SLUDGE AND MUD DEPOSITS.</h2> -</div> - -<h3 class='c010'>COLLECTION OF SAMPLE.</h3> - -<p class='c011'>Collect a representative sample of the material. In general more -than one sample should be taken from a spot and a large number -of samples should be collected rather than a few large samples. -If the surface layer is darker and a lower layer consists of pure -clay sample only the surface layer. Samples may be analyzed -either separately or as composites of careful mixtures. After the -sample has settled a few minutes roughly drain or siphon the excess -water. Allow sewage sludge to stand for one hour before draining -it free from excess water unless it is essential to determine the -moisture content of the sample originally collected. If sludge -cannot be analyzed within twenty-four hours it is better not to -use air-tight bottles and to add small quantities of chloroform and -keep in the ice box to retard decomposition. At the time of collection -carefully examine mud from the bottom of surface water for -evidence of sewage pollution and macroscopic and microscopic animal -and plant organisms. Record the predominant species. Note the -physical appearance of the material, particularly its color, odor, -and consistency. Express all analytical results in percentage on a -dry basis.</p> - -<h3 class='c010'>REACTION.</h3> - -<p class='c011'>Determine the reaction by diluting a definite quantity of the -wet sludge and titrating by the methods given under alkalinity and -acidity (pp. <a href='#Page_35'>35</a>–39 and 39–41).</p> - -<div> - <span class='pageno' id='Page_74'>74</span> - <h3 class='c010'>SPECIFIC GRAVITY.</h3> -</div> - -<p class='c011'>Weigh to the nearest tenth of a gram a wide-mouthed flask of -100 to 300 cc. capacity, according to the quantity of material -available. Then completely fill the flask with distilled water -to the brim and weigh it again. Empty the flask and fill it completely -with fresh sewage sludge or mud. If the material is of such -consistency that it flows readily fill the flask to the brim and weigh. -The specific gravity is equal to the weight of the sludge or mud -divided by the weight of an equal volume of distilled water.</p> - -<p class='c009'>If the material does not flow readily fill the weighed flask as -completely as possible without exerting pressure during the procedure. -Weigh and then fill the flask to the brim with distilled -water. Let it stand for a few minutes, until trapped air has -escaped, then add more water if necessary and weigh. Subtract -the weight of the added water from the weight of the water that -completely fills the flask; the specific gravity is equal to the weight -of the material divided by this difference. Record the specific -gravity only to the second decimal place.</p> - -<h3 class='c010'>MOISTURE.</h3> - -<p class='c011'>Heat approximately 25 grams of sludge or mud in a weighed -nickel dish on the water bath until it is fairly dry. Dry the residue -in an oven at 100° C., cool, and weigh. Repeat to approximate -constant weight. The loss in weight is moisture.</p> - -<h3 class='c010'>VOLATILE AND FIXED MATTER.</h3> - -<p class='c011'>Ignite, at dull red heat in a hood, the residue from the determination -of moisture until all the carbon has disappeared. Cool the -residue in a desiccator and weigh it. The residue is the fixed matter. -The volatile matter is the difference in weight between the original -dried sludge and the ignited sludge.</p> - -<h3 class='c010'>TOTAL ORGANIC NITROGEN.</h3> - -<p class='c011'><em>Preparation of sample.</em>—For the determination of organic nitrogen -and fats dry approximately 50 to 75 grams of the sludge or mud in a -porcelain dish first on the water bath and finally in the hot-water -oven until all the moisture has disappeared. Grind the dry -material to a fine powder and keep it in a glass-stoppered bottle.</p> - -<table class='table1' summary=''> - <tr><td class='c012' colspan='2'><span class='pageno' id='Page_75'>75</span></td></tr> - <tr> - <td class='c020'><em>Reagents.</em>—1.</td> - <td class='c014'>Sulfuric acid. Concentrated, nitrogen-free.</td> - </tr> - <tr> - <td class='c020'>2.</td> - <td class='c014'>Copper sulfate solution. Ten per cent.</td> - </tr> - <tr> - <td class='c020'>3.</td> - <td class='c014'>Potassium permanganate. Crystals.</td> - </tr> -</table> - -<p class='c009'><em>First procedure.</em>—Weigh accurately 0.5 gram of dried sludge or 5.0 -grams of dried mud and put it into a 500 cc. Kjeldahl flask. Digest -it with 20 cc. of sulfuric acid, or more if necessary, and 1 cc. of -copper sulfate solution to assist the oxidation. Boil for several -hours until the liquid becomes colorless or slightly yellow. Oxidize -the residue with 0.5 gram of potassium permanganate, and follow -the “Procedure for Sewage” (pp. <a href='#Page_21'>21</a>–22).</p> - -<p class='c009'><em>Second procedure.</em>—The following method is convenient for routine -work at sewage disposal plants. After digestion as described in -the first procedure, cool, transfer to a glass-stoppered 100 cc. flask, -dilute with distilled water to 100 cc., and mix well. Transfer 50 cc. -with a pipette into another 100 cc. volumetric flask, and make -this portion alkaline with 50 per cent sodium hydroxide, testing a -drop of the liquid on a porcelain plate with phenolphthalein to -insure neutralization. The formation of a floc usually indicates -that neutralization is complete. Dilute the solution to 100 cc., -pour it into a small glass-stoppered bottle and permit it to stand -until the next day. Nesslerize an aliquot portion of the clear supernatant -liquid, and calculate the percentage of nitrogen in the material.</p> - -<h3 class='c010'>ETHER-SOLUBLE MATTER.</h3> - -<p class='c011'>Fats are usually determined only on sewage sludge, but some -mud deposits contain small quantities due to the presence of trade -wastes.</p> - -<p class='c009'><em>Procedure.</em>—Weigh 0.5 to 25 grams of dry material according to -the quality of the sludge or mud. Add water to the weighed -portion in a porcelain dish and acidify the mixture with N/50 -sulfuric acid in the presence of litmus tincture or azolitmin solution -as indicator. Avoid adding too much acid as an excess gives too high -results on account of fatty acid residues. Evaporate the acidified -mixture to dryness on the water bath, and heat it in the hot air -oven at 100° C. two to three hours. Extract the dry residue with -boiling ether, rubbing the sides and bottom of the dish to insure -complete solution of the fat. Three extractions with ether are -usually sufficient. Filter the ether solution through a 5 cm. filter -paper into a small flask. Evaporate the ether slowly, dry the fatty -<span class='pageno' id='Page_76'>76</span>extract for half an hour at 100° C., cool in a desiccator, and weigh. -If it is desirable, particularly with certain industrial wastes, to determine -the quantity of saponified fat determine the fats with and -without the addition of acid. The difference between the quantities -found by the two determinations is the content of saponified -fat.</p> - -<h3 class='c010'>FERROUS SULFIDE.</h3> - -<p class='c011'>The liberation of hydrogen sulfide on adding dilute hydrochloric -acid to a sludge indicates the presence of ferrous sulfide. As ferrous -sulfide quickly oxidizes on exposure to air a quantitative -determination of this constituent must be made immediately after -collection of the sample.</p> - -<p class='c009'><em>Procedure.</em>—Heat a definite portion of the sludge with hydrochloric -acid in a flask. Pass the liberated gas through bromine -water or hydrogen peroxide. Determine gravimetrically the sulfate -in the oxidizing solution, and calculate the equivalent of ferrous -sulfide by multiplying the weight of barium sulfate by 0.376.</p> - -<h3 class='c010'>BIOCHEMICAL OXYGEN DEMAND.</h3> - -<p class='c011'>The quantity of river mud most suitable for the determination -of the biochemical oxygen demand ranges within certain limits, -largely according to the amount of oxidizable matter present. For -examinations of river mud prepare a 1 per cent stock suspension -in distilled water or tap water saturated with oxygen and free from -nitrate; use in the test a dilution of this stock suspension equivalent -to a concentration of 1 to 10 grams per liter of mud. For -examinations of fresh sewage sludge prepare a 1 per cent stock suspension -in a similar manner, but use in the test a dilution equivalent -to only 0.1 to 1.0 gram per liter of wet material. For examinations -of dried sludges, which have undergone more or less oxidation -higher concentrations may be required.</p> - -<p class='c009'><em>Procedure.</em>—Place a measured portion of the sample, or the -proper amount of the 1 per cent stock suspension of the sample, in -a 300 cc. narrow-mouth glass-stoppered bottle, and dilute it to the -desired concentration with water saturated with oxygen. Determine -the oxygen content at 20° C. of the waters that are used for dilution. -This determination must be made before the mud or sludge is added -because iron sulfide in the mud or sludge rapidly consumes part -of the dissolved oxygen. Incubate at 20° C. for five days.</p> - -<p class='c009'><span class='pageno' id='Page_77'>77</span>Shortly before the determination of the oxygen remaining in -solution at the end of five days rotate the bottle once or twice -to mix its contents and allow sedimentation for about 30 minutes. -Siphon the greater part of the liquid through a narrow-bore siphon -into a 150 cc. bottle, which has been filled with carbon dioxide. -Reject the first 25 cc. of the siphoned liquid and allow a little to -overflow at the end of siphoning. Determine the oxygen content -of the solution in the bottle in the usual way (pp. <a href='#Page_65'>65</a>–68). Report -the oxygen demand in percentage of the dried mud or sludge.</p> - -<div class='chapter'> - <h2 class='c005'>ANALYSIS OF CHEMICALS.</h2> -</div> - -<p class='c008'>The following sections describe the accepted methods for the -analysis of the chemicals commonly used in the treatment of water.</p> - -<h3 class='c010'>REAGENTS.</h3> - -<p class='c011'>1. Distilled water. In practically all the tests of chemicals it is -necessary to use exclusively distilled water that has been freshly -boiled to free it from carbon dioxide and oxygen.</p> - -<p class='c009'>2. Concentrated hydrochloric acid. Sp. gr. 1.20.</p> - -<p class='c009'>3. Hydrochloric acid, N/2.</p> - -<p class='c009'>4. Hydrochloric acid, N/10.</p> - -<p class='c009'>5. Ammonium hydroxide. Redistilled; sp. gr. 0.90.</p> - -<p class='c009'>6. Dilute sulfuric acid. Dilute 1 part of concentrated sulfuric -acid with 3 parts of freshly boiled distilled water.</p> - -<p class='c009'>7. Methyl orange indicator. See page <a href='#Page_36'>36</a>.</p> - -<p class='c009'>8. Phenolphthalein indicator. See page <a href='#Page_36'>36</a>.</p> - -<p class='c009'>9. Bromine water.</p> - -<p class='c009'>10. Stannous chloride, N/20. This should be frequently standardized -by titration against a standard iron solution. One cc. of -N/20 stannous chloride is equal to 0.0028 gram of iron (Fe) -estimated in the ferrous state.</p> - -<p class='c009'>11. Sodium hydroxide, N/1. Free from carbonate. This should -be frequently standardized by titration against a standard acid -solution in presence of phenolphthalein indicator. One cc. of N/1 -sodium hydroxide is equal to 0.049 gram of sulfuric acid (H<sub>2</sub>SO<sub>4</sub>), -or to 0.03645 gram of hydrochloric acid (HCl).</p> - -<p class='c009'>12. Sodium hydroxide, N/20. Free from carbonate.</p> - -<p class='c009'>13. Standard potassium permanganate. A N/10 solution. One -<span class='pageno' id='Page_78'>78</span>cc. of N/10 potassium permanganate is equal to 0.0056 gram of -iron (Fe) estimated in the ferrous state.</p> - -<p class='c009'>14. Alcohol. Ethyl alcohol, 95 per cent.</p> - -<p class='c009'>15. Sugar. Solid granulated cane sugar.</p> - -<h3 class='c010'>SULFATE OF ALUMINIUM.</h3> - -<p class='c011'>Determine and report insoluble matter, aluminium oxide (Al<sub>2</sub>O<sub>3</sub>), -ferric oxide (Fe<sub>2</sub>O<sub>3</sub>), ferrous oxide (FeO), basicity ratio, and, if -present, free acid as H<sub>2</sub>SO<sub>4</sub>. If the material is what is known as -“granular” sulfate mix it well before sampling. If it is in lump -form crush it to ⅛ to ¼ inch size, mix, and sample it. It is -unnecessary to grind the sample to a fine powder, but it is preferable -to have the particles fairly uniform in size.</p> - -<h4 class='c016'>INSOLUBLE MATTER.</h4> - -<p class='c011'>Treat 10 grams of the sample with 100 cc. of distilled water and -digest one hour at boiling temperature. Filter through a weighed -Gooch crucible and wash the insoluble matter with hot water freshly -boiled to free it from carbon dioxide. Dry the crucible to constant -weight at 100° C., cool, and weigh. Report the percentage of -insoluble matter.</p> - -<h4 class='c016'>OXIDES OF IRON AND ALUMINIUM.</h4> - -<p class='c011'>Dilute the filtrate from the determination of insoluble matter -to 500 cc. with water free from carbon dioxide and thoroughly mix -the solution. Transfer 50 cc. of the solution to a 250 cc. beaker, -add about 150 cc. of water and 5 cc. of concentrated hydrochloric -acid, and heat to boiling. Add ammonium hydroxide in slight -excess; when the solution has been almost neutralized it is convenient -to add a drop of methyl orange indicator and then to add -about 0.5 cc. of ammonium hydroxide after the solution is neutral -to the indicator. Digest at about 100° C. for a few minutes and -filter. Some analysts prefer to wash this gelatinous precipitate with -hot water by decantation, and some to wash it evenly distributed -over the surface of a filter paper; either method may be used. It -is difficult to free it completely from impurities and it is not necessary -to do so unless unusual quantities of calcium, magnesium, sodium, -or potassium are present. While the precipitate is being washed -do not allow it to become dry, as it then packs and can not -<span class='pageno' id='Page_79'>79</span>be washed clean. After most of the water has drained drying the -filter may be hastened by placing it on a sheet of blotting paper. -If much iron is present completely dry the precipitate, remove it -from the paper, and ignite the paper separately. Finally, blast -the precipitate, with free access of air to the crucible, for five or -ten minutes, cool, and weigh as oxides of iron and aluminium -(Fe<sub>2</sub>O<sub>3</sub> + Al<sub>2</sub>O<sub>3</sub>).</p> - -<p class='c009'>Subtract the content of total iron, expressed as ferric oxide -(Fe<sub>2</sub>O<sub>3</sub>), from the weight of the combined oxides and report the -difference as aluminium oxide (Al<sub>2</sub>O<sub>3</sub>), in percentage.</p> - -<h4 class='c016'>TOTAL IRON.</h4> - -<p class='c011'>As filter alum usually contains 0.2 to 0.3 per cent of iron use a -10 gram sample for the determination of total iron. Treat the -sample with 50 cc. of freshly boiled distilled water and add 5 cc. of -concentrated hydrochloric acid and 1 cc. of bromine water. Evaporate -the solution to dryness, dissolve the residue in water, and wash it -into a flask with sufficient water to make the volume about 50 cc. -Add 50 cc. of concentrated hydrochloric acid, boil to expel oxygen, -and titrate, as hot as possible, with N/20 stannous chloride.</p> - -<p class='c009'>If a 10 gram sample is used the percentage of iron (Fe) is equal -to the number of cubic centimeters of stannous chloride used -multiplied by 0.028, and the percentage of iron expressed as ferric -oxide is equal to the number of cubic centimeters of stannous -chloride used multiplied by 0.040.</p> - -<h4 class='c016'>FERRIC IRON.</h4> - -<p class='c011'>As filter alum usually contains 0.02 to 0.04 per cent of ferric iron -use a 20 gram sample. Boil 50 cc. of distilled water to expel -oxygen, add 50 cc. of concentrated hydrochloric acid, and add the -sample while the solution is boiling. Keep it boiling till the sample -is dissolved. The flask should be kept filled with carbon dioxide -during this process by dropping in occasionally small amounts of -sodium carbonate. When solution of the sample is complete -titrate it hot immediately with N/20 stannous chloride.</p> - -<p class='c009'>If a 20 gram sample is used the percentage of ferric oxide (Fe<sub>2</sub>O<sub>3</sub>) -is equal to the number of cubic centimeters of stannous chloride -used multiplied by 0.020.</p> - -<div> - <span class='pageno' id='Page_80'>80</span> - <h4 class='c016'>FERROUS IRON.</h4> -</div> - -<p class='c011'>The content of ferrous iron is the difference between total and -ferric iron. The percentage of ferrous oxide (FeO) is, therefore, -equal to 0.90 times the difference between the percentage of total -iron expressed as ferric oxide and the percentage of ferric iron -expressed as ferric oxide. Report the percentage of ferrous oxide -(FeO).</p> - -<h4 class='c016'>BASICITY RATIO.</h4> - -<p class='c011'>Transfer 50 cc. of the filtrate from the determination of insoluble -matter to a 200 cc. casserole and dilute it to 100 cc. Boil the -solution and titrate it at boiling temperature with N/1 sodium -hydroxide in presence of phenolphthalein indicator. The percentage -of acidity in equivalent of sulfuric acid (H<sub>2</sub>SO<sub>4</sub>) is equal to the -number of cubic centimeters of sodium hydroxide used multiplied -by 4.9. In this titration iron and aluminium are precipitated as -hydroxides and any free acid is neutralized.</p> - -<p class='c009'>Calculate the percentage of sulfuric acid equivalent to the -determined percentages of aluminium oxide, ferric oxide, and -ferrous oxide by the following formula:</p> - -<div class='nf-center-c0'> - <div class='nf-center'> - <div>2.88 Al<sub>2</sub>O<sub>3</sub> + 1.83 Fe<sub>2</sub>O<sub>3</sub> + 1.36 FeO.</div> - </div> -</div> - -<p class='c009'>If this percentage of acid equivalent is less than that found by -titration report the difference as percentage of free acid. If the -percentage of acid equivalent is greater than that found by titration -the difference divided by 2.88 is the percentage equivalent to the -excess of aluminium oxide present. Divide this excess by the -percentage of total aluminium oxide and report the quotient as the -basicity ratio.</p> - -<h3 class='c010'>LIME.</h3> - -<p class='c011'>Mix well the sample, which should contain no lumps. If foreign -matter is present grind the sample to pass a 100–mesh sieve.</p> - -<p class='c009'>Place 20 grams of granulated cane sugar and 1 gram of the sample -in a 250 cc. glass-stoppered bottle, tightly stopped, and mix the -mass by rolling. Do not shake hard as much of the lime could -thus be lost as dust. Then add 187.4 cc. of distilled water freshly -boiled to expel carbon dioxide. This makes 200 cc. of sugar -solution. The lime is mixed dry with the sugar and the water -added later to keep the lime from lumping. After shaking the -sugar solution one hour titrate 50 cc. of it with N/2 hydrochloric -<span class='pageno' id='Page_81'>81</span>acid in presence of methyl orange indicator. The acid used is -equivalent to the carbonate and hydroxide in 0.25 gram of the -sample.</p> - -<p class='c009'>Filter the remainder of the sugar solution, discarding the first 25 -cc. of filtrate. Titrate 50 cc. of the filtrate with N/2 hydrochloric -acid in presence of methyl orange indicator. The acid used is -equivalent to the hydroxide in 0.25 gram of the sample.</p> - -<p class='c009'>If a 1 gram sample is used the percentage of calcium oxide (CaO) -is equal to 5.6 times the number of cubic centimeters of hydrochloric -acid used in the second titration; and the percentage of calcium -carbonate (CaCO<sub>3</sub>) equivalent to the carbonate present is equal -to 10 times the difference in cubic centimeters between the results -of the two titrations.</p> - -<h3 class='c010'>SULFATE OF IRON.</h3> - -<h4 class='c016'>INSOLUBLE MATTER.</h4> - -<p class='c011'>Treat 10 grams of the sample with 100 cc. of freshly boiled distilled -water cooled to 30° C. or less. When solution is complete filter -through a weighed Gooch crucible, wash, dry, cool, and weigh. -Report the weight of the residue, in percentage, as insoluble matter.</p> - -<h4 class='c016'>IRON AS FERROUS SULFATE.</h4> - -<p class='c011'>Dissolve 1 gram of the sample and dilute to 200 cc. with freshly -boiled distilled water cooled to 30° C. or less. Add 5 cc. of dilute -sulfuric acid (1 to 3) to a 50 cc. portion of the solution and titrate -with N/10 potassium permanganate. The percentage of ferrous -sulfate (FeSO<sub>4</sub>.7H<sub>2</sub>O) is equal to 11.12 times the number of cubic -centimeters of potassium permanganate used.</p> - -<h4 class='c016'>ACIDITY.</h4> - -<p class='c011'>Shake 12.25 grams of the sample in a 150 cc. bottle with 75 cc. -of 95 per cent alcohol for ten minutes. Run a blank. Filter -rapidly both sample and blank and wash rapidly with alcohol -sufficient to make 100 cc. of filtrate. Titrate with N/20 sodium -hydroxide in presence of phenolphthalein and subtract the result -of titrating the blank from that of titrating the solution of the -sample. The percentage of acidity, expressed as sulfuric acid -(H<sub>2</sub>SO<sub>4</sub>), is equal to 0.02 times the number of cubic centimeters of -sodium hydroxide used.</p> - -<div> - <span class='pageno' id='Page_82'>82</span> - <h3 class='c010'>SODA ASH.</h3> -</div> - -<h4 class='c016'>INSOLUBLE MATTER.</h4> - -<p class='c011'>Treat 5.305 grams of the sample with 200 cc. of freshly boiled -and cooled distilled water. When solution is complete filter through -an asbestos mat in a weighed Gooch crucible, dry, cool, and weigh. -Report the weight of the residue, in percentage, as insoluble matter.</p> - -<h4 class='c016'>AVAILABLE ALKALI.</h4> - -<p class='c011'>Dilute the filtrate from the determination of insoluble matter -to 1,000 cc. and thoroughly mix. Titrate 25 cc. of this dilution -with N/10 hydrochloric acid in presence of methyl orange indicator. -The percentage of available alkali, expressed as sodium carbonate -(Na<sub>2</sub>CO<sub>3</sub>), is equal to 4 times the number of cubic centimeters of -hydrochloric acid used.</p> - -<div class='chapter'> - <h2 id='CHEMICAL' class='c005'>CHEMICAL BIBLIOGRAPHY.</h2> -</div> - -<p class='c008'>The subjoined bibliography comprises the publications cited in -the text of this report. The references are arranged alphabetically -by authors’ names and under each author in order of dates -of publication. When different pages of a single work are cited -letters are used in connection with the number that refers to the -work.</p> - -<div class='footnote' id='f1'> -<p class='c009'><a href='#r1'>1</a>. <span class='sc'>Andrews, L. W.</span> Sprengel’s method for colorimetric determination of -nitrates: <cite>J. Am. Chem. Soc.</cite>, Vol. 26, pp. 388–91, 1904.</p> -</div> - -<div class='footnote' id='f1a'> -<p class='c009'><a href='#r1a'>1a</a>. <span class='sc'>Assoc. Off. Ag. Chemists.</span> Determination of iodine and bromine: -<cite>J. A. O. A. C.</cite>, Vol. 1, No. 4, pt. 1, pp. 47–8, 1916.</p> -</div> - -<div class='footnote' id='f1b'> -<p class='c009'><a href='#r1b'>1b</a>. <span class='sc'>Bachmann, Frank.</span> A new seal for the prevention of aeration in deaerated -liquids: <cite>J. Ind. Eng. Chem.</cite>, Vol. 6, pp. 764–5, 1914.</p> -</div> - -<div class='footnote' id='f2'> -<p class='c009'><a href='#r2'>2</a>. <span class='sc'>Bartow, Edward</span>, and <span class='sc'>Rodgers, J. S.</span> Determination of nitrates by reduction -with aluminium: <cite>Am. J. Public Hygiene</cite>, new ser., Vol. 5, pp. 536–44, -1909; also <cite>Illinois Univ. Bull.</cite>, Vol. 7, No. 2 (Water Survey Ser. No. 7), -pp. 14–27, 1909.</p> -</div> - -<div class='footnote' id='f2a'> -<p class='c009'><a href='#r2a'>2a</a>. <span class='sc'>Blinn, William.</span> Determination of manganese as sulfate and by the -sodium bismuthate method: <cite>J. Am. Chem. Soc.</cite>, Vol. 34, pp. 1379–98, -1912.</p> -</div> - -<div class='footnote' id='f2b'> -<p class='c009'><a href='#r2b'>2b</a>. <span class='sc'>Buswell, A. M.</span> Modified apparatus for the putrescibility test: <cite>J. Ind. -Eng. Chem.</cite>, Vol. 6, p. 325, 1914.</p> -</div> - -<div class='footnote' id='f3'> -<p class='c009'><a href='#r3'>3</a>. <span class='sc'>Caldwell, G. C.</span> A method in part for the sanitary examination of water -and for the statement of results, offered for general adoption: <cite>J. Anal. -Chem.</cite>, Vol. 3, pp. 398–403, 1889.</p> -</div> - -<div class='footnote' id='f4'> -<p class='c009'><a href='#r4'>4</a>. <span class='sc'>Calkins, G. N.</span> A study of odors observed in the drinking waters of Massachusetts: -<cite>Report Mass. State Board of Health</cite>, pp. 355–80, 1892.</p> -</div> - -<div class='footnote' id='f5'> -<p class='c009'><a href='#r5'>5</a>. <span class='pageno' id='Page_83'>83</span><span class='sc'>Chamot, E. M.</span>, and <span class='sc'>Pratt, D. S.</span> A study on the phenoldisulfonic acid -method for the determination of nitrates in water: <cite>J. Am. Chem. Soc.</cite>, -Vol. 31, pp. 922–8, 1909; Vol. 32, pp. 630–7, 1910; and <span class='sc'>Redfield, H. W.</span>, -Vol. 33, pp. 366–81, 381–4, 1911.</p> -</div> - -<div class='footnote' id='f6'> -<p class='c009'><a href='#r6'>6</a>. <span class='sc'>Clark, H. W.</span> Experiments upon the purification of sewage and water at -the Lawrence Experiment Station: <cite>Report Mass. State Board of Health</cite>, -pp. 427–578, 1896.</p> -</div> - -<div class='footnote' id='f7'> -<p class='c009'><a href='#r7'>7</a>. <span class='sc'>Clark, H. W.</span>, and <span class='sc'>Forbes, F. B.</span> Methods for the determination of -lead, tin, zinc, and copper in drinking waters: <cite>Report Mass. State Board -of Health</cite>, pp. 577–85, 1898; pp. 498–506, 1900.</p> -</div> - -<div class='footnote' id='f8'> -<p class='c009'><a href='#r8'>8</a>. <span class='sc'>Cohn, A. I.</span> Tests and reagents, 1st ed., p. 216, John Wiley & Sons, New -York, 1903.</p> -</div> - -<div class='footnote' id='f9'> -<p class='c009'><a href='#r9'>9</a>. <span class='sc'>Dibdin, W. J.</span> The purification of sewage and water, 3d ed., pp. 345–51, -D. Van Nostrand Co., New York, 1903.</p> -</div> - -<div class='footnote' id='f10'> -<p class='c009'><a href='#r10'>10</a>. <span class='sc'>Dole, R. B.</span> The quality of the surface waters in the United States: <cite>U. S. -Geol. Survey Water-Supply Paper</cite> 236, pp. 15–9, 1909.</p> -</div> - -<div class='footnote' id='f11'> -<p class='c009'><a href='#r11'>11</a>. <span class='sc'>Draper, H. N.</span> Lacmoid and carminic acid as reagents for alkalies: <cite>Chem. -News</cite>, Vol. 51, pp. 206–7, 1885.</p> -</div> - -<div class='footnote' id='f13'> -<p class='c009'><a href='#r13'>13</a>. <span class='sc'>Drown, T. M.</span>, and <span class='sc'>Martin, Henry</span>. Determination of organic nitrogen -in natural waters by the Kjeldahl method: <cite>Tech. Quart.</cite>, Vol. 2, No. 3; -<cite>Chem. News</cite>, Vol. 59, pp. 272–6, 1889.</p> -</div> - -<div class='footnote' id='f14'> -<p class='c009'><a href='#r14'>14</a>. <span class='sc'>Drown, T. M.</span> The chemical examination of waters and the interpretation -of analyses: <cite>Examinations by the State Board of Health of water supplies -of Mass. 1887–90</cite>, pt. 1, Examination of water supplies, pp. 519–78, -1890.</p> -</div> - -<div class='footnote' id='f15'> -<p class='c009'><a href='#r15'>15</a>. ——. Report upon the examination of the outlets of sewers and -the effect of sewage disposal in Massachusetts: <cite>Report Mass. State Board -of Health</cite>, pp. 285–452, 1902.</p> -</div> - -<div class='footnote' id='f16'> -<p class='c009'><a href='#r16'>16</a>. ——, and <span class='sc'>Hazen, Allen</span>. A report of the chemical work done at -the Lawrence Experiment Station: <cite>Examinations by the State Board of -Health of water supplies of Mass. 1887–90</cite>, pt. 2, Purification of -sewage and water, pp. 707–34, 1890.</p> -</div> - -<div class='footnote' id='f17'> -<p class='c009'><a href='#r17'>17</a>. <span class='sc'>Dupre</span>, Dr. Some observations on the permanganate test in water analysis: -<cite>Analyst</cite>, Vol. 10, pp. 118–22, 1885.</p> -</div> - -<div class='footnote' id='f18'> -<p class='c009'><a href='#r18'>18</a>. <span class='sc'>Ellms, J. W.</span> A study of the relative value of lacmoid, phenacetolin, and -erythrosine as indicators in the determination of the alkalinity of water -by Hehner’s method: <cite>J. Am. Chem. Soc.</cite>, Vol. 21, pp. 359–69, 1899.</p> -</div> - -<div class='footnote' id='f20'> -<p class='c009'><a href='#r20'>20</a>. ——, and <span class='sc'>Beneker, J. C.</span> The estimation of carbonic acid in -water: <cite>J. Am. Chem. Soc.</cite>, Vol. 23, pp. 405–31, 1901.</p> -</div> - -<div class='footnote' id='f21'> -<p class='c009'><a href='#r21'>21</a>. <span class='sc'>Farnsteiner</span>, <span class='sc'>Buttenburg</span>, and <span class='sc'>Korn</span>, <cite><span lang="de" xml:lang="de">Leitfaden für die chemische Untersuchung -von Abwasser</span></cite>, Berlin, p. 20, 1902.</p> -</div> - -<div class='footnote' id='f22'> -<p class='c009'><a href='#r22'>22</a>. <span class='sc'>Fitzgerald</span>, and <span class='sc'>Foss</span>, <cite>Report Boston Water Board</cite>, p. 86, 1893.</p> -</div> - -<div class='footnote' id='f23'> -<p class='c009'><a href='#r23'>23</a>. <span class='sc'>Forbes, F. B.</span>, and <span class='sc'>Pratt, G. H.</span> The determination of carbonic acid in -drinking water: <cite>J. Am. Chem. Soc.</cite>, Vol. 25, pp. 742–56, 1903.</p> -</div> - -<div class='footnote' id='f24'> -<p class='c009'><a href='#r24'>24</a>. <span class='sc'>Fowler, G. J.</span> Sewage works analyses, pp. 21–37, John Wiley & Sons, New -York, 1902;</p> -</div> - -<div class='footnote' id='f24a'> -<p class='c009'><a href='#r24a'>24a</a>. pp. 31–4;</p> -</div> - -<div class='footnote' id='f24b'> -<p class='c009'><a href='#r24b'>24b</a>. pp. 58–60;</p> -</div> - -<div class='footnote' id='f24c'> -<p class='c009'><a href='#r24c'>24c</a>. pp. 86–9;</p> -</div> - -<div class='footnote' id='f24d'> -<p class='c009'><a href='#r24d'>24d</a>. pp. 89–95;</p> -</div> - -<div class='footnote' id='f24e'> -<p class='c009'><a href='#r24e'>24e</a>. pp. 96–7;</p> -</div> - -<div class='footnote' id='f24f'> -<p class='c009'><a href='#r24f'>24f</a>. pp. 98–100.</p> -</div> - -<div class='footnote' id='f26'> -<p class='c009'><a href='#r26'>26</a>. <span class='sc'>Fowler, G. J.</span> <cite>Univ. of Manchester Lecture</cite>, March, 1904, Pamphlet, p. 7.</p> -</div> - -<div class='footnote' id='f27'> -<p class='c009'><a href='#r27'>27</a>. <span class='pageno' id='Page_84'>84</span><span class='sc'>Fox, Charles J. J.</span> On the coefficients of absorption of nitrogen and oxygen -in distilled water and sea water and of atmospheric carbonic acid in sea -water: <cite>Trans. Faraday Soc.</cite>, Vol. 5, pp. 68–87, 1909.</p> -</div> - -<div class='footnote' id='f29'> -<p class='c009'><a href='#r29'>29</a>. ——. The composition of sewage in relation to problems of disposal: -<cite>Tech. Quart.</cite>, Vol. 16, pp. 132–160, 1903.</p> -</div> - -<div class='footnote' id='f30'> -<p class='c009'><a href='#r30'>30</a>. ——. Experiments upon the purification of sewage and water at -the Lawrence Experiment Station: <cite>Report Mass. State Board of Health</cite>, -pp. 447–700, 1894.</p> -</div> - -<div class='footnote' id='f31'> -<p class='c009'><a href='#r31'>31</a>. <span class='sc'>Haywood, J. K.</span>, and <span class='sc'>Warner, H. J.</span> Arsenic in papers and fabrics: <cite>U. S. -Agri. Dept. Bur. Chem. Bull. 86</cite>, pp. 25–7, 1904.</p> -</div> - -<div class='footnote' id='f32'> -<p class='c009'><a href='#r32'>32</a>. <span class='sc'>Gill, A. H.</span> On the determination of nitrates in potable water: <cite>J. Am. -Chem. Soc.</cite>, Vol. 16, pp. 122–32, 193–7, 1894.</p> -</div> - -<div class='footnote' id='f33'> -<p class='c009'><a href='#r33'>33</a>. <span class='sc'>Gooch, F. A.</span> A method for the separation and estimation of boric acid: -<cite>Am. Chem. J.</cite>, Vol. 9, pp. 23–33, 1887.</p> -</div> - -<div class='footnote' id='f34'> -<p class='c009'><a href='#r34'>34</a>. ——. A method for the separation of sodium and potassium from -lithium by the action of amyl alcohol on the chlorides: <cite>Am. Chem. J.</cite>, -Vol. 9, pp. 33–51, 1887; also <cite>U. S. Geol. Survey Bull. 422</cite>, p. 175; also <cite>U. -S. Agri. Dept. Bur. Chem.</cite>, <cite>Bull. 152</cite>, p. 80, 1911.</p> -</div> - -<div class='footnote' id='f35'> -<p class='c009'><a href='#r35'>35</a>. <span class='sc'>Gottschalk, V. H.</span>, and <span class='sc'>Roesler, H. A.</span> Action of soap on calcium and -magnesium solutions: <cite>J. Am. Chem. Soc.</cite>, Vol. 26, pp. 851–6, 1904.</p> -</div> - -<div class='footnote' id='f36'> -<p class='c009'><a href='#r36'>36</a>. <span class='sc'>Grandval, Al.</span>, and <span class='sc'>Lajoux, H.</span> <span lang="fr" xml:lang="fr">Nouveau procédé pour la recherche et le -dosage rapide de faibles quantités d’ acide nitrique dans l’air, l’eau, le -sol, etc., <cite>Comptes rend.</cite></span>, Vol. 101, pp. 62–5, 1885.</p> -</div> - -<div class='footnote' id='f37'> -<p class='c009'><a href='#r37'>37</a>. <span class='sc'>Handy, J. O.</span> Determination of acidity or alkalinity: <cite>Proc. Engineers Soc. -West. Pa.</cite>, Vol. 19, p. 705, 1903.</p> -</div> - -<div class='footnote' id='f38'> -<p class='c009'><a href='#r38'>38</a>. <span class='sc'>Harrington, Charles</span>, and <span class='sc'>Richardson, M. W.</span> A manual of practical -hygiene, 5th ed., pp. 457–62, Lea & Febiger, Phila. and New York, 1914.</p> -</div> - -<div class='footnote' id='f39'> -<p class='c009'><a href='#r39'>39</a>. <span class='sc'>Hazen, Allen.</span> On the determination of chlorine in water: <cite>Am. Chem. J.</cite>, -Vol. 11, pp. 409–14, 1889.</p> -</div> - -<div class='footnote' id='f40'> -<p class='c009'><a href='#r40'>40</a>. ——. Apparatus for the determination of ammonias in sand -sewage: <cite>Am. Chem. J.</cite>, Vol. 12, pp. 427–8, 1890.</p> -</div> - -<div class='footnote' id='f42'> -<p class='c009'><a href='#r42'>42</a>. ——. Report on the chemical precipitation of sewage: <cite>Examinations -by the State Board of Health of water supplies of Mass., 1887–90</cite>, -pt. 2, Purification of water and sewage, pp. 735–91, 1890.</p> -</div> - -<div class='footnote' id='f43'> -<p class='c009'><a href='#r43'>43</a>. ——. A new color standard for natural waters: <cite>Am. Chem. J.</cite>, -Vol. 14, pp. 300–10, 1892.</p> -</div> - -<div class='footnote' id='f44'> -<p class='c009'><a href='#r44'>44</a>. ——. Experiments on the purification of sewage at the Lawrence -Experiment Station: <cite>Report Mass. State Board of Health</cite>, pp. 393–448, -1892.</p> -</div> - -<div class='footnote' id='f45'> -<p class='c009'><a href='#r45'>45</a>. ——, and <span class='sc'>Clark, H. W.</span> On the effect of temperature upon the -determination of ammonia by Nesslerization: <cite>Am. Chem. J.</cite>, Vol. 12, pp. -425–6, 1890.</p> -</div> - -<div class='footnote' id='f46'> -<p class='c009'><a href='#r46'>46</a>. ——, and ——. On the determination of nitrates in water: -<cite>Chem. News</cite>, Vol. 64, pp. 162–4, 1891.</p> -</div> - -<div class='footnote' id='f47'> -<p class='c009'><a href='#r47'>47</a>. <span class='sc'>Hehner, Otto.</span> Estimation of hardness without soap solution: <cite>Analyst</cite>, -Vol. 8, pp. 77–81, 1883.</p> -</div> - -<div class='footnote' id='f48'> -<p class='c009'><a href='#r48'>48</a>. <span class='pageno' id='Page_85'>85</span><span class='sc'>Hillebrand, W. F.</span> The analysis of silicate and carbonate rocks: <cite>U. S. -Geol. Survey Bull. 422</cite>, pp. 113–8, 127–8, 141–6, 219–20, 221, 222, and -230, 1910.</p> -</div> - -<div class='footnote' id='f49'> -<p class='c009'><a href='#r49'>49</a>. <span class='sc'>Hollis, F. S.</span> Methods for the determination of color and the relation of -the color to the character of the water: <cite>J. N. E. Water Works Assoc.</cite>, -Vol. 13, pp. 94–118, 1898.</p> -</div> - -<div class='footnote' id='f50'> -<p class='c009'><a href='#r50'>50</a>. <span class='sc'>Howe, Freeland, Jr.</span> A new method for determining the color of the -turbidity of water: <cite>Eng. Rec.</cite>, Vol. 50, pp. 720–1, 1904.</p> -</div> - -<div class='footnote' id='f51'> -<p class='c009'><a href='#r51'>51</a>. <span class='sc'>Ilosvay, L.</span> <span lang="fr" xml:lang="fr">L’acide azoteux dans la salive et dans l’air exhalé: <cite>Bull. de la -Sociéte Chimique</cite></span>, ser. 3, Vol. 2, pp. 388–91, 1889.</p> -</div> - -<div class='footnote' id='f52'> -<p class='c009'><a href='#r52'>52</a>. <span class='sc'>Jackson, D. D.</span> Permanent standards for use in the analysis of water: -<cite>Tech. Quart.</cite>, Vol. 13, pp. 314–26, 1900.</p> -</div> - -<div class='footnote' id='f52a'> -<p class='c009'><a href='#r52a'>52a</a>. ——, and <span class='sc'>Horton, W. A.</span> Experiments on the putrescibility -test for sewage and sewage effluents: <cite>J. Ind. Eng. Chem.</cite>, Vol. 1, pp. -328–33, 1909.</p> -</div> - -<div class='footnote' id='f53'> -<p class='c009'><a href='#r53'>53</a>. ——, and <span class='sc'>Ellms, J. W.</span> On odors and tastes of surface waters, with -special reference to anabaena, a microscopical organism found in certain -water supplies of Massachusetts: <cite>Tech. Quart.</cite>, Vol. 10, pp. 410–20, 1897.</p> -</div> - -<div class='footnote' id='f54'> -<p class='c009'><a href='#r54'>54</a>. <span class='sc'>Johnson, G. A.</span> Report on sewage purification at Columbus, Ohio, made to -the chief engineer of the Board of Public Service, p. 47, 1905.</p> -</div> - -<div class='footnote' id='f55'> -<p class='c009'><a href='#r55'>55</a>. <span class='sc'>Kendall, L. M.</span>, and <span class='sc'>Richards, E. H.</span> Permanent standards in water -analysis: <cite>Tech. Quart.</cite>, Vol. 17, pp. 277–80, 1904.</p> -</div> - -<div class='footnote' id='f56'> -<p class='c009'><a href='#r56'>56</a>. <span class='sc'>Kimberley, A. E.</span>, and <span class='sc'>Hommon, H. B.</span> The practical advantages of the -Gooch crucible in the determination of the total and volatile suspended -matter in sewage: <cite>Pub. Health Papers and Repts.</cite>, <cite>Am. Pub. Health Assoc.</cite>, -Vol. 31, pt. 2, pp. 123–35, 1905.</p> -</div> - -<div class='footnote' id='f57'> -<p class='c009'><a href='#r57'>57</a>. <span class='sc'>Kinnicutt, L. P.</span> Quoted by Gage, <cite>J. Am. Chem. Soc.</cite>, Vol. 27, p. 339, -1905.</p> -</div> - -<div class='footnote' id='f58'> -<p class='c009'><a href='#r58'>58</a>. <span class='sc'>Kjeldahl, J.</span> <span lang="de" xml:lang="de">Neue Methode zur Bestimmung des Stickstoffs in organischen -Körpern</span>: <cite>Z. anal. Chem.</cite>, Vol. 22, pp. 366–82, 1883.</p> -</div> - -<div class='footnote' id='f59'> -<p class='c009'><a href='#r59'>59</a>. <span class='sc'>Klut</span>, <cite><span lang="de" xml:lang="de">Mitt. a. d. König. Prüfungs</span></cite>, Vol. 12, p. 186.</p> -</div> - -<div class='footnote' id='f60'> -<p class='c009'><a href='#r60'>60</a>. <span class='sc'>Leach, A. E.</span> Food inspection and analysis, pp. 493, 495, and 497, John -Wiley & Sons, New York, 1904.</p> -</div> - -<div class='footnote' id='f60a'> -<p class='c009'><a href='#r60a'>60a</a>. <span class='sc'>Lederer, Arthur.</span> A new method for determining the relative stability -of sewage, effluent, or polluted river water: <cite>J. Infect. Diseases</cite>, Vol. -14, pp. 482–97, 1914.</p> -</div> - -<div class='footnote' id='f60b'> -<p class='c009'><a href='#r60b'>60b</a>. ——. A serious fallacy of the “standard” methylene blue -putrescibility test: <cite>Am. J. Pub. Health</cite>, Vol. 4 (old series Vol. 10), pp. -241–8, 1914.</p> -</div> - -<div class='footnote' id='f60c'> -<p class='c009'><a href='#r60c'>60c</a>. ——. Notes on the practical application of the “saltpeter -method” for determining the strength of sewages: <cite>Am. J. Pub. Health</cite>, -Vol. 5, pp. 354–61, 1915.</p> -</div> - -<div class='footnote' id='f60d'> -<p class='c009'><a href='#r60d'>60d</a>. ——. Determination of the biochemical oxygen demand by the -saltpeter method in stockyards, tannery, and corn products wastes: -<cite>J. Ind. Eng. Chem.</cite>, Vol. 7, pp. 514–6, 1915.</p> -</div> - -<div class='footnote' id='f61'> -<p class='c009'><a href='#r61'>61</a>. <span class='sc'>Leeds, A. R.</span> Estimation by titration of dissolved carbon dioxide in water: -<cite>J. Am. Chem. Soc.</cite>, Vol. 13, pp. 98–9, 1891.</p> -</div> - -<div class='footnote' id='f62'> -<p class='c009'><a href='#r62'>62</a>. <span class='pageno' id='Page_86'>86</span>——. The alteration of standard ammonium solutions when kept -in the dark: <cite>Proc. Am. Chem. Soc.</cite>, Vol. 2, p. 1, 1878.</p> -</div> - -<div class='footnote' id='f63'> -<p class='c009'><a href='#r63'>63</a>. <span class='sc'>Leffman, Henry.</span> Examination of water, 3d ed., pp. 46–50, P. Blakiston’s -Son & Co., Philadelphia, 1895;</p> -</div> - -<div class='footnote' id='f63a'> -<p class='c009'><a href='#r63a'>63a</a>. pp. 44–6;</p> -</div> - -<div class='footnote' id='f63b'> -<p class='c009'><a href='#r63b'>63b</a>. pp. 57–8.</p> -</div> - -<div class='footnote' id='f64'> -<p class='c009'><a href='#r64'>64</a>. ——. Examination of water, 7th ed., pp. 35–7, P. Blakiston’s -Son & Co., Philadelphia, 1915;</p> -</div> - -<div class='footnote' id='f64a'> -<p class='c009'><a href='#r64a'>64a</a>. pp. 64–7.</p> -</div> - -<div class='footnote' id='f65'> -<p class='c009'><a href='#r65'>65</a>. <span class='sc'>Levy, D. D.</span> <cite><span lang="fr" xml:lang="fr">Ann. de l’Observatoire de Mont-Souris</span></cite>, 1883 <em>et seq.</em></p> -</div> - -<div class='footnote' id='f66'> -<p class='c009'><a href='#r66'>66</a>. <span class='sc'>Lovibond, J. W.</span> A description of the tintometer with some remarks on its -application to chemical analysis: <cite>J. Soc. Chem. Ind.</cite>, Vol. 7, pp. 424–6, -1888.</p> -</div> - -<div class='footnote' id='f67'> -<p class='c009'><a href='#r67'>67</a>. <span class='sc'>Mallet, J. W.</span> Water analysis: <cite>Annual Report National Board of Health</cite>, -pp. 189–354, 1882.</p> -</div> - -<div class='footnote' id='f68'> -<p class='c009'><a href='#r68'>68</a>. <span class='sc'>Mason, W. P.</span> Examination of water, 4th ed., pp. 85–9, John Wiley & -Sons, New York, 1910;</p> -</div> - -<div class='footnote' id='f68a'> -<p class='c009'><a href='#r68a'>68a</a>. pp. 33–41;</p> -</div> - -<div class='footnote' id='f68b'> -<p class='c009'><a href='#r68b'>68b</a>. pp. 59–74;</p> -</div> - -<div class='footnote' id='f68c'> -<p class='c009'><a href='#r68c'>68c</a>. pp. 106–9.</p> -</div> - -<div class='footnote' id='f69'> -<p class='c009'><a href='#r69'>69</a>. <span class='sc'>McGowan, George.</span> Kjeldahl process for the estimation of total nitrogen -and (indirectly) of total organic nitrogen: <cite>Royal Commission on Sewage -Disposal</cite>, Vol. 4, pt. 5, pp. 24–31, 1904;</p> -</div> - -<div class='footnote' id='f69a'> -<p class='c009'><a href='#r69a'>69a</a>. pp. 37–41;</p> -</div> - -<div class='footnote' id='f69b'> -<p class='c009'><a href='#r69b'>69b</a>. pp. 47–8.</p> -</div> - -<div class='footnote' id='f70'> -<p class='c009'><a href='#r70'>70</a>. <span class='sc'>Palmer, A. W.</span> Chemical survey of the waters of Illinois, Report for years -1897–1902, pp. 27–8, Univ. Ill., 1903.</p> -</div> - -<div class='footnote' id='f71'> -<p class='c009'><a href='#r71'>71</a>. ——. Report of the University of Illinois [in Report of streams -examination, Sanitary Dist. Chicago], p. 60, Chicago, 1903;</p> -</div> - -<div class='footnote' id='f71a'> -<p class='c009'><a href='#r71a'>71a</a>. p. 56;</p> -</div> - -<div class='footnote' id='f71b'> -<p class='c009'><a href='#r71b'>71b</a>. pp. 61–4.</p> -</div> - -<div class='footnote' id='f72'> -<p class='c009'><a href='#r72'>72</a>. <span class='sc'>Parker, G. H.</span> Report of the biologist: <cite>Examinations by the State Board of -Health of water supplies of Mass., 1887–90</cite>, pt. 1, Examination of water -supplies, pp. 583–7, 1890.</p> -</div> - -<div class='footnote' id='f73'> -<p class='c009'><a href='#r73'>73</a>. <span class='sc'>Parmelee, C. L.</span>, and <span class='sc'>Ellms, J. W.</span> On rapid methods for the estimation of -the weight of suspended matters in turbid waters: <cite>Tech. Quart.</cite>, Vol. 12, -pp. 145–64, 1899.</p> -</div> - -<div class='footnote' id='f74'> -<p class='c009'><a href='#r74'>74</a>. <span class='sc'>Pfeifer, J.</span>, and <span class='sc'>Wartha, Prof.</span> <span lang="de" xml:lang="de">Kritische Studien über Untersuchung und -Reinigung des Kesselspeisewassers: <cite>Z. angew. Chem.</cite></span>, Vol. 15, pp. 193–207, -1902.</p> -</div> - -<div class='footnote' id='f75'> -<p class='c009'><a href='#r75'>75</a>. <span class='sc'>Phelps, E. B.</span> A critical study of the methods in current use for the determination -of free and albuminoid ammonia in sewage, <cite>Public Health Papers -and Reports, Am. Pub. Health Assoc.</cite>, Vol. 29, p. 354, 1904; J. Infect. Dis., -Vol. 1, p. 327, 1904.</p> -</div> - -<div class='footnote' id='f76'> -<p class='c009'><a href='#r76'>76</a>. ——. The determination of the organic nitrogen in sewage by -the Kjeldahl process: <cite>J. Infect. Dis.</cite>, Supp. 1, pp. 255–72, 1905.</p> -</div> - -<div class='footnote' id='f77'> -<p class='c009'><a href='#r77'>77</a>. ——. The determination of small quantities of copper in water: -<cite>J. Am. Chem. Soc.</cite>, Vol. 28, pp. 368–72, 1906.</p> -</div> - -<div class='footnote' id='f78'> -<p class='c009'><a href='#r78'>78</a>. ——. Putrescibility and stability of sewage effluents: <cite>Contrib. -Sanit. Research Lab., Mass. Inst. Tech.</cite>, Vol. 5, p. 87, 1909; also The -disinfection of sewage and sewage filter effluents: <cite>U. S. Geol. Survey Water-Supply -Paper 229</cite>, pp. 74–88, 1909.</p> -</div> - -<div class='footnote' id='f79'> -<p class='c009'><a href='#r79'>79</a>. Preface to report of committee on the pollution of water supplies: <cite>Public -Health Papers and Reports, Am. Pub. Health Assoc.</cite>, Vol. 23, pp. 56–7, -1897. Report, pp. 58–100.</p> -</div> - -<div class='footnote' id='f80'> -<p class='c009'><a href='#r80'>80</a>. Report of committee on standard methods of water analysis: <cite>Public Health -Papers and Reports, Am. Pub. Health Assoc.</cite>, Vol. 27, pp. 377–91, 1901.</p> -</div> - -<div class='footnote' id='f81'> -<p class='c009'><a href='#r81'>81</a>. <span class='pageno' id='Page_87'>87</span><span class='sc'>Proctor, H. R.</span> Some recent methods of technical water analysis: <cite>J. Soc. -Chem. Ind.</cite>, Vol. 23, pp. 8–11, 1904.</p> -</div> - -<div class='footnote' id='f82'> -<p class='c009'><a href='#r82'>82</a>. ——. On a modified form of tintometer or colorimeter: <cite>J. Soc. -Chem. Ind.</cite>, Vol. 14, pp. 122–4, 1895.</p> -</div> - -<div class='footnote' id='f83'> -<p class='c009'><a href='#r83'>83</a>. <span class='sc'>Richards, E. H.</span>, and <span class='sc'>Ellms, J. W.</span> The coloring matter of natural waters, -its source, composition, and quantitative measurement: <cite>J. Am. Chem. Soc.</cite>, -Vol. 18, pp. 68–81, 1896.</p> -</div> - -<div class='footnote' id='f84'> -<p class='c009'><a href='#r84'>84</a>. <span class='sc'>Rideal, Samuel.</span> Sewage, 2d ed., pp. 38–40, John Wiley & Sons, New York, -1901;</p> -</div> - -<div class='footnote' id='f84a'> -<p class='c009'><a href='#r84a'>84a</a>. pp. 31–4.</p> -</div> - -<div class='footnote' id='f85'> -<p class='c009'><a href='#r85'>85</a>. Royal Commission on Sewage Disposal, Testimony, Vol. 2, pp. 326–37, 1902.</p> -</div> - -<div class='footnote' id='f86'> -<p class='c009'><a href='#r86'>86</a>. <span class='sc'>Scholl, Clarence.</span> The perchloric method of determining potassium as -applied to water analysis: <cite>J. Am. Chem. Soc.</cite>, Vol. 36, pp. 2985–9, 1914.</p> -</div> - -<div class='footnote' id='f87'> -<p class='c009'><a href='#r87'>87</a>. <span class='sc'>Seyler, C. A.</span> Notes on water analysis: <cite>Chem. News</cite>, Vol. 70, pp. 82–3, -104–5, 112–4, 140–1, 151–2, and 187, 1894.</p> -</div> - -<div class='footnote' id='f88'> -<p class='c009'><a href='#r88'>88</a>. ——. The estimation of carbonic acid in natural waters: <cite>Analyst</cite>, -Vol. 22, pp. 312–9, 1897.</p> -</div> - -<div class='footnote' id='f89'> -<p class='c009'><a href='#r89'>89</a>. <span class='sc'>Smart, Chas.</span> Report of the committee on pollution of water supplies: -<cite>Public Health Papers and Reports, Am. Pub. Health Assoc.</cite>, Vol. 20, pp. -72–82, 1895;</p> -</div> - -<div class='footnote' id='f89a'> -<p class='c009'><a href='#r89a'>89a</a>. pp. 459–516.</p> -</div> - -<div class='footnote' id='f90'> -<p class='c009'><a href='#r90'>90</a>. <span class='sc'>Sprengel, Hermann.</span> <span lang="de" xml:lang="de">Ueber die Erkennung der Salpetersaüre: <cite>Ann. Physik -und Chemie</cite></span>, Vol. 121, pp. 188–91, 1864.</p> -</div> - -<div class='footnote' id='f91'> -<p class='c009'><a href='#r91'>91</a>. Standard methods of water analysis: <cite>Science</cite>, new ser., Vol. 12, pp. 906–15, -1900.</p> -</div> - -<div class='footnote' id='f92'> -<p class='c009'><a href='#r92'>92</a>. <span class='sc'>Stearns, F. P.</span>, and <span class='sc'>Drown, T. M.</span> Discussion of special topics relating to -the quality of public water supplies: <cite>Examinations by the State Board of -Health of water supplies of Mass., 1887–90</cite>, pt. 1, Examination of water -supplies, pp. 740–9, 1890.</p> -</div> - -<div class='footnote' id='f93'> -<p class='c009'><a href='#r93'>93</a>. <span class='sc'>Street, J. P.</span> Report on nitrogen: [In <cite>Proc. Assoc. Off. Agri. Chemists</cite>]; -<cite>U. S. Agri. Dept. Bur. Chem. Bull. 49</cite>, pp. 12–25, 1897.</p> -</div> - -<div class='footnote' id='f94'> -<p class='c009'><a href='#r94'>94</a>. <span class='sc'>Sutton, Francis.</span> Volumetric analysis, 10th ed., pp. 72–4, P. Blakiston’s -Son & Co., Philadelphia, 1911;</p> -</div> - -<div class='footnote' id='f94a'> -<p class='c009'><a href='#r94a'>94a</a>. pp. 99–101;</p> -</div> - -<div class='footnote' id='f94b'> -<p class='c009'><a href='#r94b'>94b</a>. pp. 239 and 477;</p> -</div> - -<div class='footnote' id='f94c'> -<p class='c009'><a href='#r94c'>94c</a>. pp. 470–1;</p> -</div> - -<div class='footnote' id='f94d'> -<p class='c009'><a href='#r94d'>94d</a>. pp. 479–83;</p> -</div> - -<div class='footnote' id='f94e'> -<p class='c009'><a href='#r94e'>94e</a>. p. 473, 479–83;</p> -</div> - -<div class='footnote' id='f94f'> -<p class='c009'><a href='#r94f'>94f</a>. pp. 484–8.</p> -</div> - -<div class='footnote' id='f95'> -<p class='c009'><a href='#r95'>95</a>. <span class='sc'>Tatlock, R. R.</span>, and <span class='sc'>Thompson, R. T.</span> The analysis of waters and their -changes in composition when employed in steam raising: <cite>J. Soc. Chem. -Ind.</cite>, Vol. 23, pp. 428–31, 1904.</p> -</div> - -<div class='footnote' id='f96'> -<p class='c009'><a href='#r96'>96</a>. <span class='sc'>Thomas, G. E.</span>, and <span class='sc'>Hall, C. A.</span> New apparatus in water analysis: <cite>J. Am. -Chem. Soc.</cite>, Vol. 24, pp. 535–9, 1902.</p> -</div> - -<div class='footnote' id='f97'> -<p class='c009'><a href='#r97'>97</a>. <span class='sc'>Thomson, R. T.</span> Use of litmus, methyl orange, phenacetolin, and phenolphthalein -as indicators: <cite>Chem. News</cite>, Vol. 47, pp. 123–7, 1883.</p> -</div> - -<div class='footnote' id='f98'> -<p class='c009'><a href='#r98'>98</a>. <span class='sc'>Thomson, Andrew.</span> Colorimetric method for determining small quantities -of iron: <cite>J. Chem. Soc.</cite>, Vol. 47, pp. 493–7, 1885.</p> -</div> - -<div class='footnote' id='f99'> -<p class='c009'><a href='#r99'>99</a>. <span class='sc'>Thresh, J. C.</span> A new method of estimating the oxygen dissolved in water: -<cite>J. Chem. Soc.</cite>, Vol. 57, pp. 185–95, 1890.</p> -</div> - -<div class='footnote' id='f100'> -<p class='c009'><a href='#r100'>100</a>. ——. The examination of water and water supplies, p. 200, Philadelphia, -1904;</p> -</div> - -<div class='footnote' id='f100a'> -<p class='c009'><a href='#r100a'>100a</a>. p. 219;</p> -</div> - -<div class='footnote' id='f100b'> -<p class='c009'><a href='#r100b'>100b</a>. p. 195;</p> -</div> - -<div class='footnote' id='f100c'> -<p class='c009'><a href='#r100c'>100c</a>. p. 282.</p> -</div> - -<div class='footnote' id='f101'> -<p class='c009'><a href='#r101'>101</a>. <span class='sc'>Tidy, C. M.</span> The process for determining the organic purity of potable -waters: <cite>J. Chem. Soc.</cite>, Vol. 35, pp. 46–106, 1879.</p> -</div> - -<div class='footnote' id='f102'> -<p class='c009'><a href='#r102'>102</a>. <span class='pageno' id='Page_88'>88</span><span class='sc'>Tiemann, Ferdinand</span>, and <span class='sc'>Gärtner, August</span>. <span lang="de" xml:lang="de">Handbuch der Wässer</span>, 4th -ed., pp. 255–8, Friedrich Vieweg und Sohn, Braunschweig, 1895.</p> -</div> - -<div class='footnote' id='f103'> -<p class='c009'><a href='#r103'>103</a>. <span class='sc'>Treadwell, F. P.</span> [translated by Hall, W. T.], Analytical Chemistry, 3d -ed., Vol. 2, pp. 687–688, John Wiley & Sons, New York, 1911;</p> -</div> - -<div class='footnote' id='f103a'> -<p class='c009'><a href='#r103a'>103a</a>. pp. -50–3.</p> -</div> - -<div class='footnote' id='f104'> -<p class='c009'><a href='#r104'>104</a>. <span class='sc'>Trommsdorff, Hugo.</span> Bestimmung der Organischen Substanzen: <cite>Zeit. -Anal. Chem.</cite>, Vol. 8, p. 344, 1869.</p> -</div> - -<div class='footnote' id='f105'> -<p class='c009'><a href='#r105'>105</a>. <span class='sc'>U. S. Geological Survey.</span> Measurement of color and turbidity of water, -Form 9–182, Washington, 1902.</p> -</div> - -<div class='footnote' id='f106'> -<p class='c009'><a href='#r106'>106</a>. <span class='sc'>Wanklyn, J. A.</span> Verification of Wanklyn, Chapman, and Smith’s water -analyses on a series of artificial waters: <cite>J. Chem. Soc.</cite>, Vol. 20, pp. 591–5, -1867.</p> -</div> - -<div class='footnote' id='f107'> -<p class='c009'><a href='#r107'>107</a>. ——. Water analysis, 10th ed., pp. 33–5, Kegan, Paul, Trench, -Trübner, & Co., Ltd., London, 1896;</p> -</div> - -<div class='footnote' id='f107a'> -<p class='c009'><a href='#r107a'>107a</a>. pp. 106–7.</p> -</div> - -<div class='footnote' id='f108'> -<p class='c009'><a href='#r108'>108</a>. <span class='sc'>Warington, Robert.</span> Note on the appearance of nitrous acid during -evaporation of water: <cite>J. Chem. Soc.</cite>, Vol. 39, pp. 229–34, 1881.</p> -</div> - -<div class='footnote' id='f109'> -<p class='c009'><a href='#r109'>109</a>. <span class='sc'>Warren, H. E.</span>, and <span class='sc'>Whipple, G. C.</span> The thermophone, a new instrument -for determining temperatures: <cite>Tech. Quart.</cite>, Vol. 8, pp. 125–52, 1895.</p> -</div> - -<div class='footnote' id='f110'> -<p class='c009'><a href='#r110'>110</a>. <span class='sc'>West, F. D.</span> The preparation of standards for the determination of -turbidity of water: <cite>Proc. Ill. Water Supply Assoc.</cite>, Vol. 6, pp. 49–51, 1914.</p> -</div> - -<div class='footnote' id='f111'> -<p class='c009'><a href='#r111'>111</a>. <span class='sc'>Weston, R. S.</span> Apparatus for the determination of ammonia in water by -the Wanklyn method, and total nitrogen by the Kjeldahl method: <cite>J. Am. -Chem. Soc.</cite>, Vol. 22, pp. 468–73, 1900.</p> -</div> - -<div class='footnote' id='f112'> -<p class='c009'><a href='#r112'>112</a>. ——. The determination of nitrogen as nitrites in waters: <cite>J. Am. -Chem. Soc.</cite>, Vol. 27, pp. 281–7, 1905.</p> -</div> - -<div class='footnote' id='f113'> -<p class='c009'><a href='#r113'>113</a>. ——. The determination of manganese in water: <cite>J. Am. Chem. -Soc.</cite>, Vol. 29, pp. 1074–8, 1907.</p> -</div> - -<div class='footnote' id='f114'> -<p class='c009'><a href='#r114'>114</a>. <span class='sc'>Whipple, G. C.</span> The observation of odor as an essential part of water -analysis: <cite>Public Health Papers and Reports, Am. Pub. Health Assoc.</cite>, Vol. -25, pp. 587–93, 1899.</p> -</div> - -<div class='footnote' id='f115'> -<p class='c009'><a href='#r115'>115</a>. ——. The microscopy of drinking water, 3d ed., pp. 186–205, -John Wiley & Sons, New York, 1914.</p> -</div> - -<div class='footnote' id='f116'> -<p class='c009'><a href='#r116'>116</a>. ——, and <span class='sc'>Jackson, D. D.</span> A comparative study of the methods -used for the measurement of the turbidity of water: <cite>Tech. Quart.</cite>, Vol. -13, pp. 274–94, 1900.</p> -</div> - -<div class='footnote' id='f117'> -<p class='c009'><a href='#r117'>117</a>. ——, and others. The decolorization of water: <cite>Trans. Am. Soc. -Civil Eng.</cite>, Vol. 46, pp. 141–81, 1901.</p> -</div> - -<div class='footnote' id='f118'> -<p class='c009'><a href='#r118'>118</a>. ——, and <span class='sc'>Parker, H. N.</span> On the amount of oxygen and carbonic -acid dissolved in natural waters and the effect of these gases upon the -occurrence of microscopic organisms: <cite>Trans. Am. Microscopical Soc.</cite>, Vol. -23, pp. 103–44, 1901.</p> -</div> - -<div class='footnote' id='f119'> -<p class='c009'><a href='#r119'>119</a>. ——, and <span class='sc'>Whipple, M. C.</span> Solubility of oxygen in sea water: -<cite>J. Am. Chem. Soc.</cite>, Vol. 33, pp. 362–5, 1911.</p> -</div> - -<div class='footnote' id='f120'> -<p class='c009'><a href='#r120'>120</a>. <span class='sc'>Winkler, L. W.</span> <span lang="de" xml:lang="de">Die Bestimmung des im Wasser gelösten Sauerstoffes</span>: -<cite>Ber.</cite>, pp. 2843–54, 1888.</p> -</div> - -<div class='footnote' id='f121'> -<p class='c009'><a href='#r121'>121</a>. <span class='sc'>Woodman, A. G.</span>, and <span class='sc'>Norton, J. F.</span> Air, water, and food, 4th ed., pp. -72–8, John Wiley & Sons, New York, 1914;</p> -</div> - -<div class='footnote' id='f121a'> -<p class='c009'><a href='#r121a'>121a</a>. pp. 85–7;</p> -</div> - -<div class='footnote' id='f121b'> -<p class='c009'><a href='#r121b'>121b</a>. pp. 90–1, -216, and 231;</p> -</div> - -<div class='footnote' id='f121c'> -<p class='c009'><a href='#r121c'>121c</a>. pp. 106–8.</p> -</div> - -<div class='chapter'> - <span class='pageno' id='Page_89'>89</span> - <h2 class='c005'>MICROSCOPICAL EXAMINATION.</h2> -</div> - -<p class='c008'>The microscopical examination of water consists of the enumeration -of the kinds of microscopic organisms (Plankton), and an estimation -of their quantity.</p> - -<p class='c009'>It may serve any one or more of the following purposes:</p> - - <dl class='dl_2'> - <dt>(1)</dt> - <dd>To explain the presence of objectionable odors and tastes. - </dd> - <dt>(2)</dt> - <dd>To indicate the progress of the self purification of streams. - </dd> - <dt>(3)</dt> - <dd>To indicate the presence of sewage contamination. - </dd> - <dt>(4)</dt> - <dd>To explain the chemical analysis. - </dd> - <dt>(5)</dt> - <dd>To identify the source of a water. - </dd> - <dt>(6)</dt> - <dd>To aid in the study of the food of fish, shellfish, and other aquatic organisms. - </dd> - </dl> - -<p class='c009'>The term “Microscopic Organisms” shall include all organisms -microscopic or barely visible to the naked eye, with the exception of -the bacteria. It includes the diatomaceae, chlorophyceae, cyanophyceae, -fungi, protozoa, rotifera, crustacea, bryophyta, and -spongidae found in water.</p> - -<p class='c009'>Fragments of organic matter, silt, mineral matter, zoöglea, etc., -shall be considered as amorphous matter. The recording of amorphous -matter usually serves no useful purpose and shall not be -considered a part of the standard method.</p> - -<p class='c009'><em>Apparatus.</em>—1. A cylindrical funnel about two inches in diameter -at the top, with a straight side for nine inches, narrowed over a distance -of three inches to a bore of one-half inch in diameter, and -terminating in a straight portion of this diameter two and one-half -inches in length. The capacity of this funnel is 500 cc. It shall be -provided at the bottom with a tightly fitting rubber stopper with a -single perforation and a disk of silk bolting cloth over the hole about -three eighths of an inch in diameter.</p> - -<p class='c009'>2. A counting cell consisting of a brass rim closely cemented to a -plate of optical glass. The shape and size of this cell are not essential -but its depth shall be one millimeter. A convenient capacity is -about one cubic centimeter.</p> - -<p class='c009'>3. An ocular micrometer ruled as follows: The ocular micrometer -is commonly of such a size that with a 16 mm. objective and a suitable -<span class='pageno' id='Page_90'>90</span>tube length, the largest square cuts off one square millimeter -on the stage.</p> - -<p class='c009'><em>Procedure.</em>—Filter 250 cc. of the water (more or less according to -the clearness of the sample) through a one-half inch layer of quartz -sand (washed and screened between 60 and 120 mesh sieves) -supported by the disk of bolting cloth and rubber stopper at the -bottom of the funnel. Suction may be applied to hasten the filtration.</p> - -<p class='c009'>Remove the stopper and catch the plug of sand and its entrained -organisms in a small beaker or test tube, washing down the inside -of the funnel into the beaker with 5 cc. of clean (preferably distilled) -water. Agitate the mixture of sand, water, and organisms to -detach the latter from the sand grains, and quickly decant the water -and the organisms in suspension to a test tube. If desired the sand -may then be again washed with 5 cc. water and the wash water added -to the first portion.</p> - -<p class='c009'>Cover the cell partially with a cover glass, and by means of a -pipette run the concentrate under the cover glass until the cell is -completely filled.</p> - -<p class='c009'>Cover and place on the microscope stage in a horizontal position -for examination.</p> - -<p class='c009'>Count the organisms in twenty fields, i. e., twenty cubic millimeters, -estimating their areas in terms of Standard Units.</p> - -<p class='c009'><em>The Standard Unit is the smallest square in the ocular micrometer, -and represents an area 20µ × 20µ, or 400 square microns on the stage.</em></p> - -<p class='c009'>Results shall be expressed in the number of Standard Units of -each kind of micro-organism per cc. and also the total number of -standard units of all kinds per cc. The general directions as to -significant figures given under Turbidity shall apply also to the -microscopical examination.</p> - -<p class='c009'><em>Caution.</em>—Many micro-organisms, especially some of those -causing odors, are so fragile that they are broken up in filtration, -especially if the agitation of the filtrate is too vigorous. A direct -examination of a fresh sample is therefore a useful supplementary -procedure. For the same reason the concentrate should not stand -long before examination. Also some organisms are carried by -specific gravity to the top of the cell which should be scrutinized as -well as the bottom layer each time.</p> - -<p class='c009'>It is always better to examine the micro-organisms in the field -when possible, and for this purpose the sling filter has been devised -<span class='pageno' id='Page_91'>91</span>consisting of a metal funnel slung to a pivoted handle, with a disk -of wire gauze in the detachable lower end to support the sand. -Filtration is hastened by imparting a whirling motion to the whole -and utilizing the centrifugal force thus generated.</p> - -<div class='figcenter id001'> -<img src='images/i_091.jpg' alt='' class='ig001' /> -<div class='ic001'> -<p>THE OCULAR MICROMETER.</p> -</div> -</div> - -<h3 id='MICROSCOPICAL' class='c010'>MICROSCOPICAL BIBLIOGRAPHY.</h3> - - <dl class='dl_3 c002'> - <dt><em>a.</em></dt> - <dd><span class='sc'>Kean, A. L.</span> A new method for the microscopical examination of - water: <cite>Science</cite>, Vol. 13, p. 132, 1889; <cite>Eng. News</cite>, pp. 21, 276, - 1889. - </dd> - <dt><em>b.</em></dt> - <dd><span class='sc'>Sedgwick, W. T.</span> Recent progress in biological water analysis: - <cite>J. N. E. Water Works Assoc.</cite>, Vol. 4, pp. 50–64, 1889. - </dd> - <dt><em>c.</em></dt> - <dd>——. A report of the biological work of the Lawrence Experiment Station: - <cite>Examinations by the State Board of Health of water supplies of Mass., - 1887–90</cite>, pt. 2, Purification of sewage and water, pp. 793–862, 1890. - </dd> - <dt><em>d.</em></dt> - <dd><span class='sc'>Parker, G. H.</span> Report upon the organisms, excepting the bacteria - found in the waters of the State: <cite>Examinations by the State Board of Health of - water supplies of Mass., 1887–90</cite>, pt. 1, Examination of water supplies, pp. - 579–620, 1890. - </dd> - <dt><em>e.</em></dt> - <dd><span class='sc'>Rafter, G. W.</span> The microscopical examination of potable water, D. - Van Nostrand Co., New York, 1910. (Contains bibliography.) -<div><span class='pageno' id='Page_92'>92</span></div> - </dd> - <dt><em>f.</em></dt> - <dd><span class='sc'>Calkins, G. N.</span> The microscopical examination of water: - <cite>Report Mass. State Board of Health</cite>, pp. 397–421, 1892. - </dd> - <dt><em>g.</em></dt> - <dd><span class='sc'>Jackson, D. D.</span> On an improvement in the Sedgwick-Rafter method - for the microscopical examination of drinking water: <cite>Tech. Quart.</cite>, Vol. 9, - pp. 271–4, 1896. - </dd> - <dt><em>h.</em></dt> - <dd><span class='sc'>Whipple, G. C.</span> Experience with the Sedgwick-Rafter method at the - Biological Laboratory of the Boston Water Works: <cite>Tech. Quart.</cite>, Vol. 9, pp. - 275–9, 1896. - </dd> - <dt><em>i.</em></dt> - <dd>——. Microscopy of drinking water, 3d ed., John Wiley & Sons, New York, 1914. (Contains - bibliography.) - </dd> - </dl> - -<div class='chapter'> - <h2 class='c005'>BACTERIOLOGICAL EXAMINATION.</h2> -</div> - -<h3 class='c010'>I. APPARATUS.</h3> - -<p class='c011'>1. <em>Sample Bottles.</em>—Any size, shape or quality of bottle may be -used for a bacterial sample, provided it holds a sufficient amount -to carry out all the tests required and is such that it may be properly -washed and sterilized and will keep the sample uncontaminated -until the analysis is made. Four- or eight-ounce, ground-glass-stoppered -bottles are recommended. These should be protected -by being wrapped in paper, or their necks covered with tin foil, -and should be placed in proper boxes for transportation.</p> - -<p class='c009'>2. <em>Pipettes.</em>—Pipettes may be of any convenient size or shape -provided it is found by actual test that they deliver accurately the -required amount in the manner in which they are used. The error -of calibration shall in no case exceed 2 per cent. Protecting the -pipettes with a cotton stopper is recommended.</p> - -<p class='c009'>3. <em>Dilution Bottles.</em>—Bottles for use in making dilutions should -preferably be of tall form, of such capacity as to hold at least twice -the volume of water actually used. Close-fitting ground-glass stoppers -are preferable, but tight fitting cotton stoppers may be used, -provided due care is taken to prevent contamination and to avoid -loss of volume through wetting of the stopper before mixing has -been accomplished.</p> - -<p class='c009'>4. <em>Petri Dishes.</em>—Petri dishes ten centimeters in diameter shall -be used with glass or porous tops<a id='r211' /><a href='#f211' class='c015'><sup>[211]</sup></a> as preferred. The bottoms of the -dishes shall be as flat as possible so that the medium shall be of -uniform thickness throughout the plate.</p> - -<p class='c009'>5. <em>Fermentation Tubes.</em>—Any type of fermentation tube<a id='r203' /><a href='#f203' class='c015'><sup>[203]</sup></a> may be -used provided it holds at least three times as much medium as the -amount of water to be tested.</p> - -<div> - <span class='pageno' id='Page_93'>93</span> - <h3 class='c010'>II. MATERIALS.<a id='r204'></a><a id='r205'></a><a id='r206'></a><a id='r207'></a><a id='r208'></a></h3> -</div> - -<p class='c011'>1. <em>Water.</em>—Distilled water shall be used in the preparation of -all culture media and reagents.</p> - -<p class='c009'>2. <em>Meat Extract.</em>—Liebig’s meat extract shall be used in place of -meat infusion. Other brands may be substituted for Liebig’s when -comparative tests have shown that they give equivalent results.</p> - -<p class='c009'>3. <em>Peptone.</em>—Armour’s, Digestive Ferments Company’s, Fairchild’s, -or any other peptone which gives equivalent results may be -used.</p> - -<p class='c009'>4. <em>Sugars.</em>—All sugars used shall be of the highest purity obtainable.</p> - -<p class='c009'>5. <em>Agar.</em>—The agar used shall be of the best quality and shall be -dried for one-half hour at 105° C. before weighing. Much of the -agar on the market contains considerable amounts of sea salts.<a id='r221' /><a href='#f221' class='c015'><sup>[221]</sup></a><a id='r225' /><a href='#f225' class='c015'><sup>[225]</sup></a><a id='r228' /><a href='#f228' class='c015'><sup>[228]</sup></a> -These may be removed by soaking in water and draining before use.</p> - -<p class='c009'>6. <em>Gelatin.</em>—The gelatin used shall be of light color, shall contain -not more than a trace of arsenic, copper, sulfides, and shall be free -from preservatives, and of such a melting point that a 10 per cent. -standard nutrient gelatin shall have a melting point of 25° C. or over. -Gelatin shall be dried for one-half hour at 105° C. before weighing.</p> - -<p class='c009'>7. <em>Litmus.</em>—Reagent litmus of highest purity (not litmus cubes) -or azolitmin (Kahlbaum) shall be used for all media requiring a litmus -indicator.</p> - -<p class='c009'>8. <em>General Chemicals.</em>—Special effort shall be made to have all -the other ingredients used for culture media chemically pure.</p> - -<h3 class='c010'>III. METHODS.<a id='r222'></a><a id='r223'></a><a id='r224'></a><a id='r226'></a><a id='r229'></a><a id='r230'></a><a id='r231'></a><a id='r232'></a><a id='r233'></a></h3> - -<h4 class='c016'>1. PREPARATION OF CULTURE MEDIA.</h4> - -<h5 class='c016'>a. <em>Adjustment of Reaction.</em></h5> - -<p class='c011'><em>aa.</em> <em>Phenol Red Method for adjustment to a hydrogen-ion concentration -of P<sub>H+</sub> = 6.8–8.4.</em> Withdraw 5 cc. of the medium, dilute with -5 cc. of distilled water, and add 5 drops of a solution of phenol red -(phenol sulphone phthalein). This solution is made by dissolving -0.04 grams of phenol red in 30 cc. of alcohol and diluting to 100 cc. -with distilled water.</p> - -<p class='c009'>Titrate with a 1:10 dilution of a standard solution of NaOH -(which need not be of known normality) until the phenol red shows -a slight but distinct pink color. Calculate the amount of the standard -NaOH solution which must be added to the medium to reach -<span class='pageno' id='Page_94'>94</span>this reaction. After the addition check the reaction by adding 5 -drops of phenol red to 5 cc. of the medium and 5 cc. of water.</p> - -<p class='c009'><em>bb.</em> <em>Titration with phenolphthalein.</em> (For the convenience of those -who wish to retain the use of this method for the present it is given -here, but it is recommended that as soon as possible the more accurate -method of determining the hydrogen-ion concentration be substituted.)</p> - -<p class='c009'>In a white porcelain dish put 5 cc. of the medium to be tested, -add 45 cc. of distilled water. Boil briskly for one minute. Add -1 cc. of phenolphthalein solution (5 grams of commercial salt to one -liter of 50 per cent. alcohol). Titrate immediately with a n/20 -solution of sodium hydrate. A faint but distinct pink color marks -the true end-point. This color may be precisely described as a -combination of 25 per cent. of red (wave length approximately 658) -with 75 per cent. of white as shown by the disks of the standard color -top made by the Milton Bradley Educational Co., Springfield, Mass.</p> - -<p class='c009'>All reactions shall be expressed with reference to the phenolphthalein -neutral point and shall be stated in percentages of normal acid -or alkali solutions required to neutralize them. Alkaline media -shall be recorded with a minus (-) sign before the percentage of -normal acid needed for their neutralization and acid media with a -plus (+) sign before the percentage of normal alkali solution needed -for their neutralization.</p> - -<p class='c009'>The standard reaction for culture media for water analysis shall -be +1.0 per cent., as determined by tests of the sterilized medium. -As ordinarily prepared, broth and agar will be found to have a -reaction between +0.5 and +1.0. For such media no adjustment -shall be made. The reaction of media containing sugar shall be -neutral to phenolphthalein. Whenever reactions other than the -standard are used, it shall be so stated.</p> - -<h5 class='c016'>b. <em>Sterilization.</em></h5> - -<p class='c011'>All media and dilution water shall be sterilized in the autoclav -at 15 lbs. (120° C.) for 15 minutes after the pressure reaches 15 lbs. -All air must be forced out of the autoclav before the pressure -is allowed to rise. As soon as possible after sterilization the media -shall be removed from the autoclav and cooled rapidly. Rapid -and immediate cooling of gelatin is imperative.</p> - -<p class='c009'>Media shall be sterilized in small containers, and these must not -be closely packed together. No part of the medium shall be more -<span class='pageno' id='Page_95'>95</span>than 2.5 cm. from the outside surface of the glass. All glassware -shall be sterilized in the dry oven at 170° C. for at least 1½ hours.</p> - -<h5 class='c016'>c. <em>Nutrient Broth. To Make One Liter.</em></h5> - -<p class='c011'>1. Add 3 grams of beef extract and 5 grams of peptone to 1,000 cc. -of distilled water.</p> - -<p class='c009'>2. Heat slowly on a steam bath to at least 65° C.</p> - -<p class='c009'>3. Make up lost weight and adjust the reaction to a faint pink -with phenol red, or if the phenolphthalein titration is used, and the -reaction is not already between +0.5 and +1, adjust to +1.</p> - -<p class='c009'>4. Cool to 25° C. and filter through filter paper until clear.</p> - -<p class='c009'>5. Distribute in test-tubes, 10 cc. to each tube.</p> - -<p class='c009'>6. Sterilize in the autoclav at 15 lbs. (120° C.) for 15 minutes -after the pressure reaches 15 lbs.</p> - -<h5 class='c016'>d. <em>Sugar Broths.</em></h5> - -<p class='c011'>Sugar broths shall be prepared in the same general manner as nutrient -broth with the addition of 0.5 per cent. of the required carbohydrate -just before sterilization. The removal of muscle sugar is -unnecessary as the beef extract and peptone are free from any fermentable -carbohydrates. The reaction of sugar broths shall be a -faint pink with phenol red or, if on titration with phenolphthalein -the reaction is not already between neutral and +1, adjust to neutral. -Sterilization shall be in the autoclav at 15 lbs. (120° C.) for -15 minutes after the pressure reaches 15 lbs., provided the total -time of exposure to heat is not more than one-half hour; otherwise -a 10 per cent. solution of the required carbohydrate shall be made in -distilled water and sterilized at 100° C. for 1½ hours, and this solution -shall be added to sterile nutrient broth in amounts sufficient -to make a 0.5 per cent. solution of the carbohydrate and the mixture -shall then be tubed and sterilized at 100° C. for 30 minutes, or it is -permissible to add by means of a sterile pipette directly to a tube of -sterile neutral broth enough of the carbohydrate to make the required -0.5 per cent. The tubes so made shall be incubated at 37° C. -for 24 hours as a test for sterility.</p> - -<h5 class='c016'>e. <em>Nutrient Gelatin. To Make One Liter.</em></h5> - -<p class='c011'>1. Add 3 grams of beef extract and 5 grams of peptone to 1,000 cc. -of distilled water and add 100 grams of gelatin dried for one-half -hour at 105° C. before weighing.</p> - -<p class='c009'><span class='pageno' id='Page_96'>96</span>2. Heat slowly on a steam bath to 65° C. until all gelatin is dissolved.<a id='rG' /><a href='#fG' class='c015'><sup>[G]</sup></a></p> - -<div class='footnote' id='fG'> -<p class='c009'><a href='#rG'>G</a>. The solution of the gelatin will be facilitated by allowing it to soak in the cold one-half hour -before heating.</p> -</div> - -<p class='c009'>3. Make up lost weight and adjust the reaction to a faint pink -with phenol red, or if the phenolphthalein titration is used, and the -reaction is not already between +0.5 and +1, adjust to +1.</p> - -<p class='c009'>4. Filter through cloth and cotton until clear.</p> - -<p class='c009'>5. Distribute in test-tubes, 10 cc. to each tube, or in larger containers -as desired.</p> - -<p class='c009'>6. Sterilize in the autoclav at 15 lbs. (120° C.) for 15 minutes -after the pressure reaches 15 lbs.</p> - -<h5 class='c016'>f. <em>Nutrient Agar. To Make One Liter.</em></h5> - -<p class='c011'>1. Add 3 grams of beef extract, 5 grams of peptone and 12 -grams of agar, dried for one-half hour at 105° C. before weighing, -to 1,000 cc. of distilled water. Boil over a water bath until all -agar is dissolved, and then make up the loss by evaporation.</p> - -<p class='c009'>2. Cool to 45° C. in a cold water bath, then warm to 65° C. in the -same bath, without stirring.</p> - -<p class='c009'>3. Make up lost weight and adjust the reaction to a faint pink -with phenol red, or if the phenolphthalein titration is used, and the -reaction is not already between +0.5 and +1, adjust to +1.</p> - -<p class='c009'>4. Filter through cloth and cotton until clear.</p> - -<p class='c009'>5. Distribute in test-tubes, 10 cc. to each tube, or in larger containers, -as desired.</p> - -<p class='c009'>6. Sterilize in the autoclav at 15 lbs. (120° C.) for 15 minutes -after the pressure reaches 15 lbs.</p> - -<h5 class='c016'>g. <em>Litmus or Azolitmin Solution.</em></h5> - -<p class='c011'>The standard litmus solution shall be a 2 per cent. aqueous -solution of reagent litmus. Powder the litmus, add to the water -and boil for five minutes. The solution usually needs no correction -in reaction and may be at once distributed in flasks or test-tubes -and sterilized as is culture media. It should give a distinctly blue -plate when 1 cc. is added to 10 cc. of neutral culture medium in -a Petri dish.</p> - -<p class='c009'>The standard azolitmin solution shall be a 1 per cent. solution of -Kahlbaum’s azolitmin. Add the azolitmin powder to the water -and boil for five minutes. The solution may need to be corrected -in reaction by the addition of sodium hydrate solution so that it -will be approximately neutral and will give a distinctly blue plate -<span class='pageno' id='Page_97'>97</span>when 1 cc. is added to 10 cc. of neutral culture medium in a Petri -dish. It may be distributed in flasks or test-tubes and sterilized -as is culture media.</p> - -<h5 class='c016'>h. <em>Litmus-lactose-agar.</em></h5> - -<p class='c011'>Litmus-lactose-agar shall be prepared in the same manner as -nutrient agar with the addition of 1 per cent. of lactose just before -sterilization. The reaction shall be a faint pink with phenol red, or, -if on titration with phenolphthalein the reaction is not already -between neutral and +1, adjust to neutral. One cc. of sterilized -litmus or azolitmin solution shall be added to each 10 cc. of the -medium just before it is poured into the Petri dish, or the mixture -may be made in the dish itself.</p> - -<h5 class='c016'>i. <em>Endo’s Medium.</em><a id='r209' /><a href='#f209' class='c015'><sup>[209]</sup></a><a id='r214' /><a href='#f214' class='c015'><sup>[214]</sup></a><a id='r215' /><a href='#f215' class='c015'><sup>[215]</sup></a><a id='r210'></a> <em>To Make One Liter.</em></h5> - -<p class='c011'>1. Add 5 grams of beef extract, 10 grams of peptone and 30 -grams of agar dried for one-half hour at 105° C. before weighing, -to 1,000 cc. of distilled water. Boil on a water bath until all the agar -is dissolved and then make up the loss by evaporation.</p> - -<p class='c009'>2. Cool the mixture to 45° C. in a cold water bath, then warm to -65° C. in the same bath without stirring.</p> - -<p class='c009'>3. Make up lost weight, titrate, and if the reaction is not already -between neutral and +1 adjust to neutral.</p> - -<p class='c009'>4. Filter through cloth and cotton until clear.</p> - -<p class='c009'>5. Distribute 100 cc. or larger known quantities in flasks large -enough to hold the other ingredients which are to be added later.</p> - -<p class='c009'>6. Sterilize in the autoclav at 15 lbs. (120° C.) for 15 minutes after -the pressure reaches 15 lbs.</p> - -<p class='c009'>7. Prepare a 10 per cent. solution of basic fuchsin in 95 per cent. -alcohol, allow to stand 20 hours, decant and filter the supernatant -fluid. This is a stock solution.</p> - -<p class='c009'>8. When ready to make plates melt 100 cc. of agar in streaming -steam or on a water bath. Dissolve 1 gram of lactose in 15 cc. of -distilled water, using heat if necessary. Dissolve 0.25 gram anhydrous -sodium sulphite in 10 cc. water. To the sulphite solution add -0.5 cc. of the fuchsin stock solution. Add the fuchsin-sulphite solution -to the lactose solution and then add the resulting solution to -the melted agar. The lactose used must be chemically pure and the -sulphite solution must be made up fresh.</p> - -<p class='c009'>9. Pour plates and allow to harden thoroughly in the incubator -before use.</p> - -<div> - <span class='pageno' id='Page_98'>98</span> - <h4 class='c016'>2. COLLECTION OF SAMPLE.</h4> -</div> - -<p class='c011'>Samples for bacterial analysis shall be collected in bottles which -have been cleansed with great care, rinsed in clean water, and sterilized -with dry heat for at least one hour and a half at 170° C., or -in the autoclav at 15 lbs. (120° C.) for 15 minutes or longer after the -pressure reaches 15 lbs.</p> - -<p class='c009'>Great care must be exercised to have the samples representative -of the water to be tested and to see that no contamination occurs -at the time of filling the sample bottles.</p> - -<h4 class='c016'>3. STORAGE AND TRANSPORTATION OF SAMPLES.</h4> - -<p class='c011'>Because of the rapid and often extensive changes which may take -place in the bacterial flora of bottled samples when stored even at -temperatures as low as 10° C., it is urged, as of importance, that all -samples be examined as promptly as possible after collection.</p> - -<p class='c009'>The time allowed for storage or transportation of a bacterial -sample between the filling of the sample bottle and the beginning -of the analysis should be not more than six hours for impure -waters and not more than twelve hours for relatively pure waters. -During the period of storage, the temperature shall be kept as -near 10° C. as possible. Any deviation from the above limits -shall be so stated in making reports.</p> - -<h4 class='c016'>4. DILUTIONS.</h4> - -<p class='c011'>Dilution bottles shall be filled with the proper amount of tap -water so that after sterilization they shall contain exactly 9 cc. or -99 cc. as desired. The exact amount of water can only be determined -by experiment with the particular autoclav in use. If desired, -the 9 cc. dilution may be measured out from a flask of sterile -water with a sterile pipette.</p> - -<p class='c009'>Dilution bottles shall be sterilized in the autoclav at 15 lbs. (120° -C.) for 15 minutes after the pressure reaches 15 lbs.</p> - -<p class='c009'>The sample bottle shall be shaken vigorously 25 times and 1 cc. -withdrawn and added to the proper dilution bottles as required. -Each dilution bottle after the addition of the 1 cc. of the sample, -shall be shaken vigorously 25 times before a second dilution is made -from it or before a sample is removed for plating.</p> - -<div> - <span class='pageno' id='Page_99'>99</span> - <h4 class='c016'>5. PLATING.</h4> -</div> - -<p class='c011'>All sample and dilution bottles shall be shaken vigorously 25 -times before samples are removed for plating. Plating shall be done -immediately after the dilutions are made. One cc. of the sample -or dilution shall be used for plating and shall be placed in the Petri -dish, first. Ten cc. of liquefied medium at a temperature of 40° C. -shall be added to the 1 cc. of water in the Petri dish. The cover of -the Petri dish shall be lifted just enough for the introduction of the -pipette or culture medium, and the lips of all test-tubes or flasks -used for pouring the medium shall be flamed. In making litmus-lactose-agar -plates, 1 cc. of sterile litmus or azolitmin solution shall -be added to each 10 cc. of culture medium either in the Petri dish or -before pouring into the Petri dish. The medium and sample in the -Petri dish shall be thoroughly mixed and uniformly spread over the -bottom of the Petri dish by tilting or rotating the dish. All plates -shall be solidified as rapidly as possible after pouring and gelatin -plates shall be placed immediately in the 20° C. incubator and the -agar plates in the 37° C. incubator. Endo plates shall be made by -placing one loopful of the material to be tested on the surface of the -plate and distributing the material with a sterile loop or glass rod.</p> - -<h4 class='c016'>6. INCUBATION.</h4> - -<p class='c011'>All gelatin plates shall be incubated for 48 hours at 20 C. in a -dark, well-ventilated incubator in an atmosphere practically saturated -with moisture.<a id='r227' /><a href='#f227' class='c015'><sup>[227]</sup></a></p> - -<p class='c009'>All agar plates shall be incubated for 24 hours at 37° C. in a dark, -well-ventilated incubator in an atmosphere practically saturated -with moisture. Glass covered plates shall be inverted in the incubator. -Any deviation from the above described method shall be -stated in making reports.</p> - -<h4 class='c016'>7. COUNTING.</h4> - -<p class='c011'>In preparing plates, such amounts of the water under examination -shall be planted as will give from 25 to 250 colonies on a plate;<a id='r202' /><a href='#f202' class='c015'><sup>[202]</sup></a><a id='r201'></a> and -the aim should be always to have at least two plates giving colonies -between these limits. Where it is possible to obtain plates showing -colonies within these limits, only such plates should be considered -in recording results, except where the same amount of water has -been planted in two or more plates, of which one gives colonies -<span class='pageno' id='Page_100'>100</span>within these limits, while the others give less than 25 or more than -250. In such case, the result recorded should be the average of all -the plates planted with this amount of water. Ordinarily it is not -desirable to plant more than 1 cc. of water in a plate; therefore, when -the total number of colonies developing from 1 cc. is less than 25, -it is obviously necessary to record the results as observed, disregarding -the general rule given above.</p> - -<p class='c009'>Counting shall in all cases be done with a lens of 2½ diameter’s -magnification, 3½X. The Engraver’s Lens No. 146 made by the -Bausch & Lomb Optical Company fills the requirements, and is a -convenient lens for the purpose.</p> - -<h4 class='c016'>8. THE TEST FOR THE PRESENCE OF MEMBERS OF THE B. COLI GROUP.</h4> - -<p class='c011'>It is recommended that the B. coli group be considered as including -all non-spore-forming bacilli which ferment lactose with gas -formation and grow aërobically on standard solid media.</p> - -<p class='c009'>The formation of 10 per cent. or more of gas in a standard lactose -broth fermentation tube within 24 hours at 37° C. is presumptive -evidence of the presence of members of the B. coli group, since the -majority of the bacteria which give such a reaction belong to this -group.</p> - -<p class='c009'>The appearance of aërobic lactose-splitting colonies on lactose-litmus-agar -or Endo’s medium plates made from a lactose broth -fermentation tube in which gas has formed confirms to a considerable -extent the presumption that gas-formation in the fermentation -tube was due to the presence of members of the B. coli group.</p> - -<p class='c009'>To complete the demonstration of the presence of B. coli -as above defined, it is necessary to show that one or more of these -aërobic plate colonies consists of non-spore-forming bacilli which, -when inoculated into a lactose broth fermentation tube, form gas.</p> - -<p class='c009'>It is recommended that the standard tests for the B. coli group -be either (A) the <em>Presumptive</em>, (B) the <em>Partially Confirmed</em>, or (C) -the <em>Completed</em> test as hereafter defined, each test being applicable -under the circumstances specified.</p> - -<h5 class='c016'>A. PRESUMPTIVE TEST.</h5> - -<p class='c011'>1. Inoculate a series of fermentation tubes with appropriate -graduated quantities of the water to be tested. In every fermentation -tube there must always be at least three times as much medium -as the amount of water to be tested. When necessary to examine -larger amounts than 10 cc. as many tubes as necessary shall be -inoculated with 10 cc. each.</p> - -<p class='c009'>2. Incubate these tubes at 37° C. for 48 hours. Examine each -<span class='pageno' id='Page_101'>101</span>tube at 24 and 48 hours, and record gas-formation. The records -should be such as to distinguish between:</p> - -<p class='c009'>(a) Absence of gas-formation.</p> - -<p class='c009'>(b) Formation of gas occupying less than ten per cent. (10%) -of the closed arm.</p> - -<p class='c009'>(c) Formation of gas occupying more than ten per cent. (10%) -of the closed arm.</p> - -<p class='c009'>More detailed records of the amount of gas formed, though -desirable for purposes of study, are not necessary for carrying out -the standard tests prescribed.</p> - -<p class='c009'>3. The formation within 24 hours of gas occupying more than -ten per cent. (10%) of the closed arm of fermentation tube constitutes -<em>a positive presumptive test</em>.</p> - -<p class='c009'>4. If no gas is formed in 24 hours, or if the gas formed is less than -ten per cent. (10%), the incubation shall be continued to 48 hours. -The presence of gas in any amount in such a tube at 48 hours constitutes -<em>a doubtful test</em>, which in all cases requires confirmation.</p> - -<p class='c009'>5. The absence of gas formation after 48 hours’ incubation constitutes -<em>a negative test</em>. (An arbitrary limit of 48 hours’ observation -doubtless excludes from consideration occasional members of the B. -coli group which form gas very slowly, but for the purposes of a -standard test the exclusion of these occasional slow gas-forming -organisms is considered immaterial.)</p> - -<h5 class='c016'>B. PARTIALLY CONFIRMED TEST.</h5> - -<p class='c011'>1. Make one or more Endo’s medium or lactose-litmus-agar -plates from the tube which, after 48 hours’ incubation, shows gas -formation from the smallest amount of water tested. (For example, -if the water has been tested in amounts of 10 cc., 1 cc., and 0.1 cc., -and gas is formed in 10 cc., and 1 cc., not in 0.1 cc., the test need be -confirmed only in the 1 cc. amount.)</p> - -<p class='c009'>2. Incubate the plates at 37° C., 18 to 24 hours.</p> - -<p class='c009'>3. If typical colon-like red colonies have developed upon the plate -within this period, the confirmed test may be considered positive.</p> - -<p class='c009'>4. If, however, no typical colonies have developed within 24 -hours, the test cannot yet be considered definitely negative, since -it not infrequently happens that members of the B. coli group fail -to form typical colonies on Endo’s medium or lactose-litmus-agar -plates, or that the colonies develop slowly. In such case, it is always -necessary to complete the test as directed under “C” 2 and 3.</p> - -<div> - <span class='pageno' id='Page_102'>102</span> - <h5 class='c016'>C. COMPLETED TEST.</h5> -</div> - -<p class='c011'>1. From the Endo’s medium or lactose-litmus-agar plate made -as prescribed under “B,” fish at least two typical colonies, transferring -each to an agar slant and a lactose broth fermentation tube.</p> - -<p class='c009'>2. If no typical colonies appear upon the plate within 24 hours, -the plate should be reincubated another 24 hours, after which at -least two of the colonies considered to be most likely B. coli, whether -typical or not, shall be transferred to agar slants and lactose broth -fermentation tubes.</p> - -<p class='c009'>3. The lactose broth fermentation tubes thus inoculated shall -be incubated until gas formation is noted; the incubation not to -exceed 48 hours. The agar slants shall be incubated at 37° C. for -48 hours, when a microscopic examination shall be made of at least -one culture, selecting one which corresponds to one of the lactose -broth fermentation tubes which has shown gas-formation.</p> - -<p class='c009'>The formation of gas in lactose broth and the demonstration of -non-spore-forming bacilli in the agar culture shall be considered a -satisfactory completed test, demonstrating the presence of a member -of the B. coli group.</p> - -<p class='c009'>The absence of gas-formation in lactose broth or failure to -demonstrate non-spore-forming bacilli in a gas-forming culture constitutes -a negative test.</p> - -<h5 class='c016'>APPLICATION OF PRESUMPTIVE, PARTIALLY CONFIRMED, AND COMPLETED TESTS.</h5> - -<h6 class='c016'>A. The Presumptive Test.</h6> - -<p class='c028'>1. When definitely positive, that is showing more than 10 per -cent. (10%) of gas in 24 hours, is sufficient:</p> - -<p class='c029'>(a) As applied to all except the smallest gas-forming portion -of each sample in all examinations.</p> - -<p class='c029'>(b) As applied to the smallest gas-forming portion in the -examination of sewage or of water showing relatively -high pollution, such that its fitness for use as drinking -water does not come into consideration. This applies -to the routine examinations of raw water in connection -with control of the operation of purification plants.</p> - -<p class='c030'>2. When definitely negative, that is showing no gas in 48 hours, -is final and therefore sufficient in all cases.</p> - -<p class='c030'><span class='pageno' id='Page_103'>103</span>3. When doubtful, that is showing gas less than 10 per cent. -(10%) (or none) in 24 hours, with gas either more or less -than 10 per cent. in 48 hours, must always be confirmed.</p> - -<h6 class='c016'>B. The Partially Confirmed Test.</h6> - -<p class='c028'>1. When definitely positive, that is, showing typical plate -colonies within 24 hours, is sufficient:</p> - -<p class='c029'>(a) When applied to confirm a doubtful presumptive test -in cases where the latter, if definitely positive, would -have been sufficient.</p> - -<p class='c029'>(b) In the routine examination of water supplies where a -sufficient number of prior examinations have established -a satisfactory index of the accuracy and significance of -this test in terms of the completed test.</p> - -<p class='c030'>2. When doubtful, that is, showing colonies of doubtful or -negative appearance in 24 hours, must always be completed.</p> - -<h6 class='c016'>C. The Completed Test.</h6> - -<p class='c028'>The completed test is required as applied to the smallest gas-forming -portion of each sample in all cases other than those -noted as exceptions under the “presumptive” and the “partially -confirmed” tests.</p> - -<p class='c030'>The completed test is required in <em>all</em> cases where the result of -the confirmed test has been doubtful.</p> - -<h4 class='c016'>9. EXPRESSION OF RESULTS.<a id='r213'></a></h4> - -<p class='c011'>In order to avoid fictitious accuracy and yet to express the numerical -results by a method consistent with the precision of the work, -the numbers of colonies of bacteria per cubic centimeter shall be -recorded as follows:<a id='r212' /><a href='#f212' class='c015'><sup>[212]</sup></a></p> - -<table class='table1' summary=''> - <tr><td class='c012' colspan='6'><span class='small'>Number of bacteria per cc.</span></td></tr> - <tr> - <td class='c019'>From</td> - <td class='c020'>1</td> - <td class='c019'>to</td> - <td class='c020'>50</td> - <td class='c019'>shall be recorded as found</td> - <td class='c021'> </td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>51</td> - <td class='c019'>〃</td> - <td class='c020'>100</td> - <td class='c020'>   〃 〃 〃 to the nearest</td> - <td class='c021'>5</td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>101</td> - <td class='c019'>〃</td> - <td class='c020'>250</td> - <td class='c019'>〃 〃 〃 〃 〃 〃</td> - <td class='c021'>10</td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>251</td> - <td class='c019'>〃</td> - <td class='c020'>500</td> - <td class='c019'>〃 〃 〃 〃 〃 〃</td> - <td class='c021'>25</td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>501</td> - <td class='c019'>〃</td> - <td class='c020'>1,000</td> - <td class='c019'>〃 〃 〃 〃 〃 〃</td> - <td class='c021'>50</td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>1,001</td> - <td class='c019'>〃</td> - <td class='c020'>10,000</td> - <td class='c019'>〃 〃 〃 〃 〃 〃</td> - <td class='c021'>100</td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>10,001</td> - <td class='c019'>〃</td> - <td class='c020'>50,000</td> - <td class='c019'>〃 〃 〃 〃 〃 〃</td> - <td class='c021'>500</td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>50,001</td> - <td class='c019'>〃</td> - <td class='c020'>100,000</td> - <td class='c019'>〃 〃 〃 〃 〃 〃</td> - <td class='c021'>1,000</td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>100,001</td> - <td class='c019'>〃</td> - <td class='c020'>500,000</td> - <td class='c019'>〃 〃 〃 〃 〃 〃</td> - <td class='c021'>10,000</td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>500,001</td> - <td class='c019'>〃</td> - <td class='c020'>1,000,000</td> - <td class='c019'>〃 〃 〃 〃 〃 〃</td> - <td class='c021'>50,000</td> - </tr> - <tr> - <td class='c019'>〃</td> - <td class='c020'>1,000,001</td> - <td class='c019'>〃</td> - <td class='c020'>10,000,000</td> - <td class='c019'>〃 〃 〃 〃 〃 〃</td> - <td class='c021'>100,000</td> - </tr> -</table> - -<p class='c009'>This applies to the gelatin count at 20° C. and to the agar count -at 37° C.</p> - -<div> - <span class='pageno' id='Page_104'>104</span> - <h5 class='c016'><span class='sc'>Summary of steps involved in making presumptive, partially confirmed and completed tests for b. coli.</span></h5> -</div> - -<table class='table3' summary=''> - <tr> - <th class='btt bbt c031' colspan='3'>Steps in procedure.</th> - <th class='btt bbt blt c032'>Further procedure required.</th> - </tr> - <tr> - <td class='c033' colspan='3'>I. Inoculate lactose broth fermentation tubes; incubate 24 hours at 37° C.; observe gas-formation in each tube.</td> - <td class='blt c034'> </td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>1. Gas-formation, 10 per cent. or more; constitutes positive presumptive test.</td> - <td class='blt c034'> </td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033'> </td> - <td class='c033'>(a) For other than smallest portion of any sample showing gas at this time, and for all portions, including smallest, of sewage and raw water this test is sufficient.</td> - <td class='blt c034'>None</td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033'> </td> - <td class='c033'>(b) For smallest gas-forming portion, except in examinations of sewage and raw water.</td> - <td class='blt c034'>III</td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>2. Gas-formation less than 10 per cent. in 24 hours; inconclusive.</td> - <td class='blt c034'>II</td> - </tr> - <tr> - <td class='c033' colspan='3'>II. Incubate an additional 24 hours, making a total of 48 hours’ incubation; observe gas-formation.</td> - <td class='blt c034'> </td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>1. Gas-formation, any amount; constitutes doubtful test, which must always be carried further.</td> - <td class='blt c034'>III</td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>2. No gas-formation in 48 hours; constitutes final negative test.</td> - <td class='blt c034'>None</td> - </tr> - <tr> - <td class='c033' colspan='3'>III. Make plate from smallest gas-forming portion of sample under examination; incubate 18 to 24 hours; observe colonies.</td> - <td class='blt c034'> </td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>1. One or more colonies typical in appearance.</td> - <td class='blt c034'> </td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033'> </td> - <td class='c033'>(a) If only “partially confirmed” test is required</td> - <td class='blt c034'>None</td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033'> </td> - <td class='c033'>(b) If completed test is required, select two typical colonies for identification.</td> - <td class='blt c034'>V</td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>2. No typical colonies.</td> - <td class='blt c034'>IV</td> - </tr> - <tr> - <td class='c033' colspan='3'>IV. Replace plate in incubator for an additional 18 to 24 hours; then, whether colonies appear typical or not, select at least two of those which most nearly resemble B. coli.</td> - <td class='blt c034'>V</td> - </tr> - <tr> - <td class='c033' colspan='3'>V. Transfer each colony fished to:</td> - <td class='blt c034'> </td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>1. Lactose broth fermentation tube; incubate not more than 48 hours at 37° C. Observe gas-formation.</td> - <td class='blt c034'>None</td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>2. Agar slant; incubate 48 hours at 37° C.</td> - <td class='blt c034'> </td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033'> </td> - <td class='c033'>(a) If gas formed in lactose broth tube inoculated with corresponding culture</td> - <td class='blt c034'>VI</td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033'> </td> - <td class='c033'>(b) If no gas formed in corresponding lactose broth tube, test is completed and negative.</td> - <td class='blt c034'>None</td> - </tr> - <tr> - <td class='c033' colspan='3'>VI. Make stained cover-slip or slide preparation, and examine microscopically.</td> - <td class='blt c034'> </td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>1. If preparation shows non-spore-forming bacilli in apparently pure culture, demonstration of B. coli is completed.</td> - <td class='blt c034'>None</td> - </tr> - <tr> - <td class='c033'> </td> - <td class='c033' colspan='2'>2. If preparation fails to show non-spore-forming bacilli or shows them mixed with spore-bearing forms or bacteria of other morphology.</td> - <td class='blt c034'>VII</td> - </tr> - <tr> - <td class='bbt c033' colspan='3'>VII. Replate, to obtain assuredly pure culture, select several colonies of bacilli and repeat steps V and VI.</td> - <td class='bbt blt c034'> </td> - </tr> -</table> - -<p class='c009'><span class='pageno' id='Page_105'>105</span>In order that tests for B. coli may have quantitative significance, -the following general principles and rules should be observed:</p> - -<p class='c009'>Ordinarily not less than three portions of each sample should be -tested, the portions being even decimal multiples or fractions of a -cubic centimeter; for example, 10 cc., 1 cc., 0.1 cc., .01 cc., etc. -It is essential that the dilutions should be such that the largest -amount gives a positive test (unless the water is such as to give -negative tests in 10 cc.), and the smallest dilution, a negative result. -To insure this result, it is often necessary to plant four or five dilutions, -especially in the examination of a sample of entirely unknown -quality. The quantitative value of a series of tests is lost, unless all -or at least a large proportion of the smallest dilutions tested have -given negative results.</p> - -<p class='c009'>In reporting a single test, it is preferable merely to record results -as observed, indicating the amounts tested and the result in each, -rather than to attempt expression of the result in numbers of B. -coli per cc. In summarizing the results of a series of tests, however, -it is desirable, for the sake of simplicity, to express the results in -terms of the numbers of B. coli per cc., or per 100 cc. To convert -results of fermentation tests to this form, the result of each test is -recorded as indicating a number of B. coli per cc. equal to the -reciprocal of the smallest decimal or multiple fraction of a cubic -centimeter giving a positive result. For example, the result: -10 cc. +; 1 cc. +; 0.1 cc. -; would be recorded as indicating one B. -coli per cc. An exception should be made in the case where a negative -result is obtained in an amount larger than the smallest portion -giving a positive result; for example, in a result such as: 10 cc. -+; 1 cc. -; 0.1 cc. +. In such case, the result should be recorded -as indicating a number of B. coli per cc. equal to the reciprocal of -the dilution next larger than the smallest one giving a positive test, -this being a more probable result.</p> - -<p class='c009'>Where tests are made in amounts larger than 1 cc., giving average -results less than one B. coli per cc., it is more convenient to express -results in terms of the numbers of B. coli per 100 cc.</p> - -<p class='c009'>The following table illustrates the method of recording and averaging -results of B. coli tests:</p> - -<table class='table1' summary=''> - <tr><td class='c012' colspan='6'><span class='pageno' id='Page_106'>106</span></td></tr> - <tr> - <th class='c035' colspan='4'>Result of Tests in Amounts Designated.</th> - <th class='c036' colspan='2'>Indicated Number of B. coli.</th> - </tr> - <tr> - <th class='c035'>10 cc.</th> - <th class='c035'>1 cc.</th> - <th class='c035'>0.1 cc.</th> - <th class='c035'>.01 cc.</th> - <th class='c035'>per cc.</th> - <th class='c036'>per 100 cc.</th> - </tr> - <tr> - <td class='c035'>+</td> - <td class='c035'>−</td> - <td class='c035'>−</td> - <td class='c035'>−</td> - <td class='c037'>0.1</td> - <td class='c038'>10.</td> - </tr> - <tr> - <td class='c035'>+</td> - <td class='c035'>+</td> - <td class='c035'>−</td> - <td class='c035'>−</td> - <td class='c037'>1.0</td> - <td class='c038'>100.</td> - </tr> - <tr> - <td class='c035'>+</td> - <td class='c035'>+</td> - <td class='c035'>+</td> - <td class='c035'>−</td> - <td class='c037'>10.0</td> - <td class='c038'>1,000.</td> - </tr> - <tr> - <td class='c035'>+</td> - <td class='c035'>+</td> - <td class='c035'>+</td> - <td class='c035'>+</td> - <td class='c037'>100.0</td> - <td class='c038'>10,000.</td> - </tr> - <tr> - <td class='c035'>+</td> - <td class='c035'>+</td> - <td class='c035'>−</td> - <td class='c035'>+</td> - <td class='c037'>10.0</td> - <td class='c038'>1,000.</td> - </tr> - <tr> - <td class='c035'> </td> - <td class='c035'> </td> - <td class='c035'> </td> - <td class='c035'> </td> - <td class='c037'><hr /></td> - <td class='c038'><hr /></td> - </tr> - <tr> - <td class='c039' colspan='4'>Totals (for estimating averages)</td> - <td class='c037'>121.1</td> - <td class='c038'>12,110.</td> - </tr> - <tr> - <td class='c039' colspan='4'>Average of 5 tests</td> - <td class='c037'>24.0</td> - <td class='c038'>2,422.</td> - </tr> -</table> - -<p class='c009'>The above method of expressing results is not mathematically -altogether correct. The average number of B. coli per cc., as thus -estimated, is not precisely the most probable number calculated by -application of the theory of probability.<a id='r220' /><a href='#f220' class='c015'><sup>[220]</sup></a> To apply this theory to a -correct mathematical solution of any considerable series of results -involves, however, mathematical calculations so complex as to be -impracticable of application in general practice. The simpler -method given is therefore considered preferable, since it is easily -applied and the results so expressed are readily comprehensible.</p> - -<p class='c009'>In order that results as reported may be checked and carefully -valuated, it is necessary that the report should show not only the -average number of B. coli per cc., but also the number of samples -examined; and, for each dilution, the total number of tests made, and -the number (or per cent.) positive.</p> - -<h4 class='c016'>10. INTERPRETATION OF RESULTS.</h4> - -<p class='c011'>While it is not within the province of this report to suggest the -proper interpretation of results obtained by the use of the methods -herein specified as standard, the committee feels that a word of -caution should be given regarding the significance of the presence -in a water of members of the B. coli group as defined in this report. -Recent work seems to indicate that the B. coli group as herein -defined consists of organisms of both fecal and non-fecal origin. -Therefore care must be exercised in judging the sanitary quality -of a water solely from the determination of the presence of members -of the group.</p> - -<h4 class='c016'>11. DIFFERENTIATION OF FECAL FROM NON-FECAL MEMBERS OF THE B. COLI GROUP.</h4> - -<p class='c011'>(1) At least 10 cultures should be used. If possible these should -be subcultured from plates made direct from the water since all of -the cultures obtained by plating from fermentation tubes may be -<span class='pageno' id='Page_107'>107</span>descendants of a single cell in the water. If cultures from water -plates are not available those obtained from plates made as prescribed -under B (p. <a href='#Page_101'>101</a>) may be used.</p> - -<p class='c009'>(2) Inoculate each culture into dextrose potassium phosphate -broth,<a id='rH' /><a href='#fH' class='c015'><sup>[H]</sup></a> adonite broth, and gelatin. For additional confirmatory -evidence inoculation may be made into tryptophane broth,<a id='rI' /><a href='#fI' class='c015'><sup>[I]</sup></a> and -saccharose broth. The dextrose broth must be incubated at 30°. -Other sugar broths may be incubated at 30° or 37° as convenient. -Gelatin should be incubated at 20°.</p> - -<div class='footnote' id='fH'> -<p class='c009'><a href='#rH'>H</a>. (a) <em>Peptone Medium for the Methyl Red Test. To Make One Liter.</em></p> - -<p class='c009'>1. To 800 cc. of distilled water add 5 grams of Proteose-Peptone, Difco., or Witte’s Peptone (other -peptones should not be substituted), 5 grams c. p. dextrose, and 5 grams dipotassium hydrogen -phosphate (K<sub>2</sub>HPO<sub>4</sub>). A dilute solution of the K<sub>2</sub>HPO<sub>4</sub> should give a distinct pink with phenolphthalein.</p> - -<p class='c009'>2. Heat with occasional stirring over steam for twenty minutes.</p> - -<p class='c009'>3. Filter through folded filter paper, cool to 20° C. and dilute to 1,000 cc. with distilled water.</p> - -<p class='c009'>4. Distribute 10 cc. portions in sterilized test-tubes.</p> - -<p class='c009'>5. Sterilize by the intermittent method for 20 minutes on three successive days.</p> -</div> - -<div class='footnote' id='fI'> -<p class='c009'><a href='#rI'>I</a>. <em>Tryptophane Broth for Indol Test.</em></p> - -<p class='c009'>To 1,000 cc. of distilled water add 0.3 gram tryptophane, 5 grams dipotassium hydrogen phosphate -(K<sub>2</sub>HPO<sub>4</sub>), and 1 gram peptone. Heat until ingredients are thoroughly dissolved, tube (6 to 8 -cc.), and sterilize in autoclave for 15 minutes after the pressure reaches 15 pounds. Some American -peptones are standardized to contain a uniform amount of tryptophane. If such peptone is used -the tryptophane in the above formula may be omitted and the peptone increased to 5 grams.</p> -</div> - -<p class='c009'>(3) After 48 hours record gas formation in adonite and saccharose -broths. Determine indol formation in tryptophane broth by -adding drop by drop, to avoid mixing with the medium, about 1 -cc. of a 2 per cent. alcoholic solution of p-dimethyl amido-benzaldehyd, -then a few drops of concentrated hydrochloric acid. The -presence of indol is indicated by a red color which is soluble in chloroform. -There may be some unconverted tryptophane still present -which will give a distinctly blue color which is insoluble in chloroform. -A mixture of the two will be either blue or violet. If from -such a mixture of colors the red of indol be extracted with chloroform -proof of the presence of indol will be complete.</p> - -<p class='c009'>(4) After 5 days apply methyl red test and Voges-Proskauer -test to dextrose broth.</p> - -<h5 class='c016'><em>Methyl Red Test.</em><a id='rJ' /><a href='#fJ' class='c015'><sup>[J]</sup></a></h5> - -<p class='c011'>Indicator solution.—Dissolve 0.1 gram methyl red in 300 cc. -alcohol and dilute to 500 cc. with distilled water.</p> - -<div class='footnote' id='fJ'> -<p class='c009'><a href='#rJ'>J</a>. (b) <em>Synthetic Medium for the Methyl Red Test.</em> To Make One Liter. Dissolve 7 grams Na<sub>2</sub>HPO<sub>4</sub> -(anhydrous) or 8.8 grams Na<sub>2</sub>HPO<sub>4</sub>.2H<sub>2</sub>O, 2 grams KHphthalate, 1 gram aspartic acid, and 4 grams -dextrose in about 800 cc. of warm distilled water. When solution is complete, cool and make up to -1 liter at room temperature. Heat in an autoclave for 15 minutes after the pressure has reached -15 pounds, provided the total time of exposure to heat is not more than one-half hour. The hydrogen-ion -concentration of the medium is fixed by the composition. It should be very close to P<sub>H</sub> 7.0, -slightly red with phenol red. All materials should be recrystallized or if used from stock furnished -by manufacturers, should be carefully examined. The di-sodium hydrogen phosphate may be used -either as the anhydrous salt obtained by dessication in vacuo at 100° C. or else as the salt containing -two molecules of water of crystallization. This is obtained by exposing the recrystallized Na<sub>2</sub>HPO<sub>4</sub>.12H<sub>2</sub>O -for two weeks. Use 0.88 per cent. of Na<sub>2</sub>HPO<sub>4</sub>.2H<sub>2</sub>O.</p> -</div> - -<p class='c009'>Procedure in test.—1. To 5 cc. of each culture add 5 drops of -methyl red solution.</p> - -<p class='c009'><span class='pageno' id='Page_108'>108</span>2. Record distinct red color as methyl red +, distinct yellow -color as methyl red -, and intermediate colors as ?.</p> - -<h5 class='c016'><em>Voges-Proskauer Test.</em><a id='r216' /><a href='#f216' class='c015'><sup>[216]</sup></a><a id='r217'></a><a id='r218'></a><a id='r219'></a></h5> - -<p class='c011'>To the remaining 5 cc. of medium add 5 cc. of a 10 per cent. -solution of potassium hydroxide. Allow to stand over night. A -positive test is indicated by an eosin pink color.</p> - -<p class='c009'>(5) Gelatin tubes should not be pronounced negative until they -have been incubated at least 15 days.</p> - -<p class='c009'>The following group reactions indicate the source of the culture -with a high degree of probability:</p> - -<table class='table2' summary=''> - <tr> - <td class='brt c026'>Methyl red +</td> - <td class='c026' rowspan='6'>B. coli of fecal origin.</td> - </tr> - <tr> - <td class='brt c026'>Voges-Proskauer −</td> - - </tr> - <tr> - <td class='brt c026'>Gelatin −</td> - - </tr> - <tr> - <td class='brt c026'>Adonite −</td> - - </tr> - <tr> - <td class='brt c026'>Indol, usually +</td> - - </tr> - <tr> - <td class='brt c026'>Saccharose, usually −</td> - - </tr> - <tr><td> </td></tr> - <tr> - <td class='brt c026'>Methyl red −</td> - <td class='c026' rowspan='6'>B. aërogenes of fecal origin.</td> - </tr> - <tr> - <td class='brt c026'>Voges-Proskauer +</td> - - </tr> - <tr> - <td class='brt c026'>Gelatin −</td> - - </tr> - <tr> - <td class='brt c026'>Adonite +</td> - - </tr> - <tr> - <td class='brt c026'>Indol, usually −</td> - - </tr> - <tr> - <td class='brt c026'>Saccharose +</td> - - </tr> - <tr><td> </td></tr> - <tr> - <td class='brt c026'>Methyl red −</td> - <td class='c026' rowspan='6'>B. aërogenes, probably not of fecal origin.</td> - </tr> - <tr> - <td class='brt c026'>Voges-Proskauer +</td> - - </tr> - <tr> - <td class='brt c026'>Gelatin −</td> - - </tr> - <tr> - <td class='brt c026'>Adonite −</td> - - </tr> - <tr> - <td class='brt c026'>Indol, usually −</td> - - </tr> - <tr> - <td class='brt c026'>Saccharose +</td> - - </tr> - <tr><td> </td></tr> - <tr> - <td class='brt c026'>Methyl red −</td> - <td class='c026' rowspan='6'>B. cloacae, may or may not be of fecal origin.</td> - </tr> - <tr> - <td class='brt c026'>Voges-Proskauer +</td> - - </tr> - <tr> - <td class='brt c026'>Gelatin +</td> - - </tr> - <tr> - <td class='brt c026'>Adonite +</td> - - </tr> - <tr> - <td class='brt c026'>Indol, usually −</td> - - </tr> - <tr> - <td class='brt c026'>Saccharose +</td> - - </tr> -</table> - -<h4 id='PROCEDURE' class='c016'>12. ROUTINE PROCEDURE FOR EXAMINATION OF SAMPLES OF WATER.</h4> - -<p class='c040'><em>First Day</em>:</p> - -<p class='c041'>1. Prepare dilutions as required.</p> - -<p class='c041'>2. Make two (2) gelatin plates from each dilution, and incubate -at 20° C.</p> - -<p class='c041'>3. Make two (2) agar plates from each dilution, and incubate -at 37° C.</p> - -<p class='c041'><span class='pageno' id='Page_109'>109</span>4. Inoculate lactose broth fermentation tubes with appropriate -amounts for B. coli tests, inoculating two (2) tubes -with each amount.</p> - -<p class='c009'>Note:—Where repeated tests are made of water from the same -source, as is customary in the control of public supplies, it is not -necessary to make duplicate plates or fermentation tubes in each -dilution. It is sufficient, in such circumstances, to make duplicate -plates only from the dilution which will most probably give from -25 to 250 colonies per plate.</p> - -<p class='c042'><em>Second Day</em>:</p> - -<p class='c041'>1. Count the agar plates made on the first day.</p> - -<p class='c041'>2. Record the number of lactose broth fermentation tubes -which show 10 per cent. (10%) or more of gas.</p> - -<p class='c009'>Note:—In case only the presumptive test for B. coli is required, -fermentation tubes showing more than 10 per cent. (10%) of gas at -this time may be discarded.</p> - -<p class='c042'><em>Third Day</em>:</p> - -<p class='c041'>1. Count gelatin plates made on first day.</p> - -<p class='c041'>2. Record the number of additional fermentation tubes which -show 10 per cent. (10%) or more of gas.</p> - -<p class='c041'>3. Make a lactose-litmus-agar or Endo’s medium plate from -the smallest portion of each sample showing gas. Incubate -plate at 37° C.</p> - -<p class='c009'>Note:—In case the smallest portion in which gas has been formed -shows less than 10 per cent. (10%) of gas, it is well to make a plate -also from the next larger portion, so that, in case the smallest portion -gives a negative end result it may still be possible to demonstrate -B. coli in the next larger dilution.</p> - -<p class='c042'><em>Fourth Day</em>:</p> - -<p class='c041'>1. Examine Endo’s medium or lactose-litmus-agar plates. If -typical colonies have developed, select two and transfer -each to a lactose broth fermentation tube and an agar slant, -both of which are to be incubated at 37° C.</p> - -<p class='c041'>2. If no typical B. coli colonies are found, incubate the plates -another 24 hours.</p> - -<p class='c042'><em>Fifth Day</em>:</p> - -<p class='c041'>1. Select at least two colonies, whether typical or not, from the -Endo’s medium or lactose-litmus-agar plates which have been -incubated an additional 24 hours; transfer each to a lactose -<span class='pageno' id='Page_110'>110</span>broth fermentation tube and an agar slant, and complete -the test as for typical colonies.</p> - -<p class='c041'>2. Examine lactose broth fermentation tubes inoculated from -plates on the previous day. Tubes in which gas has been -formed may be discarded after the result has been recorded. -Those in which no gas has formed should be incubated an -additional 24 hours.</p> - -<p class='c042'><em>Sixth Day</em>:</p> - -<p class='c041'>1. Examine lactose broth fermentation tubes reincubated the -previous day.</p> - -<p class='c041'>2. Examine microscopically agar slants corresponding to lactose -fermentation tubes inoculated from plate colonies and -showing gas-formation.</p> - -<h3 id='BACTERIOLOGICAL' class='c010'>BACTERIOLOGICAL BIBLIOGRAPHY.</h3> - -<div class='footnote' id='f201'> -<p class='c011'><a href='#r201'>201</a>. <span class='sc'>Bovie, W. T.</span> A Direct Reading Potentiometer for Measuring and Recording -both the Actual and the Total Reaction of Solutions. <cite>Jour. Med. -Research</cite>, 33, 1915–16, 295.</p> -</div> - -<div class='footnote' id='f202'> -<p class='c009'><a href='#r202'>202</a>. <span class='sc'>Breed, R. S.</span> and <span class='sc'>Dotterrer, W. D.</span> The Number of Colonies Allowable -on Satisfactory Agar Plates. <cite>Jour. of Bact.</cite>, 1, 1916, 321.</p> -</div> - -<div class='footnote' id='f203'> -<p class='c009'><a href='#r203'>203</a>. <span class='sc'>Browne, W. W.</span> A Comparative Study of the Smith Fermentation Tube -and the Inverted Vial in the Determination of Sugar Fermentation. <cite>Amer. -Jour. of Public Health</cite>, 3, 1913, 701.</p> -</div> - -<div class='footnote' id='f204'> -<p class='c009'><a href='#r204'>204</a>. <span class='sc'>Clark, W. M.</span> An Hydrogen Electrode Vessel. <cite>Jour. Biol. Chem.</cite>, 23, -1915, 475.</p> -</div> - -<div class='footnote' id='f205'> -<p class='c009'><a href='#r205'>205</a>. <span class='sc'>Clark, W. M.</span> The “Reaction” of Bacteriological Culture Media. <cite>Jour. -of Inf. Diseases</cite>, 17, 1915, 109.</p> -</div> - -<div class='footnote' id='f206'> -<p class='c009'><a href='#r206'>206</a>. <span class='sc'>Clark, W. M.</span> The Final Hydrogen Ion Concentrations of Cultures of -Bacillus Coli. <cite>Science</cite>, n. s. 42, 1915, 71.</p> -</div> - -<div class='footnote' id='f207'> -<p class='c009'><a href='#r207'>207</a>. <span class='sc'>Clark, W. M.</span> and <span class='sc'>Lubs, H. A.</span> Hydrogen Electrode Potentials of Phthalate, -Phosphate, and Borate Buffer Mixtures. <cite>Jour. Biol. Chem.</cite>, 25, 1916, 479.</p> -</div> - -<div class='footnote' id='f208'> -<p class='c009'><a href='#r208'>208</a>. <span class='sc'>Clark, W. M.</span> and <span class='sc'>Lubs, H. A.</span> The Differentiation of Bacteria of the -Colon-Aërogenes Family by the Use of Indicators. <cite>Jour. of Inf. Diseases</cite>, -17, 1915, 160.</p> -</div> - -<div class='footnote' id='f209'> -<p class='c009'><a href='#r209'>209</a>. <span class='sc'>Endo, S.</span> <span lang="de" xml:lang="de">Ueber ein Verfahren zum Nachweis der Typhusbacillen Centbl. -f. Bakt. <cite>Erste Abt.</cite></span>, 35, 1903–4, 109.</p> -</div> - -<div class='footnote' id='f210'> -<p class='c009'><a href='#r210'>210</a>. <span class='sc'>Gillespie, L. J.</span> The Reaction of Soil and Measurements of Hydrogen Ion -Concentration. <cite>Jour. Wash. Acad. of Sciences</cite>, 6, 1916, 7.</p> -</div> - -<div class='footnote' id='f211'> -<p class='c009'><a href='#r211'>211</a>. <span class='sc'>Hill, H. W.</span> Porous Tops for Petri Dishes. <cite>Jour. Med. Research</cite>, 13, 1904, 93.</p> -</div> - -<div class='footnote' id='f212'> -<p class='c009'><a href='#r212'>212</a>. <span class='sc'>Hill, H. W.</span> The Mathematics of the Bacterial Count. <cite>Public Health -Reports and Papers</cite>, 33, 1907, 110.</p> -</div> - -<div class='footnote' id='f213'> -<p class='c009'><a href='#r213'>213</a>. <span class='sc'>Itano, A.</span> The Relation of Hydrogen Ion Concentration of Media to the -Proteolytic Activity of Bacillus Subtilis. <cite>Bulletin 167</cite>, 1916, Mass. Agric. -Ex. Station.</p> -</div> - -<div class='footnote' id='f214'> -<p class='c009'><a href='#r214'>214</a>. <span class='pageno' id='Page_111'>111</span><span class='sc'>Kendall, A. I.</span> and <span class='sc'>Walker, A. W.</span> The Isolation of Bacillus Dysenteriae -from Stools. <cite>Jour. Med. Research</cite>, 23, 1910, 481.</p> -</div> - -<div class='footnote' id='f215'> -<p class='c009'><a href='#r215'>215</a>. <span class='sc'>Kinyoun, J. J.</span> and <span class='sc'>Deiter, L. V.</span> On the Preparation of Endo’s Medium. -<cite>Amer. Jour. Public Health</cite>, n. s. 2, 1912, 979.</p> -</div> - -<div class='footnote' id='f216'> -<p class='c009'><a href='#r216'>216</a>. <span class='sc'>Levine, M.</span> On the Significance of the Voges-Proskauer Reaction. <cite>Jour. -of Bacteriology</cite>, 1, 1916, 153.</p> -</div> - -<div class='footnote' id='f217'> -<p class='c009'><a href='#r217'>217</a>. <span class='sc'>Lubs, H. A.</span> and <span class='sc'>Clark, W. M.</span> On Some New Indicators for the Colorimetric -Determination of Hydrogen-ion Concentration. <cite>Jour. Wash. Acad. -of Sciences</cite>, 5, 1915, 609.</p> -</div> - -<div class='footnote' id='f218'> -<p class='c009'><a href='#r218'>218</a>. <span class='sc'>McClendon, J. F.</span> New Hydrogen Electrodes and Rapid Methods of -Determining Hydrogen Ion Concentrations. <cite>Amer. Jour. of Physiology</cite>, -38, 1915, 180.</p> -</div> - -<div class='footnote' id='f219'> -<p class='c009'><a href='#r219'>219</a>. <span class='sc'>McClendon, J. F.</span> A Direct Reading Potentiometer for Measuring Hydrogen -Ion Concentrations. <cite>Amer. Jour. of Physiology</cite>, 38, 1915, 186.</p> -</div> - -<div class='footnote' id='f220'> -<p class='c009'><a href='#r220'>220</a>. <span class='sc'>McCrady, M. H.</span> The Numerical Interpretation of Fermentation-tube -Results. <cite>Jour. Inf. Diseases</cite>, 17, 1915, 183.</p> -</div> - -<div class='footnote' id='f221'> -<p class='c009'><a href='#r221'>221</a>. <span class='sc'>Noyes, H. A.</span> Agar Agar for Bacteriological Use. <cite>Science</cite>, n. s. 44, 1916, -797.</p> -</div> - -<div class='footnote' id='f222'> -<p class='c009'><a href='#r222'>222</a>. <span class='sc'>Rogers, L. A.</span>, <span class='sc'>Clark, W. M.</span> and <span class='sc'>Davis, B. J.</span> The Colon Group of Bacteria. -<cite>Jour. of Inf. Diseases</cite>, 14, 1914, 411.</p> -</div> - -<div class='footnote' id='f223'> -<p class='c009'><a href='#r223'>223</a>. <span class='sc'>Rogers, L. A.</span>, <span class='sc'>Clark, W. M.</span> and <span class='sc'>Evans, A. C.</span> The Characteristics of -Bacteria of the Colon Type Found in Bovine Feces. <cite>Jour. of Inf. Diseases</cite>, -15, 1914, 99.</p> -</div> - -<div class='footnote' id='f224'> -<p class='c009'><a href='#r224'>224</a>. <span class='sc'>Rogers, L. A.</span>, <span class='sc'>Clark, W. M.</span> and <span class='sc'>Evans, A. C.</span> The Characteristics of -Bacteria of the Colon Type Occurring on Grains. <cite>Jour. of Inf. Diseases</cite>, -17, 1915, 137.</p> -</div> - -<div class='footnote' id='f225'> -<p class='c009'><a href='#r225'>225</a>. <span class='sc'>Smith, H. M.</span> The Seaweed Industries of Japan. <cite>Bulletin of the Bureau of -Fisheries</cite>, 24, 1904, 135.</p> -</div> - -<div class='footnote' id='f226'> -<p class='c009'><a href='#r226'>226</a>. <span class='sc'>Sörensen, S. P. L.</span> <span lang="de" xml:lang="de">Enzymstudien. <cite>Biochem. Ztschr.</cite></span>, 21, 1909, 131 and -201.</p> -</div> - -<div class='footnote' id='f227'> -<p class='c009'><a href='#r227'>227</a>. <span class='sc'>Whipple, G. C.</span> On the Necessity of Cultivating Water Bacteria in an -Atmosphere Saturated with Moisture. <cite>Tech. Quart.</cite>, 12, 1899, 276.</p> -</div> - -<div class='footnote' id='f228'> -<p class='c009'><a href='#r228'>228</a>. <span class='sc'>Whittaker, H. A.</span> The Source, Manufacture and Composition of Commercial -Agar-agar. <cite>Jour. Amer. Pub. Health Assoc.</cite>, n. s. 1, 1911, 632.</p> -</div> - -<div class='footnote' id='f229'> -<p class='c009'><a href='#r229'>229</a>. <span class='sc'>Clark, W. M.</span> and <span class='sc'>Lubs, H. A.</span> The colorimetric determination of the -hydrogen-ion concentration of bacteriological culture media. <cite>Jour. Wash. -Acad. Sciences</cite>, 6, 1916, 483.</p> -</div> - -<div class='footnote' id='f230'> -<p class='c009'><a href='#r230'>230</a>. <span class='sc'>Clark, W. M.</span> and <span class='sc'>Lubs, H. A.</span> The colorimetric determination of hydrogen-ion -concentration and its application in bacteriology. <cite>Jour. of Bact.</cite>, 2, -1919, 1 and 109.</p> -</div> - -<div class='footnote' id='f231'> -<p class='c009'><a href='#r231'>231</a>. <span class='sc'>Cohen, B.</span> and <span class='sc'>Clark, W. M.</span> The growth of certain bacteria in media of -different hydrogen-ion concentrations. <cite>Jour. of Bact.</cite>, 4, 1919, 409.</p> -</div> - -<div class='footnote' id='f232'> -<p class='c009'><a href='#r232'>232</a>. <span class='sc'>Fennel, E. A.</span> and <span class='sc'>Fisher, M. A.</span> Adjustment of culture medium reactions. -<cite>Jour. of Inf. Diseases</cite>, 25, 1919, 444.</p> -</div> - -<div class='footnote' id='f233'> -<p class='c009'><a href='#r233'>233</a>. <span class='sc'>Jones, H. M.</span> A rapid hydrogen-ion electrode method for the determination -of hydrogen-ion concentrations in bacterial cultures or other turbid or -colored solutions. <cite>Jour. of Inf. Diseases</cite>, 25, 1919, 262.</p> -</div> - -<div class='chapter'> - <span class='pageno' id='Page_113'>113</span> - <h2 class='c005'>INDEX.</h2> -</div> - -<ul class='index c003'> - <li class='c043'><div class='center'>A.</div></li> - <li class='c043'>Acidity, determination of, <a href='#Page_39'>39</a>.</li> - <li class='c043'>Acids, mineral, <a href='#Page_41'>41</a>.</li> - <li class='c043'>Agar, nutrient, <a href='#Page_94'>94</a>, <a href='#Page_96'>96</a>. - <ul> - <li>lactose-litmus, <a href='#Page_97'>97</a>.</li> - </ul> - </li> - <li class='c043'>Alkali carbonates, <a href='#Page_39'>39</a>.</li> - <li class='c043'>Alkalinity, determination of, <a href='#Page_35'>35</a>.</li> - <li class='c043'>Albuminoid nitrogen, <a href='#Page_20'>20</a>.</li> - <li class='c043'>Aluminium sulfate, determination of, <a href='#Page_41'>41</a>. - <ul> - <li>analysis of, <a href='#Page_78'>78</a>.</li> - </ul> - </li> - <li class='c043'>Aluminium and iron, determination of, <a href='#Page_57'>57</a>.</li> - <li class='c043'>Ammonia nitrogen, determination of, <a href='#Page_15'>15</a>.</li> - <li class='c043'>Apparatus, bacteriological, <a href='#Page_93'>93</a>.</li> - <li class='c043'>Application of colon group tests, <a href='#Page_102'>102</a>.</li> - <li class='c043'>Arsenic, determination of, <a href='#Page_63'>63</a>.</li> - <li class='c043'>Azolitmin solution, <a href='#Page_96'>96</a>.</li> - <li class='c003'><div class='center'>B.</div></li> - <li class='c043'>Bacillus aërogenes, reactions, <a href='#Page_108'>108</a>. - <ul> - <li>cloacae, reactions, <a href='#Page_108'>108</a>.</li> - <li>coli, reactions, <a href='#Page_108'>108</a>.</li> - </ul> - </li> - <li class='c043'>B. coli group, tests, <a href='#Page_100'>100</a>. - <ul> - <li>application of, <a href='#Page_102'>102</a>.</li> - <li>fecal and non-fecal, <a href='#Page_106'>106</a>.</li> - <li>summary of tests, <a href='#Page_104'>104</a>.</li> - </ul> - </li> - <li class='c043'>Bacteriological examination, <a href='#Page_93'>93</a>. - <ul> - <li>bibliography, <a href='#Page_110'>110</a>.</li> - </ul> - </li> - <li class='c043'>Basicity ratio, <a href='#Page_80'>80</a>.</li> - <li class='c043'>Bibliography, - <ul> - <li>bacteriological, <a href='#Page_110'>110</a>.</li> - <li>chemical, <a href='#Page_82'>82</a>.</li> - <li>microscopical, <a href='#Page_91'>91</a>.</li> - </ul> - </li> - <li class='c043'>Biochemical oxygen demand, <a href='#Page_71'>71</a>. - <ul> - <li>in sludge and mud, <a href='#Page_76'>76</a>.</li> - </ul> - </li> - <li class='c043'>Bismuthate method (Mn), <a href='#Page_49'>49</a>.</li> - <li class='c043'>Boric acid, <a href='#Page_63'>63</a>.</li> - <li class='c043'>Bottles, sample, <a href='#Page_1'>1</a>, <a href='#Page_93'>93</a>. - <ul> - <li>dilution, <a href='#Page_93'>93</a>.</li> - </ul> - </li> - <li class='c043'>Bromine and iodine, determination of, <a href='#Page_61'>61</a>.</li> - <li class='c043'>Broth, nutrient, <a href='#Page_95'>95</a>. - <ul> - <li>sugar, <a href='#Page_95'>95</a>.</li> - </ul> - </li> - <li class='c003'><div class='center'>C.</div></li> - <li class='c043'>Calcium, determination of, <a href='#Page_57'>57</a>.</li> - <li class='c043'>Carbon dioxide, determination of, <a href='#Page_40'>40</a>.</li> - <li class='c043'>Chemical analysis, water and sewage, <a href='#Page_1'>1</a>. - <ul> - <li>bibliography, <a href='#Page_82'>82</a>.</li> - </ul> - </li> - <li class='c043'>Chemicals, analysis of, <a href='#Page_77'>77</a>.</li> - <li class='c043'>Chloride, determination of, <a href='#Page_41'>41</a>.</li> - <li class='c043'>Chlorine, determination of, <a href='#Page_64'>64</a>.</li> - <li class='c043'>Coefficient of fineness, <a href='#Page_8'>8</a>.</li> - <li class='c043'>Collection of samples, bacteriological, <a href='#Page_93'>93</a>. - <ul> - <li>chemical, <a href='#Page_1'>1</a>.</li> - </ul> - </li> - <li class='c043'>Colon group, tests (see “B. coli”), <a href='#Page_100'>100</a>.</li> - <li class='c043'>Color, determination of, <a href='#Page_9'>9</a>.</li> - <li class='c043'>Copper, determination of, <a href='#Page_53'>53</a>, <a href='#Page_55'>55</a>.</li> - <li class='c043'>Counting (bacterial), <a href='#Page_99'>99</a>.</li> - <li class='c043'>Cultural characters of colon group, <a href='#Page_108'>108</a>.</li> - <li class='c043'>Culture media, <a href='#Page_94'>94</a>. - <ul> - <li>azolitmin solution, <a href='#Page_96'>96</a>.</li> - <li>Endo’s medium, <a href='#Page_97'>97</a>.</li> - <li>litmus-lactose-agar, <a href='#Page_97'>97</a>.</li> - <li>litmus solution, <a href='#Page_96'>96</a>.</li> - <li>methyl red test, <a href='#Page_107'>107</a>.</li> - <li>nutrient agar, <a href='#Page_96'>96</a>.</li> - <li>nutrient broth, <a href='#Page_95'>95</a>.</li> - <li>nutrient gelatin, <a href='#Page_96'>96</a>.</li> - <li>sterilization, <a href='#Page_95'>95</a>.</li> - <li>sugar broth, <a href='#Page_95'>95</a>.</li> - <li>titration, <a href='#Page_94'>94</a>.</li> - <li>tryptophane broth, <a href='#Page_107'>107</a>.</li> - </ul> - </li> - <li class='c003'><div class='center'>D.</div></li> - <li class='c043'>Dilution (bacteriological), <a href='#Page_98'>98</a>.</li> - <li class='c043'>Dissolved oxygen, <a href='#Page_65'>65</a>.</li> - <li class='c003'><div class='center'>E.</div></li> - <li class='c043'>Effluents, relative stability of, <a href='#Page_69'>69</a>. - <ul> - <li>biochemical, oxygen, demand of, <a href='#Page_71'>71</a>.</li> - </ul> - </li> - <li class='c043'>Endo’s medium, <a href='#Page_97'>97</a>.</li> - <li class='c043'>Erythrosine indicator, <a href='#Page_36'>36</a>.</li> - <li class='c043'>Ether—soluble matter, <a href='#Page_69'>69</a>. - <ul> - <li>in sludge and mud, <a href='#Page_75'>75</a>.</li> - </ul> - </li> - <li class='c043'>Evaporation, <a href='#Page_29'>29</a>.</li> - <li class='c043'>Expression of results (see under “Results”).</li> - <li class='c003'><div class='center'>F.</div></li> - <li class='c043'>Fat, determination of, <a href='#Page_69'>69</a>, <a href='#Page_75'>75</a>.</li> - <li class='c043'>Fecal and non-fecal members, colon group, <a href='#Page_106'>106</a>.</li> - <li class='c043'>Fermentation tubes, <a href='#Page_93'>93</a>.</li> - <li class='c043'>Ferrous sulfide in sludge and mud, <a href='#Page_76'>76</a>.</li> - <li class='c043'>Ferrous iron, determination of, <a href='#Page_47'>47</a>.</li> - <li class='c043'>Ferric iron, determination of, <a href='#Page_48'>48</a>.</li> - <li class='c043'>Fineness, coefficient of, <a href='#Page_8'>8</a>.</li> - <li class='c003'><span class='pageno' id='Page_114'>114</span><div class='center'>G.</div></li> - <li class='c043'>Gelatin media, <a href='#Page_94'>94</a>, <a href='#Page_96'>96</a>.</li> - <li class='c003'><div class='center'>H.</div></li> - <li class='c043'>Hardness, determination of, <a href='#Page_30'>30</a>. - <ul> - <li>bicarbonate, <a href='#Page_37'>37</a>.</li> - <li>carbonate, <a href='#Page_38'>38</a>.</li> - <li>hydroxide, <a href='#Page_38'>38</a>.</li> - <li>non-carbonate, <a href='#Page_34'>34</a>.</li> - <li>temporary, <a href='#Page_34'>34</a>.</li> - </ul> - </li> - <li class='c043'>Hydrogen sulfide, determination of, <a href='#Page_63'>63</a>.</li> - <li class='c043'>Hydrogen-ion determination, <a href='#Page_94'>94</a>.</li> - <li class='c003'><div class='center'>I.</div></li> - <li class='c043'>Ignition, loss on, <a href='#Page_30'>30</a>.</li> - <li class='c043'>Incubation, <a href='#Page_99'>99</a>.</li> - <li class='c043'>Indol test, broth for, <a href='#Page_107'>107</a>.</li> - <li class='c043'>Indicators, <a href='#Page_36'>36</a>, <a href='#Page_94'>94</a>, <a href='#Page_107'>107</a>.</li> - <li class='c043'>Iodine and bromine, determination of, <a href='#Page_61'>61</a>.</li> - <li class='c043'>Iron and Aluminium, separation, <a href='#Page_57'>57</a>. - <ul> - <li>analysis of, <a href='#Page_79'>79</a>.</li> - </ul> - </li> - <li class='c043'>Iron, determination of, <a href='#Page_43'>43</a>. - <ul> - <li>standards, <a href='#Page_45'>45</a>.</li> - <li>sulfate, determination of, <a href='#Page_41'>41</a>.</li> - <li>analysis of, <a href='#Page_81'>81</a>.</li> - </ul> - </li> - <li class='c003'><div class='center'>L.</div></li> - <li class='c043'>Lacmoid indicator, <a href='#Page_36'>36</a>.</li> - <li class='c043'>Lead, determination of, <a href='#Page_51'>51</a>, <a href='#Page_55'>55</a>.</li> - <li class='c043'>Lime, analysis of, <a href='#Page_80'>80</a>.</li> - <li class='c043'>Lithium, determination of, <a href='#Page_60'>60</a>.</li> - <li class='c043'>Litmus reagent, <a href='#Page_94'>94</a>. - <ul> - <li>lactose-agar, <a href='#Page_97'>97</a>.</li> - <li>solution, <a href='#Page_96'>96</a>.</li> - </ul> - </li> - <li class='c003'><div class='center'>M.</div></li> - <li class='c043'>Manganese, determination of, <a href='#Page_48'>48</a>.</li> - <li class='c043'>Materials, bacteriological, <a href='#Page_93'>93</a>.</li> - <li class='c043'>Meat extract, <a href='#Page_93'>93</a>.</li> - <li class='c043'>Media, culture (see “Culture media”), <a href='#Page_94'>94</a>–7, <a href='#Page_107'>107</a>.</li> - <li class='c043'>Methyl orange indicator, <a href='#Page_37'>37</a>.</li> - <li class='c043'>Methyl red media, <a href='#Page_107'>107</a>. - <ul> - <li>test, <a href='#Page_107'>107</a>.</li> - </ul> - </li> - <li class='c043'>Microscopical bibliography, <a href='#Page_91'>91</a>. - <ul> - <li>examination, <a href='#Page_89'>89</a>.</li> - </ul> - </li> - <li class='c043'>Mineral analysis, <a href='#Page_56'>56</a>.</li> - <li class='c043'>Moisture in sludge and mud, <a href='#Page_74'>74</a>.</li> - <li class='c043'>Mud deposits, analysis, <a href='#Page_73'>73</a>.</li> - <li class='c003'><div class='center'>N.</div></li> - <li class='c043'>Nessler’s reagent, - <ul> - <li>color standards, <a href='#Page_10'>10</a>.</li> - <li>ammonia determination, <a href='#Page_19'>19</a>.</li> - </ul> - </li> - <li class='c043'>Nitrogen, <a href='#Page_15'>15</a>. - <ul> - <li>ammonia, <a href='#Page_15'>15</a>.</li> - <li>albuminoid, <a href='#Page_20'>20</a>.</li> - </ul> - </li> - <li class='c043'>Nitrogen, in sludge and mud, <a href='#Page_74'>74</a>. - <ul> - <li>nitrate, <a href='#Page_23'>23</a>.</li> - <li>nitrite, <a href='#Page_22'>22</a>.</li> - <li>organic, <a href='#Page_21'>21</a>.</li> - <li>total, <a href='#Page_25'>25</a>.</li> - </ul> - </li> - <li class='c043'>Nutrient media (see “Culture media”), <a href='#Page_94'>94</a>, <a href='#Page_107'>107</a>.</li> - <li class='c003'><div class='center'>O.</div></li> - <li class='c043'>Odor, <a href='#Page_12'>12</a>.</li> - <li class='c043'>Organic nitrogen, <a href='#Page_21'>21</a>.</li> - <li class='c043'>Oxygen consumed, <a href='#Page_25'>25</a>. - <ul> - <li>demand, biochemical, <a href='#Page_71'>71</a>.</li> - <li>dissolved, <a href='#Page_65'>65</a>.</li> - <li>in fresh and sea water (table), <a href='#Page_68'>68</a>.</li> - </ul> - </li> - <li class='c003'><div class='center'>P.</div></li> - <li class='c043'>Peptone, authorized brands, <a href='#Page_93'>93</a>.</li> - <li class='c043'>Persulfate method (Mn), <a href='#Page_48'>48</a>.</li> - <li class='c043'>Petri dishes, <a href='#Page_93'>93</a>.</li> - <li class='c043'>Phenoldisulfonic acid method (nitrate), <a href='#Page_23'>23</a>.</li> - <li class='c043'>Phenolphthalein indicator, <a href='#Page_36'>36</a>, <a href='#Page_94'>94</a>.</li> - <li class='c043'>Physical examination, <a href='#Page_4'>4</a>.</li> - <li class='c043'>Pipettes, bacteriological, <a href='#Page_93'>93</a>.</li> - <li class='c043'>Plating, bacteriological, <a href='#Page_99'>99</a>.</li> - <li class='c043'>Platinum-cobalt color standard, <a href='#Page_9'>9</a>. - <ul> - <li>wire turbidity, <a href='#Page_5'>5</a>.</li> - </ul> - </li> - <li class='c043'>Potassium, determination of, <a href='#Page_59'>59</a>.</li> - <li class='c043'>Presumptive tests, colon group, <a href='#Page_102'>102</a>.</li> - <li class='c003'><div class='center'>R.</div></li> - <li class='c043'>Reactions of colon group, <a href='#Page_108'>108</a>.</li> - <li class='c043'>Reaction of culture media, <a href='#Page_94'>94</a>. - <ul> - <li>of sludge and mud, <a href='#Page_73'>73</a>.</li> - </ul> - </li> - <li class='c043'>Reduction method (nitrate), <a href='#Page_24'>24</a>.</li> - <li class='c043'>Relative stability method, <a href='#Page_71'>71</a>.</li> - <li class='c043'>Residue on evaporation, <a href='#Page_29'>29</a>.</li> - <li class='c043'>Results, expression of, - <ul> - <li>bacteriological, <a href='#Page_103'>103</a>.</li> - <li>chemical examination, <a href='#Page_14'>14</a>.</li> - <li>color, <a href='#Page_8'>8</a>.</li> - <li>odor, <a href='#Page_12'>12</a>.</li> - </ul> - </li> - <li class='c043'>Results, interpretation of (bacteriological), <a href='#Page_106'>106</a>.</li> - <li class='c043'>Routine procedure (bacteriological), <a href='#Page_108'>108</a>.</li> - <li class='c003'><div class='center'>S.</div></li> - <li class='c043'>Samples, - <ul> - <li>bacterial, <a href='#Page_93'>93</a>.</li> - <li>bottles, <a href='#Page_1'>1</a>.</li> - <li>chemical, <a href='#Page_1'>1</a>.</li> - <li>interval before analysis of, <a href='#Page_2'>2</a>.</li> - <li>quantity required, <a href='#Page_1'>1</a>.</li> - <li>representative, <a href='#Page_3'>3</a>.</li> - <li>sludge and mud, <a href='#Page_73'>73</a>.</li> - </ul> - </li> - <li class='c043'>Sewage sludge, analysis, <a href='#Page_73'>73</a>.</li> - <li class='c043'>Silica, determination of, <a href='#Page_56'>56</a>.</li> - <li class='c043'><span class='pageno' id='Page_115'>115</span>Soda ash, analysis of, <a href='#Page_82'>82</a>.</li> - <li class='c043'>Soap method (hardness), <a href='#Page_31'>31</a>.</li> - <li class='c043'>Sodium and potassium, <a href='#Page_58'>58</a>.</li> - <li class='c043'>Solids, total, fixed, volatile, <a href='#Page_29'>29</a>.</li> - <li class='c043'>Specific gravity of sludge and mud, <a href='#Page_74'>74</a>.</li> - <li class='c043'>Stability, relative, of effluents, <a href='#Page_69'>69</a>. - <ul> - <li>method, relative, <a href='#Page_71'>71</a>.</li> - </ul> - </li> - <li class='c043'>Standards, - <ul> - <li>ammonia, <a href='#Page_17'>17</a>.</li> - <li>chlorine, <a href='#Page_65'>65</a>.</li> - <li>color, <a href='#Page_9'>9</a>.</li> - <li>hardness, <a href='#Page_32'>32</a>.</li> - <li>iron, <a href='#Page_45'>45</a>.</li> - <li>Nessler, color, <a href='#Page_10'>10</a>.</li> - <li>platinum-cobalt, <a href='#Page_10'>10</a>.</li> - <li>turbidity, <a href='#Page_4'>4</a>.</li> - </ul> - </li> - <li class='c043'>Sterilization of media, <a href='#Page_95'>95</a>.</li> - <li class='c043'>Storage of samples, <a href='#Page_2'>2</a>, <a href='#Page_98'>98</a>.</li> - <li class='c043'>Sugars for media, <a href='#Page_94'>94</a>.</li> - <li class='c043'>Sugar broths, <a href='#Page_95'>95</a>.</li> - <li class='c043'>Sulfate, K and Na, <a href='#Page_58'>58</a>.</li> - <li class='c043'>Suspended matter, <a href='#Page_30'>30</a>.</li> - <li class='c003'><div class='center'>T.</div></li> - <li class='c043'>Tin, determination of, <a href='#Page_54'>54</a>, <a href='#Page_55'>55</a>.</li> - <li class='c043'>Tintometer, Lovibond, <a href='#Page_11'>11</a>.</li> - <li class='c043'>Titration of media, <a href='#Page_94'>94</a>.</li> - <li class='c043'>Total nitrogen, <a href='#Page_25'>25</a>. - <ul> - <li>residue on evaporation, <a href='#Page_29'>29</a>.</li> - </ul> - </li> - <li class='c043'>Tryptophane broth, <a href='#Page_107'>107</a>.</li> - <li class='c043'>Turbidity, <a href='#Page_4'>4</a>. - <ul> - <li>coefficient of fineness, <a href='#Page_8'>8</a>.</li> - <li>platinum wire method, <a href='#Page_5'>5</a>.</li> - <li>rod, graduation, <a href='#Page_6'>6</a>.</li> - <li>standard, <a href='#Page_4'>4</a>.</li> - <li>turbidimetric method, <a href='#Page_7'>7</a>.</li> - <li>turbidometer, graduation, <a href='#Page_8'>8</a>.</li> - </ul> - </li> - <li class='c003'><div class='center'>V.</div></li> - <li class='c043'>Voges-Proskauer test, <a href='#Page_107'>107</a>.</li> - <li class='c043'>Volatile matter, <a href='#Page_29'>29</a>. - <ul> - <li>in sludge and mud, <a href='#Page_74'>74</a>.</li> - </ul> - </li> - <li class='c003'><div class='center'>Z.</div></li> - <li class='c043'>Zinc, <a href='#Page_52'>52</a>.</li> -</ul> - -<div class='pbb'> - <hr class='pb c002' /> -</div> -<div class='tnotes'> - -<div class='section ph2'> - -<div class='nf-center-c0'> -<div class='nf-center c004'> - <div>TRANSCRIBER’S NOTES</div> - </div> -</div> - -</div> - - <ol class='ol_1 c003'> - <li>Silently corrected typographical errors and variations in spelling. - - </li> - <li>Archaic, non-standard, and uncertain spellings retained as printed. - - </li> - <li>The <a href='#CHEMICAL'>Chemical Bibliography</a> was reformatted in footnote style. - - </li> - <li>The <a href='#BACTERIOLOGICAL'>Bacteriological Bibliography</a> was reformatted in footnote style - and the numbering was increased by 200. - </li> - </ol> - -</div> - - - - - - - - -<pre> - - - - - -End of the Project Gutenberg EBook of Standard methods for the examination -of water and sewage, by American Public Health Association - -*** END OF THIS PROJECT GUTENBERG EBOOK STANDARD METHODS FOR THE *** - -***** This file should be named 61462-h.htm or 61462-h.zip ***** -This and all associated files of various formats will be found in: - 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