Disposal of Cheese Whey by Digestion

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<ul><li><p>Disposal of Cheese Whey by DigestionAuthor(s): David BackmeyerSource: Sewage Works Journal, Vol. 20, No. 6 (Nov., 1948), pp. 1115-1118Published by: Water Environment FederationStable URL: http://www.jstor.org/stable/25030997 .Accessed: 15/06/2014 03:44</p><p>Your use of the JSTOR archive indicates your acceptance of the Terms &amp; Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp</p><p> .JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact support@jstor.org.</p><p> .</p><p>Water Environment Federation is collaborating with JSTOR to digitize, preserve and extend access to SewageWorks Journal.</p><p>http://www.jstor.org </p><p>This content downloaded from 185.2.32.109 on Sun, 15 Jun 2014 03:44:04 AMAll use subject to JSTOR Terms and Conditions</p><p>http://www.jstor.org/action/showPublisher?publisherCode=wefhttp://www.jstor.org/stable/25030997?origin=JSTOR-pdfhttp://www.jstor.org/page/info/about/policies/terms.jsphttp://www.jstor.org/page/info/about/policies/terms.jsp</p></li><li><p>Vol. 20, No. 6 DISPOSAL OF CHEESE WHEY BY DIGESTION 1115 </p><p>This is not an entirely new prece dent since this division has made some </p><p>tests in the past on special occasions, </p><p>particularly for the Fire Prevention </p><p>Bureau, but has never had the person nel to do such work regularly nor in the amount requested. </p><p>It is recommended that a special assistant to the chemist be employed to do the. testing under the direct su </p><p>pervision of the chemist and the </p><p>undersigned. This assistant would also receive training in sewage labora </p><p>tory work to the end that he would be available to take over the duties of the chemist whenever that may become nec </p><p>essary. The cost of operating this bu reau would be negligible outside of the assistant's salary and the initial mod est expenditure for equipment. </p><p>A summary of plant operation data is given in Table IV. </p><p>TABLE IV.?Summary of Operation of the </p><p>Item Average </p><p>Rainfall (in.). 36.50 </p><p>Design flow (m.g.d.): Mean D.W.F. 80.0 </p><p>Max. D.W.F. 140.0 </p><p>Raw sewage flow (m.g.d.). 46.3 </p><p>Screenings (cu. yd. per month).... 204 </p><p>Grit removed (cu. yd. per month).. 73 </p><p>Suspended solids (p.p.m.) : </p><p>Raw sewage. 199 </p><p>Plant eflluent.. 96 </p><p>Per cent removal. 51.4 </p><p>B.O.D. (p.p.m.): Raw sewage. 205 </p><p>Plant eflluent. 96 </p><p>Per cent removal. 34.4 </p><p>Per cent volatile solids: </p><p>Raw sewage. 65.4 </p><p>Digested sludge. 44.4 </p><p>Digested sludge (cu. yd.) : </p><p>To marsh. 30,525 </p><p>(Ohio) Sewage Treatment Plant for 1947 </p><p>Item Average </p><p>To drying beds. 11,440 Tons dry sludge pulverized for </p><p>fertilizer. 915 Tons fertilizer sold. 950 </p><p>Total sales ($). 9,525 Bay View pumping station costs </p><p>($ per m.g.) : </p><p>Purchased power. 0.30 </p><p>Supplies. 0.33 </p><p>Supervision and labor. 3.38 </p><p>Total. 4.01 </p><p>Sewage works costs ($ per m.g.): Power. 0.008 </p><p>Supplies. 1.15 </p><p>Supervision and labor. 5.86 </p><p>Total. 7.02 </p><p>Gas engine economy ($) : </p><p>Pumping cost if power purchased 23,638.49 Actual pumping cost. 6,058.91 Gas engine saving. 17,579.58 </p><p>DISPOSAL OF CHEESE WHEY BY DIGESTION By David Backmeyer </p><p>Superintendent, Water and Sewage Treatment Utilities, Marion, Ind. </p><p>The sewage treatment and garbage </p><p>disposal plant at Marion, Indiana, was </p><p>completed and placed in operation in </p><p>July, 1940. This plant, which utilizes </p><p>activated sludge for secondary treat </p><p>ment, is equipped with complete fa </p><p>cilities for separate sludge digestion of </p><p>both sewage and garbage solids, to </p><p>gether with gas engines for utilization </p><p>of the digestion gas. The resident </p><p>population of Marion in 1940 was </p><p>26,676. The total gas production in </p><p>1947 was 23.167 million cu. ft., which </p><p>is the equivalent of 2.37 cu. ft. per capita per day. </p><p>Whey Waste Problem </p><p>During the past 3 years the sewage plant has been seriously overloaded </p><p>during the spring months of each year from cheese whey discharged to the </p><p>sanitary sewer by one of the local milk </p><p>processing plants. As the treatment </p><p>plant had been disposing of digested sludge in liquid form by hauling in tank trucks (Figure 1), the facilities of </p><p>This content downloaded from 185.2.32.109 on Sun, 15 Jun 2014 03:44:04 AMAll use subject to JSTOR Terms and Conditions</p><p>http://www.jstor.org/page/info/about/policies/terms.jsp</p></li><li><p>1116 SEWAGE WORKS JOURNAL November, 1948 </p><p>^v*' ' </p><p>&gt;v </p><p>FIGURE 1.?Liquid fertilizer tank trucks used for hauling whey to sewage plant. </p><p>the sludge disposal plant were offered to the industry in an effort to com </p><p>pletely eliminate the discharge of the </p><p>whey to the sewer. </p><p>In March, 1947, arrangements were </p><p>made with the industry to haul the </p><p>whey from their storage tank directly to the sewage treatment plant in city tank trucks. The whey is unloaded at the plant directly into the garbage </p><p>well from which it is pumped to the </p><p>sludge digestion units. In this way the soluble B.O.D. load does not mix </p><p>with the raw sewage flow and cannot, therefore, reach the activated sludge secondary treatment units. </p><p>Whey Mixed With Garbage </p><p>In the processing of the garbage at the treatment plant, the green gar bage is unloaded from the collection trucks onto an open platform at grade level, and is then shoveled into the </p><p>hammermill grinder hopper. Sluicing water is added in the grinding process to bring the final slop to a solids eon tent of from 5.0 to 7.5 per cent, on dry solids basis. </p><p>After some experimentation it was </p><p>found that the liquid cheese whey made </p><p>an ideal substitute for the sluicing water. The temperature of the whey </p><p>was always from 100? to 140? F. when </p><p>unloaded from the tank trucks. This warm liquid would serve as a temper </p><p>ing agent when added to the garbage being ground, particularly in the cold </p><p>months of November and December. Instead of pumping garbage slop to the digesters at 55? F., it was possible to maintain the temperature of this </p><p>mixture of ground garbage and whey at 90? to 95? F. by unloading the whey tank truck as the garbage was fed to the grinder. </p><p>Whey Increases Gas Production </p><p>Cheese whey contains from 4.5 to 7.0 per cent total dry solids, and only about 8 or 9 per cent of the solids is </p><p>inorganic ash. The other constituents, </p><p>sugar, protein and fat, are readily di </p><p>gestible and are easily converted into </p><p>gas in the sludge digesters. By sub </p><p>stituting whey for water in the gar </p><p>bage grinding process it was further </p><p>possible to recover valuable gas from the whey without overloading the plant digesters from the standpoint of liquid </p><p>This content downloaded from 185.2.32.109 on Sun, 15 Jun 2014 03:44:04 AMAll use subject to JSTOR Terms and Conditions</p><p>http://www.jstor.org/page/info/about/policies/terms.jsp</p></li><li><p>Vol. 20, No. 6 DISPOSAL OF CHEESE WHEY BY DIGESTION </p><p>TABLE I.?Effect of Whey on Plant Operation </p><p>1117 </p><p>Plant Operation Data Before and During Whey Discharge to Sewers </p><p>Batch Discharge of Whey </p><p>to Sewers, June 23 to </p><p>July 7, 1946 </p><p>Continuous Discharge of Whey to Sewers </p><p>Feb. 18 to Mar. 12, 1947 </p><p>May 18 to 30, 1948 </p><p>Average for </p><p>1946 </p><p>Average for 76 Months </p><p>Prior to Jan. 1, 1947 </p><p>B.O.D. (p.p.m.): Raw </p><p>Settled Final </p><p>% Reduction </p><p>232 162 </p><p>7 96.8 </p><p>212 182 31 85.4 </p><p>219 149 29 86.7 </p><p>174 152 </p><p>13 92.8 </p><p>188 134 </p><p>13 93.4 </p><p>Sludge Index (Mohlman) 138 118 107 91 81 </p><p>D. 0. Aerator Effluent </p><p>(p.p.m.) 1.8 0.9 0.8 3.1 </p><p>Activated Sludge Volatile Solids (%) 65 75.7 68.4 61.5 58.9 </p><p>Air Supplied, Cu. Ft./Gal. </p><p>Sewage 1.04 1.06 1.32 0.90 0.89 </p><p>volume fed daily into the digestion system. </p><p>A sharp rise in the gas production rate was evident within 30 minutes after the garbage-whey mixture was </p><p>pumped to the digesters. On several </p><p>days when peak loads of whey were </p><p>handled it was necessary to pump the </p><p>pure whey to the digesters without the addition of ground garbage. Gas pro duction volumes on these days soared to as much as 108,000 cu. ft. per 24 hour period. </p><p>Although the addition of whey to the already heavily loaded digestion system made it extremely difficult to </p><p>withdraw clear supernatant from the </p><p>digesters, at no time was there any evi dence of foaming or excessive volatile acid accumulation in the digestion sys tem. The carbon dioxide content of the gas produced would increase from 33.0 per cent when small volumes of </p><p>whey were being handled to about 36 </p><p>per cent when large volumes were taken and gas production was at its </p><p>peak. No difficulty was encountered in using this fuel in the plant gas en </p><p>gines. </p><p>Effect of Whey on Plant Operation </p><p>Two tables of plant operation data are presented. Table I shows the </p><p>effect of the whey on the activated </p><p>sludge units when it is dumped to the </p><p>city sanitary sewers. When whey reaches the aerators a series of rapid changes takes place. The color of the </p><p>activated sludge will change in a 12 </p><p>hour period from chocolate brown to </p><p>slate gray. The volatile content of the </p><p>sludge rises rapidly within a period of 6 to 10 days. It is almost physically </p><p>impossible to supply enough air to </p><p>maintain dissolved oxygen in the </p><p>mixed liquor. Septic conditions, of </p><p>course, lead to black sludge and the </p><p>complete loss of the active sludge if </p><p>part of the load is not diverted by by passing after primary treatment. </p><p>The plant effluent becomes murky and B.O.D. reduction drops sharply. The sludge index rises rapidly and within several days, if the overload </p><p>continues, a reduction in flow volume to the final tanks must be made. </p><p>This content downloaded from 185.2.32.109 on Sun, 15 Jun 2014 03:44:04 AMAll use subject to JSTOR Terms and Conditions</p><p>http://www.jstor.org/page/info/about/policies/terms.jsp</p></li><li><p>1118 SEWAGE WORKS JOURNAL November, 1948 </p><p>TABLE II.?Whey Discharged to Digesters During 1947-48 </p><p>Month I Loads Thousand Gallons </p><p>Per Cent Dry </p><p>Solids </p><p>Thousand Pounds </p><p>Dry Solids </p><p>Per Cent Volatile </p><p>Solids </p><p>Thousand Pounds Volatile </p><p>Solids </p><p>Thousand Pounds Sludge </p><p>Dry Solids, to Plant </p><p>Percentage Whey Solids </p><p>of Sludge Solids </p><p>B.O.D. of Whey (p.p.m.) </p><p>1947 March </p><p>April May </p><p>July August </p><p>September October </p><p>November </p><p>December </p><p>1948 March </p><p>April May </p><p>Average </p><p>23 </p><p>27 </p><p>43 </p><p>34 </p><p>25 </p><p>2 </p><p>61 </p><p>73 </p><p>103 </p><p>76 88 10 </p><p>47 </p><p>29.7 </p><p>36.9 </p><p>43.0 </p><p>34.0 </p><p>25.0 </p><p>2.0 </p><p>61.0 </p><p>73.0 </p><p>103.0 </p><p>76.0 </p><p>88.0 </p><p>10.0 </p><p>48.5 </p><p>5.60 </p><p>5.74 </p><p>6.31 </p><p>6.03 </p><p>5.50 </p><p>6.48 </p><p>5.65 </p><p>5.19 </p><p>5.13 </p><p>4.73 </p><p>4.90 </p><p>6.14 </p><p>5.61 </p><p>14.2 </p><p>17.8 </p><p>23.0 </p><p>17.0 </p><p>11.5 </p><p>1.1 </p><p>28.8 </p><p>31.3 </p><p>43.9 </p><p>26.2 </p><p>14.5 </p><p>4.6 </p><p>19.5 </p><p>92.0 </p><p>91.5 </p><p>91.7 </p><p>91.5 </p><p>91.0 </p><p>94.5 </p><p>92.5 </p><p>90.9 </p><p>91.1 </p><p>89.4 </p><p>91.1 </p><p>95.4 </p><p>91.7 </p><p>13.1 </p><p>16.3 </p><p>21.1 </p><p>15.5 </p><p>10.4 </p><p>1.0 </p><p>26.6 </p><p>28.4 </p><p>40.0 </p><p>23.4 </p><p>13.2 </p><p>4.4 </p><p>17.8 </p><p>223.1 </p><p>113.6 </p><p>205.5 </p><p>288.6 </p><p>292.3 </p><p>276.8 </p><p>236.2 </p><p>176.7 277.6 </p><p>275.5 </p><p>259.1 </p><p>253.8 </p><p>239.0 </p><p>6.35 </p><p>15.70 </p><p>11.20 </p><p>5.89 </p><p>3.92 </p><p>0.39 </p><p>12.16 </p><p>17.70 15.85 </p><p>9.53 </p><p>5.57 </p><p>1.83 </p><p>8.80 </p><p>33,100 46,200 36,300 34,700 33,200 </p><p>34,700 32,340 </p><p>35,700 </p><p>Shock loads resulting from dump </p><p>ing of batches of whey to the sewers </p><p>may result in an immediate overload on the plant as high as 60 to 70 per cent above the normal load. If these loads were to be treated successfully, the operator needs three additional treatment plants as stand-by units to </p><p>handle them. The solution to the </p><p>problem is to completely eliminate the </p><p>dumping of any whey to the sewer. </p><p>Digester Organic Loads </p><p>Table II is presented to show the volume and extent of the organic load </p><p>contributed by the whey waste to the </p><p>digesters during several months of 1947 and 1948. In the third column from the right the pounds of normal </p><p>dry sludge solids removed from sewage are shown so that a comparison can be </p><p>made indicating the extent of the dry solids load which resulted from the </p><p>handling of the whey. During the </p><p>peak month of November, 1947, the volatile organic load from whey was </p><p>greater than the equivalent load from all the garbage ground and added to the digesters. </p><p>Whey Disposal Charge </p><p>A charge of $1.00 was assessed for each 500 gal. of whey hauled from the </p><p>dairy plant. The B.O.D. strength varied from 18,000 p.p.m. to 46,000 p.p.m. as shown in the right hand col umn of Table II. The net cost to the </p><p>industry was, therefore, $6.50 to $13.00 per 1,000 lb. of B.O.D. removed, de </p><p>pending upon the concentration of the </p><p>product hauled. The wide variation in solids content and B.O.D. was due to the fact that some of the whey was acid treated at the milk plant to re </p><p>move the casein, and not all of the </p><p>liquid hauled was whole whey. </p><p>Summary </p><p>This method of final disposal of cheese whey has been satisfactory from the standpoint of accomplishing a </p><p>temporary solution to a difficult indus trial waste problem. Utilization of the cheese whey by the dairy industry is </p><p>certainly a more logical solution. The </p><p>industry may then expect to realize some net revenue from the product, and the sewage treatment plant will not have to expend money for special treatment of a waste that is extremely high in B.O.D. </p><p>This content downloaded from 185.2.32.109 on Sun, 15 Jun 2014 03:44:04 AMAll use subject to JSTOR Terms and Conditions</p><p>http://www.jstor.org/page/info/about/policies/terms.jsp</p><p>Article Contentsp. 1115p. 1116p. 1117p. 1118</p><p>Issue Table of ContentsSewage Works Journal, Vol. 20, No. 6 (Nov., 1948), pp. 1-26, 999-1148, iii-xxii, 27-46Volume InformationFront MatterSewage WorksSludge Digestion Experiences with the External Heat Exchanger [pp. 999-1007]A Statistical Approach to Sewage Chlorination [pp. 1008-1024]Oxidation Ponds: Report of the Committee on Sewage Disposal, Engineering Section, American Public Health Association [pp. 1025-1031]Similarities and Differences between a Biofilter and a Standard Filter [pp. 1032-1040]The Polarographic Determination of Dissolved Oxygen in Water and Sewage [pp. 1041-1053]The "Wide Band" Air Diffusion System [pp. 1054-1058]</p><p>Industrial WastesLaboratory Studies on Effect of Alkali-Chlorinated Cyanide, Case Hardening, Copper and Zinc Plating Wastes on Aerobic and Anaerobic Sewage Treatment Processes [pp. 1059-1073]The Toxicity to Warm-Water Fishes of Certain Cyanide Plating and Carburizing Salts before and after Treatment by the Alkali-Chlorination Method [pp. 1074-1083]Compressed Yeast Waste Treatment: I. Nature of Materials and Physical-Chemical Treatment [pp. 1084-1090]</p><p>The Operator's CornerOn Becoming a Full Man [p. 1091-1091]Central States Sewage Works Association 1948 Operators' Breakfast Forum [pp. 1092-1106]Interesting Extracts from Operation ReportsAnnual Report of the Sewage Works Manager, Borough of Slough, England, for the Year 1947-48 [pp. 1106-1110]Seventh Operation Report of the Sewage Treatment and Garbage Disposal Plant, Marion, Ind., for the Year 1947 [pp. 1111-1113]Sixteenth Annual Report of the Division of Sewage Disposal, Toledo, Ohio, for 1947 [pp. 1114-1115]</p><p>Disposal of Cheese Whey by Digestion [pp. 1115-1118]Cleaning a Sewer Clogged by Industrial Waste [pp. 1119-1122]Gas Line Clogged by Corrosion Deposit [pp. 1122-1123]Tips and Quips [pp. 1124-1127]</p><p>EditorialsTime to Modernize Public Works Contracts [pp. 1128-1129]Apologies to Los Angeles County [p. 1129-1129]</p><p>Proceedings of Member Associations [pp. 1130-1134]Reviews and Abstracts [pp. 1135-1147]Book ReviewReview: untitled [p. 1148-1148]</p><p>Back Matter</p></li></ul>

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