IndustriaZ W a d
RECOVERY OF FERMENTATION MESIIDUES AS FEEIDS C. S . BORUFF Hiram Walker & Sons Inc., Peoria, 111.
b b T h e brewers and grain distillers have developed equipment and an attractive market for their recovered grains. The molasses alcohol distillers are still f a d with a difficult r-very-disposal problem. Producers of butanol and acetone from molasses are finding a market for their dried stillage because of its vitamin and es-ally
its h i l a content. Plants producing yeast from molasses now have available a low cost dispoaal process -iring very little attention. Wineries must develop .-me practical method of recovarinp or disposing of their stillage. The recovery of tartrates in California wineries was greatly expanded during the recent war period.
W.
at the present per capita rate, the beverage (grain) r$tillers will process about 40,000,oM)bushels of grain per year to meet this demand. At a potential recovery figure of 17 pounds per 5 6 pound bushel of grain processed, this means a continuous potential of 340,000 tons of by-product feeds per year. For a twoyear period (194?48)the grain distillem will operate at near castocks sold pacity (grain supply permitting) to replenish +g during and since the war. They could not replenish these stocks during the war because of their operations on alcohol for the war effort, nor for some time after the war b e c a w of grain allocations. (Grain allocations, within certah limitations, were removed December 1, 1946.) It is astimated that the by-product feed recovery for this two-year period will run around 750,000 tons per year. The actual recent annual production of all types of distillers feeds is given in Figure 1. Before Prohibition, stillage from grain distilleries (referred to at that time as slop) presented an acute disposal probl~m. A few of the larger plants dried the screenable matter. Those who tried evaporation of the screened stillage and drying of the concentrate with the screenings reportedlittle to no profit or f i n a n d lams. Most of the stiUage was wet fed to livestock, mainly beef cattle, considerable nuieance. or was Nn into stres3as, ~~~h with the d v e n t of Repeal many of the large distillers installed screens, evaporators, and driers; the d e r distillers, in the main, me& and dried the screenings, and the screened was ~n to Of the grains.wd by distillers between 1934 and World War I1 the maximum average recovery for the industry for any one year was only 20% of the potential 17 pounds per 56pouud bushel of grain processed. The lowest recovery for any one year was 11% of the potentid recovery pomible from the total bushels processed by the industry. Became of the great demand for all feeds during the war, esGially protein and vitamin concentrate feeds like distillers’ uaina, and the Govement’s insistence and aid in the mstdlation of recovery equipment, by January 1944 the industry wm actually drying 35% of the potential recoverable tonnage while operating all distilleries at maximum capacity. On tbis same date there were contracts let and installations under way to inorease recovery in the industry to 78% of poteqtial, while all existing grain distaeries were o p e r a t i at capacity. Fourteen per cent of the s t i e was being fed in wet form, leaving only 8% of all potentialstillage solids (small plants) that would go to waste
ASTE is animproperwordtousetodaywhenreferringto residues from most of the fermentation industries. “Feed and foods” are better words to use in describing the tmtmtes recovered from wineries and the feeds recovered from breweries, butanol-acetone plants, and grain distilleries. The purpose of this paper is to outhne the recovery and value of these products and disc- some of the remaining waste problem in certain of the fermentation industria The h e r a g e alcohol industry was legally d e d in the United States from 1919 60 1933. During this period no one was intereded in fermentation residues exeept government agents who used these wastes as tracer materiala in locating hidden “hwch” operations. The past ten yeam have Been not only an improvement in recovery methods but also the development of valuable new by-products. The war years and their shortages and high prices led the Federal Government and the fermentation industries into an intensive recovery program, part of which wa8 financed with federal funds. GBAJN DISTILLERIES
For this discussion djstilleries may be divided into those processing grain and those PrOCesSing mOlasSes. During world War I1 most of the molasses Plants on the were equipped 80 that they could also PrpCe=.Uain Or grain concentrates. The production capacity of distilleries based upon the preceding method of classification follows: No. of
Plants 152 26 178
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Grain plantab Molaasea plants Total
Produotion Capacit Maion Gal. of Proo€/Yesr 324.3 222.5 548.8
Ida’
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Revised data based on u. 8. Department of Apio“l(ure nlc-ps by P. Burke Jamb May 1945. ?mductlon of wnthetio eth I aicohol IS not lnoludd in thia kabls or diacusamn. Produotion capacity Lased on a 3Wd s owati?gyyesr. . Prodvatlon of mmn pllants indudes aJ1 beverage plants and ten straight industrial alcohol olants. ~
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It is reasonhblcto expect that in the near future no ethyl alcohol used for industrial purposes will be produced from grain, but dl will be fermented from molasses.or produced synthetically. The latter will set the price: On this basis and assuming tbat the general public will continue consuming distilled grain beverages 602
waste,
'in tbe Rmertrch Department
feaiible~bytlie industry. Tlie'centrifugedcake al P. .-.!
the evflporators may be
Solid Basket Centrifuges for Clarifying Screened Stillage
INDUSTRIAL AND ENGINEERING CHEMISTRY
604
Table 1. Tvpical Percentage Analrsis of Distillers Feeds from Corn and Rye Pressure-Cooked Grainss Dried Dark Grains (Grains with Solubles) R~~ 85%, barley malt rye malt 10% 15%
corn
11 28 9 7
Moisture Protein Fat Fiber
Ash
11 29 3
a
6 39
Iiitrogen-free extract6
Dried Solubles R~~ 85%, barley malt rye malt
corn go%,
6 43
10%
15%
5 25 6 1 9
5 36
54
1 1
9 48
a Analyses vary within small limits because of processing variables and anal ?is of t h e cereal grains mashed. b B y difference.
1938
I939
1940
1941
1942
1943
1944
The unit cost of a complete stillage recovery plant varies with its size. During the war these plants averaged $23.00 per annual ton for those installations in which rotary dryers %ere used to dry the solubles on the screenings. For those plants where the solubles were dried as a separate product, the cost averaged $30.00 per annual ton. These costs provide for both steam and water demands and a recovery building. The 100% recovery of stillage in medium t o large size grain distilleries is a profitable operation. I n modern plants processing 10,000 or more bushels of grain per day, the net profit from the by-products feed department pays for the cost of converting the incoming cereal grains to alcohol or whisky ready to enter the barrel. Even the small distiller can realize a profit on these operations if the installation is properly engineered and operated and steam is produced economically. STILLAGE DISPOSAL.The Peoria Sanitary District has thermophilically digested part of the grain and molasses waste of Commercial Solvents Corporation for a number of years ( 2 3 ) . Broad irrigation and lagooning are used t o a very limited extent. It is reported (28) t h a t one acre of land is needed for every 10,000 gallons per day of stillage. I n one small distillery during mid-year when stillage is not taken by farmers, whole stillage is satisfactorily disposed of by this method at the rate of 6000 to 10,000 gallons per acre per day. Other processes for the recovery and/or disposal of grain stillage have been studied and proposed (9, 29, 29, 30). GLYCEROL RECOVERY.Chemical Abstracts reveal recent patents on the recovery of glycerol from grain and molasses alcohol stillage, but no installations have been reported. Synthetic a n d soap by-product glycerol will control the market in the near future.
Figure 1. Annual Production of All Distillers Dried Feeds (Year Ending June 30)
Figure 2.
Vol. 39, No. 5
Annual Production of Distillers Dried Solubles (Year Ending June 30)
MOLASSES DISTILLERIES
Stillage from the alcoETHYL.$LCOHOL. holic fermentation of molasses possesses a high pollution load-that is, a total solids content of 5%, organic solids content of 4%, and a 5-day B.O.D. of 22,000 p.p,m. .4t present most of these wastes, except in the S e a Orleans area, are concentrated to 5060% solids in multiple-effect evaporators and used as a molasses substitute in cattle feeds or dried and used in mixed feeds. From 6 to 8 pounds of dried stillage are recovered per wine gallon of 190-proof alcohol produced or for each 2.4 gallons of molasses mashed. The dried material is very hygroscopic. .AIthough only small amounts can be incorporated into feeds because of its high mineral content (25%) and, hence, laxative effect, a large tonnage is being used in small percentages in livestock feeds. Incineration of the stillage for use of the recovered ash (Itorape, :ind bottling departments. The a i quantity and strength of the heavy n-nste- are given in Table The quantity of cyiellor liquor will tlcpriid upon xhether the brciver uses lauter tanks or filters for the rrmoval of graiiii from the xvo1.t. In one -anitary survey (22) only 24c'; of the pollution load from the brtwery could be accounted for lby the firlt fire item5 given in Table 111. Tlie remainiiig 76'; of the polllition load TYRY d u e t o n-ashings from the bottle-. :ind equipment, beer spillage, a i d sanitnry Tvastes: the total na-tc (indu,strial and military) on a %lay 15.O.D. bask p o s e lent of 13 per tinrrel of beer produced. barrel have h e t i reported, but nm-t iii
Table 111. T?pical Analysis of Brew-erg Wastesa (22) Quantity per A v . 5-Day To of Total Bbl. of Beer B.O.D., Pollution Load Produced, Gal. P.P.31. (R.O.D. Basis) 15,000 3.5 Expellor liquorb 0.6-1.0 7,340 1.1 Hop press liquor 0.4 Mash filter-cloth wash u-ater 2.5 4,930 4.6 l e a s t wash mater 0.5 7,400 1.3 0.5 69,000 13 3 Beer filtrate from yeast. Equipment wash u-ater, waste beer, cooling water, and sanitary wastes (By difl'erence) i6.2 Total, 1 t o 5 , inclusive 4.5 14,000 23.8 Total waste (sewer samples) 400 660 100.0
1.
2. 3. 4.
5. 6. 7. 8.
Distribution of conrentrated wastes will depend on equipment used (lauter tank or filters, etc.). b Liquid from brewers' grains press. '1
Yeast recovery iq profitable aiid mnterinlly reduces pollution load (1,:). If a brewer does not practice yeast recovery, his yen-t is usually picked up by a central proce->or \ r h o conr-Prts it into feed yeast. Many h e w e r s are producing d(,liittrrrd yeast for pharmaceutical LiFe. An average of 1 poiind of dry (3'; moi+ is produced per 10 barrels of beer Iire\ved. From 2.5 t o 2 7 l ; of the origiiinl \wiglit of gr:iiii u-ed i n :I bre\rery is recovered n- dried tireivcr-' grainy, o r n i l eclriiv:ilvnt amount sold as n.et grains t o feeder.. This :iniouiit. to :I rccovery of about 10 pounds of dried bretver,' gr:iiiis y r h w l of beer producrd. Residue hops from the hops pm+ are usii:dly buriietl under the boiler. The average aiial dried breir-erz' grains reaching the market during tlic past few years folloiv: Analysis Moisture, So Crude f a t , 70 Crude protein, 70 Fiber 70 Sitro'gen-free extract, 70 Mineral,, % Riboflavin, gamma/gram a b
8 7 26-28 15 41-39 4 0.57
Marketing Year5 Tonsb1940-41 106,100 1941-42 142,100 1942-43 232.400 1943-44 230,700 1944-45 2 l i ,400 1945-46 211,900
Year beginning October 1. 25-27% of original weight of grain used is recoverable as brewers' grain>.
The concentrated wastes in a breivery are too vied; and too small in volume to justify recovery throiigh evaporation and subsequent drying x i t h the brewers' grains. These wastes do not lend themselves to chemical treatment but are being successfully disposed of alone or in combination n-ith doniestic sen-age through digestion and secondary aerobic etabilization (12, 24). Fahr (I?) described a settling, digestion, and trickling filter treatment of brewery wastes that reduces a raiv \Taste possessing a 5-day B.O.D. of 916 p.p.ni. t o an effluent of 25 p.p.m. YEAST PRODUCTION
Undiluted waste from yeast plants using molasses as a Tubstrate containsfrom 1to3Y0 totalsolids (75700rganic)and possesses a &day B.O.D. of 7000 t o 14,000 p.p.m., depending on the ma-
Vol. 39, No. 5
tcrinli and concentrations used in developing the yen-t. This n-azte is too I o n in solids content and food or feed value to justify recovery. Various disposal methods hxve been :tudied, but t h a t proposed by Busir-ell and Boruff and first installed (1941) a t the Fleisclininnn T e s t plant in Pekin, Ill., appears the most feasible (8, 2 2 ) . In this process the n-aste is freed of its filter aid during a settling period of allout 4 hours and is then automatically pumped into the fiwt stage of a beriei of tn-o or three covered digestion tnnlci. The novelty and success of this particular pioccw depends upon controlling the volatile acid and nitrogen contents in the digesters through back circulation and other patented procedures ( I S , 14, 25). K h e n the final digester effluent, at a B.O.1). of 1000 p.p.m. or less, is diluted with plant condenser water in the ratio of 1 part of digested waste to 15 or 20 parts of condenser n-ater, it gives a nonoffensive effluent t h a t may lie run into the river. If further treatment of the effluent is desired this c:in be accomplished through the use of trickling filters, n-ith rrcycliiig of p u t of the final effluent into the liquor being treated on the filters (26). Practically no sludge is formed during the stahilizntion because of the high organic and low fiber content of the naste. The process permits heavy loadings (0.1 pound orgauic matter per cubic foot per day); hence large qunntitiea of fuel g:ii (0.7 cubic foot per tiny per cubic foot of tank capacity) are produced (25). U'ISEKIES
The origin of wine nialting in the United States dates back to the earliest colonial settlers. Commercial production has been ii \Yell established enterprise for more than a century. Prior t o Prohibition, n-ineries were mainly small units ividely scattered in rural districts located close t o t h e vineyard grnpe supply. Tlie reqnisance of the wine industry has lieen accompanied by proKreFuive expansion. This has complicated and increased the w > t e problem. .1description of the processes involved in the manufacture of various types of Tvines may be found in the literature. \Vinery \r-:ihtes consist of atemi, pomace, lees? and stillage. T h e stems atid pomace (skins, piilp, and seeds) removed during the production of wine, which amount to 15 t o 20'3 of the weight of the original grape;, :ire risuslly piled near the winery and then periodically removed from the premises and spread on vineyards for their fertilizrr value. T h e pomace piles may become quite objectionable, depending on their treatment and general climatic conditions. Lees is the sludge remaining in fermenting and aging tanks after the wine is racked (decanted). This material runs high in pot asslum .. ' bitartrate. Stillage is the dealcoholized effluent from stills producing bevt r:ige o r fortifying brandy. The material distilled may be wine, lee-, pomace, or pomace ivashings with the character of the stillage varying accordingly. These stillages average 16 to 20 gallons per gnllon of fortifying brandy (189-proof) recovered. Recent studies conducted for the \Vine Institute included chemical oi aboiit one hundred samples of stillage from sixty ditilleric-. Conventional stillage averaged 1.6c0 total solids, of which ahout 0.5% was suspended solids, mostly yeast. The stillage \\-as acidic (pH 3.4 t o 4.2; total acids as tartaric, 0.2 t o 0.7 gram per 100 cc.). The oxygen demand ranged from 5600 t o 32,000 p.p.ni. ivith an average of 12,300 p.p.m. Five-day B.O.D. data run shout half the oxygen-consumed values. Pomace stillage; (less than 20% of California production) run about 3'3; total solids, with 2 5 suspended, and possess ouygen consumed values of 15,900 t o 18,600 p,p.m. Various mechanical and chemical treatments reduced the organic load by 25 to 5 0 5 . Stillage is the least readily disposable of the four winery wastes listed. S o w t h a t the industry is expanding and concentrating, this problem is becoming more and more acute. The increase being noted in the sale of dessert wines means t h a t more brandy
May 1947
IN1
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PRIAL AND ENGINEERING CHEMISTRY
Rotary Dium Dryers Used to Dry Diritillere Solubles
c
must be prduced to
oomodate Satisfaitorily the volume of &iUage produced; .therefore decomposition soon 'Beti m, and foul and 'nauseating .oilom are produced. Greater basin &rea wduld, mgerially sjd. in &mimting this nuisance. A report on intermittent. ponding bas recently been published (38). ' Tbe only mm'ercid soume of tartrate is'from'krape juice and wine. The reoovery of the tartrates from leea, pornaee, nrgols, md distilled m a t e ~ l h Bbeee B expanded in~C&fornisduring the pBBt 'Our The normal prewar Of tartratas in"the united 86ates was about 15,000,000~Porn&, PrdiCauY dl Of which WBB imported. ' About 1j300,000pounds of refined material . , werkecovered in California in 1 9 d . ' These fib= indicate that the wBBkproblemin the wine industry ie €be dispod of the stillage prcd"ced during the manuf d u r e of'brandy. The compoa&h of this stillage have not b&n extensively teated for their nu+ritionbl value, but on' the' basis of their low protein cdntent i+would appesr that they, de6nitely not in t h e ' s m e class BB brewery and 'distillery (byproduct ~ S j n s . The severity of the Wine S w ' P m b l e m has been recognized by the Wine Institute; thia p u p recently initiated research designed to achieve maximum efficiency in the disposal of winery waste materials. '
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GITERATURE CITED
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(9) B m 6 , C. S., IND. ENQ.C-., 31, 1336 (1939J. i .' (10) B o d . C. S., and BUsWeU, A. M.; 16id.. 24,.33 (1932j. (11) BoruE, C. S., and Miller, D. L., Sewwe Works En(r.,Mu?~@ Sonit., 9, 289 (1938). (12) Bushee, R J., Sewage Woorks J., 11, 295 (1939): (13) Buswell, A. 'M., and Boruff, C. 8.: U. 5. Patent .1,990.523 ,(Feb; 12, 1936). ' . . (14) Ib& 2,029,702 (Feh. 4, 1936).. (16).Coates, Ellis,W.. M d m Biewery A m 2 6 (16) COoley, b. 8.. IND. ENQ.CEBM.. SO, 615 (17) Fsbr, I;.,L.. Am. Biewar. 79, No. 4, 19-%'(1946). (18) Fsirbanks, B. W., KFider, J. L.,Cartoll, W.IL,J . A.i& Sei., 3, 29 (1944). . < - , (19) Frvber, .Eduard, et el., CAm. & News. l . 23, ,617 (1946)., , (20) Graschke, A. C.. and Bird. € R., I ; Uniy. Md. Agr. : E q t . Sb.. Bull. A-6 (1941). (21) H a , P. w., Soott; M. L.. No&. L. C., Hew?; G. P.. FmW SCi., 23. 263 (1944). ' 122) IUinois Dept. of Public Health, Div. Sanit. Eng. Aug. 4-17, 1941. (23) KpG L;5.. Swwe Wmks 5, 627 (1933). (%) Mohlmm,.F. w., Modern Brewer, 21, 35 (1939). , (25) saem,xhw,swe wmb J . , 16, 604 (1944). (26) Schlene, Hatry, Buswell. A. M.. and Tstlock, M. W., Ibid., 18, 19 (1947). (27) Synold., R. E., .Ccerriok, C. W,.Roberts, R. E., i d Hsuge, 5. M., P e d W Sei., 22, 323 (1942). (28) U. 5. Public Health Service. Suppl. D, Industrial W&e Guides, ;pp:1041 aod.1140 (1943). ' (29) WdImh, Abraham, and W . . o h w , A M , S m w e Wm'b J.;14, 382 (194%). (30) Wallemwin. J. S., ad, IND.ENQ.CHEW... 36. 772 (1944). (31) Willkie. H. F., and B W . C. 8. (to Hirm &'SOna, , Inc. U. S;'Pstent 2;16.5,960 (July 11, 193 (32) Wins
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(1) Anonymous,,CAem.82 Met: Eng.. 52, 130 (1945). (2) Bauernfeind, J. C., a n d B o d , C. S., Am. M U k , 72, Jan., 182; Febi, 63; .March, 50 (1944). (3) BauBmfeind, J. C.. et el., Cam2 Clqa., 21, 42 (1944). (4) Bsuernfeind, J. C., et d., IND. ENQ.C-., 36, 76 (1944). (6) Bsumgsrten, W., et al., Csreal Chm,.. 23; 135 (1948); (6) Bsumgarten, W.; d e l . , ' h ~ENQ. , W h . , 36,344 (1944). (7)' Bird, H. R.. and Mattinply, J:P., Poultry Sd..24,34.(1945). (8) Black, Haye. and Klaasqn, Clsrence.W., S w e ~ o r l o aE w . Munic. Sanit., 12, 74 (1941).
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. . :1: Pasaamlio before theJndwtrial Waste Bympord-.a+.tha 111th Me# of the A Y ~ ~ UCHIY;& N SOCI-. Atlantia City, N. J.
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