hla\-. 1927
~
_
_ IAYDC,STRI.41JA S D E S G I S E E R I S G
CHEJIISTRY
_____.
577
Lime in the Treatment of Pea Cannery Wastes' By L. F. Warrick BLKEAL OF
~\\ITAKI
BP.(,I~EERI\C.\VIZCOVSIV STATE R O A R U OF H E L L T H A I \ u h < ~ v\VIS ,
T h i s paper is a report of cooperative investigations cond u c t e d by t h e \%'isconsin Canners' Association, S t a t e Conservation Commission, a n d S t a t e Board of H e a l t h i n t h e t r e a t m e n t of pea cannery wastes w i t h ferrous sulfate a n d l i m e a t Poynette, Wis., d u r i n g J u n e a n d J u l y , 1926. Before describing the experimental work t h e characteristics of t h e various pea-canning wastes a r e discussed. Preliminary s t u d i e s were m a d e i n t h e Sanitary Engineering Laboratory of t h e University of Wisconsin w i t h wastes artificially prepared f r o m c a n n e d peas t o ascertain which Fvere m o s t effective i n t h e removal of organic m a t t e r . These preliminary studies were used a s a guide i n p l a n n i n g t h e investigations a t t h e pea cannery.
The Sen- J e r ~ e yStritc 13ii:ircl [if EIealtli c.c~llc*lutlcclafter laborator>- study of toiii:ito-cnllliillg~-caiii~iiig nxste-. tlint .-c.reeniiig alone or treatiiient with h i e , ferrous suliatc. cnlciiiiii aiid alum. either singly or in \-)mioiis [ ' ( i i n ulcl not yield a .>table,clarified li(iiiiir,l,* settling tank> were reconinieiided as preliminary treatillelit. the efflueiit being discharged into a streani if .d€icieiit clilution was afforded. otliern-ise onto a plouglicd field. The S e w T o r k State Board of Health has also r~~coninientletl t m k treatment for the pea cannery wastes. h a t it has Iieeii fouiicl that there is \-ery little improvement in t lie character of tlie effluent as compared ~ ~ i tthe l i iiifluent.' -1 clieiiiic.:il-precil,itatioti n-aste treatiiient prcice+ ib iisrd by the -1. & 1'. Product? Corporation nt tlicir c.niiiiery in Rrockpurt, S.I-., n-ith satisfactory results." The trcatiiieiit coiisi>ts of screeniiig t o remore coarse solids:. fiilloncd 11y tlie :dcI(Iitioii of ierroiih sulfate :tnd link in :mount> qiiivd(~iitto 1.7 pounds of ferrous d f a t e and 12.9 poiintls iit liine per 1000 gallon> of n-mte. The Illinois State Kater Survey concluded froni cniiningi'nctory waste clihpoal experiments a t Kashingtoii. Ill., that the problem T V : ~ adeqiiately solved by disch:irging the screened wastes on h a d irrigation beds. Chemical precipitation experiments on a laboratory wile, using \-arying aniounts of aluniina cream as a precipitsiit for corncanning wastes. led to the conclusion that such treatment was of little practical application. Experiments in the treatment of tomato-canning wahte? conducted by the United States Public Health Service a t .Iinelia, Ohio, indicated that about 85 per cent of the $it-pended matter could be renioved by tank treatment, arid that a clear, non-putrescible effluent could be obtained by first filtering the settled wastes through beck of coarse cinders and later through beds of s a n d 5 Preliminary tests by the TT'isconsin State Board of Health during the pea-canning season of 1925 indicated that the application of 5 pounds of ferrous sulfate and i pounds of lime per 1000 gallons would effect' a reduction of froni GO to 70 per cent in the organic The results of these tests, together with the lack of definite data in the literature concerning the chemical treatment of pea cannery wastes, suggested the inrrestigation under discussion. Chemical rather than biological niethods were advocated because of the time required for the latter to become effective and the short duration of the pea-canning season.
:i
ETH01)S fur batisi'actorily aiitl economically (lis111i-iiigof riitiiiery Tvastes i i i the. 1)rei-etitioil of m i >:iticc,- a i i t l ol),jectionahlestreaiii 1)uIlutiiJii hnvcx lieeii -ciuglit I)? c:ii:iier>~ clieiiii.t-3 :iiitl >:init:iry eiigiiieer- f(ir :L ll~Iiill)(~r i i f y ~ : i r > . l'lic1,se tlel-e!ol)etl liai-e h e i i Lilt partially f i l l i 11' c~iily( ~loc~nl i zipplicatioii. Tlie p l ' ( J l ) l C l l l S pieiwhte- 1iaT.iiig I w c 0 1 i i ~more ~ :mitt\ [ i i i , in w - c d -t:ites, consicleralil(~ J- clirectetl tiinnrtl their ,duticiii. The 1)i.iiiiuy piirpo,+e of this paper i j t[J gii-e details arid rebii!t< c~~iic.eriiitig :in in\. tion cwitlucted at Pciyilettc.. ie:ison ill tlie ireat~iieiitof errous sulfxte and li~iie. ' r h p ilii-e-tigstioii n m ClJllClLlcted jointly h y tlie Kihconsiii Cmiiier.' .-i.ssuc.iatioii. State Ihartl of Health, nncl State CoiiLcmxtiim (.'uiiinii,+ion. funds to eoi-er the cost of calieiiiic-alh :iiicl ecluipiiient being furni~hetlby tlir Canners' -IssociatiiJii :itid t h e iieceaxary technically trained perwnncl beiiig ~)roi-itletlby tlie state through an appropriatioii for the control r ~ fhtreatii pollution. L-nder the agreement tlie technical phase* of the work were directed by the Bureau of P:initary Eiigineeriiig or' the State Board of Health, and the field nork TVB' perfornied by iiieniberh of the staff. A411 taiice was reiidered by officials of the Canners' d?sociatioii a. well as local officials nt the cannery selected for tlir. investigation. Sorinally, about half of the nation's canning peas are produced in Wisconsin. Since a n~uniberof the canneries in the state pack peas exclusively, and as the wastes protluced offer the most difficult disposal probleni, it was decided to devote all treatment activities to these specifically. The probleni is rendered particularly difficult by the facta that the period? of hottest weather and lowest streani flonN a t u r e of Wastes generally O C C U ~ during the pea-canning seasoii. Consequently, it is apparent that these wastes need most thorough -1brief discussion of the characteristics of the various treatment in the prei-ention of local nuisances and serious pea-canning wastes is necessary to give a clear conception streani pollution. of the problem. To facilitate discussion the wastes have been classified according to their source, as follows: Previous Investigations
M
1 review of d l available literature concerning the treatiiient c.)f canning-plant wastes was niade before starting esperiniental work. Yery little information could be found concerning the treatnient of caniierp wastes generally, and pea cannery wastes in particular. -1 divergence of opinion was expressed as to the success and practicability of treating tlie wastes by chemical methodSs 1 Received April 4, 1 9 2 i . Presented tinder the title "Lime T r e a t ment in Disposal of Pea Cannery Wastes."
I-T'iner
wastes (produced in threshing peas)
(1) Vines--used as stock food (2) Silage juice-seepage from stacked vines
11--Factory wastes (produced in the canning process) (1) Produce washings-before and after blanching (2) Blancher effluent ( 3 ) Floor washings (4) Water used to cool canned peas after sterilization ( 5 ) Sewage from toilets and lavatories
* Numbers in text refer to bibliography a t end of article.
\ - i s t i t \\.~s,srEs~f:anning peas are harvested in a manner sorne\diat similar to hay or grains. The vines :ire cut and carted to viners, i n which the peas are removed by a threshing process. The vines are st,iicked in t,he open or in silos to he used 8s Sood for stock.
Anelynrs of Pra V i n e Silage* Moisi
SArnP*.il
U K Y HASLS
T h e fermentation OS this d n g e i s oftau res~ionsibleSor very disagreeable odors in tlie vieiiiity OS the viner stations. The care of tlie stacks to prevent local nuismices involves cleanline.% arottid the stack a n d tlic free uiic of lime as n disinfectant :uid deodorant. In threrhiiig, the riiies are liriiiscd arid inacerated and, on staekiiig, the nioisture reeps out and gercnliLtes down through the rine?, acquiring :I rcry high orgenic content. Tliis liquid slack ctnucilt is tlic so-called silage juice. It off very offmisire odors, and strcarn it, uses u p the dissolved od vcrt,iiin other aquatic life. :ti, r,u~gcl~-coiis:ilned\.aloe "E ely 200 t,iines that for strong domestii: siwrgi:. v,>lwric h i t i g niilxiininn flow is estim:itcd at 1000 to 1500 g:dIms jx:r day per 100 neres of vine..:'
FiBure L---Chemlcsl Feed Equipment and Screen U n i t of the Pea Cannery Waste Treatment Plant, Poyneffe. Wls. house b-screen unit c--Dry feeder for lime d-Dischilige pipe for lime
a--Motor
e-Ferrous suitate solution tanks f-. Orifice tank for fermnr sulfate 6-ChemicaI precipitation tank
Lime treatment, for this waste has resulted in some i n pro\-einr~nt,but is n u t rcgarded its ciitirely s:rtisfactriry. Cheiniral prccipitatioii cxjieriincnts prorlileed an amount OS sludge uhnost~(aliial to the original volrinie of ilre silage juiw. I'reseiit pmrtir~?.ho er, t,o lociitc virier stations z t t i l e i::innery in ordcr to rnike unI f viiies by the farmer has niiiteri:illy pniblcni. The vohinie of silage juice g conipnrntively small, it c i i n gencrally ahsorpt ion or by spreading and pion= ing u~iilcri ~ riiearliy i land. In view (if the high orgmir content, of silage jnicc containing npprecitiblc amouiits of c:iriiohydriites, it is possible that starch: sugar, alcrihol, and otlier such by-prodnets might be
ecouomically recovered. '1'his is a inatter for consideration by the canning industry, no attempt having been made to utilisc or treat viner n tes in the experimerital vork at l'ognette, \Vis. F ~ C T O R Y \V.wr&?s-.-'Ilie blancher effluent, produce, and floor washings constitute the objectionable wastes resulting from the pea-canning process proper, which require special treatment. Tlie other f:ict,ory wastes are oS secondary importance iii the general problem, since the cooling water is unpolluted and the disposal OS domestic sewage is 3 separat,e considemtion. 'Illre bisncher effluent i s tile strongest waste produced in tlie pea cannery. It contains the gummy coating from the surlace of the peas together with the organic constibiients in colloidal and true removed during tho hln~icliingpro1 solution. Analyses by Aiicl iiird JViIey, and reported by Bitting,Sgive suiiie idea as t,o the c1i:iractcr of the organic matt.er. Analyses of Peas (Kesiilis crprcrscd _Ls ,>eicrn*,gr ttotal) A V I i i o n i i ~ \V.\?EPR I'ROTSIS PIT STKCII fai.i.ir.
These aiial~sesi~1~1ical.c tli,zt, :tboiit 42 per ceot of the carbohydrate contcnt of i l i e green peas is reiiioved in the '' c:rrb~~hydrt~tt: content, ticcording o i l :mil Churchill.' comprise5 24 to 60 per cent of pc:ts, &out 80 per cent heiiig starch and 20 per emit g:&tctnris, pentimans, and other fermentable sugiirs. h cowidcr:ihlc portioii of t Iicse coristitnents is hclievcd tu be in true or colloiilal soliltion iii tlic bl;incher ciheiit, together \rit,li :it lcast. ii part. of the organic m:ittcr reprcseiited by the reiluct,ions iii protein, fat, and i:elluio;e r:l>ll~eJitS. Itcsearchcs by Jliisrvell, Greenfield, niid ShireRconcerning the characteristics of pea cannery wastes, in which 1.1 per cent alcolrol was formed by yeast fernient,siion(if blancher effluents, provide fwtlier evidence of the presence of fermentable sugars. T h e oxygen consumed value for this waste, 130 to 170 times greater than that for domestic sewage, is ascribed to t.licse sugars. An oxygen demand of 11,000 p. p. m. roported for the same waste is undoubtedly due to the converaivii of t,he proteins and carbohydrates to more stable compounds. 13ecause of the large nnstnble organic content OS the lilanehor efAuent, and resultant high oxygen requirement., it is considered the most ohject,ionable of the factory wastes Srom the stream pollution point of view. The other wastes contain considerably less organic mattcr in true solution. Wastes produced in washing peas before blanching contain dirt, broken pods, and pieces of vines, while those produced in rewashing after b1ant:liing contaiii largely light-weight split peas and loose skins, a large portion of which can be removed by tlie screen unit of a treatment plant. This applies also to the floor and ni:ichinery washings, which contain dirt, wast,e peas, and other such substances, but only a relatively siriall arnourit OS organic matter in true solut,ion. As st,ated previously, the cooling \vat.er and domestic sewage do not enter into the general treatment problem. The lormer, having received no organic matter, is either by-passed around a cannery-waste treatment plant or utiliecd as a boiler feed water t o reduce fuel costs. Tlie domestic sewage is usually discliarged into the locsl mu-
May, 1927
INDUSTRIAL AND ENGINEERING CHEMISTRY
nicipal sewer system, when such is available, or disposed of separately since the cannery-waste screenings are frequently used as hog feed. The wastes treated in the Poynette experiments included only the blancher effluent and produce and floor washings. There were no viners at the cannery, all being situated on nearby farms where the silage juice was disposed of by soil absorption. The cooling water was used for boiler feed purposes and the domestic sewage was taken care of by a septic tank and dry well. The volume of canning-plant wastes for all practical purposes can be considered equal to the total daily water consumption. This amounts to about 100,000 gallons for an average two-line pea cannery, equivalent to one gallon of water per can (No. 2 size). Since the water is used in about 12 hours, the rate of consumption is approximately twice this figure. Preliminary Studies
Before the field work in the chemical treatment of pea cannery wastes was started, certain preliminary experiments were conducted in the Sanitary Engineering Laboratory, University of W i s c o n ~ i n . ~These experiments, with wastes artificially prepared from canned peas, involved the application of various precipitants to ascertain which were most effective in removal of the organic matter. The results obtained in this experimental work indicated that: 1-Lime and ferrous sulfate treatment will accomplish good clarification and bring about a material reduction in the oxygen demand of the waste. 2-Similar results can be obtained with lime and alum, but much more careful control is required than in the treatment with ferrous sulfate and lime. 3-TO obtain good results in either case, thorough mixing of the chemicals and wastes is essential. 4-Further reduction in the oxygen demand of the clarified waste is effected by aeration. 5-The addition of clay, fuller’s earth, and other such substances t o the waste does not materially aid in the chemical coagulation and precipitation of the organic matter. 6-Hydrogen-ion concentration and biochemical oxygen demand tests can be used in controlling and measuring the effectiveness, respectively, of the chemical treatment applied to the waste.
These results of the preliminary studies were used as a guide in planning the experimental investigations carried out in the field during the pea-canning season of 1926. Experimental Plant
A modern two-line pea cannery with a daily capacity of 100,000 No. 2 cans, owned by the Poynette Canning Company, was selected for this field work. The selection was made on the basis of convenient location to Madison and of good facilities provided for the waste treatment investigation. The company had previously installed a rotary screen unit and settling tank for the factory wastes, exclusive of the cooling water and domestic sewage which, as previously mentioned, were disposed of separat,ely. Since chemical treatment had been contemplated in this installation, only a little added equipment and construction were necessary before the experimental work could be carried out. The m o d s e d treatment plant consists of a rotary screen unit, feed-regulating devices for lime and ferrous sulfate, mixing facilities, a hopper-bottom chemical precipitation tank, sludge pumping and drying equipment, and apparatus for flow measurements. Some of these units are shown in Figure 1, while the flow sheet for the treatment, process is presented in Figure 2. The Berlin rotary screen used a t Poynette is covered with a 20-mesh wire and is driven a t
579
18 r. p. m. by a one-horsepower electric motor. The wastes enter in at one end of this unit and flow out through the 20mesh wire covering into the screen pit, where they are mixed with the lime and ferrous sulfate. Mixing is facilitated by six angle-iron ribs fastened to the outside of the rotary screen. Lime treatment is regulated by means of a Gaunt dry feeder, a spray device being provided in the discharge spout to dissolve the lime partially and prevent it from blowing about as a fine dust. High-calcium, hydrated lime is used in the treatment of the wastes, since it is considered essential to satisfactory results. Ferrous sulfate is added as a solution of known strength, the dosage being controlled by an orifice tank. As a portion of the coagulating value of the ferrous sulfate is lost by this method of application, a dry feeder for this chemical is much more desirable. After addition and thorough mixing of the chemicals with the cannery wastes in the screen pit, they flow into the hopper-bottom settling tank. This tank is built of reenforced concrete, with inside dimensions of 30 by 12 by 3 feet effective depth. The two hoppers, shaped like inverted pyramids, have a slope of 1:12, instead of 1:2 according to the original design. This change in specifications by the contractor, made because of local soil conditions, was the cause of some difficulty in sludge removal. Wooden baffles extending 6 inches below the flow line were built across the tank near the inlet and outlet to provide equal Wastes from Cannery 3 Floor WashinqS
Gravity
Gravity
Gravity
Figure 2-Flow Sheet for the Experimental Plant Used in the Chemical Treatment of Pea Cannery Wastes, June-July, 1926
distribution of flow through the tank and prevent scum from escaping with the effluent. Because of a scouring action, due to the flow being directed downward at the inlet end, the baffle there was replaced by a galvanized iron trough during the latter part of the investigation. Three sludge-drying beds were provided by sinking wooden frames 10 feet square by 1 foot deep into the sandy soil surrounding the treatment plant. At the start of the work a small pitcher pump was used in transferring sludge from the tank to the drying beds, but, this being unsatisfactory, a small electric motor-driven centrifugal pump was installed for the purpose. It gave continual difficulty in operation,
I S D U S T R I A L A N D ENGINEERING CHEJfISTRY
580
however, and was finally replaced by a 4-inch gasolinedriven diaphragm trench pump with very good results. The effluent from the treatment plant was measured during the experimental work by a weir and continuous flow recorder. It was then passed through a small lath and gravel filter used as a catch-all for any peas, pods, or such material that might pass through the tank, and finally discharged into a small stream bordering a nearby swamp. The effect of the treated waste on this stream is discussed later.
6 t o 13, are representative of effective treatment. The large amount of precipitate in the last three cylinders was due to the collection of these samples during the clean-up period, when the treatment was increased to take care of the large volume of floor and machinery washings and blancher wastes. The analytical results given in Table I, obtained with the simultaneously collected samples of raw and treated wastes in these cylinder control tests, indicate that with ineffective treatment the oxygen consumed values of the raw wastes were reduced from 1.2 t o 18.2 per cent, and with effective treatment from 18.8 t o 51 per cent. Coniparison of biochemical oxygen demand tests made with the untreated wast'es and clarified supernatant liquids in t,he cylinders gave reductions ranging from 22 to 67 per cent. Subsequent test's indicated that greater reduction in oxygen consumed and biochemical oxygen demand values could be acconiplished with ferrous sulfate dosages in excess of 2 pounds per 1000 gallons of waste. Best' results were noted when the pH value of the treated wastes was 10 or higher. The clarification effected is shown by the decrease in turbidity. practically all the suspended matter being removed with effective treatment in the cylinder tests. In the operation of t'he treatment plant', composite sainples of the raw and treated wastes were collected for coinplete chemical analysis to determine the efficiency of the process in the removal of the unstable constituents. Though the results obt'ained for the first fern days indicated effective treatnient? this efficiency rapidly decreased. -4 thick scum appeared at the surface of wastes in the tank and considerable suspended matter was observed in the effluent. Increasing the chemical treatment did not improve the situation. The sludge, which had been allowed to occuiiiulate iii the tank due to inadequate sludge-removal facilities,
Tests
Kaste treatment was commenced a t the beginning of the pea-canning season, every effort being concentrated on ascertaining the lime and ferrous sulfate dosages most effective for clarification and removal of the unstable organic matter. Oxygen demand, oxygen consumed, turbidity, and pH determinations, made in accordance with standard methods, were used as field control tests.1° The ratio and quantities of lime and ferrous sulfate added t o the wastes were varied, samples were collected a t the inlet of the tank and alloTyed to settle in graduated cylinders, and the control tests mere applied to the supernatant liquid. Some of the cylinders showing the clarification accomplished by different treatments are presented in Figures 3 and 4,while results of the control tests made with each are given in Table I. In Figures 3 and 4 the differences in the degree of clarification accomplished by various amounts of lime and ferrous sulfate are clearly brought out. The lime dosages were varied from 3.6 to 26.4 pounds, and those for ferrous sulfate from 0.5 to 2.1 pounds, per 1000 gallons of waste. Cylinders 1 to 5 show ineffective treatment, resulting from the use of insufficient lime to react with the ferrous sulfate in the formation of a satisfactory floc. The remaining cylinder-, T a b l e I-Results
FeSOI
DER
SLUDGE
Lime
P.p . m.
Lbs./lOUO gal 1
0 83
4.0
-
1
1.16
3.57
3
1 84
4.14
4
1 96
4.3
5
1 37
13.8
ti
2.1
12.7
1.86
11.3
8
0.72
10.1
9
0.56
11.4
10
0 52
18.6
11
0.89
21.3
12
1 .S i
25 4
13
0.50
"
of C y l i n d e r C o n t r o l T e s t s , Chemical T r e a t m e n t of Pea C a n n e r y Wastes CHEMICAL rZNALYsES
CHEMICAI.S
CYLIZ-
14.0
& d a y a t 20' C.
VOl. 19, s o . 5
Raw Treated 70Reduction Raw Treated yo Reduction Raw Treated 70Reduction Raw Treated L7, . " Reduction Raw Treated 70Reduction Raw Treated yo Reduction Raw Treated 7cReduction Raw Treated cZ Reduction Raw Treated Cj-, Reduction Raw Treated yc Reduction Raw Treated yo Reduction Raw Treated yc Reduction Raw Treated 70Reduction
1720 1700 1.2 2060 1820 11.7 2190 1950 11 2250 1840 18 2 3030 2,540 16 2 2860 1480 50 2960 1580 46.6 1640 1220 25.8 2980 2420 18.8 3140 2060 34.5 3080 1840 40.3 3060 1500
51
P. p . m. ... ... ...
... ...
... ... ...
...
P.p . m. 7.4 9.8 7.3 9.6
7.2 8.8
cc.
': b y 5'01.
430 33.7 600 450 25 1000
"po
20
8
'
T a n floc; poor coagulation a n d precipitation
3%
12.8
23
0.2
34
13 6
30
12
34
13.6
42
16.8
30
12
T a n , rapidly settling floc, clear Yiipern a t a n t liquid
30
12
T a n floc b u t only fair clarification
32
12 3
T a n , rapidly settling floc with clarification
50
20
T a n , rapidly settling floc; good clarification; clean UP
i0
28
Brownish green, rapidly settling f l o c , very clean i t a r t of blancher waste
50
"0
Dense blue-green, rapid settling floc, concentrated blancher wahte
Green and t a n floc; poor coagulation a n d settling action
JJ
2650 2250 15
7.4 8.9
... ...
7.2
4050 1333 67 1302 550 58 1750 1250 29.6 3650 2850 22 3750 2550 32 1050 450 57 2450 1000 60 23,400 15,000 36
7.6 10.0
. .
Cc./ZjO
700
9.2
7.4 10
+ 7.6 10 + 7.0 10 t
7.: 10 T 7 3 10
+
7 0 10f
600 250 48.4
1000 320 68 600 100 83.3 900
75 91.7
800 50 93.8 850 180 78.8 YO0
90 90 800 70 91.3 3;: 92 -
6.8
!I00
8.9
"0 78
I
1
Blue-green, rapidly iettling floc; poor clarification
I
( S e w FeSO: solution)
I
Brownish green, rapidly settlinq floc. very good clarification
I
fair
by untreated pea caniiery waites. 7-The estimated cost of waste treatment for a tnoline cannery IS $13 to $15 per day of capacity operatloii. Further Work Planned
Further ~inestigatiorisare contemplated foi tire ~ornmg mnning beason to develop piaLttca1 control tests a i d ~lietliods iii the operation of chemical ticiitrnciit planti for pea cannery wastes, to determilie tlie efficreiicy iind i>racticability of aeration as secondary treatment, and to make comparative s t u d i e s wit11 o t h e r Figure t s a m p l e s of Treated Pes Cannery Wastes Showing EKect m e t h o d s of cannery of Sludae Decomposing a n d Going i n t o Solution waste treatmeiit being This p&rtirliy accounted lor the poor results.obtained during the first part of the investigiltion nt Poynrtie. Wts. (See Table 11) experimented with in other states. Itesearch largely to accumulations of organic matter carried through 1s suggested iri regard the tank during the early part of tlie work, a i d to decreased to utilization of some stream flow. of t h e pea-caniiin g Kn offensive odors were caused by the lime and ferrous wastes, p a r t i c u l a r 1y su1fat.e treatinelit of t.lie pea cannery wastes or by the method the silage j u i c e a n d nf sludge disposal. Thongli a slight sour odor was noticed b l a n c h e r wastes, benear tlie ditch a t the edge of the swamp during the hot cause of tile conztderweaiher, no locd riuisance was created. This could prob- able amount of carboably have been prevented if effective treatinelit had been h y d r a t e p r e s e n t in maintained throughout the work. According to employees thern. Thiz also applies of the carinirig company, conditiolis were much iinprored to the screenings with over those existing when n~ clieinieal treatment was ap- rcspect to converting plied. them into marketable There are a number of pea canneries in Wiscoiisin wliich nrod,,r.ti; iil0.R 8..~ $ snrdischarge wastes into municipal sewerage systems. Tliese ciai feeds for fowls or Figure 6-Removal of Sludge from wastes impose a Iienvy burdeli on sewage disposal plants, Drying Beds of Pee Cannery Waste Disposal Plant, Poynette, Wis. froniicntlv resultinz iii their failure to function satisfnctorilv during the caniring season. Accordingly, experiments were Acknowledgment conducted by canners at Ripon aiid Ocoiiornowocl \Vis., in the coagulation of the eariniiig factory wastes with lime and hckiiawledgnieiit is hercwith mnde of tlie activities ferrous sulfate prior to discharging them into the city sewers. of C. 11.1. Baker, state mnitary enginccr of V\’inaoiisin, in The object was to asccrtiiin wlretlicr such t,reatment would makirig possible tiie experimental work desr:ribed i n this obviate tlie necessity of slutlgc renioval in tnrrks at the paper, The excellent coiiperation of W. E. Siclioloy, cannery in suc,li cases. The results indicated tlmt littlc executive secretary, arid other officinls of tlic Wisconsin is accoinplislied in improving i:unditions at the sewage Canners’ Association, as \%-ell:is tliosc of tile Researcli L a h r a disposal plants, and that, removal of the coagulntcil orgaiiic tory of the Sational Canners’ Assoriatioii, assisted mtitcrially matter at tlie cniinery is esseiit,i:rl. in conriuct,ine t,lie investieation. Tlie willine he. b of M. ._ Starr Sichols, chief chemist, St.& Lnboratory of Hygiene, Conclusions and J. P. Smith, assist,ant sanitnry eiigiiiccr, greatly faciliwastes ciiii l i e tated tlie niialyt,ical work in the laboratory a,rid in the field, I-The oxygen demand of ped carin reduced approximately 75 per cent by screening arid taiik respectively. ‘flie courtesy of the Satiorisl Lime Association treatnient with t,lie applientioii of 7lIt pounds of liirie and arid American Steel and Wire Company in furnishing the lime and ferroiis suliate aided eonsidernl~lyin reducing ex3’/“ pounds of ferroiis snlfate per 1000 gallons.
-.-
i,
I
May, 1927
INDUSTRIAL A N D ENGINEERING CHEMISTRY
perimental costs. Many helpful suggestions were made by their representatil-es, and other interested engineers and chemists. Bibliography 1-Daniels, Trade Wastes from Tomato Canning, Report of New Jersey State Board of Health, 1910, p. 248. 2-Stream Pollution by Cannery Wastes, Report of the New York State Board of Health, 1911, p. 825. 3-Baker, Canning A p e , 6, 895 (1925). 4-University of Illinois, Bull. 38, May 18, 1924, Water Surpey Series N o . 11, p. 330.
5-Hommon,
583
U. S. Pub. Health Service, Bull. 118 (September, 1921).
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~I~~~~no,",n,".&u~c$~'; ~ ~ 1 . ~ ~ ~ ; , * ~ ; ;fi4 ~ , (1921), 8-Buswel1, Greenfield, and Shive, Ind. Eng. Chem., 18, 1083 (1926). 9-Bishop and Mickle, "Treatment of Wastes from Pea Canneries," Thesis. University of Wisconsin, 1926. 1WAmerican Public Health Assoc., Standard Methods of Water Analysie, 1925. 11-Anon, Canning Age, 4, 13 (August, 1923). 12--Anon, Public Works, 62, 191 (1922). l3-"Stream Pollution in Wisconsin," Joint Report Wisconsin State Board of Health and State Conservation Commission, April, 1927.
An X-Ray Study of Limes Having Different Plasticities' By Marie Farnsworth2 KOSMETALLIC MINERALS EXPERIMENT STATION,BUREAU OF M I N E S , N E W BRUNSWICK, X. J.
Marble and precipitated calcium carbonate are burned in air at 1800", 2000", and 2200" F. and marble in a vacu u m furnace at temperatures from 1200' to 2400' F. in steps of 200" F. The plasticities of the hydrates of all these samples are measured ar,d x-ray powder photographs of the oxides and hydrates taken. The samples burned in a vacuum are found to be more plastic than the samples burned in air. The CaO samples which give a plastic hydr!te give a face-centered cubic pattern with. unit edge 4.79 A; the plastic hydrates give a hexagonal pattern with an axial ratio 1.40. The patterns of the less plastic samples are complicated by additional lines corresponding, if CaO films, to strong lines of the Ca(OH)2and CaC03 films, and if Ca(OH)*films, to strong lines on the CaC03film. In every case the intensity of these extra lines can be taken as a direct measure of the plasticity of the sample; these lines are the same for samples burned at high and low temperatures, but for samples burned at the higher temperatures, the intensity is less. Experiments were not carried out with over-burned samples. Whether or not the Ca(OH)*and CaC03 are the cause of the decrease in plasticity of the lime, or simply an accompanying phenomenon. is discussed.
LTHOUGII lime-burning is one of the oldest known industries, there is very little scientific information in regard t#oit, especially in regard to plasticity. Some limestones will make a good finishing hydrate and other limestones with almost the same chemical composition will not; two limestones of very different chemical composition will often give equally good hydrates. Since the underlying cause does not seem to be chemical, it is natural to seek a physical explanation of this difference, and therefore an x-ray study of the basic materials involved and of hydrates of different plasticities mas undertaken.
A
1) in the Research Laboratory of Applied Chemistry of the Massachusetts Institute of Technology. The tube employed was the usual Coolidge water-cooled molybdenum anode type operated a t 15 milliamperes and 30,000 volts R. ill. S. The x-rays were restricted by means of two slits, 0.5 mm. wide and 10 cm. apart, in a copper cylinder with a lead end. A zirconium oxide filter, free from hafnium, mas placed over the slit near the target. This practically eliminated from the primary beam the white (general) radiation, and the characteristic molybdenum beta and gamma rays. The diffraction pattern, as recorded on the photographic film, v a s therefore caused by the molybdenum alpha doublet. The cassettes ser\-ed as holders not only for the films but also for the specimens. The powdered specimens (finer than 200 mesh) were packed into thin-walled special tubes of glass, free from heavy metals, of about 1 nim. inside diameter and sealed with collodion so that the specimen would not be affected by air or moisture. A septum divided the cassette so that two substances could be recorded directly on the same film. The film ( 1 7 / 8 X 16 inches or 4.7 X 41 cm.) was automatically held on a semicircle of 13 cm. radius a t whose center the specimen was fixed. The use of a semicircle, rather than a quadrant, for powder work permits measurement of the pattern without reference to the trace of the zero beam. The zero beam passed through the sample and on a brass stoppiece, enclosed by a sheet brass baffle to prevent secondary radiation from reaching the film. Sheet aluminum (0.3 111111. thick) was used on the sample side of the film to filter out light rays and to pass the x-rays. .I calcium tungstate intensifying screen was used on the side of the film farthest from the x-ray beam t o cut down the time of exposure. In this manner the diffraction pattern is recorded as a series of lines on the film; the interpretation of various patterns will be given in a later paragraph. Preliminary Experiments
X-Ray Methods
Owing to the nature of the materials to be studied, the pictures were limited to powder photographs as developed by Debye Scherrer3 and independently by Hull.4 The pictures were taken on a multiple diffraction apparatus (Figure 1 Received Kovember 17, 1926. Presented under the title "X-Ray Studies of Limes". Published by permission of the director, IJ. S. Bureau of Mines. 2 Present address, Washington Square College, N e w York University, New York, h7.T. a Kgl. Gesell. R-iss., Gattingen, December, 1915; P h y s i k . Z., 17, 277 (1916). 1 Phys. Rev., 10, 661 (1917).
Preliminary experiments were carried out using ordinary commercial samples. The samples were contained in small glass tubes; a plug of cotton was put in the middle and a sample of low plasticity was put in one end and a sample of high plasticity in the other end. If two oxides or two hydrates were employed, in all cases extra Iines not occurring for the sample of high plasticity appeared on the film of the sample of low plasticity. If two carbonates were used (provided they had approximately the same chemical composition) no difference in lines was observed. These photographs were Yery complicated, as there were lines due to magnesium 6
Clark, Brugmann, and Aborn, J Oblical SOL.Im , l a , 379 (1926).
