Industrial Wastes
Pharmaceutical and Biological Pl.trnts ER AND S. H. BABCOCK, JR. Lederle Laboratories Division ean Cyanamid Company, New York 20, N. Y. ounds of beef and pork livers, and carried with it of disposal of large amounts of liquids and tansof
h these labo-
of %heslrmed f o m for theXf6saving prod
cells, was pro-
The production of dry liver products, of sulfadiazine, anh of many other drugs in tablet and powder form to supply not only our own armies but those of our allies, the manufacture of vi& mine for the United Nations Relief and, Rehabilit&ion Administration, involving the mixing and compressinginto tablets of huge amounts of powdered drugs, created waste dust problems with
whi~theindustryhsdneverhedtoconteddonsuch,alaPgescale.
y knew~them*.of
corn-steep liquor medium, which becomes was of the.penicillin by mesns of mlyents such as
Vmoines also were require&in large amounts diuing the war, because every man in the service received inoculations for protection +inst a variety ofdiseasea. Oneplantpmc4more than35,ooO egeg every day for the production of typhusvaccinealone, inoculsting eachegg aseptically witb the organism, bating the eggs for ral days, then withthe vim-laden m each egg indi, after which the ere discarded as Other biologicals pro-
e x p a d t h e i r equipment and working forces toproduce in unhesrd+f quantitiea. The waste disposd problem, w@& in the past had been relatively unimportant, suddenly mushr6omed . ,. into a major problem. m e n y t e Oonsiated of'a few pa& of mlid-material. a hole could be d t q in which to bury it, and nature did the rest. Similarly, a fear gallona of liquid could be dumped in the s e and ~ forgotten, but when there were created tons of mlids and thousands of gallons of liquids, which might, ba noxious or even the problem a m e r e n t aspect. Some forkupte Iaboratories and plante situated in heavily populstedocnters served by large '' . cient +wsgec~s found that their effluent
ducedthroughanimals,such as smallpox vaccine, gas gangfe4 antitoxin, diphtheria antitoxh, etc., were responsible for large quantities of animal wastes requiring suitable dispasd. Tbe mrtnufaCture of injectable liver products involved the proceesing of
Centrifuges Which Separate P h m a and Waste Red Blood Cells 5s
On the other h plants found it
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.May 1947
INDUSTRIAL AND ENGINEERING CHEMISTRY
b b The manufacture of new- products, particularly those developed during World War I1 and of continuing peacetime usefulness, has greatly increased the quantities of w-asteproduced i n pharmaceutical and biological plants.
The location of a
plant on a potable water shed requires that satisfactory disposal of the w-aste involved be integrated
with
each
matiufactiirinp process.
The
district sanitary sew~erand local streams were formerly sufficient for this purpose;
to these have now- been added an industrial sew-er, located on the premises. rotary drvers, a spray dryer. a large oil-fired incinerator and smaller incinerators, dust collectors, and special pretreating equipment. Each w-asteis given the particular treatment required by its nature.
Where possible.
raw materials and
solvents are recovered for re-use, and by-products are collected for sale.
Their combined value par-
tially offsets operating costs of the disposal s)-stem and the expense due to capital expenditures involved in its installation.
Some specific problems
in the manufacture of calcium pantothenate, riboflavin, penicillin, vaccines, serums, antitoxins, liver products,
tablets, and capsules are mentioned.
t o adopt such expensive espedients as hauling their waste long distances in tank trucks to locations which allom-ed for its disposition. Since the end of the TTar the demonstrated usefulness of many of the war-expanded products has merely shifted the demand from military into civilian channels, so that, in the case of many items, large production has continued without letup, with the waste problems grox-ing in importance; because, with the ending of the war emergency, temporary expedients in dealing with these problems were no longer justified. Permanent and sound methods for eliminating nuisances became necessary. The pharmaceutical laboratory with which the authors are most familiar had a number of these problems, the solution of which may be of interest. .it the outset of this discussion, it should be explained t h a t the laboratory around which the discussion centers is located on a water shed which drains to streams constituting the upper reaches of potable water supply systems, a n d which therefore can not be contaminated with industrial waste product,s. For this reason the plant is necessarily wasteconscious and looks upon disposal problems as being as important as process problems. I n these circumstances a process is not considered workable until a satisfactory method for dealing with its wastes has been developed. The waste finally discharged by the plant must be dispoeed of by one of several possible routes, the route selected depending upon the character of t,he \Taste. The presently available routes are as follows:
1. h trout brook having a normal flov- of about. 300,000 gallons per day, which runs through the property and feeds a domestic water supply system. 2. h prirat,e selvage system n-hich discharges to a domestic sewage disposal plant of 1,000,000 gallons per day designed capacity. The liquid effluent from this plant is delivered into a st.ream which al-o constitutes part of a potable water supply system. 3. Evaporation and drying to a solid. 1. Incineration to complete destruction, either in a modern oilfired incinerator used for general purposes or in local incinerators serving specific areas and operations in which the wastes originate.
579
.ill liquid wastes must be properly treated before final release so that contaminants which n d l not be destroyed during natural stream flow, or removed in the course of treatment by the sewage disposal plant, are destroyed by suitable treatment before discharge. -4ny toxicity, bitterness, taste, or color v-hich persists will ultimately be found in the domestic water supply by whichever route the liquid leaves the plant, and charges of c:rrbohydrates, proteins, solvents, or disinfectants \Till endanger the operation of the domestic treatment plant if disposed of by diimping t o the sewer. Because the capacity of the municipal sewage plant is not large, t h e industrial wastes sent out by this route must he comparatively innocuous or, if concentrated, must be small in quaiitity. This poses the problem of classifying the vaiious types of n.astes and of pretreating some of them in the laboratory sewage treating plant; in many cases it involves giving them a special pretrcatnient a t the point where the wastes issue from process. Because of the complexity of the problem and the considernhle expense involved in t,hese treatments, some attention has been given t o the matter of recovery of by-products TThich serve to offset, a t least in part, the cost of these operations. Originally, before large plant expansion h2d taken place, most of the plant effluents were disposed of by sending to the district sanit'ary sewer, which carries the town drainage to the local domestic selvage treatment plant; but as the effluents increased in volume and as the character of these effluents was altered by the increasing industrial load, substantial changes in disposal methods were made necessary. These new disposal plans resulted in the development of several separate systems for the disposal of the different types of wast,es. WASTE WATER SYSTEM
This drainage system collects and carries o f f roof and surface drainage, condenser and jacket cooling water, and other harmless waters t o accumulating reservoirs of 5,000,000-gallon capncity ; the overflow from the reservoirs is discharged into the trout stream previously mentioned, which in turn feeds a municipal water supply. A pumping station draws on these reservoirs and, by means of a return system, supplies cooling n-ater to condensers, coolers, and water jackets throughout the plant,; the station thus serves not only to reduce the demand for ne-iv water but, by keeping this cooling water out of the sanitary sewer system, considerably reduces the total load of effluent going t o the district sewage disposal plant,. The reservoirs are treat,ed lightly a t intervals wit'h copper sulfate, and the water as pumped is given a small dose of chlorine to keep algae under control. It is expected that later, as the heat load increases on the reservoir,?, cooling towers will be installed to hold the water temperatures within a satisfactory range. SANITARY SEWER SYSTEM
This system collect,s sanitary wastes only from 3 major part of the plant and discharges direct t o the municipal sewer main. This effluent constitutes no problem because it approximates in character ordinary domestic sewage for which t,he municipal plarlt was designed. Biochemical oxygen demand (B.O.D.) averages around 200 and p H about 7. INDUSTRIAL SEWER SYSTEM
This system collects various industrial wastes and small amounts of sanitary waste and delivers them, either by gravity or by pumping, t o a small sewage treatment plant on the property; there a preliminary treatment is given, most of the solids are removed, and the effluent is discharged to the municipal sewer (Figure 1). The laboratory sewage treatment plant consists of a rotary screen and settling tank, tlso holding tanks of about 100,000gallon capacity, a degreaser, a n aerated flocculator, a trickling
CHEMISTRY
Vd. 39, No. S
In SomecBses these industrial wastea are made up of floor w a s h i and vessel washings only and in.some cases of actual process wastea, but in all cases every effort is made to prevent direct dumping to sewers of mate& which may overload or interfere with the satiafantory operation of the municipal plant. DRYING OF.WASTEB
Certain wsstes which cannot be satisfactmi$ h d l e d by the district sewage treatment plant are best disposed of by drying. Two methods a~ now in use, depending upon the kind of material to be dried. For w p l e , heavy solids, such 88 animal tissues, precipitatea, and filter cakes, a~ dried in steam-jacketed vacuum rotary dryers. The resulting product is then sold if there is a msrket, or i t is incinerated if no outlet bas'been developed. 'Liquids, in some cases carrying solids such ss molds, are pumped to a spray dryer where the water is evaporated; they leave a powder residue which may or may not have value., If useful, it is bagged for shipment; if not, i t iS sent to the main plant incinerator, for .. burd&nn. This spray dryer; only .recently compl8td and .now undergoing test runs, has a dsaigned evaporating capacity of about 35,000 gallons of water per day and is equipped with an auxiliary Butlovac concentrator, which gives flexibility as well as additional capacity when needed. ..It consists of two chambers, one'for pray drying proper, tbe other acting as a dust scrubber .and preheater for the liquids. The 'dry product is delivered to a setiea of bins by means of conveyors, the bins being served withdehumidified air in order to prevent hygroscopic products from picking up moisture. Additional conveyors will carry the product to a bagger where it will be packaged. I
'INCINERATION
Figure 1. Schemntic Plan of Industrial Treatment Works
Complete destruction of certain types of waste is desirAble, and, since incineration is eflective and certain, it has been adopted for the dispoSal of noxious, d,angerous, or resistant materib where such, a co-.is indicated,.even though in some cwes the mrtterial must be dried prior to burning. A modem o i l - h d incinerator having a designed capacity ,of 32 tons per day w&s recently constructed.. Almost any Wd'of dry or nearly dry waste can be e5ciently destroyed in it. In order to conserve oil, the incinerator is &a fed witb dry combustible material collected throughout the day from all parts of the p h t by means of Dempster dump truoks. Gombustible kr&h from all operating departments is deposited ip conv'eniently located steel collection boxes just outside the door of each building. T h e boxes arc picked up at regular intervals and hauled to the incinerator. There the contents are dumped on the feed floor and fed gradually to the incinerator furnace. .The incinerator is of heavy duty construction, witb a mdn fur'nade and an auxiliary combustion chamber ensuring complete d&uction of fumes and smoke. The furnace is,equippedwith a Hekeshoff heartb onto which wet materials may be fed by a screw conveyor. After. the moisture is evaporakd,, rakes feed $he dry material slowly though the main f E d opening to the ro;tatin@:hearth below, where it is mixed with the combustible ma&al from the &in Feed floor. s;wl k p l e t e l y burned:. Sur,
B
flter, and a chlorinator. The holding tanks assnt m levellng out day and night loads and in averaging the character of the e5uent before it is h h a r g e d to the municipal plant. The e5uent is heavily chlorinated, ae much as 200 pounds per million gdons being required at times, and just before discharge to the municipal Ewer the pH is adjusted with lime and caustic soda to about the normal pE of ordjnsry domestic sewage. The final mixed streams which make up the total discharge from the laboratory will ordinarily have a B.O.D. from 175 to 225 and a pH of 7 to 7.5. The solida removed by the preliminary settling m d Screening are dried on conventional glasscovered &ying beds and disposed of by burning in &' oil-fired incinerator. Fats and greases removed by the degreaser are collected and a l incinerated. ~ ~ The industrial sewage is made up of a peat variety of liquids carrying various kinds and quantities of nitrogenousand carbonaceous wastes collected from many different process streams. Each variety has been considered from the viewpoint of its deet upon a domestic sewage disposal plant and, where necessary, has
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May 1947
INDUSTRIAL AND ENGINEERING CHEMISTRY
581
Distilling Apparatus for Recovering Solvents from Waste Broths
rounding the rotating hearth is a circular grate which dumps to a hopper in which the ash is accumulated, ready to he trucked to the dump. .lny given plant procedure may well require the use of several of the available disposal methods which have been mentioned. A few esamples n.ill serve to illustrate the approach to such special problems. CALCIUM P.%STOTHESATE ~IASUFACTURE. The lactone, dL-0hydroxy-@,+dimethyl butyrolactone, is saponified to the sodium salt of the corresponding acid, and the latter is treated with brntil:? hydrochloride. The brucine salts of the dextro and levo acids thus formed are separated by fractional crystallization. Each salt is hydrolyzed with caustic and the precipitated brucine recovered by filtration for re-use. The filtrates from these operations are acidified ivith sulfuric acid and extracted with ti solvent into irliicli each lactone goes, leaving behind a spent aqueoua p l m c containing sodium chloride, sulfate, and disolved brucine. The solvent is recovered by distillation for re-use. The d-lactone is then mcemized for reintroduction at the beginning of the process and the I-lactone is further purified for combining with t'he calciuni salt of 3-alaIline to make the desired d-calcium pantothenate. Since the solvriits involved are recovered, the primary ivaste problem is the diqiosal of tlie spent silt solution saturated with brucine. The lntter compound is tosic and hac a very bitter taste, detectable in a s little as one part per million. Since it may be present also in floor washings, thepe, together with the pioceea xvastes, are collected in two Tvaite t:inks. oon as one tank is full, collection is liegun in the other, and the contents of the first
.
tank are treated x i t h calcium hypochlorite Fvhich destroys the brucine. K h e n tests made by the plant chemist show that the brucine is destroyed, the tank is discharged to the industrial sewer, slowly, to ensure good dilution. The cost of this pretreatment is unimportant because volume is small and care is esercised to avoid spills. Consequently, only 10 t o 15 pounds per day of calcium h?-pochlorite are required. The chemist in regular attendance on the n-hole operation assumes the responsibility of waste control, so that no extra labor is required. RIBOFLAYIS ~ I A X F A C T U R,lEmash . consisting of protein, sugar, and minerals is fermented by a riboflavin-producing mold. At the elid of the fermentation t,he mold is killed and removed by filtration. The riboflavin is then precipitated from the filtrate, removed from the ni:ish by filtration, and further purified by chemical treatment and crystallization, By-puducts from this plant consist of the mold and of the filtrate from the riboflavin precipitation step. The latter coiitains the nutrients unused b y the mold, together hyith the solulile nonriboflavin by-products of the fermentation The U.O.D. is on the order of 5000 t o 10.000. Iniismuch as tons of raw material are required t o produce pountls of riboflavin, thr by-product diaposal problem is out of proportion t o the quantity of product manufactured. I n this case the essentially riboflavin-free filtrnte and the mold are brought together again, thcNrouglily mised, and pumped to a spray dryer, 1%-heretlie water is evnpornted and the solids are left as a ponder. This dried n-aste then can he iiicinerated or disposed of by other suitable meaiw. The priiicipal item of cost in this case is the heat required by tlic spray dryer, hut thiQi i not n .wrious matter hecause thc qunritit>-of water to
582
INDUSTRIAL AND ENGINEERING CHEMISTRY
Vol. 39, No. 5
Attempts have 5een made to create a market for
is reason% TeIi a r t of the cost of recovery may be offset by the value of the by-products recovered. Only tank and floor washings from this plant go t o the industrial sewage system. BIOLOGICALS.In the manufacture of vaccines, serums, antitoxins, etc., a variety of problems arise, such a i the disposal of meat broths, eggs, animal carcasses, etc. Waste broths made from meats are rather small in quantity and are sent to the industrial sewer, the solids to the tank house dryers. Large animal carcasses are processed in the tankage plant where they are converted into tankage by cooking, drying, and pressing into cake which has a ready sale. Skins are alco .sold. Small animal rarc'asses originating largely in the testing departments are destroyed in smokeless and odorless incinerators situated in the several buildings devoted to the testing work. Such immediate complete destruction eliminates any disease hazard ahi.ch might be involved in handling and transporting t o the main Spray Dryer for Evaporating Liquid Wastes to Dr? Powder plant incinerator. Eggs are disposed of by way of the main plant incinerator. LIVER PRODCCTS. Livers are ground and cooked, be evaporated is moderate. Only tank and floor n-ashings and and the solids and liquids separated by filtration. The solids spills from this plant are sent to the industrial sewer. const,itute the principal waste product; they are dried in large PESICILLIS MANUFACTURE. A mash consisting of corn-st,eep vacuum drum dryers, ground, bagged, and sold as extracted liver liquor, lactose, and inorganic salts is fermented with a penicillinmeal. The liquids pass through a series of operations leading to the producing mold. d t the end of the fermentation period the mold is removed by filtration. The broth is then acidified and the production of liquid injectable liver and of certain solid liver items. Liquid wastes from these operations carrying solvents penicillin removed by extraction into amyl acetate. The latter are collertrd and the solvents recovered by distillation, the slops solution is in turn extracted with a buffered salt solution, :ind the penicillin in it is further purified by extraction into and out of a being discharged to t h e industrial sewage syotem. I n the manufacture of dry products, such as second solvent. The final aqueous solution containing the 80DRYPRODCCTS. dium salt of penicillin is sterile-filtered, filled into vial>, frozen, tablets and capsules, and in the handling of powdered substances, and dried. fine dry particles and dusts constitute a problem, not only bcSince all solvents in the process are recovered by distillation for cause of the health hazard but because of the high value of the re-use, the principal disposal problems involve the mold and the materials ivhich are lost. X vacuum collection system now gathers these materials from each machine. Every collection penicillin-extracted mash. .Again, as in the case of the riboflavin, tons of raw materials are fermented to produce a fev- pounds of point is equipped with a small centrifugal separator, Ivhich immefinished product. It may he of interest to note that thecorndiately salvages the major part of the dry particles, returning steep liquor used in the fermentation process is itself a by-product, them to process; the air carrying t,he balance of the fines dicwhich came into the market as a result of studies made for the charger into an efficient hag collector system. which removes the purpose of preventing the pollution of streams by the manulabt traces of dust. The cleaned air, which originated in airfacturers of corn products. conditioned roomy, is sent back t o certain rooms, so that load on The penicillin-free xvaste is difficult to handle in dome-tic the air-condition in^ system is reduced. tem has produced vel at,isfactory savings: sewage plant; it affects trickler beds by sealing them up, inhibits the action of the digesters, and destroys gas production. The about 00% of the fines originally lost are iiow being recovered. problem appears to have plagued a considerable part of the inThe bag dust collectors are emptied a t long intervals and t h e dustry. It has been our experience that even in the absence of contents destroyed by incineration. formaldehyde, reported in use by some plants, domestir -e\wge plants may develop grave difficulties when attempting to handle CONCLUSIOS this waste even in small quantities. T h e R.O.D. is notoriously This di-cui>ion of the treatment accorded the lvaste disposal high (several thousand), and oxidation is slow and difficult. problems of a pharmaceutical and biological laboratory s h o w The solid mold, removed by filtration, decomposes rapidly a t that it is possible to eliminate the nuisances created by such a ordinary temperatures; consequently it must be handled without plant, and to do YO a t riot too great an operating cost, provided undue delay if intensely disagreeable odors are to be avoided. id sale or utilization of by-products is kept in mind. The method of disposal n-hich has been found successful is to run lent i.< required because of the nethe liquid waste through a column still to strip off and recover the temh and for .-pecial treatment or amyl acetate, which is then redistilled and re-used. The slops disposal facilities. By-products ivill prohahly never be profitab!e from the still are then combined with the filter cake solids (m>-cestanding alone, therefore, but they should contribute considerlium), and the whole is thoroughly broken up, mixed, and sent to ably ton-ard the cost of eliminating the nuisances. a dryer, where the water is evaporated. A fine hygroscopic powder is left which can be disposed of by incineration or other PRESENTED before t h e Industrial Waste Symposium at the 111th hleetirig means. of the AMERICAN CHEMICAL SOCIETY, ;itlantic City, S. 5 .
