October, 1926
IAiD U S T R I A L A N D ENGINEERING CHEMISTRY
1085
Disposal of Some Organic Trade Wastes' By Edward Bartow UNIVGRSITY OF IOWA, IOWACITY,IA
Packing-House Waste
N 1921 the writer was called upon to investigate and report upon the disposal of the wastes from a packing house a t Mason City, Ia. It was necessary to take immediate action without preliminary experimental work. Drawing conclusions from invest'igations made jointly by the Sanitary District of Chicago and the Chicago packing houses a t the Union Stock Yards in ChicagoJ2the actiyatedsludge process was adopted for the plant. This packing house handled fresh meat, especially pork, with some beef, veal, and mutton. Later pork was handled exclusively. Products included cured meats, lard, edible tallow, sausage, grease, fertilizer, and hair. The waste is from water used in washing in the various processes and contains blood, manure,, grease, hair, pieces of flesh, and other organic matter. It IS highly putrescible. Owing to the expansion of the packing plant and the lack of experimental data, the sewage plant as first designed was not large enough. It has now been enlarged and in its present form there are two aeration tanks, compressed air being used for aeration, with a capacity of approximately 1,200,000 gallons, which would give a n 8-hour detention period. There were added a preliminary sedimentation basin and a preliminary Dorr clarifier 27 feet in diameter. The sludge-settling tank is a Dorr clarifier 36 feet in diameter and 14 feet deep, with bottom sloping slightly toward the center. Sludge was first returned by air lift and later by centrifugal pumps to the aeration chamber. The effluent flows from the rim of the tank, which has a quarter of its circumference depressed. The depressions were made by inserting 2 by 4's every 16 inches in the frame into which the soft concrete was poured. The distribution of flow is very satisfactory, much more so than if a n attempt had been made to use the entire circumference for overflow. A satisfactory sludge developed within 10 days from the beginning of operation. Trouble was experienced after a Sunday shutdown, owing it is believed, to the rather large settling capacity. This trouble was remedied by returning the sludge a t the same rate during the shutdown as during the period of maximum operation. Addition of sufficient water to form a current through the settling basin should prevent putrefaction during a shutdown. With a shortage of water effluent could be recirculated. The greatest difficulty has been with the disposal of sludge. Sdding sulfuric acid to the excess sludge causes the solids to rise to the surface and comparatively clear liquid can be drawn from the bottom. This sludge has been used a t times in the by-products house. It is not economical to add the acid-treated sludge to the driers without further dewatering. Attempts were made to dewater the sludge wit'h a Berrigan press, but under the conditions at the plant the process was not entirely successful. Considerable quantities of sludge have been emptied on low ground, where i t dries and decomposes without special nuisance. It is to be regretted that no satisfactory method of dewatering and drying the sludge has yet been developed. The dried sludge contains 6 to 8 per cent of nitfrogen, the value of which is lost when the sludge is disposed of on the low ground.
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1 Presented a s part of the Disposal of Trade Wastes Symposium at the Midwest Regional Meeting of the American Chemical Society, Madison, Wis., May 27 t o 29, 1926. 2 Report on Industrial Waste from Stock Yards and Packingtown, 2 , 30 (1921).
The most recent sewage disposal plant for packing houses has been constructed a t Fort Rorth, Texas, where the wastes from the various packing houses are brought together and treated.3 The partially treated effluent from this treatment plant is emptied into the city sewer and, mixed with the domestic sewage, is treated in tanks and sprinkling filters. The concentration of the city sewage has become so great that only part of it can be handled in the present plant. The activated-sludge process, to date, seems to be the best method for the treatment of packing-house wastes unless there is chance of high dilution. Waste from a Beet-Sugar Factory
The waste from a beet-sugar industry contains large quantities of putrefactive organic matter, both in suspension and solution.4 Much effort has been exerted to save any valuable material and prevent trouble from the waste in streams and water ways. There still remains waste of four kinds of different amounts and concentrations. There is in a plant of 1000 tons daily capacity, approximately 4,000,000 gallons of beet-washing water, 600,000 gallons of battery water, 150,000 gallons of lime waste, and 250,000 gallons of Steffens waste. The beet-washing water has low oxygen-consuming power compared with the other wastes and, if there is a chance for dilution, can be allowed to flow without treatment into the streams. The battery water should have all the suspended pulp removed by fine screens, and in some plants the waste is treated with lime and with carbon dioxide and returned to the process. This scheme has been used a t Decatur, Ind., at the Decatur plant of the Holland-St. Louis Sugar Company. The battery water can be passed through tanks or ponds and further purified on sprinkling filters, but the process is expensive. The lime-sludge waste consists of calcium carbonate and other calcium salts precipitated in the Steffens process. The calcium salts will settle readily, but the supernatant liquid contains organic soluble matter and when neutralized is putrescible. It should be possible to use it in tanks or ponds with the battery water. The Steffens waste contains practically no suspended matter, but has oxygen-consuming capacity of about 3000 parts per million. During the war attempts were made to dispose of i t by evaporation and incineration with the expectation that the potassium salts could be obtained. Potassium salts made in this way are for the most part carbonate and are not satisfactory for use as fertilizer. Experiments with Steffens waste have been made in the laboratories of the Bureau of Standards, the Mellon Institute, and the University of Iowa. At the University of Iowa nearly 100 per cent pure potassium chloride, sulfate, and nitrate have been obtained, together with betaine hydrochloride and glutaminic acid. If use can be found for the salts of potassium and for betaine and glutaminic acid, or products obtained from them. the disposal of Steffens waste will be satisfactorily solved. However, the amount obtained from all the beet-sugar factories is SO great that it would seem a difficult matter to dispose of all of the material. a Moor and Wayne, THISJOURKAL, 18, 239 (1926). 4
Trans. A m I n s l . Chem E n s , 16, 47 (1923).
I N D U S T R I A L A N D ENGINEERIXG CHEMISTRY
1086
Vol. 18, No. 10
Starch Wastes
the maximum grind usually occurs, the process was not satisfactory. Measured in terms of total organic nitrogen I n the early days of the starch industry in this country present in the waste, it seemed impossible to treat satispractically everything from corn except the starch was factorily a waste containing more than 30 parts of nitrogen wasted. Large deposits of hulls have been known to collect per million. in rivers below starch factories. When this was declared a Further experiments were made diluting the waste with nuisance the starch manufacturers arranged to dry and water from the drainage canal, and experiments were made sell it for feed. Oil, a t first a waste product, has become a with sprinkling filters. Dilution with water from the drainstandard food, and that part which cannot be used in food age canal was not entirely satisfactory, possibly because is suitable for the manufacture of soap, The water in which the sludge was out of condition before dilution was attempted. the corn was steeped, a t first a waste, is now evaporated The disposal of wastes on sprinkling filters could be acand adds a very valuable constituent to the feed. complished a t the rate of 500,000 to 750,000 gallons per acre The water used in washing the ground corn and separating per day. A stable effluent was obtained the year around. starch and gluten constitutes the principal part of the 1vast.e There was some trouble from pooling, which would necessiat the present time. Large quantities of water used in the tate an allowance of rest periods in planning a commercial condensers contain no organic waste and can be passed into plant. Preliminary treatment in a settling tank with a a stream or returned to a water supply without harmful Dorr clarifier or an Imhoff tank afforded no advantage over results. A number of years ago, when asked to make rec- treatment of the raw material on sprinkling filters. As a .ommendations concerning the disposal of waste from a result of the experience with the activated sludge and sprinkstarch factory, the evaporation of the wash water was care- ling filters during 1924-25, i t was recommended that the fully considered. The dried residue is of the same compo- concentration of the waste be reduced within the plant. It sition as dried steep water and would be a valuable constit- was proposed that water be removed from the process and uent of food, but it was considered that the cost of evapora- then returned to the process a t a point earlier in the flow and tion of the large amount of water would be too great to allow in such a way that it could leave the system through the ;the evaporation to be carried out practically. I n 1920 steep water into the feed. the Sanitary District of Chicago and the Corn Products Preliminary experiments were promising and modifications Company began a series of experiments to determine the were adopted which will eventually so reduce the amount best method of disposing of the waste. Previous experience of organic matter that only a small purification plant, probindicated that evaporation would not be feasible. ably of the sprinkling-filter type, will be needed. The activated-sludge process had been found suitable It is reported that a t the Penick & Ford plant at Cedar for the disposal of packing-house wastes of similar organic Rapids schemes have been adopted in which nearly all concentration and therefore seemed to give promise of suc- the waste is utilized, leaving less than 0.5 per cent of the cess. Preliminary tests were made with waste water from weight of the corn to be wasted to the sewer. the gluten settlers and the starch settlers. alone, and with Conclusion varying proportions of condenser water up to the total waste from the plant. Dilution of the concentrated waste The history of the disposal of organic trade wastes has in most cases shown profit to the industry. It should be strongwith condenser water was found necessary. During the summer and during periods of minimum ly emphasized that it is better to use a waste with profit grind of corn, the activated-sludge method seemed to be very in a plant than to throw it into the sewer to be treated satisfactory. During cold weather, during which period at great expense in a sewage disposal plant.
An All-Glass Circulating Pump for Gases' By Frank Porter, D. C. Bardwell, and S. C. Lind FIXED NITROGEN RESEARCH L A B O R A T O RWY~, S H I N G T ODN , C
HE electromagnetic pump described herein was devised some time ago in the laboratory of the Bureau of Mines in Washington, especially for the circulation of electrolytic hydrogen-chlorine mixture. Its description was postponed to accompany a n account of the experiments in which it was used. These experiments will be described elsewhere in the near future, b u t t h e details of the pump are now given in order to make it available without further delay. This is rendered more urgent by the appearance of a description by Francis2 of a more elaborate type of construction of this pump, which appears to have several disadvantages in comparison with our original, on which Mr. Francis' design was based.
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Description of Pump
The solenoid A operates the glass piston R within the tube C , with which it makes a close but free fit in its rise and fall 1
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Received June 4, 1926 Fuel, 5, 39 (1926).
through 3 cm. The core consists of a soft iron rod ( 5 cm. long and 0.2 em. in diameter) sealed in a glass tube, D, and fastened by means of lead glass to the inside of the piston near its top. The iron rod should be fixed in the glass tube (by de Khotinsky cement). The ball and socket valves F and F' are hollow glass spheres (about 0.25 cm. in diameter and about 25 mg. in weight) making a ring contact with the sockets. The lower socket was ground by means of a rod, the end of which was a hemisphere of slightly larger diameter than that of the valve. The upper socket, to avoid weakening, was not ground. The capillary stems from which the small hollow spheres were blown should be sealed off long enough to prevent the balls from turning over. h water jacket G is placed between the solenoid and the pump to maintain an even temperature. To move the piston the solenoid is supplied by direct current of about 0.5 ampere from a 110-volt circuit, which is interrupted three times a second by an electric oscillating relay (metronome type). A 50-watt lamp is connected
