February, 1927
INDUSTRIAL A N D ENGINEERING CHEMISTRY
this plant and the 1700 gallons of silk-and-cotton boil-off may be discharged directly to the sewer. If i t were necessary to treat the sludge by filtration the settling would be made more efficient and it would run to filters, but there is no premium on efficiency in settling beyond a certain point, when a 10 per cent allotment is available. Effect of the Effluent on Fish Life The practical test on which the polluting or non-polluting character of waste is often judged is whether or not i t prevents or destroys fish and plant life in the stream. The waste from this plant will flow through a park lake stocked with goldfish. A series of tests on goldfish showed that the undiluted waste after treatment was only slightly toxic. When diluted it should offer no hazard to fish life. Practicability and Cost
The method of treatment outlined has been studied in its application to several other plants, six of t>hem similar to but larger than the one under discussion. In all but one case the plants tvere so departmentalized that by simple changes in accessible drainage lines the desired separation of wastes could be obtained. This includes a large plant which has been in operation for only a few months. The cost of chemicals for treatment a t current prices
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is about $8 a day. A revenue of approximately $5 per day is derived from the boil-off, giving a net cost of about $3 per day. I n a larger plant it is usually possible to separate some of the wash waters without treatment, so that the total cost of treatment for a large plant is somewhat less than a direct multiple according to size. English practice has shown separate treatment of soap and boil-off liquors to be more economical than their treatment as part of a mixed waste with dyes and other wastes. T r e a t m e n t Plant
The plant as designed has an averaging basin of 5000 gallons capacity to operate with continuous i d o w and overflow. The discharge from this will be a mixture containing varying amounts of the waste for several preceding hours. Not more than half of this will consist of inflow from the preceding half-hour, provided mixing is efficient. The settling basin has a capacity of 50,000 gallons, which allows for increase of plantiacilities. Acknowledgment
The results given in this paper were obtained in cooperation with Gerald W. Knight, Consulting Sanitary Engineer of Passaic, N. J. They are published by permission of the Passaic Piece Dye Works, Passaic, N. J.
Disposal of Trade Waste from a Plant Mercerizing, Bleaching, and Dyeing Cotton Materials’ By Walter E. Hadley CLARK T H R E ACo., D NEWARK N., J.
Efforts to Prevent Pollution in Passaic Valley
OR a number of years increasing legislation has been enacted by different states relative to the disposal of
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trade wastes into their waterways. Particularly noticeable in this respect has been the action of the State of New Jersey in its effort to clear the Passaic River and its tributaries between the Great Falls in the city of Paterson and the mouth of the river a t Newark Bay. Since the completion of the Passaic Valley Sewer a very real effort has been made to prevent the further pollution of the Passaic River, and it now shows the effect of the decreased discharge of polluting substances into the stream. The Passaic Valley Sewerage Commission has now entered suit against several concerns who they claim are still discharging polluting matter into the waterway, such action being based upon Chapter 10 of the Session Laws of 1907, which reads as follows: Every municipality, corporation and individual is hereby prohibited and forbidden to discharge, directly or indirectly, a n y sewage or other polluting matter into the waters of the Passaic River a t any point between the Great Falls, in the city of Paterson, and the mouth of the said river, at Newark Bay, or into any tributaries of the Passaic River which empty into the Passaic River between said points, after the twelfth day of December, in the year 1912; and the Passaic Valley Sewerage Commissioners a r e hereby authorized and empowered t o enforce the provisions of this act over and throughout all municipalities which may, or the inhabitants of which may, directly or indirectly discharge sewage or other polluting matter into the waters of the Passaic River between the points above designated, or into the tributaries aforesaid after the said twelfth day of December, 1912. 1
Presented under the title “Some Experiences in the Practical Dis-
posal of Trade Waste Produced in the Mercerizing, Bleaching, and Dyeing of
Cotton Material” before the Division of Water, Sewage, and Sanitation Chemistry a t the 72nd Meeting of the American Chemical Society, Philadelphia, Pa., September 5 to 11, 1926.
Each year the date was carried forward by the legislature, but the date now on the statute books has been fixed as December 31, 1923, when pollution should have ceased. The Passaic Valley Sewerage Commissioners are further authorized and empowered t o institute in their corporate name suits at law or in equity, as may be deemed necessary or appropriate to enforce the provisions of this section of the act after said twelfth day of December, in the year 1912; and the Court of Chancery of this State is hereby vested with special jurisdiction to enforce the provisions of this section of this act in a summary manner upon application of the Passaic Valley Sewerage Commissioners.
During the year 1924 the act was still further amended and now gives individuals the right to start suit, in the name of the commissioners, against anyone polluting the Passaic River or its tributaries. The interpretation given by the Passaic Valley Sewerage Commissioners of the term “polluting matter” has been outlined by them as follows: In a great industrial section such as ours, with a tidal river flowing through it, which probably will never again be used for potable purposes, this term of necessity must be interpreted to mean something different from t h a t which it would were i t applied t o a pure mountain stream being used for potable purposes. From a practical point of view, then, the determination of what constitutes “polluting matter” must be based on the broad ground of resulting effect upon the river rather than a literal definition of this expression. Also the physical impossibility of preventing certain forms of “polluting matter” from being discharged into the river, temporarily must be taken into account.
This would include street wash and discharge from combined sewers during a period of heavy storm.
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I X D US1’RIAL A X D ENGIN E E R I N G CHEMIST R Y
Conclusions are condensed as follows: Any solid or liquid discharged into the Passaic River or tributaries thereto within the Passaic Valley drainage area which is injurious t o public health or creates a public or private nuisance; which is injurious t o property; which creates odors, gases, or fumes due t o the putrefaction of organic matter or the presence of chemicals; which reduces the dissolved oxygen content of the waters t o such a n extent as t o interfere with major fish life; which substantially discolors the waters, results in the presence of oil or grease on the surface or otherwise renders them objectionable t o the sight, shall be considered “polluting matter.”
The Passaic River could not be cleared up until the Passaic Valley Sewer was complete. The sewer was constructed upon the basis of receiving 10 per cent of the total estimated amount of trade waste within the district in terms of the ultimate year, which will probably be about 1940, a t which time the sewer will be running full capacity. It will therefore be necessary for 90 per cent of the trade waste to be discharged directly into the river or its tributaries. The expenses relative to the operation of the sewer are to be borne by the several municipalities using it. It is therefore encumbent upon them that the flow to the sewer be restricted as much as possible, and that the effluent finding its way directly to the sewer shall consist, as far as possible, of those substances which would be the most polluting, and then discharge the purer waste directly to the waterway. T h e Problem
I n the early days of the textile industry, little or no attention was paid to the disposal of its wastes. One of the requisites of this industry was an ample supply of pure water, and hence the majority of the textile mills were located on streams which offered such a supply, and which a t the same time served as a means of removing the wastes produced. As the industry grew the streams were, in many instances, unable to care for the wastes properly and became more or less polluted, The Passaic River was a n excellent illustration of this condition. A few years ago the company with which the writer is associated moved its dyehouse, mercerizing, and bleaching departments to a short distance outside of Newark. Sewerage facilities were not available a t the new plant, which made it necessary to discharge the trade waste into a small brook flowing through the property. Bearing in mind that there must be no interference with aquatic life in the stream, and taking cognizance of the steps already taken by the state to prevent pollution, a thorough investigation was made to determine the best procedure to meet the requirements. Apparatus
The apparatus was purchased from the D o x Company and consists of a large circular tank approximately 55 feet in diameter, 7 feet deep at the sides, sloping to the center where it attains a depth of 10 feet. A large vertical shaft constantly rotates in the center of the tank, and to this shaft are attached four arms, which move around about 2 inches from the bottom. Small strips of iron are attached to the arms in such a manner as to draw the sludge gently toward the center of the tank, whence it is removed by means of a suction pump. Two large tanks holding approximately 200,000 gallons each, located at a higher level than the clarifier proper, serve as mixing and storage tanks to receive the raw waste liquor and to hold i t until such time as we are ready to proceed with the clarification. The tanks can be operated singly or together.
Vol. 19, s o . 2
D e t e r m i n a t i o n of C h a r a c t e r of W a s t e
After the tank is filled with the waste liquor, the character of the waste is determined by chemical and physical tests. The works’ chemist then prescribes the proper treatment for the batch. The chemical feeders are set to supply the required number of pounds of chemicals per 1000 gallons of waste liquor. Before beginning operations, an attempt was made to predict the character of the composite trade waste, but no accurate data could be obtained as the different departments were then widely separated and the various discharges occurred a t different times, and in different volumes, throughout the day. While every care was used to collect a composite of the trade wastes prior to the completion of the collection tanks, the first tank full of waste was of an entirely different character and completely upset the theories as to the treatment that would be required. It was then found that the heavy brown kier liquor coming from the cotton boil-off discharged during the late afternoon, mixed with the clearer wash waters coming from the liming and souring operations of the early morning, produced a much lighter colored liquor than had been anticipated. Process
The process employed consists mainly of the well-known method employing lime and alum, producing a sludge which settles in the tank, leaving a supernatant liquor which is discharged over the periphery of the tank. The system has a rated capacity of 50,000 gallons per hour. The system originally received the liquor into a central well after treatment with the proper chemicals, and was diffused throughout the tank until it found its way over the periphery. After experimentation it was found that better results were obtained by blocking off about one-quarter segment a t the top of the tank nearest the feeders, and allowing the treated wastes t o enter this section and then travel directly across the tank before discharge. This gave a positive control of the treatment, as within a quarter of a minute after the treatment with the chemicals the dosage could be changed a t will. I n other words, the sample removed at any time is now an absolute index to the treatment which the liquor is receiving. Disposal of Sludge
Bt first, a great deal of difficulty was experienced in disposing of the sludge produced by the process. Filter beds were constructed, filter presses used, and various other experiments tried, none of which were successful. Finally the idea was conceived of simply pumping this sludge into a large area of land and allowing it to dry out. The sludge then agglomerated with the soil and thus solved the problem of its disposal. After the waste liquors have been treated as above, they pass through a long wooden sluiceway and enter the brook as a clear, water-white solution. Where the treated effluent enters the brook is a large box containing live fish, giving ample evidence that the process is a success. Furthermore, the bed of the stream, a s well as plant life within and upon its banks, is still in the same excellent condition as when operations were started a number of years ago. W a s t e Disposal in Various Parts of P l a n t
Operations a t the new plant were started in the bleach house, and the composite waste was very nearly neutral in character and it was possible to bring it to complete neutrality and produce an excellent weight sludge and a clear liquor by the use of hydrated lime and a finely ground alum.
February, 1927
I-VDUSTRIAL A N D ENGI,VEERING CHEMISTRY
The mercerizing department was next opened and the wash waters, which did not carry enough concentration of caustic soda to pay for recovery by evaporation, entered the general collection tank. The solution was then quite alkaline and a greatly increased quantity of alum was necessary to effect neutralization. Moreover, the clarifier tank rapidly filled with sludge, a t a time in the experience of the company when it did not know what to do with the sludge it already had. A large iron cylinder was installed to hold 66" BB. sulfuric acid, and this treatment immediately reduced the volume of sludge. I n the dyeing department there was no real difficulty in the removal of the color from the wash waters or from the used dye baths, except in few instances such as the naphthanil and basic colors, and these could be quite easily destroyed by adding bleach liquor to the concentrated dye bath before discharging to the central collection tanks. Before these colors were discharged in the concentrated form they were released into the composite waste and thereafter some difficulty was experienced in clearing the color. Water Treatment The water used is quite hard and is softened by a zeolite treatment. I n the regeneration of the zeolite beds with common salt, i t was found that magnesium chloride was
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produced from the magnesium in the water. The wash water was collected in a special sump outside the filter house and was treated with caustic soda solution (60-70" Tw.) which had to be carried a considerable distance and thoroughly mixed with the effluent. This was not only very expensive but extremely inconvenient. By placing a siphon from this sump to the central sump in the basement it was possible to bring this waste in conjunction with the caustic wash waters from the mercerizing plant and have the one act against the other thus materially reducing costs. Conclusion The problem which this company has had to meet in the disposal of its trade waste is no doubt similar to that which confronts other textile manufacturers in the same locality if a n earnest effort is made by them to produce a treated waste of equally high standard. Owing to the high cost of treat,ing its trade waste, this company is facing an unfair competition from manufacturers in other sections of the country, who are not obliged, through legislation, to give their industrial wastes special treatment. It would therefore seem advisable that some form of municipal or state system be established by which a more economical method could be devised for treating the entire industrial wastes of the section.
Effect of Temperature on Sewage Sludge Digestion',' By Willem Rudolfs S E W JERSEY h G R I C U L T U R A L
EXPBRIXENT STATION,
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N A X effort to determine the effect of temperature on sludge digestion, unseeded fresh solids (raw sludge) were placed in bottles in the laboratory and subjected to the following constant temperatures: lo", 18', 24' 29.5', and 35" C. Portions of the same fresh solids were treated with hydrated lime sufficient to produce a slightly alkaline reaction of the medium (pH 7.3). The materials were analyzed every week for total alkalinity, biochemical oxygen demand, solids, ash, total nitrogen, sulfates, and pH values. The gas was collected and analyzed for carbon dioxide, oxygen, methane, and hydrogen. Weekly counts of total bacteria and protozoa were made and the different groups of bacteria and kinds of protozoa were determined. The complete data obtained with a thorough discussion are to be published in bulletin form from the New Jersey Agricultural Experiment Station and only some of the outstanding results are embodied in this paper. Organic Matter Reduction and Ash Increase
The material digested after the least number of days is taken as a basis of comparison. Gas production from this material had practically stopped and all indications were' that further decomposition of the more resistant material would be very slow. The comparison is made after 108 days, but the sludge in question was ready for drawing in 58 days. Figure 1 shows the percentage reduction of organic matter and the percentage increase in ash of the sludges a t the different temperatures. Digestion is very slow below 10" C.
* Presented before the Division of Water, Sewage, and Sanitation Chemistry at the 72nd Meeting of the American Chemical Society, Philadelphia, Pa., September 5 t o 11, 1926. * Paper No. 310 of the Jotirnal Series, New Jersey Agricultural Experiment Station, Department of Sewage Disposal
N E W BRUNSWICK, N. J.
Raising the temperature a few degrees has comparatively little effect. Raising the temperature of unseeded and unadjusted (without lime) material from 10" C. to 18" C . has far less effect during the first 108 days than would be expected. To be sure, the organic matter decreased from 17 to 19 per cent, but the ash content remained practically constant. The percentage of ash in the original material was 22.8 per cent. It was surprising to find that unseeded and unadjusted material subjected to 24" C. did not digest much more rapidly than a t 18" C., although the rate of gas production was greater at the higher temperature. Raising the temperature to 29.5" C. caused a rapid decrease in organic matter and a nearly equal rapid increase in ash content, while a temperature of 35" C. retarded the digestion processes as compared with activities a t 29.5" C. The effect of adjusting the reaction with the aid of hydrated lime is quite remarkable. Where a t lower temperatures the unlimed material liquefied to a certain extent (reduction of organic material without a comparable increase in ash) the lime-treated material mineralized nearly as rapidly as it liquefied. The plotted data are corrected for the lime added. At 29.5' C. the limed material showed less reduction in organic matter than the unlimed, but the ash increase was considerably greater. At 35' C. lime did not seem to have much effect, and it would appear from these curves to be detrimental. However, if gas production is taken into consideration, lime was at this high temperature beneficial. Total Gas Production
The total gas production per gram organic matter in 108 days is presented in Figure 2. It should be emphasized that the total amount of gas produced from a gram organic
