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T INDUSTRIAL Industrial Safety Series No. Qjiea WASTE DISPOSAL and Bibliography on Chemical Published by National Safety Council 20 North Wacker Drive, Chicago 6 Wastes^ sit/' 1. This pamphlet outlines briefly the hazards and problems. of the complex processes of safe , disposal of industrial waste. It contains some suggestions for the elimination of such hazards, but answers to many questions regard ing safe and proper methods are not yet available. 2. Inasmuch as kind of waste, amount, existing facilities, and plant location differ so widely, the pamphlet makes no attempt to provide detailed answers to spe cific problems. The bibliography gives an index to more detailed discussions of some of the prob lems. However, each problem has to be solved by itself and should be handled by an expert. 3. Interest in the subject of industrial waste disposal is in creasing rapidly and will probably continue to increase as more is known about the protection of pub lic water supplies and wild life and as industries become more con cerned with providing pleasant communities where living condi-' tions are good. 4. The problem is important to safety men because improper methods of disposal have caused injury and disease among plant personnel and members of the gen eral public, as well as damage to property. Improper practices have created nuisances such as deterioration of the recreational value of lakes and streams and "increased load on water treatment facilities. Such occurrences can he considered valid reasons for some of the ill will which has been directed toward certain in dustries. 5. Sometimes municipal or district sewage disposal depart ments will not accept industrial waste which, interferes with effi This pamphlet is one of more than 150 Safe Practices and Health Practices Pam phlets. It is a compilation of experience in accident prevention from many sources. It should not be assumed, however, that it includes every acceptable procedure in the field covered. It must not be confused with American Standard safety codes; fed-, e'ral laws; insurance requirements; state' laws, rules and regulations ; and municipal ordinances. Additional copies of this pam phlet are available. Member price, 40 cents each. Quantity and non-member prices on request. cient operation of their disposal processes. Some liquid wastes and chemicals have properties that do strongly interfere and may cause serious overloading of the dispos al facilities. 6. To meet increasing demands for proper waste disposal, the following information must be secured: amounts and kinds of wastes being-made, properties and characteristics of these materi als, and methods of disposal for each kind. Present disposal pjrac.^ tices should be- - examined for.. SS4S00SBE* " 7. The investigator should find out whether local, state or district ordinances or regula tions on air or stream pollution are being violated by his plant. These regulations or ordinances may be published by departments of health, by departments of waterways or conservation, or by fish and game commissions. Such regulations may be particularly inportant in the selection of a site for a new plant.. 8. Manufacturing concerns in the same type of business do not necessarily have the same kind of waste disposal problems. Much depends upon the location of the plant - whether it is in a manu facturing, residential, or farming district - as well as upon varia tions in the processes used. A solution applicable at one plant may not be at all satisfactory at another plant employing a similar process. One of the most important factors which determine the suit ability of a solution is the ability of receiving streams to assimilate the waste without damage. 9. The following list of industries or processes' which sometimes produce nuisance or ha^cdois.>y6ste^ is by^M means coalite, but it may serve as a guide: Chemical pulp and paper manufac turing . Vegetable canning and packing Ore smelting ;Milk depots (sr (butter, cheese, and by-products) Beet sugar manu facturing Sawmilling Wool scouring Distilleries Oil refineries Fertilizer plants Gas plants Viscose rayon plants Yeast manufac turing Oil production and refining Ore flotation (tailing piles) Fish and meat packing and canning Textile finishing and bleaching Tanning Steel plants (pickling) Laundries Millboard manu facture Breweri es Acid plants Chemical manu facturing Coal manufac turing .. Coke plants Explosives manu facturing Coal mining and washing Machine shops (waste cutting oil) Metal mining (Copyright, 1948,. National Safety Council. All rights reserved. Printed in U.S.A.) J~Chea. 7 INDUSTRIAL SAFETY SERIES No. Che a. 7 10. When a survey of wastes is being made, they can sometimes be listed according to the follow'ng classification: a. Waste disposed of by release into the air h. Waste disposed of in streams (or other bodies of water) c. Waste disposed of in dumps or on the land d. Waste disposed of by evaporation Air Contaminants 11- In the group of possible air contaminants are: 14* Direct heating of stack gases by a coal-fired Dutch oven or a gas burner will expedite atmospheric dissemination, some times more economically than ex cessive stack height, particularly when peak loads of short duration are being handled. 15. Seme gases can be partially burnt before being put into the stack provided that they will support combustion or can be economically enriched. This method destroys many objectionable odors, such as those produced in the tanning and fertilizer in dustries. Smoke and fly ash from power plants Sulfur dioxide* from smelters Dust from foundries,cement.mills, etc. Hydrogen sulfide and carbon disulfide from viscose rayon plants Oxides of nitrogen from nitration pro cesses Fluorides from metal reduction plants and fertiliser works Acid gases from chemical operations and pickling and plating Toxic gases (carbon monoxide, chlorine, hydrogen cyanide, and many others) from chemical and metallurgical op erations objectionable odors Organic solvent vapors 12. Smoke and some objection able gases can be safely discharged through stacks ranging from 150 to 300 or more feet in height. The lower stacks are relatively inexpensive. The important factors to he considered in the use of this method are the nature of the surrounding territory, the direction of the prevailing wind, the toxicity or nuisance value of the particular contaminant, and its reasonable allowable limits. 13. Acid gases may be con densed in raindrops and,.even though discharged from high stacks, may descend to damage materials or crops. In some in stances processes must be dis continued during certain weather conditions such as rain or parti cular wind directions. 16. Solids can be removed from suspension in the air (and recovered if desired) by dry filters, wet collectors, cyclones, electrostatic precipitators, or combinations of these kinds of equipment. Here the important factors are the amount of the re covered solid, its value, if any, and the physical and chemical characteristics of the material. 17. Wet or soluble gases and dusts can be absorbed in spray towers, which are rather simple and inexpensive. The amount of the gas, its chemical properties, its reasonable allowable limits, and disposal of the waste solu tion - often a serious problem are important considerations. Sulfur dioxide and many of the acid gases are in this class. 18. Many organic solvent vapors and gases can be absorbed or adsorbed. Commercial systems and uni ts designed for this purpose are available. One advantage of absorption or adsorption methods is that useful volatile chemicals and solvents can be recovered by means of them. One objection to general use of these methods is the relatively high initial cost, but in a number of instances the systems have more than paid for themselves in the value of the re covered chemicals. Stream Contaminants Sttlfar dioxide is ose particularly harm ful air contaminant because, in concen trations not perceptible to the senses of naan beings, it has a serious effect on vegetation. Fluorides are also especially harmful. Deposited upon the vegetation eaten by fern animals, they have caused illness among the animals. 19. Some of the industrial wastes which may under some cir cumstances become objectionable stream contaminants are listed below: Waste pickle liquor and rinse waters from pickling Spent acids Sulfide liquor (and other chemical pulp wastes) Spent plating solutions and rinse wa ter from electroplating operations Spent viscose spinning bath solutions Spent tanning baths Used cleaning solutions Spent dye baths - soap solutions Chemical wastes of all kinds and par ticularly those producing tastes or odors or both A large number of animal and vegetable wastes in solution or suspension, by-products of food or beverage manufacturing* Waste oils of all kinds Wool scouring wastes Phenolic chemicals Paper mill machine water Beater wastes Acid waters from mining operations 20. Before waste disposal plans are made for such streampolluting materials, each wasteproducing process should be studied to determine if such wastes or such volumes are abso lutely necessary. Many solutions now wasted, such as plating solu tions, viscose spinning baths, and spent acids, can be used almost indefinitely by filtration, clari fication, and refortification. In some chemical processes wash waters and rinses can be used as make-up water for the next batch. 21. A usable orsalable product can sometimes be recovered at a profit. Usually, however, systems for recovery require additional equipment or buildings, and re covery costs more than the product is worth. 22. B9WSfy"is always worth consideration - particularly if the waste disposal problem is acute. It is often cheaper to recover a material from waste than to destroy the waste and buy the material. An outstanding ex ample of recovery from waste ma terials is the feed recovery process employed in whisky dis tilleries. 23 Jfllfeduction of the volume or concentration of waste waters may increase economy of operations in some industrial processes. For example, re-use of the white water in paper manufacture has prevented These neterials are innocuous is thenaelrea, but serious nuisances because of their tendency to putrefy. INDUSTRIAL WASTE DISPOSAL Chen. 7 -3 the loss of valuable fiber as well as heat and chemicals, in addi tion to reducing the waste disposal problem. 24. Other outstanding ex amples, although somewhat limited in application, are the recovery of alcohol or vanillin from waste sulfite liquor and the recovery of copperas or pigment grade iron oxide from waste pickle acid. 25. The investigator should get some measure of the volume, as well as the chemical strength, of the liquid wastes inhis plant. If an organic waste is being pro duced, the biological character istics may be more important than the chemical strength. A complete study of liquid waste which is being discharged into a stream will provide-information on the flow of the stream and its capacity to absorb such waste without damage. Calculation of minimum stream flow during dry periods is essential. 26. Information should also be secured on all uses of the stream below the point of waste discharge. The requirements for water purity of a stream will vary widely depending on whether the water is a source for municipal supply, for industrial use, for recreation, for commercial fish ing, or possibly for general farm uses. 27. Some liquid wastes can be treated or neutralised chemically. This method is feasible when the products of the chemical treatment are less objectionable than the original waste or when they pre sent an easier disposal problem. Many acidic and basic wastes are in this class and can be neutral ized, then filtered or settled and decanted. 28. Objectionable solids in suspension can be settled with or without coagulants or by filtra tion. Occasionally filter aids facilitate the process. Some exceedingly fine materials in suspension (colloids) can be settled satisfactorily, and the clear effluent can be decanted if such flocculating agents as alum or soluble iron salts or such aids to flocculation as lime are first added. many liquid wastes so improves the require additional processing and effluent that further treatment equipment. is not necessary. This process of natural, purification ispar'tic--r * 35. If by-products cannot be ulacly'ijnportant where operations recovered, the possibility of re are seasonal'arid do'not. warrant a utilization of the waste water in large expenditure for waste dis the process, or reduction of the posal facilities. Vegetable volume or concentration of the canning 'plants have made conside r- waste, or both, should be investi able use of lagoons for natural gated. Frequently re-utilization purification. will solve the problem. Treat ment should be resorted to only 30. Liquid wastes produced when the other two possible courses intermittently can sometimes be have been exhausted. held in storage and released either at a slow, controlled rate or at times of high water flow. The storage method minimizes the probability of damage which might occur if the wastes were released in large batches, as produced, and sometimes eliminates the need for further treatment. It almost always facilitates the applica tion and control of treatment. 31. Many liquid wastes, mainly those from the food processing industry, contain organic sub 36. Where recovery is not practicable, or where the waste liquids have objectionable pro perties after recovery, treatment is necessary. This treatment is usually the kind of processing employed in municipal waste dis posal plants, modified according to the characteristics of the waste. Often treatment at the source is more practical than treating the entire plant effluent. In any case, treatment is em phatically a job for experts. stances in solution or in suspen sion. These substances are not poisonous in themselves, but they do putrefy and change into highly offensive solid and gaseous by products. A stream contaminant may thus become an odorous air contaminant even at seme distance from the source. 37. Waste waters may be safely skimmed and discharged if in soluble oils which can be removed by the skimming process are the only contaminant. Some emulsified oils can be separated from the water by the process of "salting out" or by flotation. Change in the pH of the mixture, electrical 32. The greater hazard, how ever, is that in the process of putrefaction the dissolved oxygen precipitation, or centrifuging are also useful methods for breaking some kinds of oil emulsions. is removed from the lake or stream or so depleted that the water cannot be used for its normal purposes. Unless the plant pro ducing this type of waste has access to suitable waste disposal systems, trouble may be expected sooner or later. Disposal of Solid Materials 38. Waste so^id waterisls usually-can be safely disposed of ori'danjpsi> Tfris necessary to know the properties of the wastes being dumped, and itisreeqamended that 33. Proper disposal of these organic wastes is a job for ex perts. However, it can be pointed out here that the problem should first be approached with the Jgareas used for dumpiag and precise lywhat has been dumped in each areal This informatibri may become important in the location of future buildings. object of recovering a usable 39. ScusnvSoLid waste may be product. Reduction or re dispersed'Ovdr-large ground-areas utilization of the waste or treat rather than eol1acted in dumps. ment of the waste can then be This method is particularly ad considered. vantageous in the disp.osal of SB&IT quantities ot hazardous 34- After the extent of the ufatfeiaab'&^urinstances in which problem has been determined, the water dilLtion is not possible. possibility of a recovery process which will either operate at a 40. Whatever method of dunping ~ "t or pay a portion of the is used, it is important, that the operating cost should be exploited dwips be fenced riff or otherwise toon fullest. This recovery may guarded and that the housekeeping 4-Chem. 7 INDUSTRIAL SAFETY SERIES No. Chem. 7 be excellent no that the dumps will not be hazardous to plant ~*rsonnel and to possible tres- ssers, particularly children. 41. If the wastes contain water soluble materials, the nat ural drainage -of the dump area and the permeability of the soil have tobe considered. Soluble chemicaJ subs;tahc'es*'placed on dumps have been"leached out by rains'and'have contaminated neighboring streams or damaged crops in nearby-fields. Soluble chemicals and oils in waste ma terials have also seeped for con siderable distances through pore us formations under dumps and have reappeared in wells used as Semites of drinking water. 42. Combustible waste ma terial has become ignited on dumps and has caused serious burns. Magnesium chips and filings may be spontaneously flammable. Certain chemicals such as sodium react violently with water, and under certain circumstances the reaction may serve as a source of ignition for other combustibles. Other chemicals such as the ? fides, cyanides, or phosphides _ay react with, water or with weakly acid solutions to produce poisonous gases. ...... 43.. Corrosive and poisonous chemicaIs, explosives,'and unstable compounds dumped'in bulk or not completely removed from discarded containers have also caused serious injuries. 44. It is a safe rule that every combustible waste material placed on a dump should be burned under controlled conditions. However, some solid materials which are only moderately com bustible can be covered with sanitary earth fill instead. 45. Containers should be discarded only after pheir con tents have been completely re moved. Strong acids and caustics should be neutralized before they are dumped. Explosive materials, unstable chemicals, or poisonous mixtures should be rendered Harm less. Containers under pressure or those which might generate pressure should be permanently vented before being discarded. 46. Waste wood, scrap paper, and such combustibles should be burned as they accumulate unless they can be baled or briquetted and some of their value recovered. Incinerators can be built to burn this kind of material safely. Their proper use improves the appearance of what otherwise might be an unsightly area. 47. Oils (after rough separa tion from water), waste solvents, and other flammable liquids can be flowed into a shallow trench (the size of which will be deter mined by the volume of material to be disposed of) and ignited from a safe distance by means of a ,fuhe. This arrangement will safely burn a number of sludges and mixtures, even greases and waJtes. 48. If a waste mixture is not flammable enough to burn alone, flammable solvents, which may themselves be wastes, can be added. Care should be taken that the smoke and gases given off by such burning wastes do not become an air pollution problem. 49. If the heat value of waste solvents or oils is high enough, they may be piped to a special tank and burned under the plant boilers. The effect of possible contaminants on furnace linings and tubes should be considered before this method is attempted. Also, no attempt should be made to recover heat from oils or solvents with flash points too low for them to pass safe ly through the burners. 50. The problem of disposal of radioactive .wastes will become increasingly important as atomic power and radioactive isotopes find applications in imdustrjj% The problem will ultimately have to be solved on a national basis, 51. It is obvious that no radioactive substances should be discarded until the amount of radioactivity has been monitored. Waste containing excessive amounts should be stored in protected, guarded areas which are monitored periodically. Such waste should he held until a national policy for the handling of it is formu lated. *. ACKNOWLEDGMENT This pamphlet was prepared by S. T. Gurney, as chairman of the Health Committee of the Chemical Section, National Safety Council. The biblio graphy, prepared by R. W. Hess, is reprinted from Industrial mdEngineering Chemistry (May 1947)_by permission of the editor and publishers. The pamphlet has been reviewed by the Council's Safe Practices Conference Committee and approved by the Council's Industrial Conference.