Disposal of Refinery Waste Waters W. B. HART,The Atlantic Refining Company, Philadelphia, Pa.
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operations, s l u d g e separation, ITTLE a t t e n t i o n w a s This paper describes the development of the acid concentration, etc. These paid to the disposal of inproblem of the disposal of refinery waste u)ater, gases or vapors are mainly hydrodustrial wastesuntil comthe recognition of the problem by the industry, carbons of low boiling point, or paratively recent years. With the machinery set UP bY the industry to combat sulfur dioxide or trioxide. Such mills and factories s c a t t e r e d , pollution resulting from this source, and the gases will quickly diffuse to an waste disposal was a comparaunnoticeable concentration, but tirely s i m p l e p r o cess and no results being obtained by the procedures which there are produced with them harm or annoyance resulted. have been instituted. The carious types of waste small concentrations of mercapThen there came the intensely waters arc’ described on the basis of the charactertans and other complex orrapid growth of industry and the istics of the Public waters which they effect, and ganic sulfur compounds of inconcentration of industrialestabbrief reference is made to methods det!eloped f o r tense and disagreeable odor. It lishments in and around populais these s u b s t a n c e s that are tion centers. I n someinstances the Drevelztion of the DOllulion which would be frequently the cause of atmosthe i n d u s t r y w a s the nucleus by the poiluting constituents of these a r o u n d w h i c h the population pheric pollution c o m p l a i n t s , ous types of waste waters. t art i c u l a r l y w h e n diffusion settled. Theultimate result was i s h i n d e r e d by smoke, dust, that industrial and residential sections were brought together and there came into existence or weather conditions. A major refinery waste is oil. It may originate anywhere the waste disposal problem as we know it today. in the plant from leakage or be discarded for various reasons, PET~ROLEUM-REFINING WASTES such as being emulsified or contaminated. It may vary in Petroleum refining has developed rapidly during the past quality from gasoline to heavy lubricants. Many refineries use large quantities of water which is disthirty years. The first oil well was drilled in 1859, and the crude oil produced that year amounted to 2 thousand barrels. carded as waste. Most of it is for cooling purposes only and In 1900 production had reached 64 million barrels and in 1929 never contacts oil. This water is unimpaired. Water used over 1 billion barrels of oil were brought t o the surface. Prac- in processes where it contacts oil, although constituting only a small percentage, dissolves various compounds. These tically all of this oil was run through the various refineries. This marked increase in refinery operation is directly trace- compounds may be simple acids or alkalies or very complex able to the development of the motor car, the internal combus- organic sulfur compounds. Phenols may also be present. tion engine, and the use of fuel oil. Prior to 1900 gasoline -411 these give the water a disagreeable taste and odor, due in was a waste. It is now a major product. One disposal most cases to the organic sulfur compounds present, although problem was solved, but many others were created. Origi- in some instances they are due to phenols. Discarded waxes, asphalts, sludges, clays, and general rubnally all crude petroleum produced was what is known as bish make up the solid wastes. Pennsylvania grade, a very high-grade crude. Further,.specifications for petroleum products were comparatively simple, DEVELOPMENT OF METHODS FOR WASTEDISPOSAL and simple refining processes would make this required quality. Then the hIidcimtinent, Texas, and California crude oils Some thought was given to the disposal of refinery wastes appeared and created new problems in refining. New proc- prior to 1919 when the American Petroleum Institute was esses were developed, not only because of the new crudes but organized. Further attention was given the subject by the also because product specifications were more difficult to Pollution Committee of the institute. Following the passage meet. All these change. combined to produce waste materials of the Federal Pollution Act of 1924 and the meeting of the that presented real problems in disposal, and in many cases International Oil Pollution Conference in 1926, the institute the development wa? rather sudden. In the desire to enter authorized an investigation of oil pollution in the United attractive markets, little thought was given t o anything but States. This was carried out in 1927 and revealed that polluthe quality of the product, the design of the process, equip- tion did occur in certain localities and that some progress ment to produce it, and the starting of operations. Kot in- mas being made in its prevention. The most important findfrequently, as soon as the operation was well under way, ing, however, was that little was known about how to dispose waste products were found t o be causing water or air pollu- of the various waste materials properly. This led to the tion. formation of a committee of technical men from various comSuch conditions were not confined to the petroleum-refining panies, known as the Committee on Disposal of Refinery industry alone or to industry as a whole. Cities and towns had Wastes. Its duty was to develop methods which would increased in size, and the sewage load had beconle propor- permit disposal of waste substances without causing damage tionately greater. Whereas dilution had been a satisfactory to others or causing nuisance. This committee began its method of disposal, the increased amount of sewage created an work in 1929, taking up‘first the disposal of waste water overload. These conditions, involving both industry and popu- containing oil. The literature was scanned for information lation, resulted in many instances of serious water pollution. but the result was not encouraging. It mas evident that the matter was a pioneering one. ?;ATURE OF PETROLEUlf REFIRERY LT‘ASTES The information gathered in the 1927 investigation was Wastes that are gases, liquids, and solids occur in present- taken as a starting point. Equipment for separating oil from day oil refining. They may occur unaccompanied by other waste water, called “separators” or “oil traps,” was known to substance or may ’bein suspension or solution in water. Gases vary greatly in design. Also, certain designs were effective or vapors are produced by distillation processm, acid-treating and others not. To determine how much oil was really 965
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present in the effluent of the separators that were considered acceptable, required a testing method. After considerable study a method using solvents was devised. Using this test, the most effecbive separators were definitely identified and their design studied, together with conditions of the water into which they discharged, as to oil films, oil markings, etc. Velocities, eddy currents, and general conditions within the separators were also studied. I t wa$ found that in all cases, low velocity and particularly freedom from eddy currents were essential to high effectiveness. But all separators discharged some oil with the effluent water, whereas laws covering the situation all specify “no oil.” It is practically impossible to meet this specification unless it is construed to mean no visible oil film such as is usually recognized as oil pollution, Based on the information obtained during the separator studies, a limit of 30 parts of oil per million parts of effluent was set. This concentration was found not to cause visible film and is probably quickly eliminated by oxidation, A separator design specification was then developed and laboratory-size equipment with glass sides constructed so that the effectiveness could be studied. Certain modifications were found necessary, and final design data were assembled. Actual applications of these data mere made a t the Philadelphia Refinery of The Atlantic Refining Company. Three large separators were modified to meet the recommendations. The results were highly satisfactory. Oil separators of this type function on the specific gravity differential between the water they are to discharge and the oil they are to retain. Obviously, emulsions of oil and water pass on through. The committee, therefore, started work on methods for “breaking” the various types of emulsions that occur in refinery practice. Much of this research was conducted by the Research Laboratories of The Atlantic Refining Company, and the methods developed were tested a t the Philadelphia Refinery. The methods vary with the type of emulsion. In some cases heat alone is all that is required, while in others a change in pH followed by a floc clarification of the water is necessary. In any event the separated oil is retained, and only water discharged to the separator or a mixture of water and oil in “free” form is discharged so that the separator can properly function. In 1931 the American Petroleum Institute published the work of its Committee on Disposal of Refinery Wastes as Section I of what is t o be a complete manual ( I ) . This section gives in detail the various methods for proper disposal. This publication is available from the institute. While preparing the publication on waste waters containing oil, the matter of atmospheric pollution had been gaining prominence. Attention of the committee mas turned t o this subject immediately, and from the literat’ure and from the experience of refineries that individually had been confronted with and had solved the problem, details of methods were accumulated. It was found that few intricate methods were involved ; closed systems, scrubbing towers, and similar means had proved effective. Again the recommended procedures mere tested under actual practice conditions and found to be satisfactory, and in 1932 Section I1 of the manual was published by the institute ( 2 ) . The most difficult problem of aU, howerer, still remained. This concerned tastes and odors in public water supplie?, oxygen depletion in streams affecting aquatic life, injury to pleasure craft from dissolved sulfides, and other similar conditions; all were said to be traceable to dissolved substances in refinery waste waters. It was a t first thought that either these conditions would be impossible t o prevent or would a t least cost almost prohibitive amounts of money, In fact, the proposal was once made to drop the whole idea on the basis that any activity would
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only further emphasize the problem. Fortunately this was not done, and work was started t80determine if refinery waste waters mere causing the conditions described and if so to what extent. There way pract’ically nothing in the literature that i ~ o u l dhelp answer these questions, and it was soon realized that to try to identify definite compounds and eliminate them was a waste of time. S o testing methods were known for the purpose. There wa.q but one thing to do and that wah to go directly to the people who were investigating the complaints and learn from them how they JTent to work and what they could offer. Thiq proved to be the most valuable decision the committee ever made. It started contacts wit.h such groups a i the engineers of t’he Pennsylvania State Sanitary Water Board, engineers in charge of various public water supply plants, fish and game commissions, and similar groups. In conversations with these men the work and problems of the Comniittee on Disposal of Refinery Wastes were outlined, and they, in turn, placed before the committee sources of information, both data and experience, that were not known before. From these conversations, together with other information at hand, it was evident that the basis of any plan should be the protection of the general characteristics of the public waters. The compounds effecting the characteristics would then assume secondary importance as tests for the characteristics themselves were already available for running down pollution sources. A practical and flexible plan was then evolved to cover acidity and alkalinity, dissolved sulfides, dissolved oxygen, tastes and odors, and total solids. The next phase of the problem involved the point at which the waste water control should become effective, whether a t the point of entering the public waters or after admixture with such waters. Considering this proposition, it was evident that, if the waste water had to be made of practically potable quality, the refinery would either have to find another location or go out of business. Further, if the water coming to the refinery were polluted, it would obviously be unfair to expect the refinery to correct this pollution. dll effort, therefore, was directed toward devising control methods that would be applied within the refinery and so correct the effluent waste waters that, after the latter were mixed with the public waters and influenced by purifying processe.; encountered, they mould not cause undue difficulty or expense in the use of the public waters by others. This makes possible wa.ste correction without prohibitive cost and serves th.e best interests of the community, for it is a community problem wherein both industry and population are concerned, and neither industry nor population stands alone under the circumstances. There is ample precedent for this idea. When industry slo~vsup, the population suffers as is TI-ell evidenced by the past several years. That cooperative effort, is successful has been demonstrated ol-er the entire count,ry. Examples may be had in the procedures of the Pennsylyania State Sanitary Kater Board as described by its chief engineer ( 3 ) ; in the Willianiette Valley Sanitary Program in Oregon; in Wii-consin, Ohio, Connecticut, and other states where modifications of this s a q e general plan are followed. The met,hods recommended for correcting refinery waste water before discharge vary with the condition to he cont,rolled. One recommendation is general and that is a thorough survey of the entire plant drainage system so that indid u a l operation wastes may be located and segregated since the waste water from a single operation may render the entire plant effluent unfit for discharge. Further, segregation means economy, for the operation may be changed or the small amount of waste mat,er recirculated or a corrective treatment applied at, a cost much lower than t’hatfor correcting t,he entire plant discharge.
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