Nonferrous Metals Manufacturing Point Practicable, a Standard Permitting Effluent Limitations Guidelines and Stand- Source Category No Discharge of Pollutants

33170 PROPOSED RULES

ENVIRONMENTAL PROTECTION which the Administrator determines to process employed and the sources of . AGENCY be achievable through application of the waste and waste waters in the opera- best available demonstrated control tion; and (2) the constituents of all ["40 CFR Part 421] technology, processes, operating meth- waste water. The constituents of the EFFLUENT LIMITATIONS GUIDELINES ods, or other alternatives, including, waste waters which should be subject to where Nonferrous Metals Manufacturing Point practicable, a standard permitting effluent limitations guidelines and stand- Source Category no discharge of pollutants. ards of performance were identified. Section 306(b) (1) (B) of the Act re- The control and treatment technolo- Notice is hereby given that effluent quires the Administrator to propose gies existing within each segment were limitations guidelines for existing sources regulations establishing Federal stand- identified. This included an identifica- and standards of performance and pre- ards of performance for categories of tion of each distinct control and treat- treatment standards for new sources set new sources included in a list published ment technology, including both in- forth in tentative form below are pro- pursuant to section 306(b) (1) (A) of the plant and end-of-process technologies, posed by the Environmental Protection Act. The Administrator published in the whch are existent or capable of being Agency (EPA) for the bauxite refining FEDERAL REGISTER of January 16, 1973 designed for each segment. It also in- subcategory (Subpart A), the primary (38 FR 1624), a list of 27 source cate- cluded an identification of, In terms of aluminum smelting subcategory (Sub- gories, includinE the nonferrous metals the amount of constituents and the part B), and the secondary aluminum category. The regulations proposed chemical, physical, and biological char- smelting subcategory (Subpart C), of the herein set forth the standards of per- acteristics of pollutants, the effluent aluminum segment of" the nonferrous formance applicable to new sources for level resulting from the application of metals manufacturing category of point the bauxite refining subcategory (Sub- each of the technologies. The problems, sources pursuant to sections 301, 304 (b) part A), the primary aluminum smelt- limitations and reliability of each treat- and (c), 306(b) and 307(c) of the Fed- ing subcategory (Subpart B), and the ment and control technology were also eral Water Pollution Control Act, as secondary aluminum smelting subeate- identified. In addition, the non-water amended (33 U.S.C. 1251, 1311, 1314 (b) gory (Subpart C), of the nonferrous quality environmental impact, such as and (c), 1316(b) and 1317(c); 86 Stat. metals manufacturing category. the effects of the application of such 816 et seq.; P.L. 92-500) (the "Act"). Section 307(c) of the Act requires the technologies upon other pollution prob- (a) Legal authority. (1) Existing Administrator to promulgate pretreat- lems, including air, solid waste, noise point sources. Section 301(b) of the Act ment standards for new sources at the and radiation were identified. The en- requires the achievement by not later same time that standards of performance ergy requirements of each control and than July 1, 1977, of effluent limitations for new sources are promulgated pursu- treatment technology were determined for point sources, other than publicly ant to section 306. Sections 421.15, 421.25, as well as the cost of the application of owned treatment works, which require and 421.35, proposed below provide pre- the application of such technologies. the best practicable treatment standards for new sources The information, as outlined above, control technology currently available within the bauxite refining subcategory as defined by was then evaluated in order to determine the Administrator pursuant (Subpart A), the primary aluminum what levels of technology constitute the to section 304(b) of the Act. Section smelting subcategory (Subpart B), and "best practicable control technology 301(b) also requires the achievement by the secondary aluminum smelting sub- not later than July 1, 1983, currently available," the "best available of effluent category (Subpart C), of the nonferrous technology economically achievable" and limitations for point sources, other than metals category. publicly owned the "best available demonstrated con- treatment works, which Section 304(c) of the Act requires the trol technology, processes, operating require tfie application of best available Administrator to issue to the States and technology economically methods, or other alternatives." In iden- achievable appropriate water pollution control tifying such technologies, various factors which will result in reasonable further agencies information on the processes, progress toward the national goal of were considered. These included the procedures or operating methods which total cost Qf application of technology eliminating the discharge of all pol- result in the elimination or reduction of lutants, in relation to the effluent reduction bene- as determined in accordance the dischargelof pollutants to implement fits to be achieved from such application, with regulations issued by the Admin- standards of performance under section istrator pursuant to section 304(b) of the the age of equipment and facilities in- 306 of the Act. The Development Docu- volved, the process employed, the Act. ments referred to below provide, pursu- en- ant gineering aspects of the application of Section 304(b) of the Act requires the to section 304(c) of the Act, infor- various types of control techniques, Administrator to publish regulations mation on such processes, procedures or process changes, non-water providing guidelines for effluent limita- operating methods. quality en- (b) vironmental impact (including energy tions setting forth the degree of effluent Summary and Basis of Proposed requirements) and other reductioh attainable through the appli- Effluent Limitations Guidelines for factors. cation of the best practicable control Existing Sources and Standards of Per- The data upon which the above an- technology currently available and the forinance and Pretreatment Standards alysis was performed included EPA per- for New Sources. mit applications, EPA sampling and in- degree of effluent reduction attainable spections, consultant reports, and indus- through the application of the best con- (1) General methodology. The effluent trol measures and practices try submissions. achievable limitations guidelines and standards of The pretreatment standards proposed including treatment techniques, process performance Piroposed herein were devel- and procedure innovations, operating herein are intended to be complementary oped in the following manner. The point to the pretreatment standards proposed methods and other alternatives. The reg- source category was first studied for the ulations proposed herein for existing sources under Part 128 of set forth effluent purpose of determining whether sepa- 40 CPR. The basis for such standards limitations guidelines, pursuant to sec- rate ;limitations and standards are ap- tion 304(b) of the Act, for the are set forth in the FDr.RAL REoIsTrn of bauxite propriate for different segments within July 19, 1973, (38 FR 19230.) The pro- refining subcategory (Subpart A), the the.category. This analysis included a primary aluminum smelting subcategory visions of Part 128 are equally applicable determination of whether differences in to sources which would constitute "new (Subpart B), and the secondary alumi- raw material used, product produced, num smelting subcategory (Subpart C), sources," under section 306 if they were manufacturing process employed, age, to discharge pollutants directly to navi- of the nonferrous metals manufacturing size, waste water constituents and other category. gable waters, except for § 128.133. That factors require development of separate section- provides a pretreatment stand- (2) New sources. Section 306 of the limitations and standards for different ard for "Incompatible pollutants" which Act requires the achievement by new segments of the point source category. sources of a Federal standard of per- The raw waste characteristics for each requires application of the "best practi- formance providing for the control of the such segment were then identified. This cable control tedhnology currently avail- discharge of pollutants which reflects included an analysis of (1) the source, able," subject to an adjustment for the greatest degree of effluent reduction flow and volume of water used in the amounts of pollutants removed by the

FEDERAL REGISTER, VOL. 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 PROPOSED RULES 33171 publicly owned treatment works. Since dense than molten aluminum, and is kept and purifying aluminum-bearing scrap standards proposed molten In a carbon crucible kmown as a to produce an alloy of marketable speci- the pretreatment the secondary alu- herein apply to new sources, § 421.15, "celr" or "pot". The carbon crucible fications. Generally, below amend § 128.133 serves as the cathode, and a carbon minum Industry gathers scrap from a 421.25 and 421.35 the to require application of the standard block, or blocks, serves as the anode. number of sources and then uses new sources- rather Electrolysis decomposes the alumina aluminum contained in the scrap to pro- of performance for second- than the "best practicable" standard into aluminum and oxygen, and because duce a variety of products. The sources under sec- of its greater density, the aluminum ary aluminum smelters comprise the applicable to existing aluminum tions 301 and 304(b) of the Act. sinks to the bottom of the cell. largest portion of secondary (2) Summary of conclusions with re- The oldest aluminum plants In the industry and consume about 70 percent States were built in the 1940's of all aluminum scrap generated in the spect to the bauxite refining subcate- United States. gory (Subpart A), the primary alumi- and, exept for minor equipment-rnodi- United smelting subcategory (Subpart B), fications and changes in operating pro- The scrap raw material used by sec- num ondary smelters can be divided Into two and the secondary aluminum smelting cedures, have been producing aluminum of the non- by this classical technology for thirty categories, solids and residues. The solids subcategory (Subpart C) bor- ferrous metals manufacturing category. years. Recently, one producer has an- are principally metal and include industry is a segment nounced plans to build a pilot plant for ings and turnings, new clippings and The aluminum forgings, old castings and sheet, and of the nonferrous metals manufacturing the production of aluminum by the direct Bauxite refining, reduction of aluminum chloride. In ad- aluminum containing iron. Residues in- category of sources. elude (1) dross and sdmmings from primary aluminum smelting, and secon- dition to eliminating the use of fluoride, recognized the process would likely require 30 per- melting operations at foundries, fabrica- dary aluminum smelting are Indus- of the aluminum cent less electrical energy than the Hall- tors and the primary aluminum as discrete segments try, and (2) slag formed during second- Industry and each is characterized by Heroult process. The heart of the production of alumi- ary smelting operations. Secondary alu- distinctly different raw materials, manu- reprocess the scrap so faqturing processes, products, and waste num is the reduction process. Depending minum smelters reason. of reduction cell used and that it can be used for consumer goods. water characteristics, For this upon the type a mod- of the aluminum in- the design of a particular facility, several In so doing, they are recycling three subcategories erately priced metal which otherwise dustry were established for the purpose other major operations such as anode limitations guide- or aluminum forming may be would become a solid waste. of developing effluent baking Secondary aluminum smelters have lines and standards of performance and conducted at an integrated site. Reduc- Documents were tion cells are of three basic types: pre- been In operation since 1904 with major three Development growth and expansion periods in the prepared. The regulations proposed baked cells, which use prebaked carbon segment 1920's and late 1940's and 1950's. Their herein apply to the aluminum anodes, and two types of Soderberg cells, numbers have decreased over the last of the nonferrous metals manufacturing which use large, single anodes continu- the Sod- decade. Most of the 85 plants currently category of sources as defined by ously baked in place over the bath. metal refining, stud or producing secondary aluminum three subcategories, bauxite erberg cells are either vertical near heavily industrialized smelting, and second- all cell types, the are located primary aluminum horizontal stud. In areas which give them proximity to a ary aluminum smelting. anode is composed of coke bound with to their customers. (1) Subpart anodes are baked supply of scrap and (i General description. pitch. The Soderberg There is no real need for them to be near A-Bauxite Refining Subcategory: by the heat released from the cell itself, plentiful supplies of electrical power and Bauxite refining is the process of ex- while prebaked anodes are normally water as in the case of primary alumi- tracting alumina from aluminum ore baked in a separate facility. If prebaked num smelters. by the Bayer process. The used, a separate facility is (bauxite) anodes are Subpart A- Bayer process dissolves the alumina in necessary to blend the anode compo- (i) Categorization. (I) solution to form sodium alumi- nents (pitch, coke, etc.) and bake the Bauxite Refining Subcategory: Bauxite a caustic the nate. Upon dilution and cooling, the anodes around copper conductors. The refining is a single subcategory for sodium aluminate is hydrolyzed to pre- organic emissions from the baking proc- purpose of establishing effluent limita- cipitate aluminum hydroxide. The pre- ess must be controlled at the baking fa- tions guidelines and standards of per- and dried to form alu- anodes are used, the formance. The consideration of the fac- cipitate is filtered cility. If Soderberg the plan, mina, the principal rawmaterial in the baking process occurs In the reduction tors such as the age and size of production of aluminum metal. cell and the anodes are baked in place. processes employed, wastes generated, feature. of the bauxite Although the need for a separate baking geographical location, raw materials A significant tech- refining process is that it produces ap- facility is eliminated, the in-place baking used, and air pollution control proximately equal amounts of alumina volatilizes the pitch components which niques support this conclusion. and red mud wastes. Red mud is the may subsequently condense in emission (2) Subpart B-Primary Aluminum term applied to the voluminous residue control systems and cause operating Smelting Subcategory: Primary alumi- remaining after extraction of .aumna problems. While the overall pollution num smelting Is a single subcategory for from bauxite by the Bayer process. at potential of a primary aluminum facility the purpose of establishing effluent limi- varies in composition according to the is not significantly affected by the anode tations guidelines and standards of per- ore from which it is derived. In the configuration, the choice of the asso- formance. The consideration of the United States, various companies process ciated air pollution control systems Is factors such as the age and size of the bauxites, principally from Jamaica, closely related to the anode type. plant, anode type, raw materials used. Surinam, and Arkansas ores. The residue In addition to the anode plant and re- and air pollution control techniques em- from processing Arkansas bauxite, which duction cell facility or potroom, a pri- ployed support this conclusion. However, is treated by a modification of the Bayer mary aluminum smelter has a casthouse. the guidelines take Into account the reprocess, is called brown mud or sinter In this facility the molten aluminum quirement for wet air pollution control mud. metal is formed into basic shapes such devices used by some existing primary (2) Subpart B-Primary Aluminum as billets or ingots by cooling in molds. aluminum producers. Smelting Subcategory: Primary alumi- The cooling process may be a source of (3) Subpart C-Secondary Aluminum num smelting is the electrolytic reduction water pollution if water is used to cool Smelting Subeategory: Secondary alumi- of purified alumina to aluminum metal. the molds. A degassing or fluxing opera- num smelting is a single subcategory for The Hall-Heroult reduction process is tion also is conducted In the casthouse. the purpose of establishing effluent limi- used by all domestic primary aluminum Wet scrubbing of the fluxing gas pro- tatlons guidelines and standards of per- producers and has remained essentially duces additional waste water from the formance. However, three principal unchanged since its inception. This proc- casthouse. waste streams resulting from three dis- ess involves the dissolving of alumina in (3) Subpart C-Secondary Aluminum tinct water uses within a secondary alu- a solution or bath of molten cryolite and Smelting Subcategory: Secondary alumi- minum smelter have been identified and other fluoride salts. The bath is less num smelting is the process of remelting are subject to Individual effluent limita-

FEDERAL REGISTER, VOL 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 33172 PROPOSED RULES tions and standards of performance. taining alumina, cryolite, and fluorides water stream. Waste water from A1F3 These are: (I) Waste water from metal of calcium and aluminum contribute to demagging gas scrubbers normally can be cooling, (ii) waste water from fume the scrubber liquor loading. In those recirculated because of the relative In- scrubbing, and (ii) waste water from plants using Soderberg anode systems in solubility of fluorides. Waste water from residue processing. Plants using water which the anode paste mix is baked in the scrubbing of chlorine demagging for cooling only will be subject to one place at the reduction cell, volatile hy- fumes, however, can be recycled only to series of effluent limitations; plants using drocarbons and oxides of sulfur also are a very limited degree because the chloride water for both cooling and fume scrub- collected in the scrubber liquor; (3) A salts are highly soluble and would soon bing will be subject to two series of efflu- third area which may employ wet scrub- build up to make the water unusable. ent limitations, etc. The consideration bing is the casthouse. Molten aluminum Thus, the discharge of the effluent from of such factors as raw materials used, from the cells is degassed or fluxed by chlorine demagging Is the principal age and size of the plant, products pro- bubbling with chlorine mixed with ni- source of waste water from fume scrub- duced, and manufacturing processes em- trogen and, sometimes, carbon monoxide. bing. ployed support the conclusion that efflu- This batch operation is carried out in Residue processing by wet methods Is ent limitations should be based on 'the gas-fired, holding-alloying furnaces and another source of waste water from sec- specific water uses within a plant. is adjusted according to specifications of ondary aluminum smelters. The residues (iii) Waste Characteristics. (1) Sub- the particular order being cast. As the used by the secondary aluminum In- part A-Bauxite Refining Subcategory: off-gas from the furnace is scrubbed, an dustry include drosses, skimmings, and The waste waters from bauxite refining acidic liquor hearing dissolved chlorine, slag and are generally composed of 10 to contain various soluble and insoluble chloride and suspended alumina is devel- 30 percent aluminum, with attached materials resulting from the following oped. The quantities vary with the extent aluminum oxide, fluxing salts (mostly principal sources: (1) Red mud residue of fluxing and time in the cycle. NaC1 and KCD, dirt, and various other from the alumina extraction process, In addition to the three plant areas chlorides, fluorides, and oxides. Separa- (2) spent liquor from salting out evapo- considered above, general housekeeping tion of the metal from the nonmetals is rators, (3) condensates from evapora- and the manner of collection and dis- done by milling and screening and may tion operations, (4) barometric con- posal of rain run-off affects the total be done either wet or dry. When done denser cooling water, (5) miscellaneous plant effluent. The run-off from used dry, dust collection Is necessary to reduce cooling water streams, and (6) storm- cathode storage or disposal areas is the air emissions and can be done either wet water run-off. source of most of the cyanide in plant or dry. Milling of dross and skimmings The most significant waste streams effluent. While cyanide is found in some will produce a dust that, when scrubbed from the bauxite refining operation, in primary aluminum plant effluents, it nor- wet, will contain insoluble solids in sus- terms of volume of waste water gener- mally is not present in high concentra- pension such as aluminum oxide and hy- ated, are the red mud and barometric tions. In addition, liquid and solid spills drated alumina, and soluble salts from condenser cooling water streams. contain pollutants. the flux cover residues such as sodium (2) Subpart B-Primary Aluminum (3) Subpart C--Secondaxy Aluminum chloride and potassium chloride. Droses Smelting Subcategory: Most of the waste Smelting Subcategory: The waste water also contain aluminum nitride which hy- waters from primary aluminum smelting from secondary aluminum smelting re- drolyzes in water to yield ammonia. result from air pollution control devices sults from three principal sources: metal When slags are milled, the waste water which employ wet scrubbers to control cooling, fume scrubbing, and residue contains more dissolved sodium and po- air emissions. Wet scrubbing can be em- processing. Metal cooling waste waters tassium chloride and fluoride salts from ployed in one or more of three general result from spraying the molds to solidify the cryolite than from dresses or skim- areas: the anode plant, the potline, and the aluminum and allow its ejection from mings. Some of the oxides of heavy the casthouse. The waste waters from the mold. In some cases, the molds con- metals are solubilized In the slag and each of these areas will be discussed in- tain internal cooling lines through which are leachable from the dust, With wet dividually: (1) The anode plant, where noncontact water is passed. Air cooling milling the dust problem is minimized the anode materials, pitch (coal tar) and of the molds may be used to. eliminate but the operation produces a waste wa- petroleum coke, are received, commi- cooling water completely. The production ter stream that has a similar composition nuted, screened, blended, and in some of shot requires water from the rapid to the scrubber waters but contains plants, pressed and baked, is a source of quenching of the molten aluminum. The higher toncentrations of contaminants. dust. The handling of pitch and anthra- molten metal is poured into a vibrating The aluminum and alumina fines ire cite (hard coal) for cathode linings also porous container which allows the metal settled rapidiy and assist in the settling produces carbonaceous dust. In some to pass through as droplets. The drops of of other waste water constituents. plants such dusts are collected in dry molten metal fall into a water bath and (iv) Significant Pollutants. (1) Sub- cyclones and bag filter houses. However, are quickly solidified. From the water part A-Bauxite Refining Subcategory: many plants use wet scrubbing systems bath they are conveyed to a dry screen- The significant pollutants in the waste for air emissions control. The resulting ing operation. waters from bauxite refining include al- liquor contains acids, hydrocarbon tars Fume scrubbing waste waters result kalinity, pH, total dissolved solids, and and oils, and sulfur oxides from the bak- from a process of removing magnesium suspended solids. Alkalinity Is significant ing operation as well as carbonaceous from the melt. The aluminum scrap nor- because of the alkaline characteristics of particulate material from materials han- mally charged into thb furnace contains the waste water from the Bayer process. dling. Such a stream is not suitable for a higher percentage of magnesium than The pH of the discharge, in addition to processing through a recovery system to is desired for the alloy produced. There- identifying alkalinity, serves to monitor the electrolytic cells, and is usually added fore, it is necessary to remove a portion slug discharges of acid cleaning solutions. to other effluent streams, treated to of the magnesium from the melt. Mag- Total dissolved solids and suspended sol- promote settling, and diverted to ponds nesium removal, commonly know in the ids and suspended solids are significant for subseqdent mixing with other plant industry as demagging, is normally ac- for this subcategory because of the po- effluent streams before discharge; (2), complished either by passing chlorine tential for high concentrations of sodium The potlines, or rows of reduction cells, through the melt, with the formation salts and insoluble Impurities in the red frequently have wet scrubbers to collect of magnesium chloride (MgCh), or by mud wastes, respectively. fumes and dust from the electrolytic mixing aluminum fluoride (AIF 3) with (2) Subpart B--Primary Aluminum process. These wet-scrubbing systems are the melt, with the formation of magne- Smelting Subcategory: The significant the source of most of the waste water sium fluoride (MgF). Heavy fuming re- pollutants in the waste waters from this constituents from primary aluminum suits from the demagging of a melt and subcategory include fluoride, suspended plants. Carbon dioxide, carbon monoxide, these fumes often are controlled by pass- solids, oil and and hydrogen grease, cyanide, and pH. fluoride are generated in ing them through a wet-scrubbing sys- luoride Is the major waste water con- the overall cell reaction. In addition, tem. The water used for scrubbing thus stitutent associated with the primary gaseous and particulate emissions con- gains pollutants and becomes a waste aluminum smelting subcategory and re-

FEDERAL REGISTER, VOL. 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 PROPOSED RULES 33M7 suits from the wet scrubbing of reduction initially constructs a mud lake of 20-40 in discharge volume is obtained by con- hectares (50-100 acres) surrounded by verting wet fume scrubbers to dry fume cell emissions. The reclamation of spent or by treating and recycling cathodes also may be a source of fluoride. a dike on four sides. After this lake is scrubbers filled, a new one is constructed adja- the water from wet scrubbers. Suspended solids result from wet scrub- The dry scrubbing of pot gas Is a sys- bing operations in the anode plant and cent to it. By using one side as a com- mon dike, only three new sides need be tem of air pollution control used by pri- potlines and from miscellaneous sources mary aluminum smelters for the removal such as casthouse cooling circuits. Oil constructed, thus reducing the capital investment. of pollutants from the gases evolved from and grease may be present in anode the electrolytic cell (pot) by contacting plant scrubber effluent, potline scrubber Mud lakes are not single-purpose operations, nor is their cost entirely as- the gases with dry alumina to effect the effluent, and casthouse effluent. Cyanide and subsequent of spent signable to pollution control. Although adsorption of pollutants may result from the leaching collecting particulates by fabric filtra- cathode storage piles. Each of these waste they are primarily receptacles for the waste mud residues, they can serve as tion. The system Is applicable to gases water constituents may be present in the immediately above the pot, i.e., effluent from a primary aluminum cooling ponds and water reservoirs. They collected can also be receptacles for other minor pot gas, having relatively higher con- smelter in significant quantities and each centrations of constituents than does pot is amenable to conventional waste water waste streams from the plant, which may include boiler and cooling tower blow- room ventilation air. The dry scrubbing treatment techniques. system Is not applicable to pot room (3) Subpart C-Secondary Aluminum downs, and treated sanitary waste effluents. If soda (sodium) concentrations ventilation air. Smelting Subcategory: The significant The outstanding features of the dry constituents of cooling waste water in- are not excessively high, they may serve to some extent as an additional mud system are the adsorption of emitted clude suspended solids, lead, manganese, which Is subsequently these waste washing stage. The basic requirement for gases on alumina and oil and grease. Each of fed to pots to produce aluminum product, water constituents may be present in suf- the disposal of the red mud residue from alumina plants has a direct effect on the associated return of fluorine com- ficient quantities to warrant'their control pounds to the pots, and the generally and treatment. plant space requirements, plant site ar- rangement and the initial design of the high levels of collection efficiency for - The significant waste water constit- compounds and (magnesium plant water system. both gaseous fluorine uents from fume scrubbing particulates, e.g., greater than 99 per- removal operations) are pH, suspended The mud lake is the central Item in any total impoundment waste control cent. The process uses no water and, solids, oil and grease, and chemical oxy- hence, eliminates the discharge of proc- gen demand. Each of these waste water program. It will be used for the alkaline mud stream and, possibly, for one ess waste water pollutants. The associ- constituents may be present in sufficient ated solid waste handling and disposal quantities to warrant their control and or more of the other waste streams. Ancillary waste streams may also utilize problems also are eliminated. treatment. dry scrubbing water constitu- the mud lake, or they may utilize other The elements of the The significant waste process include hoods and ducts to col- ents from residue processing are pH, similar clear water or stormwater reservoirs instead. The alternatives for the lect and deliver the gases from the pots suspended solids, aluminum, copper, unit, usually located in a fluoride, ammonia, and chemical oxygen recycling of the other streams are, in to an operating demand. Each of these waste water con- general, flexible enough so that optional courtyard between potline buildings, possibly a cyclone type device to separate stituents may be present in sufficient solutions are possible. This will include the recycling of barometric condenser coarse particulates, a reactor section in quantities to warrant their control and are contacted with the treatment. cooling water. In some refineries, con- which the gases alumina, and a fabric filtration stage, v) Control and Treatment Technol- ventional cooling towers are used in a barometric condenser cooling water cir- from which the gases are released to the ogy. (1) Subpart A-Bauxite Refining atmosphere, usually through a stack. As- Subcategory; The only feasible technol- cuit. In others, the red mud lake or clearwater lake will be used, with the sociated equipment includes fans, alu- ogy for the control of the red and brown de- mud wastes produced by bauxite refin- barometric condenser water combined mina delivery, storage and removal - baghouse auxiliary equipment. eries is impoundment (controlled land with the process water. vices, and A critical item in the total impound- Three commercial variations of the disposals). The muds are impounded in dry process exist. In one type of dry large diked lakes, ranging in size from ment process Is the management of tile general aqueous wastes from the refinery. scrubber, the contacting of gas and 40 hectares (100 acres), to 800 hectares alumina is accomplished in a fluidized (2,000 acres). The impoundment areas or A well-designed system will include con- in either of crete curbs around all process areas bed, with the fabric filters, or a baghouse mud lakes are constructed at the top of the same chamber. In two basic ways. The dikes may be erected where spills or leaks of process solutions are possible, with the drains all con- another design, the air at relatively high to their full height initially, so that the a ven- lake is available from the be- nected to a collection system." The ulti- velocity is blown upward through complete turi throat, into which alumina is in- ginning, and additional dike construc- mate disposition of such a system gen- the life of the erally will be the red mud lake or one of jected downward. The result is ex- tion is not required during of the solid" lake; or, a low dike may be constructed the other lakes in the total recycle cir- tremely turbulent mixing to cuit. The failure to install curbs or repair and gas In the throat and in the column initially and continually rebuilt throat. The gases and eluted greater heights as the lake fills with the cracks and crevices in concrete floors above the may permit the escape of alk'ine process solids are drawn from the column and mud. to the baghouse stage. In the third In all mud lake construction, care solutions. then (2) Subpart B-Primary Aluminum design, the collected gases are drawn at must be taken to insure that the bottom high velocity through a horizontal duct is impervious. Soil tests may be made to Smelting Subeategory: The existing be technologies for controlling the waste with the alumina being injected down- evaluate the bottom, and clay may gases. Again, tur- used to line the bottom if an undesirable water volume in the primary smelting of ward into the moving aluminum include dry fume scrubbing, bulent mixing and intimate contact of porosity is indicated. Depending on the with the gases structural characteristics of the under- and recycle of water to wet scrubbers gases and solids occur, in, after precipitation of fluorides. The subsequently drawn through a baghouse. lying soil, the dike also may be keyed of the dry scrub- by excavating a trench down its cen- treatment methods for reducing pollut- The three variations ant concentrations include cryolite pre- bing process have been demonstrated on ter line before its construction. one system has Dike heights will depend upon soil cipitation, precipitation by lime or alum, a commercial scale and been operating for'three years. To date, characteristics and upon mud character- adsorption on activated alumina or hy- (20-30 feet) droxylapatite, and reverse osmosis. Con- proven applications have been on pre- istics. Heights of 6-9 meters stud Soderberg are usual with good underlying soil control technology refers to any practice ap- bake anode and vertical plied to reduce the volume of waste wa- anode cells. ditions and a mud which readily solidi- from wet scrubbers can be be as high as 18 ter discharged. In the primary aluminum The water fies. Arkansas dikes can treated in various ways to remove Im- meters (60 feet). Typically, a refinery industry the most significant reduction

FEDERAL REGISTER, VOL 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 33174 PROPOSED RULES purities so that the partially purified control of metal quality. Certain alloys facilities would depend on the production water can be continuously recycled to or melting stock thereford require the capacity of the smelter. It is possible to the wet scrubber. In the case of primary elimination of impurities to achieve the reduce flow rates in metal cooling such potline and secondary potroom wet specified properties of strength, ductility, that the cooling water is totally evapo- scrubbers, the fluoride dissolved in the electrical conductivity, etc. Each of the rated by the hot ingots. Specially de- water can be precipitated and settled. degassing procedures noted above is in signed nozzles may be used to, give a This treatment simultaneously reduces commercial use in one or more producing water mist spray that reduces the the suspended solids and oil and grease plants. Therefore, it is concluded that steam-to-metal interface and to reduce content. In general, the method used to there are currently available alternative water consumption. Consumptive cool- remove the soluble fluoride values from process methods which eliminate cast ing may require longer conveyors to as- the waste water is precipitation either as house waste water from degassing sure that thle ingots have cooled sufi- cryolite or as calcium fluoride. In the operations. ciently to be handled. Air streams also first case, sodium aluminate (or NaOH Numerous treatment techniques are may be used to cool the ingots. Air cooling and hydrated alumina) is added; and in available to primary aluminum smelters is accomplished by conveying the hot in- the second, a lime slurry (or in one case to reduce the concentration of pollutants gots through an air tunnel fitted with CaCIh is used. After precipitation, the in waste waters before discharge. The entrance and exhaust blowers, The con- thickening of the slurry is accomplished "treatment of recycled fluoride waste veyors are approximately twice the in clariflers or thickeners. streams is effected by the reaction of the length of water cooling conveyors. Main- The treatment of wet scrubber liquors waste stream with calcium chloride or tenance is higher on the air-cooled sys- to recover cryolite is a significant prac- lime to precipitate calcium fluoride. Ade- tem because of the longer conveyor, the tice because it removes a sufficient quate detention time will-also reduce the added heat load on the lubricants, and quantity of fluoride to permit recycle of concentration of suspended solids and the additional blower motors. In some the treated liquor to the scrubbers, and oil and grease in the effluent. The treat- cases a water mist Is added to the air to in the process recovers the fluoride in a ment of dilute, once-through, fluoride improve the cooling rate but this water form which usually can be returned to waste streams can be effected by several Is completely evaporated. The waste the aluminum reduction cells. The value processes. Although these processes are water from both once-through and re- of the cryolite recovered represents a not in general use by the industry, they circulating cooling operations requires credit to the treatment process. Total re- are adequately demonstrated in other treatment to remove the oil and grease cycle cannot be achieved by this treat- industrial'or municipal applications and and suspended solids before discharge, ment because of the presence of sulfates are considered practicable treatment Since it Is more efficient to treat waste in the liquor. Sulfur impurities in the technologies. They include: (i) Alumi- water with high levels of pollutants than raw materials, principally in the petro- num sulfate (alum) treatment, (Ii) with low levels, the treatment of the leum coke and pitch used in anode prep- activated alumina adsorption, (il) hy- recirculated water is preferable. Special- aration, are converted to sulfur oxides droxylapatite filtration, and (iv) reverse ized skimming devices are available for during electrolysis and are collected in osmosis. The waste water from anode the removal of oil and grease from water. the scrubber water as sulfates. If total bake furnace scrubbers may be treated Grease traps can reduce the levels of oil recycle of the liquor is attempted, the with lime and settled. After settling, oil and grease so that such specialized solubility of sodium sulfate would even- and grease materials are skimmed from equipment is not overloaded. The re- tually be exceeded. Therefore, a small the pond surface. moval of suspended solids from cooling bleed is maintained from the scrubber For water pollution control, a dry waste water requires settling. The com- liquor circuit to keep the sulfate concen- scrubbing -system is obviously the best, ponents of the suspended solids are pri- tration sufficiently low to prevent the when it can be used. Plants" precipitation committed marily aluminum hydroxide or hydrated of sodium sulfate. This to potroom air cleaning, i.e., secondary oxide which are excellent coagulants. bleed stream is relatively low in volume air scrubbing, cannot use a dry scrubbing The recirculation of cooling water will but high in fluoride content and repre- system because of the inefficiency of dry build the suspended solids level to con- sents the major portion of the fluoride systems at low concentrations of emis- effluent centrations great enough to effect rapid from the entire plant. The re- sions. In addition, the use of dry scrub- settling between cooling operation cycles. cycle system uses the clarified overflow bing on the anode bake plant effluent is from the thickener Sludge removal, if required, may be done tanks as the scrub- not practiced at the present time, al- periodically. The supernatant water may bing medium. though at least one plant achieves the Degassing is an operation in be pumped into a holding tank during which equivalent of a dny system by controlled sludge removal and then reused. Sludge dissolved hydrogen and other impurities firing. are removed from the settling tank may be disposed from molten aluminum There are notable differences between of in an impervious lagoon or an accept- just before it is cast into product form. the two wet scrubber systems, once- able landfill. Classical degassing is the bubbling of through and recycle. The recycle system chlorine gas through the melt to react The fumes formed during chemical with is considerably more effective in the re- magnesium removal must be controlled and remove the hydrogen as hydro- ductionof fluorides, suspended solids gen chloride gas and the other impurities and to reduce air emissions to acceptable -oils and greases. Fluoride quantities are levels. Numerous wet scrubbing tech- as chloride salts. Emissions to the air about 5-10 kg/kkg ordinarily have been controlled (10-20 lb/ton) of niques have been employed for this pur- by alka- aluminum when a once-through system pose. The discharge from these wet fume line wet scrubbing. The raw waste water is used and 0.5 to 1 kg/kkg (1-2 lb/ton) stream produced may vary from scrubbing devices contains most of the acid to of aluminuku when a recycle system is volatile metal salts entrained in the gas alkaline, depending on operating con- used. ditions, and contains significant amounts flow. When chlorine is used for magne- (3) Subpart C-Secondary Aluminum sium removal, aluminum chloride and of dissolved salts, principally sodium Smelting Subcategory: The amount chloride. of magnesium chloride are the principal waste water generated from metal cool- waste water constituents. When alumi- There are a variety of degassing pro- ing can be controlled by recirculation num fluoride is used for magnesium re- cedures which eliminate the use of water and cooling. A waste water discharge during can moval, the principal volatile products the degassing of molten alumi- be eliminated by adopting either total may be silicon tetrafluoride and hydro- num. These include: (i) Degassing with consumption through regulated water gen fluoride, which are formed from the mixtures of chlorine and other gases, flow or air cooling. However, these two high temperature hydrolysis of the (ii) degassing with inert gases (nitrogen alternatives are not suited to smelters slightly volatile fluoride salts reacting or argon), and (iII) degassing by filtra- producing deoxidizer shot. -A recircula- with moisture in the air. In both types tion. The necessity for degassing varies of magnesium removal processes, the air with product specifications. Products tion system may consist of a cooling tower, a cooling pit, an auxiliary holding pollutants are transferred into water which must be especially pure and free pollutants. The control of air emissions from pin holes caused by gas bubbles tank, associated plumbing, and neces- (e.g., aluminum during magnesium removal can be done foil) require stringent sary pumps. The size and cost of these either dry or wet. Dry emission control

FEDERAL REGISTER, VOL. 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 PROPOSED RULES 33175 tecl;niques must contend with rather tended gas residence times achieved by Waste water generated during wet corrosive gases for both types of mag- employing gas-liquid contractors. For milling of residues is treated in settling nesium removal. Anhydrous chloride very dirty scrap a short period of pre- ponds in which the insoluble materials salts hydrolyze to produce hydrogen chlorination in the furnace Is necessary are removed. Depending on the nature chloride gas which, in turn, reacts with to improve fluxing. The system has been of the residue being milled, the amounts water vapor to form hydrochloric acid. operated on a commercial scale. of dissolved solids an insoluble solids in Hydrogen fluoride, and hydrofluoric The coated baghouse (Teller) process the raw waste water vary. When the res- acid are formed only at high tempera- is a modification of a baghouse opera- idues are slags from secondary smelters. tures; however, once formed, they re- tion. Baghouses normally have not been the waste water contain's large amounts main present in the gases being scrubbed. effective in the removal of fumes from of dissolved salts. When the residues are Three processes exist for fume control demagging operations because blinding drosses or skimmings from primary or without major use of water either in the occurs during collection of the submicron foundry sources, the amount of dissolved process or in fume control. These are the particulates. These particles enter the salts in the waste water is greatly re- Derham process, the Alcoa process, and interstices of the weave and create a duced; however, the insoluble solids the Teller process. The Derham process barrier to gas flow. When blinding oc- fraction approaches .70 percent by vol- includes equipment and techniques for cursi the pressure drop rises rapidly and ume. At most residue milling facilities, magnesium removal with chlorine from gas flow diminishes. One system has both types of residues are handled and secondary aluminum melts with mini- been installed at a secondary aluminum both types of raw waste water are gen- mum fume generation and without smelter. Basically, the system differs erated from the same milling operation. major use of water in either the process from a normal baghouse irk that the bags Waste water also is generated from the or in fume control. The principal con- are precoated with a solid and are de- wet control of dust from a dry milling cept is the entrapment of magnesium signed to absorb effluent gases as well as operation. Wet milling of primary alumi- -chloride, the reaction product of mag- particulates. Upon saturation, the coat- num residues and secondary aluminum nesium removal with chlorine, in a liq- ing and the collected dust are removed slags by a countercurrent process may uid flux cover, with the flux subsequently by vibration. A fresh coating then is ap- be the only practical method to recover being used in the melting operations. The plied. The collected particulate and spent salts. By using a countercurrent milling principal components consist of a separ- coating are disposed of in an acceptable and washing approach, two advantages ate bath of the metal to be treated with landfill. The system is suited for collec- are realized. The final recovered metal its special flux cover, and means to cir- .tion of emissions from operations using is washed with clean water, thereby pro- fluoride for demagging. A providing a low-salt feed to the reverbera- culate the molten metal to and from that aluminum the waste water with separate bath. totype has been installed in such a fa- tory furnaces. Also, The treatment bath may be integrated cility where its performance is being the insolubles removed would be of a with, or separate from, the smelting evaluated. The evaluation program also concentration suitable for economical furnace depending on whether the par- is to establish Its effectiveness for the salt recovery by evaporation and crystal- ticular installation is a new or existing collection of emissions from operations lization. Heat for evaporation could be The molten metal circulation using chlorine for demagging. supplied by the waste heat from the re- facility. verberatory furnaces. The process ulti- from the main furnace hearth to the Wet scrubbing techniques to remove mately must dispose of the dirt, trace Derham unit is accomplished by pump- demagging fumes from the air transfer (usually with an air-drive siphon) metals, and insolubles recovered from ing pollutants to the water. The treatment the chlorine which contain low levels rather than by less direct methods such applied to the waste water prior to Its as mechanical stirring or nitrogen-gas of soluble salts. Such salt recovery in- 'discharge or re-use depends upon the stallatlons are operating in England and sparging or agitation. method used for magnesium removal. The molten metal brought to the Switzerland and the salts recovered are The water from fume scrubbing opera- since they are treatment unit is treated in the usual tions using chlorine for magnesium re- credits to the operation, manner with gaseous chlorine to achieve reusable as fluxing salts by the secondary moval is highly acidic due to the hydrol- aluminum industry. Such a system has magnesium removal. Molten magnesium ysis of aluminum chloride and product.. By not been operated in the United States, chloride is the reaction magnesium chloride. Neutralization to although preliminary research to do so maintaining a relatively thick cover on pH of 6-7 will precipitate most of the the bath in the treatment unit, the emis- is underway. aluminum and magnesium as hydroxide. The alternative to wet residue milling sions of aluminum chloride to the atmos- The coprecipitation of heavy metal hy- produced by demagging and the resulting waste water treatment phere usually droxides also occurs. The effectiveness of of the residues. Impact are nearly completely arrested. As the neutralization is diminished if too mubh is dry milling saturated with mag- mills, grinders, and screening operations flux cover becomes alkali is added since resolubilization of are used to remove the metallic alumi- nesium chloride, it is removed and may aluminum hydroxide occurs at about pH num values from the nonmetallic val- be used as a flux in the main melting 9. Solids removal by settling follows cast into ues. The high levels of dust formed in furnace. The flux is usually neutralization. The supernatant may be these operations are vented to bag- cakes. After grinding it may be used as a recycled to the scrubber system. well of the houses. The baghouse dust and the non- covering flux at the charging The water from fume scrubbing opera- metallic fines from the screening con- melting furnace. Any gaseous effluents tions using aluminum fluoride for mag- the treatment unit are blended, stitute the solid waste from the opera- from nesium removal may be neutralized and tion. Theie solids normally are stored with the combustion gas effluent and re- recycled continuously. The continuous the stack. Emission control re- on the plant site on the surface of the leased to recycle system scrubs the emissions with ground. The runoff should be controlled quirements vary and may be satisfied by a venturi-type scrubber followed by a the approach of blending the gases. In by containing dissolved salts in drainage packed tower and demisting chamber. ditches which feed to suitable impervi- situations requiring particulate control The waste water is collected in a settling chloride emissions, ous impoundment areas. with baghouses, the tank where it is treated with 5 percent (vi) Best Practicable Control Tech- although hygroscopic, are usually dilute caustic to neutralize the hydrogen fluo- enough not to interfere with baghouse nology Currently Available, Best Avail- ride formed from hydrolysis. The sodium able Technology Economically Achieva- operation. fluoride formed reacts with particulate The Alcoa process is a fumeless tech- ble, and Best Available Demonstrated aluminum fluoride carried with the Control Technology, Processes, Operating nique for magnesium removal. It re- emission to form insoluble cryolite. The covers molten magnesium chloride as a Methods, or Other Alternatives. magnesium fluoride, cryolite, and other (1) Subpart A - Bauxite Refining product. The unit is installed between insolubles are separated in setting tanks the holding furnace and a casting ma- Subcategory: The best practicable con- and the alkaline supernatant Is recycled trol technology currently available for chine and. removes magnesium continu- to the scrubbed system. There is no water ously as the metal flows through. The the bauxite refining subcategory is the operation uses no flux salts and attains discharge except for that removed with total impoundment of process waste wa- the high chlorine efficiencies through ex- the sludge. ter with recycle as required to elimi-

FEDERAL REGISTER, VOL 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 33176 PROPOSED RULES

nate the discharge of process waste to the scrubbing system. Alternate tech- solids removal, and (1) when aluml- water pollutants to navigable waters. nologies for fluoride removal are identi- num fluoride Is used for magnesium re- The corresponding effluent limitation is cal to the best available technology moval, adjustment of the scrubber elflu. no discharge of process waste water pol- economically achievable. entpH to between 6.5 and 8.5 followed lutants. The best available technologay The treatment of waste water from the by settling for solids removal. After neu- economically achievable and the best casthouse consists of impoundment of tralization and settling, the supernatant available demonstrated control techno2- the bleed stream from the cooling water is recycled continuously and the solid ogy also is total impoundment of proc- circuit or treatment of the cooling wa- fluorides are removed continuously to ess waste waters. The corresponding ef- ter for solids and oil and grease removal. eliminate the discharge of process waste fluent limitation and standard of per- Alternate technologies for the control of water pollutants. The fume scrubber formance s no discharge of process casthouse waste water include air-cooled, water from magnesium removal with waste water pollutants. solid-state rectifiers, which eliminate the chlorine, upon pH adjustment, cannot (2) Subpart B-Primary Aluminum discharge of rectifier cooling water, and be recycled continuously because of the Smelting Subcategory: The best prac- a number of alternative methods for excessive buildup of sodium chloride. ticable control technology currently molten metal degassing which eliminate However, partial recycle of the clarified available for the primary aluminum the discharge of casthouse scrubber waste treated effluent to" reduce the volume smelting subcategory Is the treatment of water. of waste water discharged Is considered wet scrubber water and other fluoride- (3) Subpart C--Secondary Aluminum practicable. containing effluents to precipitate the Smelting Subcategory: The control and fluoride, The best available technology eco- followed by settling of the pretreatment technologies applicable to sec- nomically achievable for the control of cipitate and recycling of the clarified ondary aluminum smelters are discussed waste water from fume liquor to scrubbing dur- the wet scrubbers as a means below for waste water generated during ing magnesium removal Is the use of of controlling the volume of waste water (i) metal cooling, (i) fume scrubbing in-process and end-of-process controls discharged. Two precipitation methods during magnesium removal, and (iii) wet and treatment to achieve no discharge are currently available: Cryolite precipi- residue processing. of process waste water pollutants. This tation, and precipitation with lime. This The best practicable control technology technology can be done using one of the following achieves an attendant re- currently available for metal cooling in approaches: (i) The use of currently duction in the discharge of suspended the secondary aluminum subcategory is available processes for fumeless chlorine solids and oil and grease. Alternate tech- the elimination of the discharge of proc- nologies magnesium removal, (i) the use of for achieving effluent limitations ess waste water through the use of the aluminum fluoride for magnesium re- based on the application of the best prac- following: (i) Air cooling, or (ii) total ticable -moval and continuous recycling of control technology currently consumption of cooling water, or (i) re- scrubbing water from emission and efflu- available are dry fume scrubbing and cycle of cooling water for deoxidizer-shot total ent control systems, and (ill) the use of impoundment (controlled land dis- cooling or ingot cooling. With re-use or aluminum fluoride for magnesium re- posal). recycle of water the need for sludge and moval and a coated baghouse system The application of the best practicable oil removal will be dictated by individual for air pollution control. control technology currently available plant procedures. The results best available demonstrated con- in a relatively low-volume, high- The air cooling method or the total trol technology, processes, operating concentration bleed stream. The best evaporation cooling method (air cooling available methods, or other alternatives, for fume technology economically method with water mist added to assist scrubbing waste water is the use of achievable is the lime treatment of such the air cooling) requires: (I) The addi- a aluminum fluoride for magnesium re- bleed stream to further reduce the dis- tion of ingot molds to the lengthened nioval and continuous recycling of scrub- charge of fluoride, suspended solids and conveyor line, (ii) the installation of oil and ber water from emission and effluent grease. Alternate technologies for blowers, and (ill) In the case of total control systems, or the use of chlorine achieving the effluent limitations based evaporation cooling, the addition of spe- on for magnesium removal with wet fume the application of the best available cial nozzles, flow meters, and controls to scrubbing and the application of the technology economically achievable in- existing water lines. 'clude dry fume best practicable control technology cur- scrubbing and total im- A recycle system for ingot cooling rently available (pH adjustment and poundment (controlled land disposal). may require: (I) The addition of a cool- settling). The best available demonstrated con- ing tower, holding tanks, and pumps trol technology The best practicable control tech- for new sources in the to the existing water cooling facility, nology currently available for control primary aluminum smelting subcategory (ii) provisions for oil and grease re- is the of the discharge of pollutants contained use of dry fume scrubbing tech- moval, and (ii) provisions for sludge in waste water from residue milling is niques on the potroom air and the treat- removal, dewatering, and disposal. The a settling ment of waste water from treatment of three to four anode plant effluent limitation associated with the stages with partial recycle of the sludge wet scrubbers and the casthouse. Since application of the best practicable con- and the clear supernatant from the final the primary smelting of the aluminum trol technology currently available requires for stage to the mill. Adjustment of the in- no process water directly, the metal cooling waste waters is no dis- take water pH is necessary to reduce principal area where the use of water can charge of process waste water pollu- be minimized in the ammonia levels in the waste water dur- design of a new tants. The best available technology eco- ing milling. When milling Is done with- plant is the application of dry fume nomicaly achievable and the best avail- scrubbing systems out pH adjustment of the Intake water, for air pollution con- able demonstrated control technology ammonia remains In solution. To aid trol. Dry fume scrubbing systems exhibit are equivalent to the best high collection practicable the settling of the milling wastes, a efficiencies. The fluoride control technology currently available polyelectrolyte may be required to reduce values contained in the fumes can be for metal cooling. the level recovered in a of suspended solids. Recircula- form amenable to re- The best practicable control tion of the sludge In the last settling cycle to the smelting process. Alternate technol- technologies ogy currentlIy available for control of pond to the mill will reduce the overall for potroom air cleaning the discharge of pollutants sludge content of the final pond, which may be employed in certain cir- contained in cumstances fume scrubber waste water from magne- The best available technolo-y eco- are wet scrubbing with total sium removal are the following: impoundment of the scrubber water or (I) nomically achievable and the best avail- with recycle of When chlorination is used for magne- able demonstrated control technology the scrubber water and sium removal, lime treatment of the bleed adjustment of the scrub- for the control of waste water from resi- stream. ber effluent pH to between 6.5 and 8.5 The treatment of the due milling Is the equivalent of totally waste water from followed by settling for solids removal dry milling methods to eliminate the the anode plant and other fluoride- or, the prior adjustment of the containing waste pH of discharge of process waste water. An al- streams consists of the scrubber liquor so that the result- ternative to dry milling is the use of lime precipitation followed by solids re- ant effluent from the scrubber is' at a moval and recycle of countercurrent wet milling techniques the clarified liquor pH of 6.5 to 8.5 followed by settling for with evaporation to reclaim salts from

FEDERAL REGISTER, VOL. 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 PROPOSED RULES 33177

ents. Tight hoods should be provided, ness of treatment of potline and potroom the process and to eliminate the dis- effluents are: charge of process 'waste water and the operation conducted In such a manner as to minimize any potroom (1) The cost difference between a dry pollutants. system and a recycle plus effluent con- (vii) Costs for the Control and Treat- contamination. (2) The most cost-effective means of trol Is negligible for new plants. ment of Waste Water. (1) Subpart A- (2) For plants which already have a Bauxite Refining Subcategory: Increases removing fluoride for those plants with existing wet scrubber systems is the recycle scrubber operation on their pot- in operating costs to eliminate the dis- line or potroom gases, the addition of charge of process waste water pollutants operation of a recycle loop to the scrubber with cryolite precipitation. The dif- further treatment of the two effluent are estimated to range from zero to streams Is both inexpensive and very $0.28/kkg (0-$0.25/ton) of alumina for ference in cost between this system and six of eight U.S. refineries. One producer the once-through system with lime treat- effective. ment is relatively low, and the fluoride (3) For plants using a once-througlh estimates that the costs incurred to elim- scrubber system, a conversion to the re- inate the discharge of process waste wa- removal efficiency is considerably better int he recycle system. cycle mode yields the best cost-benefit. ter pollutants would be $6.40 to $7.74/kkg Although an activated alumina adsorp- ($5.76 to 6.97/ton). Based on operating The treatment techniques for fluoride removal will tend to remove suspended tion process added to the once-through costs of $55/kkg of alumina ($50/ton), costs approximately the 11-14 per- solids. In the dry systerh, any suspended scrubber water this would be an increase of same, about ten times the amount of cent in operating costs for two plants in solids will be caught in the collection system. Since wet systems for fluoride pollutants would be discharged in the the industry. Neither of these two plants water from the activated alumina currently has facilities for impounding control involve a settling operation, the process wastes. Every other plant in the suspended solids alsb will tend to settle. system. some Therefore, conclusions about the cost ef- (3) Subpart C-Secondary Aluminum subcategory currently practices Smelting Subcategory:- The costs for the form of impoundment. fectiveness of fluoride removal also apply to suspended solids control. application of waste water control and (2) Subpart B-Primary Aluminum secondary re- Oils and greases emitted from the treatment technologies for the Smelting Subcategory: The costs of aluminum smelting subcategory are de- ducing the discharge of pollutants from abode consumption in the potline also tend to be removed with the suspended scribed for the following operations: (i) primary aluminum smelting is directly (ili) fume scrubbing, and related to the cost of removing fluoride. solids and fluoride. At least one plant Metal cooling, lagoons scrubber water from the anode (i) residue precessing. it is apparent that the cost increases as cost of approximately $0.43/ the amount of fluoride in the effluent bake plant and indicates that the oil A capital and and greaie content (as well as suspended annual kkg of aluminum is needed to stream decreases. The most effective existing once-through water also the most expensive option to control solids) can be reduced by 60 percent in a convert an of a wet scrub- pond with a residence time of 21 hours. cooling system to a recirculation system. fluorides is the conversion re- on-the potline to a dry This residence time is relatively long. An operating cost of $0.15 per kkg is bing system exclusive of savings resulting scrubbing system. A dry scrubbing sys- However, concentrations of oils and quired, greases are low (less than 10 mg/i with from decreased water use. The conver- tem, however, may not be feasible for a water-cooled ingot line to use on potroom secondary air or for an incoming suspended solids concen- sion from tration of 100 mg/I. Very likely, further an air-cooled line would require an in- horizontal stud Soderberg potlines. of $9.20/kkg and an operating The relatively high capital required for reduction of oil and grease can be ef- vestment sys- fected by longer residence times with cost of $2.25/kkg, also exclusive of the the installation of a dry scrubbing savings credit. The evaporation tem applies only to those plants which proportionately higher costs. Another water plant achieves good reduction In oil and of the blowdown from the cooling tower would be converting from a wet system. system would require The initial installation of a wet scrub- grease (95 percent) by using a cooling in a recirculating fans, tower and aerated lagoon treatment of a capital cost of $0.30/kkg and an oper- bing system, including the scrubber, The treatment etc., costs about $38/annual ton of alu- the blowdown from the cooling tower at ating cost of $0.05/kkg. a cost of $1.60/annual kkg capital and of metal cooling waste water to remove minum. Thus, the difference in cost be- oil and grease would require a capital tween the two systems for a new plant $0.40/kkg operating. The choice of additional schemes for the treatment of cost of $0.08/kkg and an operating cost would only be about $2/annual ton bbosed that no dis- on an average investment cost of $40/ scrubber water effluent depends primar- of $0.07/kkg. It Is concluded ily on whether a recycle system or once- charge of process waste water pollutants annualton for dry scrubbing. from metal cooling can be achieved for The recycle mode of scrubbing water through system is in use. In a recycle system, the additional control of fluo- an added cost of $0.15 to $l.00/kkg of control on both potline (primary) gases aluminum produced. and potroom (secondary) gases results in rides, suspended solids, and oil and less than 1 kg/kkg of grease can be effected by the lime or A capital cost of aproximately $2.751 fluoride effluents of aluminum is required to aluminum (2 lb/ton). An average cost CaC 2 treatment of the filtrate stream annual kkg for this means of control is about $10/ from the cryolite recovery system and install a PH adjustment-settling treat- annual ton capital and $4.60/ton operat- the bleed stream from the scrubber. The ment capability to control the discharge ing. This treatment scheme is the model costs for this treatment are $1.50/annual of pollutants form chlorine fume scrub- for the best practicable control tech- kkg capital and $0.64/kkg operating. ber systems. An operating cost of $1.50/ nology currently available. The use of This cost includes a mixing tank for kkg is estimated for such an installation -once-through water in the wet scrubbing chemical addition, a thickener tank, with somewhat lesser expendituree re- .system of potlines with lime treatment pumps, piping services, etc. The costs quired for plants currently neutralizing before discharge results in effluent fluo- are relatively low compared with other the scrubber effluent. Those plants using ride levels of about 5 kg/kkg of alumi- fluoride treatment processes because of aluminum fluoride for magnesium re- num (10 lb/ton). Costs associated with the low volume of effluent to be treated, moval require, in addition to neutraliza- this treatment process are $7/annual ton about 120 l/minute (30 gpm), and high tion and settling, a means to recirculate and remove solids capital and $2.50/ton operating. This concentration of fluoride, about 1,000 the scrubber water treatment scheme is not considered mg/l. It Is expected that this treatment continuously. This requires a capital equivalent to the best practicable control also will reduce suspended solids and/or investment of $9.90/annual kkg and an technology currently ivailable. The fol- grease. The addition of a treatment proc- operating cost of $2.45/kkg. The cost of lowing conclusions can be made regard- ess to water eMuent from the once- eliminating the discharge of pollutants ing the cost effectiveness of fluoride through potline and potroom scrubber from fume emission control systems de- control: after lime treatment is more costly than pends upon which of three available techniques is used. The Derham process (1).The most cost-effective means of the treatment of recycle effluents. In once-through systems, large volumes of for magnesium removal requires a capi- control for new plants with prebake or tal expense of $3.40/annuaI kkg of ca- vertical stud. Soderberg anode configu- water with low concentrations of fluorides and other pollutants are treated. pacity and an operating cost of $2.60/ ration is the installation of a dry scrub- kkg. The Alcoa process requires a capital bing system on the potline gaseous efflu- The conclusions about the cost effective-

FEDERAL' REGISTER, VOL 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 Nqo. 230-Pt. 11-2 33178 PROPOSED RULES

cost of $5.90/kkg and an operating cost tamination of- subsurface waters. Im- plication of the Derham process may be of $2.90/kkg, exclusive of a credit for the poundment sites should be located and* too high in soluble salts for economic sale of magnesium chloride recovered. engineered to avoid direct hydraulic processing by residue milling techniques The use of aluminum fluoride for mag- continuity with surface or subsurface* for metal recovery -nd, therefore, con- nesium removal combined with the con- waters, and any leachate or subsurface stitute a solid waste. The application of tinuous recirculation of scrubber water flow into the disposal area should be aluminum fluoride with continuous requires a capital expenditure of $14.00/ contained within the site unless treat- scrubber water recirculatlon will produce annual kkg and an operating cost of ment is provided. Where appropriate, a solid waste. The application of chem- $5.40/kkg. The use of a, chemically the location of the disposal site should be ically-treated baghouse systems for dry treated baghouse system (Teller system) permanently recorded in the office of air' pollution control also results In a for the reduction of air emissions from legal jurisdiction. solid waste since the bag coating and the magnesium removal by aluminum flu- (2) Subpart B-Primary Aluminum collected dust and fumes may contain oride, requires an estimated capital cost Smelting Subcategory: Because the fluoride salts. of $27.70/annual kkg of capacity and an energy requirements of control and The application of settling techniques operating cost of $7.30/kkg. treatment methods for primary alumi- to treat the waste waters from residue A capital cost of $8.70 to $15.30! num smelters relIresent only a small milling produces a solid waste. Both dry annual kkg of molten aluminum and op- fraction of the total energy consumed in milling and wet milling of residues gen- erating costs of $3.30 to $10.90/kkg are the primary aluminum -industry, it is erate large quantities of solid wastes, required to treat waste waters from concluded that energy requirements will ranging from 2.3 to 9 kkg/kkg of alumi- residue pfocessing by settling. The varia- not be the deciding factor in the choice num recovered, depending on the grade tions in costs result from (i) the amount of control and treatment technology. of residue. Generally the solid waste of water used in milling, and (ii) the The total energy requirement for a from dry milling contains the highly solids content of the residue. The cost cryolite recovery and recycle system soluble chloride salts which are removed of eliminating the discharge of pol- which is equivalent to the best practi- during wet milling. These salts may be lutants from the milling of residues is cable control technology currently avail- leachable to groundwater. Dry milling estimated to be $130.00/annual kkg of able is about 1 percent of the energy also generates large quantities of air- aluminum capacity. This cost is for consumed by the smelting operation borne dust. Appropriate collection sys- building a new facility to convert from itself. tems normally are able to control the wet to dry milling. The costs for recovery A number of the control and treat- atmospheric emissions of the dust. The of salts from residue milling waste waters ment technologies identified produce recovery of salts from wet milling opera- is dependent upon the type of residue solid waste. Dry scrubbing does not pro- tions will require additional consump- processed. The estimated capital costs duce a solid waste but, rather, allows the tion of thermal energy of 8.6 x 101 kg cal for evaporation of low-salt residue waste collected particulates and gases to be re- for the low-salt residue waste water and waters is $16.00/annual kkg and the turned to the electrolytic cell. Wet scrub- 176 x 101 kg cal for the high-salt resi- operating cost is $24.00/kkg. High-salt bing methods and due waste water per kkg of aluminum re- subsequent waste covered. content residues may require a capital water treatment produce sludges in expenditure of as much as $200.00/ amounts ranging from 60 to 123 kg/kkg (ix) Economic Impact Analysis. The annual kkg and an operating cost of of aluminum. The calcium fluoride proposed effluent limitations guidelines $124.00/kkg. sludge should be disposed of in an ac- are expected to have only minimal effect- (viii) Nonwater Quality Aspects of ceptable landfill, which means a landfill on the secondary aluminum subcategorv Pollution Control. (1) Subpart A- at which complete long term protection with practically no impact on the primary Bauxite Refining Subcategory: The is provided for the quality of surface and subcategory. While, in general, simi- energy requirements for the total im- subsurface waters, from hazardous sub- lar conclusions have been reached con- poundment of red mud wastes result stances contained in the wastes deposited cerning the bauxite refining subcategory, from pumping and heat exchange. The therein, and against hazard to the public it should be recognized that two plants energy consumed in pumping red mud health and the environment. in this industry (representing about 24 and other effluents to an impoundment (3) percent of total industry supply) are Subpart C-Secondary Aluminum likely area is consideied comparable to that Smelting Subcategory: to incur very significant costs in The nonwater meeting the proposed required for pumping to an outfall so quality environmental impact of the con- guidelines, the incremental energy usage is nominal. trol and treatment of cooling waste Within the primary aluminum sub- Similarly, the energy required to return waters category, the current trend toward dry consists of: (i) An incremental scrubbers for the supernatant from a lake to the plant addition to' the thermal load of the plant air pollution control should Is comparable to that required for by thermal radiation minimize, if not eliminate, the problems pump- from air cooling of of water pollution Ing freshwater from another source. ingots, (it) added electrical energy re- control. Accordingly, Depending upon the overall plant design, quirements there should be only minimal cost In of abbut 11 kwhr per kkg meeting management of the plant water would be needed for the proposed effluent limitations circuit, air cooling opera- for 1977 and 1983. and plant location, the evaporation of tions, and (iii) negligible impact on air No price increases are excess water may be quality from water expected and no plant closings or em- necessary to avoid evaporation either ployment discharging process waste water pol- from consumptive water-mist cooling or impacts are anticipated. There lutants. Thus, the use of fossil from sludge should be no Impacts on the balance of fuel in drying. Sludges from a re- trade or variable quantities may be necessary. circulating cooling water system should industry growth as a result of However, the water to be evaporated be disposed of .in an acceptable water pollution control requirements. land- Noticeable price always will be significantly less than the fill. The only significant nonwater qual- increases are not ex- quantity routinely evaporated ity environmental impact pected within the secondary aluminum in the of the control industry as manufacturing process. and treatment of waste waters from a result of the proposed fume scrubbing guidelines. With the exception of the wet The volume of solid wastes, i.e. red during magnesium re- dross processing mud, generated moval is the potential effect on soil sys- sector (less than 4 per- annually by the bauxite cent of secondary capacity) cost refining industry would occupy 12 million tems due to the reliance upon the land In- for ultimate disposition creases are expected to be less than 1.1 cubic yards. This is equivalent to 7600 of final solid percent of the sale acre-feet per year. waste from the water treatment. value of aluminum. Assuming a mud lake The Excepting Isolated cases of regional is filled to a depth of 25 feet, 300 acres solid wastes are primarily inorganic and nonleachable. However, monopolies, competition within the in- would be required. This land require- the solid waste dustry should ment for the control from fluoride recovery can affect ground prevent these costs from of bauxite refining being passed on asprce increases. Plant wastes is the only practical disposal waters adversely if not adequately con- alternative tained. Therefore, the solid closings are expected only in those plants available. However, the use wastes should using wet processes of land impoundment be disposed of in an acceptable landfill to for dross and slag for the control of milling. In such plants the combined 1077 waste waters does not relieve the refiner lprevent contamination of subsurface and 1983 proposed from the responsibility guidelines could lead to avoid con- waters. The residues resulting from ap- to cost increases equal to 6 percent or

FEDERAL REGISTER, VOL. 38, NO. 230--FRIDAY, NOVEMBER 30, 1973 PROPOSED RULES 33179

of the regulations being proposed herein Health, Colorado Department of Public more of the sale value of aluminum Health, and California Water Resources to 100 and are available for inspection In the (1.50/lb or more) and equivalent 227, Control Board. percent or more of profits. There are four EPA Information Center, Room West Tower, Waterside Mall, Washing- The comments were highly variable, known wet dross plants and two other but the principal issues raised in the de- plants with wet dross departments. These -ton, D.C., at all EPA regional offices, and at State water pollution control offices. velopment of the proposed effluent limi- six operations represent approximately ' tations guidelines and standards of per- 160 employees and less than 1.0 percent A supplementary analysL prepared for EPA of the possible economic effects of formance and the treatment of these is- of total aluminum production. None of as follows: should the proposed regulations Is also available sues herein are these closures or curtailments the have noticeable community impacts and for inspection at these locations. Copies (1) One commentor criticized the impacts of the guidelines on the bal- of these documents are being sent to treatment of all bauxite refineries in a ance of trade and industry growth should persons or institutions affected by the single subcategory and cited the com- be negligible. proposed regulations, or who have placed bination of factors of ore type, net ac- The majority of the costs for meeting themselves on a mailing list for this pur- cumulation of rainfall, and soil condi- the proposed guidelines have already pose (see EPA's Advance Notice of Public tions as circumstances which preclude been incurred by seven of the nine plants Review Procedures, 38 FR 21202, Au- the achievement of the proposed effluent in the bauxite refining subcategory. Cost gust 6,1973). An additional limited num- limitation of no discharge of process increases for these seven plants are ex- ber of copies of all reports are available. waste water pollutants. Each of the eight pected to range from zero to 1.6 percent Persons wishing to obtain a copy may domestic bauxite refiners was visited. of the sale value of alumina depending write the EPA Information Center, En- Variations in raw materials (ore type) on the levels of control already in place. vironmental Protection Agency, Wash- and geographic location (net accumula- Cost increases for the remaining two ington, D.C. 20460, attention: Mr. Philip tion of rainfall and soil conditions) were plants (approximately 24 'percent of in- B. Wisman. considered, among other factors, as pos- dustry supply) may range from $6.72 to (c) Summary of public participation. sible bases for further subcategorization over $9.36 per ton of alumina or an equiv- Prior to this publication, the agencies and rejected for the reasons outlined in "alent of 10 percent to 13 percent of the and groups listed below were consulted the Development Document. One plant sale value of raw alumina. Due to the low and given an opportunity to participate using the same ore type as the commen- cost increases for the other seven plants in the development of the effluent limi- tor currently achieves no discharge of and the competitive structure of the in- tations guidelines and standards of per- process waste water pollutants. Six of dustry, it is not likly that the cost to formance for the aluminum subcategory. eight domestic refiners currently prac- these two plants can be recovered through The following are the principal agencies tict impoundment of red mud wastes, a price increases. While the high percent- and groups consulted: (1) Effluent major step toward the goal of no dis- age of industry capacity represented by Standards and Water Quality Informa- charge of process waste water pollutants. these two plants make their closure seem tion Advisory Committee (established (2) Several comments were received unlikely, it should be recognized that the under Section 515 of the Act), (2) which questioned the achievement of potential for closure does exist. Their All State and U.S. Territory Poliu- "no discharge" by the application of the estimated cost for meeting the guidelines tibn Control Agencies, 43) Ohio River best practicable control technology cur- are quite high, with investment costs Valley Sanitation Commission, (4) New rently available. The phrase "no dis- being equal to about 18 percent of re- England Interstate Water Pollution charge" has been modified to b? placement cost of an alumina facility Control Commission, (5) Delaware River "no discharge of process waste water and annual cost being equivalent to 30. Basin Commission, (6) Conservation pollutants." percent or more of the total profits nor- Foundation, (7) Businessmen for the (3) One commentor stated that cost mally realized on the manufacture of Public Interest, (8) Environmental De- Information provided the EPA contractor finished aluminum. These high costs in fense Fund, Inc., (9) Natural Resources was nbt considered in the development light of some distinct advantages to over- Defense Council, Inc., (10) The Ameri- of the guidelines. The subject infornna- seas bauxite refining may cause the own- can Society of Civil Engineers, (11) tion has been included in the Develop- ers to give serious consideration to clos- Water Pollution Control Federation, (12) ment Document and conclusions about ing these plants. Such actions could re- National Wildlife Federation, (13) The the projected costs for the bauxite result in significant short term disruptions American Society of Mechanical Engi- fining Industry to meet effluent limita- within the aluminum industry. In addi- neers, (14) U.S. Department of Health, tions have been revised to include the tion, an estimated 1220 jobs could be lost Education and Welfare, (15) U.S. De- producer's estimates. -withpotential seconidary unemployment partment of Commerce, (16) Water Re- (4) Comments were received that the for an additional 2,400 people. The bal- sources Council, (17) U.S. Department of anode bakin" an use of controlled firing on ance of trade would be affected by the Interior, (18) The Aluminum Asso- furnaces Is not technically feasible for estimated $950 million dollars per year. ciation, and (19) Aluminum Recycling dry systems Docu- all plants and that totally Reports entitled "Development Association. for air pollution control are not ade- -ment for Proposed Effluent Limitations The following organizations responded quately demonstrated on all potential Guidelines and New Source performance with comments: General Counsel of the waste streams from primary aluminum Standards for the Bauxite Refining Sub- Department of Commerce, Texas Water smelters. Further analysis revealed that category of the Aluminum Segment of Quality Board, Georgia Department of of performance should be Manufacturing the standards the Nonferrous -Metals Natural Resources, Reynolds Metals revised to reflect the possible require- Point Source Category," "Development Company, United States Department of ment for wet air pollution control devices Document for Proposed Effluent Limita- the Interior, Office of the Assistant Sec- on the anode bake plant and small dis- tions Guidelines and New Source Per- retary of Defense, Scientist's Institute charges of coolingwater. Standards for the Primary formance for Public Information, Illinois Environ- One commentor cited a cost of Alumninum Smelting Subcategory of the mental Protection Agency, Kaiser Alumi- (5) of the Nonferrous $120/annual ton for a dry scrubbing sys- Aluminum Segment num and Chemical Corporation, Arizona an operating primary smelter Metals Manufacturing Point Source Florida De- tem at State Department of Health, and disagreed with the figure of $40/ Category," and '"Development Document partment of Pollution Control, Aluml- $40/ Limitations Guide- annual ton. The source(s) of the for Proposed Effluent num Recycling Association, United are cited in the Devel- lines and New Source Performance Resources Council, Ormet annual ton figure States Water opment Document. It should be noted Standards for the Secondary Aluminum Corporation, Aluminum Company of do Subcategory of the Aluminum that the proposed effluent limitations Smelting America, Maine Department of Environ- not imply dry systems for existing sources Segment of the Nonferrous Metals Man- mental Protection, New York State De- 2 de- and that the difference In cost between ufacturing Point Source Category" partment of Environmental Conserva- is scribe the analysis undertaken in support wet and dry systems for new sources tion, Nebraska Department of Environ- ton of mental Control, Copper and Brass Fabri- estimated to be $2/annual 'Filed as part of the original document. cators Council, Hawaii Department of aluminum.

FEDERAL REGISTER, VOL 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 PROPOSED RULES

1 (6) A comment questioned the ability PART 421-EFFLUENT LIMITATIONS (b) The term "process waste water" of the proposed best practicable control GUIDELINES FOR EXISTING SOURCES shall mean any water which, during tho technologies currently available for fume AND STANDARDS OF PERFORMANCE refining process, comes into direct con- scrubbing and residue milling in the AND PRETREATMENT STANDARDS FOR tact with any raw material, Intermediate secondary aluminum smelting subcate- NEW SOURCES FOR THE NONFERROUS product, by-prdouct or product used In or gory to achieve the effluent limitations METALS MANUFACTURING POINT resulting from the manufacture of alum- specified. Further analysis revealed that SOURCE CATEGORY ina from bauxite. the application of the best practicable Subpart A-Bauxite Refining Subcategory (c) The term "process waste water pol- control technology currently available Sec. lutants" shall mean the pollutants con- would not effect a reduction in dissolved 421.10 Applicability; description of baurite tained in the process waste water, solids. The effluent characteristics and refining subcategory. the associated effluent limitations were 421.11 Specialized definitions. § 421.12 Effluent limitationq guilelhiei revised to reflect the additional data 421.12 Effluent limitations guidelines repre- representing the degree of effluent senting the degree of effluent re- reduction attainable by the applica- analysis. tion the (7) One comment indicated that duction attainable by the applica- of best practienble control the technology currently available. best available demonstrated control tech- tion of the best practicable con- nology for secondary trol technology currently available. (a) Subject to the aluminum smelters 421.13 Effluent limitations guidelines repre- provisions of para- could not achieve the proposed standard senting the degree of effluent re- graph (b) of this section, the following of performance of no discharge of proc- duction attainable by the applica- limitations constitute the quantity or ess waste water pollutants. The stand- tion of the best available tech- quality of pollutants or pollutant prop- ards of performance were revised to per- nology economically achievable. erties which may be discharged after ap- mit new sources to discharge process 421.14 Standards of performance for new plication of the best practicable control waste water pollutants from chlorine sources. technology currently available by a point magnesium removal 421.15 Pretreatment standards for new source subject to the processes only, after sources. provisions of this the application of the best practicable subpart: There shall be no discharge of control technolozy currently available. Subpart B-Primary Aluminum Smelting process waste water pollutants to navi- Interested persons may participate in Subcategory gable waters. this rulemaking by submitting written 421.20 Applicability; description of primary (b) During any calendar month in comments in triplicate to the EPA In- aluminum smelting subcategory. which the precipitation exceeds the formation Center, Environmental Pro- 421.21 Specialized definitionS. evaporation in the area in"which a proc- tection Agency, Washington, D.C. 2G460, 421.22 Effluent limitations guidelines repre- ess waste water Impoundment is located Attention: senting the degree of effluent re- as established Mr. Philip B. Wisman. Com- duction attainable by the applica- by the U.S. National ments on all aspects of the proposea tion of the best practicable control Weather Service (or as otherwise deter- regulations are solicited. In the event technology currently available. mined if no monthly evaporation data comments are in the nature of criticisms 421.23 Effluent limitations guidelines repre- have been established by the National as to the .adequacy of data which is avail- senting the degree of effluent re- Weather Service for such area), there able, or which may be relied upon by the duction attainable by the applica- may be discharged from such impound- Agency, comments should identify and, tion of the best available tech- ment either a volume of process waste if possible, provide any additional data nology economically achievable. water equal to the difference 421.24 Standards of performance for new between the which may be available and should in- sources. precipitation and the evaporation for dicate why such data is essential to the 421.25 Pretreatment standards for new that month or a volume of process waste development of the regulations. In the sources. water equal to the difference between event comments address the approach Subpart C--Secondary Aluminum Smelting the mean precipitation and mean evan- taken by the Agency in establishing an Subcategory oration for that month as established by effluent limitation guideline or standard 421.30 Applicability; description of second- the U.S. National Weather Service for of performance, EPA solicits suggestions ary aluminum smelting subcate- the preceding 10 year period, whichever as to what alternative approach should gory. Is greater. be taken and why and how this alterna- 21.31 Specialized definitions. § 421.13 Effluent limitations tive better satisfies the detailed require- 421.32 Effluent limitations guidelines repre- guidelines senting the degree of effluent representing the degree of effluent ments of sections 301, 304(b), 306 and re- reduction attainable by the applica- 307 of the Act. duction attainable by the application of the best practicable control tion of the best available technology A copy of all public comments will be economically achievable. available for inspection and copying technology currently available. at 421.33 Effluent limitations guidelines repre- the EPA Information Center, Room 227, (a) Subject to the provisions of para- senting the degree of effluent re- graph West Tower. Waterside Mall, 401 1 duction attainable by the applica- (b) of this section, the following Street, SW., Washington D.C. A copy of tion of the best available technol- limitations constitute the quantity or preliminary draft contractor reports, the ogy economically achievable. quality of pollutants or pollutant proper- Development Documents and economic 421.34 Standards of performance for new ties which may be discharged after appli- study referred to above and certain sup- sources. cation of the best available technology plementary 421.5 Pretreatment standards for new economically achievable by a point source materials supporting the sources. study of the industry concerned also will subject to the provisions of this subpart: be maintained at this location for public Subpart A-Bauxite Refining Subcategory there shall be no discharge of process review and copying. The EPA informa- waste water pollutants to navigable tion regulation, 40 CFR Part 2, provides § 421.10 Applicability; description of waters. that a reasonable fee may be charged bauxite refining subcategory. (b) During any calendar month In for copying. The provisions of this subpart are ap- which the precipitation exceeds the evap- All comments received on or before plicable to discharges resulting from the oration In the area in which a process waste water December 31, 1973 will refining of bauxite to alumina by the impoundment Is located as be considered. established by the U.S. National Weather Steps previously taken by Bayer process or by the combination the Environ- process. Service (or as otherwise determined if mental Protection Agency to facilitate no monthly evaporation data have been public response within this time period § 421.11 Specialized definitions. established by the National Weather are outlined in the advance notice con- For the purpose of this subpart: Service for such area), there may be discharged from such Impoundment cerning public review procedures pub- '(a) The term "bauxite" shall mean ore either lished on August 6, 1973 (38 FR 21202). containing a volume of proces waste water equal to alumina monohydrate or the difference between the precipitation Dated: November 19,1973. alumina trihydrate which serves as the principal raw and the evaporation for that month or a material for the production volume of process waste water equal to JOHN QUAiLES, of alumina by the Bayer process or by the Acting Administrator. the difference between the mean pro- combination process. cipitation and mean evaporation for thab

FEDERAL REGISTER, VOL. 38, NO. 230-FRIDAY, NOVEMBER 30, 1973 PROPOSED RULES 33181

Na- production of aluminum from alumina by Effluent month as established by the U.S. process. eharacteristic Effluent limitation tional Weather Service for the preced- the Hall-Heroult Cyado Maximum for any one whichever is greater. definitions. day 0.01 kg/kkg of ing 10 year period, § 421.21 Specialized product (0.01 lb/ § 421.14 Standards of performance for For the purpose of this subpart: i,000 Ib). new sources. (a) The term "process waste water" Maximum average of the daily values for any (a) Subject to the provisions of para- shall mean any water which, during period of 30 consecu- graph (b) of this section, the following manufacturing process, comes into direct tive days 0.006 Wg,/ limitations constitute the quantity or contact with any raw material, anode kkg of product (0.005 quality of pollutants or pollutant prop- material, cathode material, intermediate lb/1,00 b). reflect- product, by-product, product, or material pH "Within the range 6.0 to erties which may be discharged 9.0. ing the greatest degree of effluent reduc- used in or resulting from the production application of of primary aluminum. tion achievable through § 421.23 Effluent limitations guidelines the best available demonstrated control (b) The term "process waste water representing the degree of effluent technology, processes, operating meth- pollutants" shall mean pollutants con- reduction attainable by the applica- ods, or other alternatives, including, tained in the process waste water. tion of the best available technology where practicable, a standard permitting (c) The term "product" shall mean hot economically achievable. no discharge of pollutants by a new point aluminum metal. following limitations constitute of this The source subject to the provisions (d) The term "oil and grease" shall the quantity or quality of pollutants or subpart: there shall be no discharge of mean that component of the waste water which may be dis- to navi- pollutant properties process waste water pollutants amenable to measurement by the method charged after application of the gable waters. described in Methods for Chemical technology economically In best available (b) During any calendar month Analyses of Water and Wastes, Environ- achievable by a point source subject to which the precipitation exceeds the evap- mental Protection Agency, Analytical the provisions of this subpart: oration in the area in which a process Control Laboratory, page 217. is located as Quality Effluent waste water impoundment (e) The term "cyanide" shall mean established by the U.S. National Weather chaara tic Effuent forinitation any one those cyanides amenable to chlorination Fluoride . . . Maximum Service (or as otherwise determined if day 0.1 kg/kkg of no monthly evaporation data have been by the method described in 1972 Annual product (01 lb/1,000 established by the National Weather Book ASTM Standards, 1972, Standard lb). Service for such area), there may be dis-. B, page 553. Maximum average of D2036-72, Method for any charged from such impoundment either (f The term "kg" shall mean kilo- daily values waste water equal to period of 30 consecu- a volume of process mean tive days 0.05 kg/ between the precipitation gram(s); The term "kkg" shall the difference the term "Ib" shall mean kkg of product (0.05 and the evapordtion for that month or a 1000 kilograms; l ,o00 lb). volume of process waste water equal to pound(s). Maximum for any one Suspended nonfill- the difference between the mean precipi- § 421.22 Effluent limitations guidelines terable solids, day 0.2 kg/kkg of tation and mean-evaporation for that representing the degree of effluent total product (0.2 lb/1.0O month as established by the U.S. National reduction attainable by the applica- 1b). for the preceding 10 control Maximum average of Weather Service tion of the best practicable daily values for any year period, whichever is greater. technology currently available. period of 30 consecu- § 421.15 Pretreatment standards for The following limitations constitute the tive days 0.1 kg/kkg new sources. of product (01 lb/ quantity or quality of pollutants or pollu- 1,000 Ib). under sec- The pretreatment standards tant properties which may be discharged Oil and grease .-- Maximum for any one tion 307(c) of the Act, for a source with- after application of the best practicable day 0.03 kg/kkg of in the bauxite refining subcategory, product; (0.03 lb/ control technology currently available by 1,000 b). which is an industrial user of a publicly the provisions owned treatment works (and which a point source subject to Mamimum average of to section of this subpart: daily values for any would be a new source subject period of 30 consecu- 306 of the Act, if it were to discharge pol- Effluent tive days 0.015 kg/ lutants to navigable waters), shall be the characteristic Effluent limitatfon kkg of product (0.015 set forth In Part 128, 40 CFR, Fluoride ...... M aximum for any one lb/l,000 tb). standard I day 2.0 kg/kkg of except that for the purposes of this sec- Cyanide ... Maximum for any one tion, § 128.133, 40 CFR shall be amended day 0.01 kg/kkg of Ib). product (0.01 lb! to read as follows: "In addition to the Maximum average of prohibitions set forth in § 128.131, the daily values for any 1000 lb). in- Maximum average of standard for incompatible pollutants period of 30 consecu- daily values for any troduced into a publicly owned treatment tive days 1.0 kg/kkg of 30 consecu- lb/ period works by a major contributing industry of product (1.0 days 0.005 kgkkg of shall he the standard of performance for 1,000 lb). product (0.005 lb/ 40 CFR, Maximum for any one 1,000 lb). new sources specified in § 421.14, Suspended nonflI- 3.0 kgfkkg of Part 421 provided that, if the publicly terablo solids, day pH Within the range 6.0 to total. product (3.0 lb/1,000 9.0 owned treatment works which receiveE lb). the pollutants is committed, in its Maximum average of permit, to remove a specified daily value3 for any § 421.24 Standards of performance for NPDES new sources. percentage of any incompatible pollu- period of 30 con.ecu- constitute standard appli- tive days 1.5 Ikg/kkg The following limitations tant, the pretreatment the quantity or quality of pollutants or to users of such treatment work; of product (1.5 lb/ cable 1,000 lb). pollutant properties which may be dis- shall be correspondingly reduced-for thai greatest degree of Oil & grease ---- Maximum for any one charged reflecting the pollutant." day 0.5 kgtkkg of effluent reduction attainable through ap- Subpart B-Primary Aluminum Smeltinj product (0.5 lb/1,000 plicatlon of the best available demon- Subcategory lb). strated control technology, processes, op- Maximum average of erating methods, or other alternatives, § 421.20 Applicability; description of daily values for any smelting subcate- Including, where practicable, a standard primary aluminum period of 30 consecu- of pollutants by gory. tlve days 0.25 kg/kkg permitting no discharge a new point source subject to the pro- this subpart are ap- of product (0.25 lb/ The provisions of 1,000 lb). visions of this subpart: plicable to discharges resulting from the

FEDERAL REGISTER, VOL. 38, NO. 230-.iRIDAY, NOVEMBER 30, 1973 33182 PROPOSED RULES

Effluent shall include, but not be limited to, any characteristic Effluent be discharged after application of the limitation water which is used in the metal cooling best practicable Fluoride ------Maximum control technology cur- for any one day process, the magnesium removal proc- rently available by a point source sub- 0.05 kg/kkg of product ess, or the residue milling process. (0.05 lb/1,000 Ib). , ject the provisions of this subpart and Maximum average of (b) The term "process waste water which processes residues by wet daily values for any pe- pollutants" shall mean pollutants con- methods: riod of 30 consecutive tained in the process waste water. days 0.025 kg/kkg of (c)The term "product" shall mean hot Effluent limittilon I product (0.025 lb/1,000 aluminum recovered. mllozramq 'ud l 1b). (d) The term "oil and grease, shall Effluent eharacteristio perkTio- 1,000 pull Suspended non- Maximum for any one day mean that measured by the analytical klograms ofprodt filterable sol- 0.1 kg/kkg of product method prescribed of product ids, total. (0.1 lb/1,000 1b). in subparagraph (d) Maximum average of of § 421.21. (e) The term "aluminum" Suspended nonailtorablo daily values for any pe- shall mean solids,total ...... 1.5 1.5 riod of 30 consecutive that component of the waste water Fluoride ------0.4 R I days 0.05 kg/kkg of amenable to measurement by the Ammonianitrogen ------0.01 0101 product (0.05 lb/1,000 Aluminum ------1.0 1.0 method described in Methods for Chemi- Copper ------0.003 0.0.3 1b). cal Analysis of Water and Wastes, Oxygen demand, chemical.. 1,0 1,I Oil and grease .... Maximum 1971, for any one day Environmental Protection Agency, Ana- pH ------() 0.03 kg/kkg of product (0.03 lb/1,000 1b). lytical Quality Control Laboratory, page 98. I Maximum average of daily values for any pWrlod of iMaximum average of daily 30 consecutive days. values for any period (f) The term "kg" shall mean kilo- 2 Within the range 7,5 to 9.0 of 30 consecutive days grams(s); The term "kkg" shall mean 0.015 kg/kkg of prod- 1000 kilograms; § 421.33 Effluent limitations guidelinci and the term "Ib" shall representing u uct (0.015 lb/1,000 Ib). mean pound(s). the degree of effluent Cyanide ------M aximum for any one day reduction attainable by the npplica. 0.01 kg/kkg of product § 421.32 Effluent limitations guidelines tion of the best available technology (0.01 lb/1,000 1b). representing the" degree of effluent economically achievable. Maximum average of daily -reduction attainable by the applica- values for any period of The following limitations constitute tion of the best practicable control the quantity 30 cqnsecutive days technology currently available. or quality of pollutants or 0.005 kg/kkg of product pollutant properties which may be dis- (0.005 lb/1,O00 lb). (a) The following limitations con- charged after application of the best pH ------Within the range 6.0 to stitute the quantity or quality of pollu- available technology economically 9.0. tants or pollutant properties which may achievable by a point source subject to § 421.25 Pretreatment standards for new be discharged after application of the the provisions of this subpart: there sources. best practicable control technology cur- shall be no discharge of process waste rently available by A point source subject water pollutants to navigable waters. The pretreatment standards under sec- to the provisions of this subpart and tion 307(c) of the Act, for a source § 421.34 Standards of perfcrnionee ;t'e' within which uses water for metal cooling: there the primary aluminum smelting shall new sources. subcategory which is an industrial user be no discharge of prbcess waste of a publicly owned treatment works water pollutants to navigable waters. (a) The following limitations cor tI- (and which would be a new source sub- (b) The following limitations con- tute the quantity or quality of pollutants ject to section 306 of the Act, if it were stitute the quantity or quality of pollu- or pollutant properties which may be dis- to discharge pollutants to navigable tants or pollutant properties which may charged reflecting the greatest degree of waters), shall be the standard set forth be discharged after application of the effluent reduction achievable through ap- in Part 128, 40 CFR, except that for the best practicable control technology cur- plication of the best available demon- purposes of this section, § 128.133, 40 rently available by a point source subject strated control technology, processes, op- CFR shall be amended to read as fol- to the provisions of this subpart and erating methods, or other alternatives, lows: "In addition to the prohibitions set which uses aluminum fluoride in its including, where practicable, a standard forth in § 128.131 the pretreatment magnesium removal process ("demag- permitting no discharge of pollutants by standard for incompatible pollutants in- ging" process): there shall be no dis- a new point source subject to the provi- troduced into a publicly owned treatment charge of process waste water pollutants sions of this subpart: there shall be no works by a major contributing industry to navigable waters. discharge of process waste water pollu- shall be the standard of performance (c) The following limitations con- tants to navigable waters. for new sources specified in § 421.24, 40 stitute the quantity or quality of pollu- (b) Application of the factors listed in CFR, Part 421, provided that, if the pub- tants or pollutant properties which may section 306(b) of the Act may require licly owned treatment works which re- be discharged after application of the variation from the standard of perform- ceives the pollutants is committed, in best practicable control technology cur- ance set forth in this section for any its NPDES permit, to remove a specified rently available by a point source subject point source subject to such standard of percentage of any incompatible pollut- to the provisions of this subpart and performance and which uses chlorine in ant, the pretreatment standard appli- which uses chlorine in its magnesium the magnesium removal process ("de- cable to users of such treatment works removal process: magging" process). If variation Is de- shall be correspondingly reduced for that termined to be necessary for any such pollutant." Effluent limitation I source, the discharge of process waste Subpart C-Secondary Aluminum Smelting Effluent characteristic Grams per Pounds per water pollutants shall be allowed from Subcategory kilograms pounds the magnesium removal process only, and magnequm magnesium removed removed such source shall be subject to effluent § 421.30 Applicability; description of limitations no less stringent than those secondary aluminum smelting sub- required category. Suspended nonfilterable by paragraph (c), § 421.32 of solids, total ....------175 0.175 this part. The provisions of this subpart are ap- Oil and grease ------2.0 0.002 § 421.35 plicable to discharges resulting from Oxygen demand, chemlcal.. 6.5 0.0065 Pretreatment standards for new the pH ------() sources. recovery, processing, and remelting of (2) aluminum scrap to produce metallic The pretreatment standards under I Maximum average of daily values for any period of aluminum alloys. 30 consecutive days. section 307(c) of the Act, for a source Within the range 7.5 to 9.0. within the § 421.31 Specialized definitions. secondary aluminum smelting (d) The following limitations con- subcategory which is an industrial user For the purpose of this subpart: stitute the quantity or quality of pollu- of a publicly owned treatment works (a) The term "process waste water" tants or pollutant properties which may (and which would be a new source sub-

FEDERAL REGISTER, VOL. 38, NO. 230--FRIDAY, NOVEMBER 30, 1973 PROPOSED RULES 3.31S3 pollutants In- NPDES permit, to remove a specified per- if it were standard for incompatible any incompatible pollutant, ject to section 306 of tle Act, a publicly owned treatment tentage of navigable wa- troduced into applicable to to discharge pollutants to works by a major contributing industry the pretreatment standard ters), shall be the standard set forth in of performance for users of such treatment works shall be that for the shall be the standard Part 128, 40 CFR, except new sources specified in § 421.34. 40 CFR, correspondingly reduced for that pol- purposes of this section, § 128.133, 40 to read as fol- Part 421, provided that, If the publicly lutant." CFR shall be amended works which receives the prohibitions owned treatment DIc.73-24804 Piled 11-29-73;8:45 am] lows: "in addition to is committed, In Its [FR set forth in § 128.131, the pretreatment the pollutants

FEDERAL REGISTER, VOL. 38, NO. 230--rRIDAY, NOVEMBER 30, 1973