5523 -•• 810R82101 IRON AND STEEL INDUSTRY REGULATION RESPONSE TO PUBLIC COMMENTS MAY 1982 EFFLUENT GUIDELINES DIVISION OFFICE OF WATER REGULATIONS AND STANDARDS U.S. ENVIRONMENTAL PROTECTION AGENCY WASHINGTON, D.C. ------- ------- PREFACE This document contains the Agency's response to comments received on the proposed regulation for the Iron and Steel Industry (46 FR 1858). The preamble to the final regulation also contains responses to certain comments received on the proposed regulation. COOG02 ------- TABLE OF CONTENTS Subcategory Comments Page A. Cokemaking 4 B. Sintering 24 C. Ironmaking 30 D. Steelmaking 42 E. Vacuum Degassing 53 F. Continuous Casting 55 G. Hot Forming 57 H. Salt Bath Descaling 64 I. Acid Pickling 66 J. Cold Forming 74 K. Alkaline Cleaning 82 L. Hot Coating 84 General Comments 86 List of Commenters 111 ------- A. .COKEMAKING 1. COMMENT The industry commented that the proposed total suspended solids limitation based upon 100 mg/1 is "more rational" than the 50 mg/1 used in prior regulations, but that it may still not account for all of the variations that can occur with biological treatment systems. RESPONSE The Agency agrees with this comment. Based upon a review of total suspended solids effluent data for coke plant biological treatment systems, the bases for the BPT total suspended solids limitations have been increased to 140 mg/1 (30 day average) and 270 mg/1 (daily maximum). As explained in detail in the development document, the Agency believes BPT limitations based upon these concentrations can be achieved with properly designed and well operated coke plant biological treatment systems. 2. COMMENT The industry commented that the Agency did not take into account properly the stoichiometric relationship concerning biological oxidation of thiocyanate to ammonia-N. Under proper conditions thiocyanate can be biologically broken down into its component parts, one of which is ammonia-N. The industry states this would result in in a doubling of the ammonia-N concentration across biological treatment systems from levels found in ammonia still effluents which preceed biological treatment systems. RESPONSE The Agency established the BPT ammonia-N limitations in this regulation at the same level as in limitations promulgated in 1974. The BPT ammonia-N limitations are demonstrated at plants that have adequate pretreatment prior to biological treatment; that is, free and fixed ammonia stills; oil and scum removal; and, adequate hydraulic and waste loading equalization. Compliance with these limitations is also demonstrated at plants without biological treatment. Data for coke plant biological treatment systems indicate that partial nitrification (ammonia-N removal) occurs, even in single stage systems. The conversion of thiocyanate to ammonia-N is largely compensated for by biological synthesis and nitrification of ammonia-N from this source and ammonia-N in the feed to the biological treatment system. Operating practices may have to be modified at some biological treatment plants to promote sufficient nitrification to achieve the ammonia-N limitations. The Agency believes that with proper pretreatment, as provided for in the BPT model treatment system, and proper operation, the ammonia-N limitations can be consistently achieved at all coke plants. 000004 ------- 3. COMMENT The industry commented that the 95% confidence level should be used t< establish the model treatment system flow for the cokemakim subcategory; and the model ammonia liquor flow should be 50 gal/ton v; 32 gal/ton. The ammonia liquor is largely comprised of moistun liberated from coal during the cokemaking process. RESPONSE In this and other steel industry subcategories, the Agency determinec the BPT model treatment system flow rates from the average of the best performing plants or the production weighted average of all plants. The Agency did, however, use statistically derived treated effluent concentrations of the limited pollutants to establish the limitations and standards. The Agency has not used statistically derived flows tc develop limitations and standards, because the industry can control discharge flow to an extent necessary to achieve the respective mode] flow rates (upon which the limitations and standards are based), whereas there are normal variations in treatment plant performance (i.e. concentration). The 32 gallons/ton model ammonia liquor flow rate was determined consistent with the above approach. This flow is based upon the average of ammonia liquor flows from many plants which process different coking coals of varying moisture contents. The Agency believes this model flow rate is representative of industry-wide ammonia liquor flow rates. Furthermore, the limitations basis. Furthermore, the limitations and standards do not require attainment of the model ammonia liquor flow rate or, for that matter, any of the individual components of the total model plant flow rate. As noted in the development document, plants with varying flow rates for ammonia liquor, benzol plant wastewaters, final cooler wastewaters, barometric condenser wastewaters, wastewaters from miscellaneous sources, and dilution flows for biological treatment, achieve the total model plant flow rates. 4. COMMENT The industry commented that the model coke plant dilution water flow for optimization of biological treatment systems should be 175 gallons/ton vs 50 gallons/ton, and higher on a site-specific basis. The industry claimed a dilution flow of 175 gallons/ton or higher is needed for proper operation of coke plant biological treatment systems; and, that it is not possible to predict dilution flow requirements until after a treatment facility is built. RESPONSE The Agency found no evidence that properly designed, well operated coke plant biological treatment systems require one to one dilution OOOCC5 ------- (175 gallons/ton of dilution water) to function properly. As shown below, many systems operate with dilution rates of less than 50 gallons/ton. The Agency recognizes that biological treatment systems at several plants operate with high dilution flows. However, improved pretreatment, better equalization of hydraulic and waste loadings, and improved wastewater and treatment system temperature control, should result in the use of less dilution water. Under these conditions some plants have operated for long periods of time without dilution water. Indeed, pilot studies conducted at the U.S. Steel Clairton Works indicate that dilution water is not needed. Dilution flows of less than 50 gallons/ton have been reported for the following seven coke plant biological treatment systems. Except for the treatment system at Plant 0534C (which is under construction) the flow data are for full scale biological treatment facilities. Plant Code Dilution Flow 0012A 20 gal/ton 0426 48 0464E 36 0584C 41 (Design Basis) 0584F-01 48 0584F-02 35 0868A 8-30 The Agency believes that treatment facilities at the above listed plants are among the better designed and operated treatment facilities in the industry, and, that these plants are representative of the model coke plant production facility. Nitrification (ammonia-N removal) is practiced at Plant 0868A and is included in the treatment facility design at Plant 0584C. The Agency also believes that a dilution flow of 50 gallons/ton is achievable for new coke plant biological treatment systems. 5. COMMENT The industry commented that additional flow allowances should be provided for those coke plants with ancillary chemical recovery systems (i.e., Benzene, Toluene, Xylene). RESPONSE The model coke plant production facility is based upon recovery of ammonium sulfate and crude light oils with no further refinement of the crude light oils into the products noted above. The level of by-product recovery included in the model production facility is common to most cokemaking operations. However, there are a few coke ------- plants with extensive by-product recovery facilities. For such plants, the additional flows which are necessarily associated with these additional by-product recovery operations were not taken into account in establishing the limitations and standards for cokemaking operations. The Agency believes the number of these plants is small, the number of additional by-product recovery operations at such plants vary and therefore should not be included in the basis for the general limitation and standards. To the extent necessary, such plants should receive additional flow allowances in determining applicable BPT and BAT effluent limitations at the permit level. These allowances should be granted only to the extent necessary, and only after all practicable flow minimization systems or operating practices are implemented. 6. COMMENT The industry commented that due to construction and low production, the data for the U.S. Steel Fairfield Alabama coke plant are not representative and should not be used as a basis for the BAT limitations. The Agency interprets this comment to mean that the commenter suggested that at less than capacity production, the treatment facility would perform better due to lower pollutant loadings and increased hydraulic retention time. RESPONSE Based upon this comment, the Agency sought supplemental data for this plant. The Agency now has data from November 1977, when the wastewater treatment facility was put into operation, to May 1981. These data demonstrate that the plant's performance is not significantly affected by production or wastewater volume applied to the treatment facility. The plant demonstrates compliance with the BAT effluent limitations, both during periods when wastewater flows approached the design basis for the treatment facility, and during periods when wastewater flows were reduced and retention time in the treatment facility was increased. Thus, the Agency believes data from this plant are appropriate for establishing effluent limitations and standards. 7 COMMENT The industry commented that the BAT effluent limitations should be developed to take into account variability in the levels of pollutants in treated effluents that has been found to occur when different wastewater treatment facilities are designed, constructed, and operated to the same specifications. RESPONSE The BAT limitations are based upon the performance of the U.S. Steel Fairfield Alabama coke plant wastewater treatment system which, in the Agency's opinion, is the best performing coke plant biological treatment system. The Agency has carefully examined the production ------- facility and by-product recovery facilities at this plant and found no factors which would make it unique in the industry or atypical in any way which would affect its selection as the model BAT treatment facility. Long-term compliance with the BAT limitations has been demonstrated at this plant. The Agency does not agree with the industry that compliance cannot be achieved due to plant to plant variability. In the example cited by the industry of two similar coke plant treatment systems performing differently (U.S. Steel's plants at Fairfield, Alabama and Clairton, Pennsylvania), the Agency notes certain significant differences in both the coke plant production facilities and the wastewater treatment facilities at these locations. The Clairton coke plant has extensive chemical by-product operations beyond those included in the Agency's model cokemaking production facility. These additional by-product recovery operations contribute significantly to the wastewater volume treated at the plant. The Fairfield plant does not have extensive chemical by-product recovery operations and conforms to the Agency's model cokemaking production facility. Extensive studies were conducted at the Clairton Plant by U.S. Steel for the Agency. From these studies, the Agency notes that the performance of the Clairton wastewater treatment facility is hampered by uneven distribution of pollutant loadings to the biological aeration basins, sludge accumulation in the aeration basins, and less than optimum process control. The Agency believes that with minor modifications to the wastewater treatment facilities and operating practices at the Clairton plant, improved effluent quality consistent with the BAT limitations should result. Also, since the Clairton plant has extensive by-product recovery operations, additional discharge allowances may be appropriate as noted above. 8. COMMENT The industry commented that the BAT total cyanide limitation based upon 2.5 mg/1 is too stringent and may not be achievable on a long-term basis. The industry suggested that the Agency re-evaluate the total cyanide limitation and take into account what it characterizes as non-treatment of complex cyanides by biological treatment. RESPONSE The proposed total cyanide limitations based upon a 30-day average effluent concentration of 2.5 mg/1 was derived from long-term, full scale performance of the model BAT treatment system. All forms of cyanide measured by the total cyanide test, including complexed cyanides, are accounted for in the effluent limitation. In response to this and other comments, additional performance data were obtained from the above mentioned model BAT plant. As shown in the development document, these data indicate a 30-day average total cyanide limitation based upon 5.5 mg/1 is more appropriate and the final limitation is based upon that value. The Agency believes the promulgated BAT total cyanide limitations are consistently achievable ------- with properly designed and well operated biological treatment facilities. The Agency considered limiting "free cyanide", or "cyanides amenable to chlorination" for cokemaking and ironmaking operations in lieu of total cyanide, but did not do so for the following reasons: 1. The Settlement Agreement and the Clean Water Act required the Agency to regulate the discharge of cyanide and cyanide compounds. Since the total cyanide test measures virtually all forms of cyanide, limiting total cyanide meets this requirement. 2. There are only limited data available for "free cyanide" and "cyanides amenable to chlorination" for steel industry model BAT treatment systems. 3. The Agency believes the reproducibility of the total cyanide analytical method is superior to that for cyanides amenable to chlorination. 4. The Agency believes that destruction of cyanide is preferable to conversion of free or simple cyanides to fixed cyanides with subsequent discharge. This could occur if only cyanide amenable to chlorination was limited. 9. COMMENT The industry commented that the proposed phenols (4AAP) limitation based upon a 30-day average effluent concentration of 0.025 mg/1 is too stringent. In making this comment the industry presented data obtained by U.S. Steel analytical contractors at the U.S. Steel Fairfield Works. .The U.S. Steel contractor data shows higher phenols (4AAP) levels than do data obtained by U.S. Steel personnel. The industry also commented that the limitation may not be achievable at coke plants located in northern parts of the country in colder climates. RESPONSE In response to this comment, the Agency reviewed the sampling and analytical methods used by U.S. Steel and its contractors for monitoring the coke plant biological treatment system at the Fairfield Works. The phenols (4AAP) data reported by the contractors are somewhat higher than those reported by U.S. Steel which are typically in the range of 0.005 to 0.025 mg/1. Personnel at the U.S. Steel Fairfield Works coke plant used the EPA promulgated analytical methodology for low level determinations of phenols (4AAP) (i.e., chloroform extraction procedure, EPA Methods Manual p. 241; and, Standard Methods - 14th Edition, p. 557); however, the samples were sometimes held for up to twelve hours prior to preservation and analysis. The samples obtained by U.S. Steel's contractors were representative of the discharge and preserved properly, but were COOCC3 ------- analysed by a "water phase" technique which is not sensitive at concentrations below 0.200 mg/1. Thus, the U.S. Steel data may have a low bias and the contractor data were obtained with analytical methods designed to detect concentrations much higher than typically found at the U.S. Steel Fairfield works. Thus, the U.S. Steel contractor data are not suitable for use in establishing effluent limitations and standards. The Agency has a third set of phenols (4AAP) data for this facility obtained by an EPA contractor. The discharge from the coke plant biological treatment facility was sampled during both warm and cold weather. These data were obtained with proper sampling, preservation, and analytical techniques and verify that the phenol (4AAP) concentrations are in the range determined by U.S. Steel plant personnel as opposed to the U.S. Steel contractors. The EPA data demonstrate the proposed 30-day average limitation based upon the 0.025 mg/1 concentration is achievable for warm weather and a 30-day average limitation based upon a concentration of 0.043 mg/1 is achievable for cold weather. Based upon these data, the Agency based the final 30-day average BAT limitation for phenols (4AAP) on a concentration of 0.050 mg/1 to take into account cold weather performance. The Agency believes the limitations are consistently achievable with properly designed and operated biological treatment systems located in both northern and southern parts of the country; and, that the limitations are well demonstrated at the U.S. Steel Fairfield Works. As noted in the response to comment A-19, the Agency made significant additions to the model treatment facility to provide for proper chemical additions and wastewater temperature control for cold weather operations such that the BAT limitations can be achieved in all parts of the country. 10. COMMENT The industry commented that advanced biological treatment for cokemaking wastewaters should not be included as part of the model BAT treatment technology and, as a result, the BAT ammonia-N limitation should be increased from 15 mg/1 to 125 mg/1. The industry also commented that ammonia-N should not be regulated at BAT, since it is not a designated priority (toxic) pollutant and that National Steel's pilot plant experience leads the industry to consider nitrification (ammonia-N) removal as an experimental process. RESPONSE The Agency has considered whether or not to limit ammonia-N at BAT and has decided to do so since cokemaking wastewaters contain substantial amounts of ammonia-N. Ammonia-N is toxic to aquatic life irrespective of its designation as a toxic pollutant. Ammonia-N has other adverse environmental effects in addition to toxicity, and economically achievable technologies are available and in use to treat ammonia-N. For these reasons, the Agency has determined that it is appropriate to limit ammonia-N at BAT. eesno ------- The Agency does not consider biological nitrification of cokemakini wastewaters to be an experimental process. Advanced bi.ologica! treatment of coke plant wastewaters, including nitrification, ii currently achieved on a full scale basis at three coke plants rangin< in capacity from about 2000 tons/day to over 20,000 tons/day. Anothei advanced coke plant biological treatment system designed to achiev< the BAT limitations is under construction (Plant 0584C), and anothei is in design (Plants 0684 A and B). The industry has conductec extensive research and development in the area of advanced coke plan! biological treatment including second-stage treatment for ammonia-! removal and modification of single-stage biological systems tc accomplish the same end by increasing sludge age or by enhancement through the addition of a substrate to .the system. The industry has recently published reports on this research that clearly state the BAT ammonia-N limitations are achievable. The Agency notes that the design basis for ammonia-N in the effluent of the coke plant biological treatment system at Plant 0584C is 10 mg/1. Plant 0584C is a National Steel facility. The BAT model treatment system includes extensive pretreatment followed by two stage biological treatment. In many cases, the Agency believes the industry will modify existing single stage biological treatment systems to achieve the limitations; and, for those coke plants without existing biological systems, install new single stage systems specifically designed to achieve the BAT limitations. Upon review of ammonia-N data for the U.S. Steel Fairfield Plant, the Agency has found that ammonia-N effluent concentrations exhibit some dependency considering monitoring results from consecutive days. The Agency increased the ammonia-N concentration from 15 mg/1 to 25 mg/1 in establishing the BAT limitations to take this into account. Ammonia-N removal to 25 mg/1 is well demonstrated at the U.S. Steel Fairfield Plant. In addition, Armco Steel has demonstrated nitrification at its Hamilton Plant. The Agency did not rely on data from the Hamilton Plant to develop the limitations, because these data were obtained with non-standard analytical methods. 11. COMMENT The industry commented that phenols (4AAP) should be used as an indicator pollutant for toxic organic pollutants and that benzene, benzo(a)pyrene, and naphthalene should not be specifically limited. The industry states that these pollutants can be removed in single stage (BPT) biological treatment systems and need not be limited. RESPONSE Industry supplied no data to support their contention that phenols (4AAP) can be used as an indicator for those toxic organic pollutants limited at BAT. Data available to the Agency do not support the use of phenols (4AAP) as an indicator for benzene, benzo(a)pyrene, and naphthalene. These pollutants and phenols (4AAP) were selected as indicators of the many volatile, base-neutral, and acid fraction toxic COSPI1 ------- organic pollutants found in cokemaking wastewaters. Available data generally show that when these pollutants are removed, other pollutants in the respective classes are also removed. The data do not demonstrate the same relationship with phenols (4AAP) and the volatile and base-neutral pollutants. While the Agency agrees that toxic organic pollutants can be removed in properly operated single stage biological treatment systems, biological treatment is not required to achieve the BPT limitations (several plants use physical-chemical treatment without activated carbon). The discharge of toxic organic pollutants from these facilities can be quite high. Hence, the Agency believes it is appropriate to limit these pollutants at the BAT level. 12. COMMENT The industry recommended that the Agency provide effluent limitations and standards based upon physical-chemical treatment as well as based upon biological treatment for cokemaking wastewaters. The industry cited the following reasons why limitations and standards based upon physical/chemical treatment should be promulgated: (1) space limitations at some older plants; (2) activated carbon adsorption is an effective treatment for the removal of toxic organic pollutants; <3) low levels of suspended solids and oil and grease can be achieved with physical/chemical treatment; and (4) investment and operating costs for biological and physical/chemical treatment systems are similar. Another commenter opposed the setting of separate effluent limitations for cokemaking operations with existing physical/chemical treatment systems, and found the lack of cyanide limitations unacceptable. The commenter stated that the Agency did not demonstrate that separate limitations are necessary; failed to document the economic impact that would be avoided; and failed to explain the logic for not regulating cyanide. RESPONSE For the reasons set out in Section X of the cokemaking development document, the Agency has provided separate, less stringent BAT effluent limitations for cokemaking operations with existing full scale physical-chemical treatment systems. The Agency does not believe it is appropriate to establish alternative, less stringent limitations and standards for other existing and new coke plant sources because either the significant investments in physical/chemical treatment facilities have not yet been made. The Agency agrees that physical/chemical treatment systems, including granular activated carbon adsorption, are effective for treatment of toxic organic pollutants and conventional pollutants. However, new physical/chemical systems can also be designed to control ammonia-N and cyanide to levels comparable to those used to establish the BAT limitations based upon biological treatment. The Agency has not precluded the use of physical/chemical treatment. The industry may use either method of treatment, provided that the appropriate limitations or standards are achieved. The Agency does not believe r:nr• nt 9 If \y O I* JL. £M ------- that space limitations would preclude attainment of the , BA' limitations at any plant. The Agency believes it has taken a reasonable approach in establishin< separate effluent limitations for the two existing full-seal* physical/chemical treatment systems that include granular activatec carbon. These systems are removing the toxic organic pollutants ii the wastewaters to levels which are comparable to the levels achievec by biological treatment systems. The capital costs for physical/chemical and biological systems are similar. The Agencj believes it would be unreasonable to require the operators of those plants to replace the existing treatment systems with biological treatment systems and incur a second capital expense to treat the sam« wastewater. Physical/chemical treatment for cokemaking wastewaters was considered as a BAT optional treatment technology in th« development of the prior regulation. The Agency did not include total cyanide limitations for the physical/chemical facilities in the regulation, because it believes it Is more appropriate to address those limitations at the permit level. The development of these limitations will require highly complex, site-specific evaluations of alternate treatment technologies, and for that reason, the Agency has decided to defer that decision to the permit stage. The absence of a cyanide limitation in this regulation does not mean that cyanide discharges from these plants will be unregulated. The Agency is providing technical assistance to the States which have NPDES permitting authority for those facilities. 13. COMMENT The industry commented that the BAT 30-day average ammonia-N limitation should be 0.05742 lbs/1000 Ibs (or 134 mg/1 at 103 gallons per ton) for physical/chemical coke plants; and, that the 30-day average phenols (4AAP) limitation should be 0.000040 lbs/1000 Ibs (or 0.093 mg/1 at 103 gallons per ton). One company suggested that a phenols (4AAP) limitation higher than that cited above would be appropriate. RESPONSE The industry's suggested ammonia-N limitation is based upon the performance of the ammonia stripping system at the Republic Steel Cleveland District coke plant physical/chemical treatment system. Long term data for the Cleveland plant demonstrate highly variable control of ammonia nitrogen with large fluctuations not characteristic of efficient ammonia stills. Republic Steel's original treatment system design called for an average ammonia-N effluent concentration of 50 mg/1. However, due to a series of design and operating problems, including the inability to properly control pH, the design value has never been consistently achieved. Since Republic Steel has one of only two physical chemical treatment systems and the other has advanced ammonia-N removal facilities, 60 mg/1 was used as the basis ------- for , the , proposed 30-day average limitation. Republic Steel's design criterion of 50 mg/1 was considered in proposing this limitation. Well designed and operated free and fixed ammonia stills can achieve ammonia-N concentrations less than 60 mg/1; however, this level is restrictive for some plants. An advanced ammonia-N stripping system operated by U.S. Steel and others consistently achieves concentrations in the range of 25 to 30 mg/1. Also, Republic Steel developed an air stripping system which is reported to be capable of achieving 50 mg/1. Based upon data from well run conventional ammonia stills, the concentration underlying the final 30-day average BAT effluent limitation for physical-chemical coke plants was increased from 60 mg/1 to 75 mg/1 to allow for additional variability. This concentration is also used as the basis for cokemaking PSES. The Agency evaluated long-term data for the Republic Steel Cleveland District Coke Plant treatment system which includes full scale activated carbon adsorption systems. These data indicate a 30-day average effluent concentration of 0.100 mg/1 is achievable and the final limitation is based upon that concentration. 14. COMMENT The industry commented that the proposed PSES and PSNS which are equivalent to BAT are overly restrictive. RESPONSE The Agency agrees and has promulgated less stringent PSES and PSNS for cokemaking operations which are based upon the same physical-chemical pretreatment provided by the industry for its on-site coke plant biological treatment systems. The reasons for establishing PSES and PSNS at those levels is set out in the development document. 15. COMMENT A commenter observed that flow equalization of indirect cokemaking wastewaters, which is essential for proper POTW operation, was apparently not considered. RESPONSE Flow equalization is part of the model treatment technology used to establish the BPT and BAT effluent limitations and NSPS, PSES, and PSNS. It was identified in the draft Development Document as the settling basin, the treatment component immediately following the ammonia stills. The Agency has corrected the labeling to clearly designate the component as an equalization basin. ------- 16. COMMENT The same commenter suggested that EPA consider ion-precipitate flotation of iron cyanide complexes to treat the discharge of total cyanide from cokemaking operations. RESPONSE The Agency did not consider this ion-precipitation flotation since it is not demonstrated on cokemaking wastewaters and the Agency does not have sufficient data to confidently project the performance, reliability and cost of this system for treating cokemaking wastewaters. 17 COMMENT A commenter recommended that BAT Alternative 2, which includes the addition of powdered activated carbon (PAC) to the two-stage biological treatment system (BAT Alternative 1), be used as the BAT model treatment technology. The commenter states available data indicate that PAC will improve the removal of toxic organic pollutants, as well as enhance biological nitrification. RESPONSE While the Agency agrees that PAC can enhance biological nitrification, and would be particularly useful for upgrading single-stage biological treatment systems, it does not believe the data cited demonstrate improved toxic organic pollutant removal. The bench-scale study (Bridle, T.R., et al, "Nitrogen and Contaminant Control of Coke Plant Effluents in an Upgraded Biological System", EPA Symposium on Iron and Steel Pollution Abatement Technology, Phildelphia, Nov., 1980) cited by the commenter, indicates certain toxic organic pollutants may be present at levels below the detection limit of the analytical method. However, the data do not show that PAC added to those bench-scale units would result in the removal of these organic pollutants. The Agency believes the sludge in coke plant biological treatment systems tends to adsorb and concentrate many of the toxic pollutants contained in the wastewater feed; and, that much of the removal is accomplished in that fashion. The study (Ostanowski, R., et al, "Advanced Treatment of Coke Plant Wastewater Using Physical/Chemical and Biological Techniques", Ibid.) conducted at Wheeling-Pittsburgh Steel Corporation does show that granular activated carbon (GAC) systems will remove toxic organic pollutants from the effluent of biological treatment systems to levels below the detection limits. However, PAC, added to biological systems will not necessarily perform at the same level as GAC. The data available at this time do not justify the application of PAC as the BAT model treatment .technology. The selected model BAT treatment technology will remove toxic organic pollutants to levels at or near the respective detection limits, as shown by the performance OOGCI5 ------- of the model technology on a full-scale basis at the U.S. Steel Fairfield Works. 18. COMMENT In response to the Agency's solicitation of comments regarding the use of single-stage biological treatment systems as the basis for establishing the BAT limitations, a commenter stated that the BAT limitations are not reliably achievable with single-stage systems and, therefore, this system should not be used as the BAT model treatment technology. RESPONSE The Agency did not select single-stage biological treatment as the model BAT treatment technology. The Agency does, however, expect that some dischargers will use single-stage systems to achieve the BAT limitations and achieve compliance at less cost than projected by the Agency. 19. COMMENT The industry commented that the Agency did not adequately address energy and chemical requirements of advanced biological treatment systems for cokemaking wastewaters and that the limitations may not be achievable in northern climates because of these inadequacies. RESPONSE In response to this comment, the Agency evaluated the model treatment system used to develop the proposed limitations and made the following modification to properly account for energy and chemical requirements. ENERGY CONSIDERATIONS 1. Equalization tank insulation was added to conserve heat during cold weather months. 2. Addition of steam through indirect heat exchangers was included to optimize and maintain biological activity during cold weather months. 3. A heat exchanger (non-evaporative cooling tower) was added to waste heat during warm weather months. CHEMICAL ADDITION 1. Chemical addition equipment was included for the purpose of adding phosphoric acid, caustic and soda ash to optimize and maintain biological activity. OOSBI6 ------- The investment and operating costs associated with these modification to the model treatment system are set out in the Development Document The Agency believes that with these modifications the BAT limitation: for cokemaking operations can be achieved throughout the year at cok< plants located in all parts of the country. The Agency reviewed the costs submitted by the industry for energy consumption necessary to heat coke plant biological treatment system- during cold weather months and finds these costs to be overstated. Ii its comments, the industry stressed the need for heat addition durinc cold weather months, particularly in northern climates. However, th< industry's cost estimate is based upon year round steam addition at all coke plants regardless of location. The Agency has added only the cost of additional energy required for cold weather months at al] plants to its cost estimates. 20. COMMENT One merchant coke producer stated that while coke plants have some similarities, there are plant-to-plant differences that cause significant variations in the wastewaters generated at each plant. The commenter cites two coke plants with similar BPT treatment systems that discharge total suspended solids at significantly different levels. The commenter states that he and his consultants could not determine which differences in the coke or chemical recovery processes cause the different results. The commenter also noted that some coke plants are part of large integrated steel plants with single central treatment systems, thus masking the contribution of pollutants from cokemaking operations; and, that receiving waters are affected differently by cokemaking operations. In summary, the commenter recommended that the effluent limitations and standards be issued as guidelines with the flexibility to consider plant-to-plant variations in treatment performance and receiving water characteristics in establishing final effluent limitations. RESPONSE In developing the proposed and final effluent limitations and standards for cokemaking operations, the Agency carefully considered several factors pertaining to subcategorization. Among those are wastewater characterisics and treatability. While there are plant-to-plant variations in cokemaking raw wastewater concentrations, the Agency found no basis to further subdivide cokemaking operations based upon those factors. Based upon effluent data obtained from several cokemaking wastewater treatment facilities, the Agency believes that wastewaters from all cokemaking operations can be treated to the final limitations and standards with the model treatment system. With respect to the commenters experiences with two cokemaking wastewater treatment facilities producing different effluent levels of suspended solids, the commenter did not provide sufficient information on the cokemaking by-product recovery processes and the design and Of»f^f •£ ff UtJ&JC. i ------- operation of the wastewater treatment facilities for the Agency to draw any conclusions. However, owing to the nature of biological treatment facilities, the Agency believes that the design and operation of the wastewater treatment facilities, rather than production processes, influence effluent suspended solids concentrations. As noted earlier, the Agency has increased the suspended solids BPT model treatment system concentration to 140 mg/1 for both merchant cokemaking operations and those associated with iron and steel production facilities. The Agency believes the BPT suspended solids limitations can be achieved at cokemaking operations with properly designed and operated wastewater treatment facilities. Although the commenter suggests that pollutants from cokemaking operations can be diluted at large integrated steel plants with central treatment systems, the Agency used data from full scale wastewater treatment facilities serving only cokemaking operations to establish the limitations and standards. Thus, the data relied upon by the Agency were not affected by dilution by wastewater or cooling waters from other operations. The Agency believes it is appropriate to establish nationwide effluent limitations and standards of performance for point sources that are applicable regardless of receiving water and, that its decision to do so is consistent with the requirements of the Clean Water Act. Consequently, the Agency did not establish these limitations and standards on the basis suggested by the commenter 21. COMMENT One commenter suggested that the Agency's proposed prohibition of combined or co-treatment of cokemaking wastewaters with wastewaters from other operations is unreasonable. The commenter stated that this proposed prohibition could potentially double the aggregate total cost of treatment of cokemaking and ironmaking wastewaters at the commentor's plant. Finally, the commenter characterized the Agency's concern about the potential for dilution rather than treatment of pollutants found in cokemaking wastewaters as overstated and ill-founded. RESPONSE First, the Agency did not propose to, and has not, prohibited expressly the combined treatment of wastewaters from cokemaking operations with those from ironmaking operations. In the preamble to the proposed regulation and in the preamble to this regulation, the Agency has set out its policy for addressing central treatment problems in the steel industry. Based upon several examples of inadequate treatment of cokemaking wastewaters in central treatment systems (Plants 06841, 0856F, 0864A), the Agency believes it is not appropriate to treat wastewaters from cokemaking operations with wastewaters from most other steel plant operations and has so stated in those preambles. The dilution of cokemaking wastewater by other wastewaters in these systems makes it impossible to achieve the same OOOGI8 ------- level of effluent reduction that can be achieved with separate treatment of cokemaking wastewaters. Under the final regulation; dischargers can co-treat cokemaking wastewaters with compatible wastewaters from other operations provided the sum of the applicable limitations and standards are achieved. However, from a practical standpoint, the Agency does not believe this can be done to any great extent because of the nature of cokemaking wastewaters and the applicable limitations and standards. The Agency believes that, under certain conditions, it may be appropriate to co-treat cokemaking and ironmaking wastewaters from existing and new sources. For example, the blowdown from BPT recycle systems on blast furnaces may be co-treated in coke plant biological treatment systems. Information provided by the commenter indicated that the commenter's existing treatment system for ironmaking wastewaters cannot accomodate cokemaking wastewaters. The Agency notes that most of the model BPT and BAT treatment technolgies are installed for ironmaking operations at this plant and that some cokemaking wastewaters are pretreated and discharged to a POTW and others are disposed of by means of deep well injection. 22. COMMENT One commenter stated that the "building block" approach to the development of limitations and standards for cokemaking operations is impractical and leads to erroneous conclusions regarding the level of treatment available. RESPONSE The Agency's building block approach as it pertains to by-product cokemaking operations includes the development of model coke production operations with certain common by-product facilities. The Agency developed one model for merchant coke production and another one for coke plants affliliated with steel production to account for the differences in wastewater generation rates at these operations. The models are based upon wastewater flows for the cokemaking and by-product recovery operations (waste ammonia liquor, benzol plant wastewaters, final cooler wastewater, barometric condenser recycle system blowdown, miscellaneous wastewater, and dilution water for optimization of biological treatment systems). In addition, special allowances for qualifying wet coke oven gas desulfurizing operations and indirect ammonia recovery operations are provided in the regulation for both iron and steel and merchant cokemaking operations. The Agency has also recognized that extensive by-product recovery is practiced at a few coke plants and that site-specific effluent limitations for the by-product recovery operations not included in the model cokemaking production facilities should be developed. As noted in the development document, the model flow rates and BPT and BAT effluent limitations for cokemaking operations are well demonstrated. The Agency found the above comment confusing in that the commenter did not provide any detail regarding why he thinks a building block eOQCI9 ------- approach is not practical. Specifically, the commenter did not detail which aspects of the Agency's methodology it finds ojectionable; or, how the Agency might improve its building block approach for cokemaking operations. Rather, the commenter made reference to its other comments regarding the achievability of the cyanide limitations, which are addressed separately (See response to comment A-8). Neither did this commenter, nor any other, provide any specific technical data or other information about differences in cokemaking or by-product recovery operations which the Agency could evaluate to determine if other approaches to developing limitations and standards for cokemaking operations might be appropraite. In summary, the Agency believes its approach to developing limitations and standards for cokemaking operations is logical and appropriate. The Agency examined the individual sources of wastewaters at cokemaking operations and formed model treatment systems that includes those sources. This method provides for the development of achievable limitations and standards for all cokemaking operations and for additional allowances for those wastewaters not found at all cokemaking operations. 23. COMMENT The industry commented that the Agency has substantially underestimated the costs of the model BAT treatment system for cokemaking operations and has not included several important annual cost items (chemical addition, energy costs), or underestimated others (operation and maintenance, capital recovery and depreciation charges, sludge disposal costs). The industry presented estimates of investment costs to install the model BAT treatment system prepared by Bethlehem Steel which are about four times higher than the Agency's estimates ($3.82 million versus $0.87 million). The industry also commented that the Agency did not include investment costs for removing suspended solids from pushing emission control wastewaters used to take the place of dilution water in the Agency's model BAT treatment system. RESPONSE The Agency believes its model based cost estimates for the cokemaking subcategory accurately reflect the actual costs to be incurred by the industry in complying with this regulation. As set out in the development document, the Agency's model based cost estimates compare favorably with actual industry costs for several BPT and BAT coke plant wastewater treatment systems, including both biological and physical/chemical treatment systems. Thus, the Agency believes its estimated industry-wide costs based upon the model BAT treatment system, which includes many of the same components as the model BPT treatment system, are also representative of the costs industry will incur in complying with the limitations. With respect to the items the industry cited as not being included in the Agency's estimates, the Agency notes the following: OODC20 ------- a. Investment costs for suspended solids removal from pushir emission control wastewaters were not included as part of th Agency's wastewater treatment costs/ since these costs wer included as part of the air pollution control system costs by th Agency's air programs office. b. As set out in the development document, the Agency has include additional costs for sodium hydroxide and sodium carbonate t operate the biological treatment systems. The Agency believe the amount of chemicals specified and associated costs ar sufficient. The use of these chemicals was not included in th Agency's model treatment system used to develop the propose regulation. c. As set out in the development document and in response to Commen A-19, the Agency made modifications to the model BAT treatmen system to provide additional energy for cold weather operations. d. The Agency's listed annual operating and maintenance cost base< upon 3.5% of the investment cost is basically a labor cost foi required operation and maintenance and is substantiated by datt for many plants. The annual costs of operations in terms oJ chemical requirements, energy usage, etc. are accounted foi separately. Thus, the Agency believes it has properly accountec for these costs. e. The industry contends that capital recovery and depreciatior charges based upon 7% interest and 10% depreciation are too low. As set out in the development document and in the economic impact analysis of this regulation, the Agency revised its capital recovery and depreciation charges. The Agency believes its revised factors are appropriate. f. The industry contends that sludge disposal costs at $5/ton are understated, notably in light of RCRA requirements. The Agency has revised its disposal costs for hazardous sludges to $18/ton from $5/ton to account for the higher costs of disposing of sludges considered hazardous under RCRA. Based upon information submitted by the industry and studies conducted by the Agency, the Agency believes these costs are representative of costs incurred for large scale operations typical of the steel industry. Regarding the industry's estimate of investment costs to install the model BAT treatment system, used to develop the proposed limitations, the Agency notes the following: Onr t»*j ------- a. The Bethlehem Steel estimate includes $2.2 million (January 1980 . dollars) for a nitrification facility and $2.4 million (1980 dollars) for an effluent filter for a process flow of 413 GPM. The total system cost is presented as $4.6 million. The production plant size is 5200 tons/day and the design flow rate is about 115 gal/ton. The Agency's estimate for the nitrification system at the Bethlehem plant (the model treatment system used to develop the final treatment system) is about $1.7 million (January 1980 dollars). Thus, the Agency's estimate compares reasonably well with that provided by Bethlehem Steel for the model BAT treatment system used to develop the final limitations. (The model treatment system does not include filters). The estimate presented by the industry was not sufficiently detailed to permit the Agency to make a more detailed comparison. The Agency notes that where the industry representatives have supplied more detailed estimates (for these and other operations), the Agency has found that excessive indirect costs were included, and some of the costs for equipment items and installation were overstated. Reference is made to the record for additional information on this issue. b. The Agency finds that the nitrification system noted above, for which Bethlehem Steel presented cost estimates, is virtually the same as the single-stage BPT treatment system installed at the Bethlehem plant. Bethlehem Steel reported to the Agency (letter of December 11, 1980 from H.A. Conahan) that the installed cost of that treatment facility is $1.2 million (1980 dollars). The Agency can find no evidence that the estimated cost for the nitrification facility should be 80% higher than the installed cost of the existing single-stage biological treatment system. The Agency's estimate for the in-place single-stage biological treatment system agrees with the actual installed cost within 5% (Agency cost estimate higher). Also, the Agency's estimated cost for the entire treatment facility installed at this plant (ammonia stills, biological treatment) also agree within 5% (Agency cost estimate low) when allocated costs for free ammonia recovery are deleted. (The Agency notes that free and fixed ammonia recovery at this plant are conducted in one operation. The Agency attributed about 35% of the total ammonia still costs to free ammonia recovery, a typical ratio for conventional free and fixed ammonia stills). As noted in the development document, the Agency considers free ammonia recovery to be a by-product recovery process and not water pollution control. c. Filtration is no longer included in the BAT model treatment system, however, the Agency believes the $2.4 million cost estimate presented above by Bethlehem Steel is overstated. The Agency could not find any basis for a $2.4 million filter cost to process 413 GPM. The industry supplied the following actual cost data for various filtration systems: OOOC22 ------- Plant Flow (Cost 1980 Dollars) 0920A 1600 GPM 0.81 million 0920N 1600 GPM 0.39 million 0920N 9400 GPM 1.09 million As shown above, these costs are significantly less than the estimat presented by Bethlehem Steel for a much smaller filter system. Whil different types of filters than those noted above are sometimes use to treat biological effluents, the Agency could find no data t support the Bethlehem Steel estimate. As noted above, based upon numerous comparisons of model-based cos estimates and actual industry costs, the Agency has determined tha its model-based cost estimates are representative of actual industr; costs and appropriate for estimating industry-wide costs to compl; with the regulation. 24. COMMENT The operator of Plant 0584F-B indicated the Agency has incorrectlj listed the benzol plant flow at 15.6 gallons/ton, when it is actuallj 32.2 gallons/ton. RESPONSE The Agency reviewed the data for this plant and agrees with the commenter. The appropriate change was made in the data base for cokemaking operations. OOOG23 ------- B. SINTERING 1. COMMENT The industry commented that the model flow of TOO gal/ton used to develop the proposed BPT effluent limitations, while higher than 50 gal/ton used to develop prior effluent limitations, is too stringent. The industry also requested the subcategory be further subdivided to take into account the difficulty of recirculating windbox scrubber waters vs recirculating other wastewaters. RESPONSE Based upon this comment and others regarding the achievability of the BPT model treatment system flow rate, the Agency re-evaluated available flow data for all sintering operations. As set out in the development document, a revised BPT model treatment system flow rate of 120 gal/ton was established. This flow rate is achieved at plants with windbox scrubbers without significant fouling, scaling and plugging problems. The Agency included data from only those plants for which representative flow data are available. The Agency believes it is not necessary to subdivide the sintering subcategory on the basis suggested by the industry, since plants with windbox scrubbers as well as other plants that do not have windbox scrubbers can achieve the revised model flow rate (120 gal/ton). At some plants this flow can be achieved on a once-through basis with no recycle. The Agency believes this model flow rate is achievable at all sintering operations. 2. COMMENT The industry commented that alkaline chlorination of sintering wastewaters should not be used as the model BAT treatment technology due to its cost and the small level of pollutant removals achieved with this technology. The industry also commented that filtration of sintering wastewaters should not be used as model treatment technology since the technology is not demonstrated on a full scale basis for stand alone sintering plants with windbox scrubbers and cost of conventional pollutant removal is too high. RESPONSE The Agency reviewed available data and agrees that the relatively low levels of ammonia-N, total cyanide and phenols (4AAP) found in sintering wastewaters do not justify the installation of alkaline chlorination technology for stand alone sintering operations. Toxic metals are found at treatable levels in sinter plant recycle system blowdowns. These metals are primarily in particulate form and can be removed by filtration, which is the BAT model treatment technology. Based upon the installation of filtration systems in this subcategory and in other subcategories with wastewaters of similar character, the Agency believes filters can be successfully installed to treat wastewaters from stand alone sinter plants with windbox scrubbers and 000024 ------- those in central treatment systems. Based upon the ab.ove, ,and cos comparisons noted in the development document, the Agency believes it cost estimates for filtering sintering wastewaters are accurate. A noted above, the filters are primarily included in the model treatmen system for toxic metal removal; since the Agency has reserved BC limitations for sintering operations, the BCT cost question is not a issue at this time. It should be noted that the industry is no required to use filters to achieve the BAT limitations for toxii metals Data in the record indicate that lime precipitation am sedimentation are as effective as filters in removing toxic metals. 3. COMMENT A comrnenter suggested that the Agency should consider dry gas cleaninc methods, and fully evaluate their effluent reduction capabilities anc non-water quality impacts. RSSPONSS The Agency recognizes that the use of dry gas cleaning systems foi sintering operations will result in eliminating the discharge of wastewater. However, the Agency does not believe that it is appropriate to establish water effluent limitations and standards that would require the industry to abandon existing wet air pollutior control systems, particularly, for those plants which are ir compliance with applicable air pollution or emission standards. Additionally, the Agency does not believe it should establish effluent limitations and standards that would restrict the industry's flexibility to have viable alternatives to comply with air pollutior requirements. Based upon current trends, the Agency believes that wet air pollution control systems, rather than dry systems, are likely tc be used to comply with air quality requirements for sintering operations. 4. COMMENT A commenter stated that long-term effluent data from two plants do not provide sufficient basis to establish BPT limitations which are less stringent than the previous BPT limitations published at 40 CFR 420.32. The commenter suggested that additional data should be obtained prior to relaxing the BPT limitations. RESPONSE The doubling of the proposed BPT limitations from the previously promulgated limitations is the result of doubling the model flow rate from 50 gal/ton to TOO gal/ton. This was based upon the analysis of all flow data available at that time. The long-term effluent data from two plants were used to support the effluent concentration basis for the proposed BPT limitations and to demonstrate the achievability of those limitations. The Agency believes that the two plants are representative of other sintering operations and that it is appropriate to rely upon the respective concentration data to ------- establish or demonstrate compliance with the BPT limitations. However, as discussed previously, the Agency reevaluated all currently available data for well operated systems and, on that basis, established the BPT model flow rate at 120 gal/ton. 5. COMMENT A commenter, expressing concern about the formation of chlorinated organic by-products as a result of treatment by alkaline chlorination, recommended that granular activated carbon be included in the model BAT treatment technology prior to the alkaline chlorination. The commenter also suggested that effluent limitations be established for benzo(a)pyrene to regulate the discharge of base/neutral toxic organic pollutants. RESPONSE The Agency has reviewed available data and has concluded that the levels of ammonia, cyanide and phenols (4AAP) (those pollutants amenable to treatment by alkaline chlorination) are found in sintering wastewaters at sufficiently low levels that establishing BAT limitations based upon alkaline chlorination treatment is not appropriate. The Agency did not find toxic organic pollutants in wastewaters from sintering operations at levels that would justify limiting benzo(a)pyrene or other toxic organic pollutants. Only one base/neutral toxic organic pollutant was found in sintering wastewaters. This pollutant was found was at relatively low levels that cannot be significantly reduced by activated carbon or other available treatment technologies. 6. COMMENT One commenter noted that the Agency did not base the limitations and standards for sintering operations on in-plant controls available for sintering operations. Recycle of treated process wastewater was cited by the commenter as being practiced at twelve plants. RESPONSE Aside from recycle of wastewaters from air pollution control systems, the Agency is not aware of any in-plant water pollution control or process control methods available for sintering operations. Recycle is included in the BPT model treatment system. The effluent limitations and standards have been based upon 92% reduction in effluent volume for those plants with wet air pollution control systems and applied water rates equivalent to that of the Agency's model treatment facility. 7. COMMENT One commenter stated that only three sintering operations were monitored for toxic pollutants and recommended that the Agency continue the, development of the data base for sintering operations COGC26 ------- after the regulation is promulgated. The same commenter also requested that the Agency clearly explain how the calculations .for concentration buildup (pickup per pass or pickup for recycle) were made. RESPONSE Data for the three sampled sintering plants are used to characterize the wastewaters from five stand alone sintering operations. The Agency believes the sampled plants are representative of the industry and the data. Thus, the Agency believes that the data base for the sintering subcategory is adequate. With respect to the pick-up for pass calculations, the Agency believes those calculations are adequately explained in the development documents. These calculations were used only to assist the Agency in determining those pollutants that may be added by the process. 8. COMMENT One commenter noted that the sintering operation at Plant 0112B is listed incorrectly in the development document as having wet air pollution control systems at both ends of the sintering process. RESPONSE In response to this comment the Agency reviewed information and data provided for this plant and found that a wet air pollution control system is used to control air emissions from both ends of the sintering operation. However, this system does not control air emissions from the windbox itself. The Agency has made the appropriate corrections in its data base for sintering operations. 9. COMMENT The industry commented that the Agency improperly calculated "the cost benefit ratio" for the proposed BPT limitations for sintering operations by taking full credit for the pollutant removal at Plant 0112A from the raw waste to the BPT level of treatment, while considering only the incremental cost from current level of treatment {which is at or close to BAT) to the BPT level of treatment. RESPONSE For the sintering and other steel industry subcategories, the Agency considered the total cost of application of the BPT technology (including costs for facilities in-place as well as costs for facilities required) and the total effluent reduction benefits. For the regulation as a whole, and for each subcategory, the Agency determined that the effluent reduction benefits justify these costs. The remaining costs to comply with the regulation were developed to assess the economic impact of the regulation on the industry. 003027 ------- 10. COMMENT The industry commented that the data obtained by the Agency do not include representative data for plants with wet windbox scrubbers. The industry recommended that the Agency restudy sintering operations with discharges from windbox scrubbers. RESPONSE The Agency believes it has adequate data to characterize wastewaters from sintering operations with windbox scurbbers. The industry indicated data for Plant 0112D are not representative because the sinter plant recycle system blowdown (windbox wastewaters included) is directed to a central treatment system. The Agency notes that wastewaters sampled at this plant are representative of BPT recycle system blowdowns. The industry reported corrosion at only this one plant. The Agency believes that, based upon the lack of similar problems of any significance noted for other plants, that corrosion in these recycle systems is controllable. Also, data obtained by the Agency at Plant 0060F, while from a clarifier underflow, are useful for determining the character of sinter plant wastewaters. Furthermore, the Agency conducted its pilot filtration studies at Plant 0060 which has windbox scrubbers. 11. COMMENT The industry commented that the Agency should use the same concentrations to develop limitations for sintering and ironmaking operations since wastewaters from those operations are often treated together. RESPONSE The proposed BAT limitations for sintering operations are based upon different concentrations for the limited pollutants. In response to this comment, the Agency based the promulgated BAT limitations for sintering and ironmaking operations on the same effluent concentrations. 12. COMMENT The industry commented that the Agency improperly calculated waste loads for sintering operations by multiplying high concentrations obtained at plants with recycle systems with high flows obtained at plants without recycle, thereby increasing projected BPT waste load removals. The industry recommended that the Agency properly recalculate late raw waste loadings from sintering operations. RESPONSE COOC28 ------- The Agency believes that its methodology used to characterize ra waste loadings is proper. Reference is made to Appendix C, Volume of the Development Document for a tabulation of the raw waste loading for sintering operations. Those data were obtained by determinin appropriate concentrations of the respective pollutants in untreate sintering wastewaters and multiplying these concentrations by th aggregate applied model flow for the wet sintering operations. Th Agency also believes its assessment of the pollutant removal at th BPT level is representative of actual removal to be achieved by th industry. 000029 ------- C.' 'IRONMAKING 1. COMMENT The industry commented that alkaline chlorination should not be the BAT model treatment technology for ironmaking wastewaters; the Agency should not use demonstrated flows from one plant and pilot plant data from another plant to establish the limitations; and, should the Agency select alkaline chlorination as the model BAT treatment technology/ the ammonia-N limitations should be based upon the performance of the technology on a full scale basis rather than upon pilot plant data. The industry also commented that the proposed BAT limitations were so stringent that promulgation of the proposed limitations would preclude the industry from using other treatment technologies, including biological treatment, for complying with BAT requirements. RESPONSE The Agency disagrees with the industry regarding alkaline chlorination. This technology is installed on a full scale basis at several plants in the industry and is particularly effective at removing ammonia-N, total cyanide, and phenols (4AAP) from blast furnace BPT recycle systems blowdowns. As explained in detail in the development document, this technology provides significant removals of those pollutants and other toxic pollutants from BPT recycle system blowdowns. The Agency has determined that the effluent reduction benefits associated with alkaline chlorination justify the costs. The Agency also believes that the generation of small amounts of chlorinated organic pollutants that may result from alkaline chlorination of ironmaking wastewaters is outweighed by the substantial removals of ammonia-N, total cyanide, phenols (4AAP) and other pollutants. While the industry has commented against the use of alkaline chlorination as the model BAT technology, it had offered no alternatives, other than to request BAT limitations that are the same as "proper" BPT limitations. The Agency recently received information from the industry indicating that it would prefer BAT limitations based upon a model treatment system flow rate of 35 gal/ton with no further treatment. In other words, a BPT recycle system operated with a minimal blowdown. The Agency rejected this alternative as it does not provide for significant effluent reduction benefits beyond those achieved at the BPT level of treatment. With respect to the second and third parts of the above comment, the Agency had only pilot plant data available at the time of proposal. In response to this comment, full scale performance data were solicited and obtained from the industry. These data were used to develop the final BAT ammonia-N limitation which is based upon a 30- day average concentration of 10.0 mg/1. A concentration of 1.0 mg/1 was used to develop the proposed limitation. As noted in the development document, the achievability of the revised ammonia-N limitation as well as the achievability of the cyanide and phenols (4AAP) limitations is demonstrated on a full scale basis in the COOC30 ------- industry. Notwithstanding the above, the Agency believes it is appropriate to use demonstrated flow rates from one plant to establish model BAT flow rates and pilot plant data from another plant tc establish BAT limitations, provided the plant used to establish the flow rate is representative of the industry and the wastewaters treated in the pilot study are also representative. In the case at hand, at proposal the Agency made the finding that both operations are representative and that use of the data in this fashion was appropriate. The Agency believes that the promulgated BAT limitations for ironmaking operations can be achieved by wastewater treatment technologies other than alkaline chlorination. One major steel company has submitted an application to use a technology which it considers innovative to comply with the BAT limitations for one of its blast furnace operations. The data submitted with this application clearly demonstrate that this technology, which includes biological treatment, can be used to achieve the BAT limitations. 2. COMMENT The industry also commented that the model BAT flow of 70 gal/ton was not well demonstrated; the model flow should be no less than the BPT model flow, or 125 gal/ton; and, NPDES permit writers should be instructed to consider site-specific moisture balances when establishing NPDES permit limits. RESPONSE The Agency disagrees. There are several blast furnace recycle systems operating consistently with blowdown rates less than 70 gal/ton. In response to the industry comment, additional data were solicited from a number of companies. Data for plants 0528A and 08561 demonstrate that 70 gal/ton is achievable on a long term basis and recent short term data for a number of other plants also support this value. For the reasons discussed in greater detail in the development document, the Agency believes it is appropriate to establish the BAT limitations based upon a 70 gal/ton model flow rate. In addition, recent information submitted by the industry indicates that 35 gal/ton blowdown rate may well be achievable on a long-term basis. At least one major steel company recommended that the Agency establish BAT limitations using this flow rate. In support of its comments, the industry provided corrected and additional data for Plant 0112. Data for this plant were used by the Agency (at proposal) to demonstrate the achievability of the 70 gal/ton BAT model flow rate. The average of the 33 months of data submitted by the industry is 77.8 gal/ton compared to 70.3 gal/ton calculated from the smaller data base available to the Agency at the time of proposal. The flow rates in the expanded data base range from 27 gal/ton to 138 gal/ton. The industry contended that flows "substantially below the average discharge rate" cannot be maintained for extended periods, due to buildup of dissolved solids which leads n n U u u ------- to increased potential for stress corrosion and mineral scaling; and, that the' high discharge rates are necessary for proper operation under certain conditions. The Agency does not believe that corrosion and scaling problems would arise at blowdown rates of 70 gal/ton. This is clearly demonstrated by the fact that the recycle system at plant 0112, as well as others in the industry, have been operated with discharge flows of 70 gal/ton and less for extended periods of time without experiencing operating problems. The company owner of Plant 0112 previously submitted information in response to Agency questionaires showing that the typical discharge rate at this plant is about 71 gal/ton and that scaling, fouling, or plugging problems were not experienced at this plant. The owner also reported that the 71 gal/ton flow rate was typical of the operation of the recycle system. The plant has been operating with a recycle system since 1962. The company also indicated the blowdown rate is controlled to achieve a water quality standard for cyanide in the receiving water (i.e., increased or decreased depending upon flow in the river) and not controlled on the basis of dissolved solids. Thus, the Agency believes that flow rates higher than 70 gal/ton at this plant are more the result of operating practices that did not emphasize consistent achievement of minimum discharge flow rates. Based upon performance at other plants, the Agency does not believe that variations in weather conditions, raw material moisture content, make-up water quality, or furnace operating conditions would prevent attainment of 70 gal-ton at this plant. The industry also presented flow data for plant 0112B which had an average discharge flow rate of 175.8 gal/ton. The industry contends that this high flow rate illustrates the wide variation in discharge flow rates caused by differences in geographical location, raw materials and furnace operations. No specific information was provided to indicate that this plant has been operated in a manner to achieve low or minimum levels of discharge. In fact, NPDES permit limitations have not been established for this discharge. Compliance is determined by monitoring in the receiving stream upstream and downstream of the plant. Thus, there has been no incentive for the company to maintain low discharge rates. As a result, the Agency does not believe that the operation of this plant is representative of well operated recirculation systems. Furthermore, the discharge flow rate of 70 gal/ton is being achieved at plants in different geographic locations using different raw materials. Finally, the industry stated that the inventory of discharge flow rates for the 54 ironmaking plants presented in the draft Development Document, indicates the discharge rates from most of these plants are well in excess of the BPT model flow rate (125 gal/ton). While the data presented in the draft Development Document show many plants discharging at blowdown rates in excess of 125 gal/ton, the Agency does not believe those data are characteristic of minimum blowdown rates achievable at blast furnace recycle systems. These data reflect operations in 1976 when several recycle systems were just put into operation. ' Since that time, the industry has made significant no n ~ o u ------- advances in reducing blast furnace recycle system blowdown' rates. Moreover, the 1974 BPT limitations were based upon' fairly higf concentrations suspended solids, ammonia-N, total cyanide, and phenols (4AAP). Hence, many dischargers can achieve the BPT limitations without paying particular attention to blowdown rate. Many have not taken steps to minimize blast furnace recycle system blowdowns anc blowdown rates of 200 to 300 gal/ton are still common. Those that have made the efforts to reduce flows, have achieved blowdown rates that meet the more stringent BAT model flow rate of 70 gal/ton. The Agency is aware of flow data for one of the blast furnace recycle systems at plant 0684F which demonstrates that blowdown rates of 3! gal/ton and less are achievable on a long-term basis without significant fouling, scaling, or plugging problems; and, as notec above, one major steel company suggested the Agency base BA1 limitations on a model flow rate of 35 gal/ton. Thus, the Agencj believes the 70 gal/ton model flow rate used to develop the BAT limitations is appropriate, and probably higher than necessary. 3. COMMENT The industry recommended that the Agency use the 95% confidence level to develop the model effluent flows used to establish the BPT and BAT effluent limitations in the ironmaking subcategory. RESPONSE The Agency has not used statistical methods to establish the mode] flow rates, since blowdown rates are not random statistical variables. Rather, at the levels at which the model flows are established, the Agency believes that the blowdown rates are within the control of the operator. The BPT model flow rate was developed using the average of the best performing plants in the development of the prior regulation. The BAT model flow rate is slightly higher than the average of the current flow data from those plants with the lowest discharge flov rates. For the reasons set out in the ironmaking subcategory report, the Agency believes the BAT model flow is achievable at all ironmakinc plants. Higher flow rates, on the other hand, are unnecessary anc result from poor operating practice. The Agency believes that the model flow rates are reasonable, and in conjunction with the performance values (concentrations) for the limited pollutants, whict were developed using a statistical methodology (equivalent to the 953 and 99% confidence intervals), appropriate effluent limitations anc standards were developed. 4. COMMENT The industry commented that it is not possible to evaporate 70 gal/tor of blast furnace blowdown on slag produced in the furnaces. RESPONSE The Agency has not based the ironmaking BAT limitations on disposal of blast furnace recycle system blowdown by evaporation on slag. 000033 ------- Nevertheless, there are some plants that operate in this manner. A close review of the draft Development Document demonstrates that the Agency did not indicate that the evaporation of 70 gal/ton on slag is the basis for BAT Alternative 1, but rather that the blowdown rate would be in balance with the consumptive use of the slag quenching and cooling system at a given furnace. This is possible, as demonstrated by some plants, and will likely become more widespread with various types of expanded slag production being considered for several blast furnaces. At the least, disposal by slag quenching can be used at furnaces with adjacent slag operations to minimize the volume of blowdown requiring additional treatment, thus minimizing investment and operating costs to comply with the BAT limitations. 5. COMMENT One commenter, with some reservation, concurred with the Agency's decision to promulgate only BPT limitations for ferromanganese blast furnaces, and to leave the BAT and BCT limitations, and NSPS, PSES and PSNS for case-by-case determinations at the permit level. The commenter was concerned about leaving any segment of the industry without guidelines. The industry, on the other hand, recommended that the effluent limitations be established on a case-by-case basis. RESPONSE The Agency has not promulgated limitations and standards, other than BPT limitations, for the ferromanganese blast furnace operations. These limitations are the same as the BPT limitations proposed in January 1981, and previously promulgated in 1974. The Agency believes that it is not necessary to promulgate any effluent limitations or standards other than BPT since there are no ferromangeanese blast furnaces in operation or projected for operation in the future. The Agency believes the limitations or standards can be effectively developed on a case-by-case basis at the permit level for any future operations and that the BPT limitations provide a firm basis to establish the appropriate BAT effluent limitations. The model treatment technologies used to develop the BAT limitations, and NSPS, PSES and PSNS for ironmaking operations are appropriate for ferromanganese operations and should be used to establish appropriate limitations or standards. 6. COMMENT The industry commented that it would not be appropriate for the Agency to promulgate zero discharge as NSPS and PSNS for ironmaking operations on the basis of evaporation of recycle system blowdown on slag. The industry commented that such a standard may interfere with furnace operations (imbalance of slag production and blowdown rate); may limit slag handling practices; and, . may curtail expansion of ironmaking operations. Another commenter, however, recommended that the zero discharge standard be promulgated, since there are no apparent reasons why slag operations cannot be installed adjacent to new blast furnaces. 000034 ------- RESPONSE The Agency considered these comments and has not promulgated NSPS anc PSNS on the basis of zero discharge. Although slag operations can b« installed adjacent to new blast furnaces/ the type of slag produced is dependent upon the available market and water consumption in a slac operation is related to the type of slag produced. Most of the slac production methods currently practiced by the industry are capable of consuming most, if not all, of the wastewater blowdown from wel] operated blast furnace recycle systems. However, the Agency has decided not to promulgate a zero discharge standard since it coulc restrict furnace design and operations. NSPS and PSNS are the same as the BAT limitations for toxic and non-conventional pollutants. 7. COMMENT A commenter recommended that activated carbon be added to the model BAT treatment system prior to alkaline chlorination to remove toxic organic pollutants, and, thereby, prevent the formation of chlorinated organic by-products. RESPONSE The Agency does not believe that the levels of toxic organic compounds present in ironmaking wastewaters or the levels of chlorinated organic compounds produced as by-products from chlorination of ironmaking wastewaters justify the addition of activated carbon to the model BA1 treatment system. The data available at proposal of this regulation indicate the formation of chlorinated organics is in the parts per billion range. Additional pilot studies conducted by EPA show formation of similar levels of chlorinated organic compounds in two-stage alkaline chlorination systems preceeded by lime precipitation. This is the BAT model treatment system. Chlorinated organics approaching 1 mg/1 were found in the effluent from single-stage pilot plant systems not preceeded by lime precipitation. The available data indicate most of the precursors to chlorinated organic compounds are removed by lime precipitation and that costly activated carbon for removing these precursors is not warranted. Two-stage chlorination with lime precipitation is required to achieve the BAT limitations because single stage systems are not capable of achieving all of the limitations. In addition, the Agency believes that alternative methods, e.g., slag quenching and innovative treatment methods without the potential for generation of chlorinated organic compounds will be used extensively in the industry to comply with the BAT limitations. As a result, the potential for discharge of chlorinated organic compounds will be minimized. This is discussed in greater detail in the ironmaking subcategory report. 8. COMMENT One commenter recommended that effluent limitations should be established for fluoride, since it is present at levels in ironmaking wastewaters at levels equivalent to those limited in other industries. OOQG35 ------- RESPONSE The treatment technology commonly applied for fluoride removal is lime precipitation which is the same technology used for toxic metals removal. The model BAT treatment system for ironmaking operations includes this technology. Thus, fluoride will be simultaneously removed to levels equivalent to those limited in other industries. In any event, the Agency does not believe that industry-wide effluent limitations or standards for fluoride, at levels found in ironmaking wastewaters, are warranted based upon its toxicity and environmental effects and because of co-treatment considerations. 9. COMMENT One commenter noted that the BAT alternative based upon sulfide precipitation followed by filtration will most likely be subject to system failure and lengthy periods of downtime. The commenter stated that sulfide precipitation will result in a rapid buildup of floe which will in turn, plug the filters. The commenter further noted that the Agency's basis for not selecting this treatment system, i.e., lack of demonstration within the subcategory and marginal incremental removal of toxic metals, is contradicted by the Agency's prior statement that this technology is demonstrated in the metals industry, could be transferred to this subcategory, and would remove substantial amounts of metal sulfides when compared to the removal of metal hydroxides. RESPONSE The Agency is no longer considering sulfide precipitation with filtration as a BAT technology in the ironmaking subcategory. The Agency agrees with the commenter that this technology is transferrable the ironmaking subcategory and would result in removal of toxic metals. However, the data available to the Agency indicate that sulfide precipitation will not accomplish a greater degree of toxic metals removal than lime precipitation in this particular application. This conclusion is based upon studies conducted on sintering and steelmaking wastewaters. 10. COMMENT One commenter contends that EPA considered sulfide precipitation only as an add-on and ignored the less expensive alternative of retrofitting an existing BPT system with sulfide precipitation and plate settler packs. RESPONSE As noted above, sulfide precipitation is no longer a BAT alternative treatment technology. With regard to the suggested alternative, the Agency does not believe that treatment of the entire wastewater flow (model flow of 3200 gal/ton) using sulfide precipitation and tube plate settlers would be less expensive, from an investment and ------- operating standpoint, than providing separate chemical .addition an filtration for a substantially reduced flow (70 gal/ton). The Agenc also does not consider the suggested alternative feasible becasue o the substantial retrofit problems involved. 11. COMMENT The commenter recommends that the Agency re-evaluate the cyanid (total) limitation and provide new limitations which take into accoun the non-treatability and non-toxic nature of complexed cyanides. RESPONSE The Agency believes that the effluent limitations established fo cyanide takes into account all forms of cyanide present in ironmakin wastewaters. The Agency is required to limit cyanide and all cyanid compounds by the Settlement Agreement (see response to comment A-8) The concentration basis for the effluent limitations are based upo; and supported by pilot plant data and by the performance of the mode treatment technology installed on a full-scale basis. Effluent dat, from pilot treatment systems demonstrate the achievability of th< cyanide levels at different plants. These data indicate that cyanide: present in ironmaking wastewater are treatable to below the level: used to develop the limitations and standards with the model treatmen technology. 12. COMMENT The industry commented that the proposed pretreatment standards basei upon BAT Alternative 4 (alkaline chorination) are too stringent. RESPONSE The Agency has promulgated categorical pretreatment standards foi ironmaking operations based upon the same technology as the model BA1 technology. As set out in the development document, the Agenc believes these standards are appropriate to minimize pass through o: toxic pollutants at POTWs. 13. COMMENT The industry commented that the Agency's comparison of its model basei estimate for one of the ironmaking BAT alternative treatment system; with an unsolicited estimate from an engineering firm shows th< Agency's estimated cost is only one-tenth of the estimate supplied b; the engineering firm, not within 4.1 percent as claimed by the Agency On this basis, the industry also commented that the Agency understate! the economic impact of the regulation. RESPONSE: The commenter apparently misread the development document with respec to this issue. As clearly stated on page 376 of Volume II of th< 000037 ------- draft" development document (EPA 440/1-80/0245, December 1980), the estimates compared are the second BAT alternative presented in the October 1979 Draft Development Document (contractor's report) (EPA 440/1-79/0243, October 1979). This alternative includes alkaline chlorination followed by activated carbon. As shown, the comparison between this Agency's model based cost estimate and that supplied by the engineering firm agree within 4.1 percent. Thus, the Agency believes its cost estimates for ironmaking operations are representative and that it has not understated the impact of the regulation. 14. COMMENT The industry commented that the Agency has seriously understated the investment costs required for alkaline chlorination treatment of ironmaking wastewaters. In making this comment, the industry claims the Agency's investment costs are 5.6 times lower than actual costs incurred at Plant 0860B for alkaline chlorination treatment, and 17 times lower for annual costs. RESPONSE: The Agency examined cost data presented for Plant 0860B in detail and found that when appropriate considerations are made for the size of the treatment system installed at Plant 0860B, the actual treatment components installed, and year of the expenditures, the actual costs incurred for this plant compare reasonably well with the Agency's cost estimate for the model treatment system used to develop the final limitations. The alkaline chlorination treatment system installed at Plant 0860B includes alkaline chlorination, filtration, and activated carbon. This system is equivalent to the Agency's BAT Alternative 5 rather than Alternative 4 which was used to develop the proposed and final BAT effluent limitations. According to the industry, this plant was designed for a flow of 4.0 mgd, far above the Agency's model flow rate. The Agency notes that this treatment system was designed and constructed before the BPT recycle system at Plant 0860B was completed and before flow minimization of the BPT recycle system belowdown had occurred. Thus, the blowdown treatment facility was not sized to the minimum blowdown rates now being achieved in the industry. The installed treatment system at Plant 0860B also includes other treatment components (classifiers, hydroclones, and a bleach generation plant) not included in the Agency's model. The Agency does not believe that classifiers and hydrocyclones are necessary to achieve the BAT limitations, since adequate suspended solids removal equipment (thickeners and clarifiers) are included in the model BPT and BAT treatment systems. Vacuum filters are also not necessary for BAT treatment, since they are included on a larger scale as part of the BPT model treatment system. The additional sludge generated with BAT Alternatives 4 and 5 is small (less than 1 percent) compared to that produced at the BPT level; and, the vacuum filters 0038 ------- included in the model BPT treatment system are adequate for de-waterinc this sludge. A bleach generation unit is not included in' the Agency's model, since chlorine rather than bleach (sodium hypochlorite) is usec as the oxidizing agent. The Agency has included costs foi chlorinators in its model treatment system. In its comments/ the industry scaled the cost of the wastewatei treatment facility installed at Plant 0860B ($17.7 million) to th« size of the Agency's treatment system on the basis of flow using th« 0.6 factor. This resulted in a projected investment cost for i similar sized facility of $4.6 million. The industry compared this cost to the Agency's cost for BAT Alternative 4 of $0.82 million anc stated the Agency's investment costs are low by a factor of 5.6. Th« Agency believes this comparison is not appropriate because it does not take into account the treatment facilities installed at Plant 0860B. The Agency's investment cost estimate for BAT Alternative 5 is $3.1! million dollars. The Agency estimates that the cost for the items installed at Plant 0860B but not required to comply with the BA1] limitations is about one million dollars. Taking these costs intc account, the Agency's model plant estimate and the industry's costs for a similar sized plant agree within 10 percent. Thus, the Agency believes its model based cost estimates accurately reflect actua] industry costs. In response to public comments, the Agency made substantial revisions to the annual costs for the model BAT treatment system. Chemical us* costs were increased by a factor of about 10 and overall annual costs including sludge disposal costs were increased accordingly. Th< Agency believes these revised costs, including the costs for solic waste disposal, are appropriate. These revised costs also compare favorably with industry's estimated annual costs for Plant 0860B wher appropriate considerations are made for the size and type of th« wastewater treatment facilities installed at Plant 0860B. Th« industry presented total annual costs of $2.83 million based upon th« industry's scaled down investment cost of $4.6 million. In makinc this estimate the industry did not adjust the operation anc maintenance expense (listed as an annual cost equivalent to 25% oi capital investment) to the size of the smaller model plant, anc assumed the energy requirements for the model plant would only be om half those of the larger plant, although the full scale plant is ter times larger than the model plant and includes substantially mor« energy consuming equipment. The Agency notes that elsewhere in th< industry's comments, the industry stated that operation anc maintenance expenses and capital charges and depreciation amount t< 27% of capital investment vs. the 25% cited above for only operations and maintenance. Finally, with respect to chemical usage, Plant 0860B is operated witl caustic soda and sodium hypochlorite for alkaline chlorination. Th< Agency's treatment system is based upon the use of lime and chlorim gas, which are less expensive. Either set of chemicals can be used t< achieve the BAT limitations. However, the Agency believes it£ selection of treatment chemicals is more cost effective. Both lim< OOOG39 ------- and chlorine gas are used on a full scale basis in the industry for wastewater treatment. Given the above, the Agency believes that both its model based investment costs and annual costs are appropriate for the selected BAT alternative treatment system. 15. COMMENT The industry also compared the Agency's capital and annual costs for the proposed BAT Alternative 4 model treatment system with cost estimates made by the industry for this treatment system. The industry concluded that the Agency's estimated capital cost is less by a factor of more than 6 and the annual costs by a factor of 8. RESPONSE; The Agency evaluated the information provided and found that its cost estimates for those few mechanical equipment items which could be isolated in the industry's cost estimate are not substantially different than those presented by industry. The level of detail provided in the industry's estimate is not sufficient for the Agency to make a detailed evaluation of other direct cost items. However, the Agency notes the following: The industry's model treatment system is similar to the Agency's proposed BAT-Alternative 4 model treatment system, except that vacuum filters are included and the flow rate (125 gal/ton) used to estimate pollutant loadings to the treatment system is nearly 80% higher than the Agency's model flow rate. As noted previously, the Agency does not believe that vacuum filters are necessary for sludge dewatering in the BAT treatment system. This equipment is included in the BPT model treatment system and is capable of processing the additional sludge produced at BAT. The Agency's BAT Alternative 4 model treatment system is based upon 70 gal/ton. Hence, the rate of chemical usage and the annual chemical and other operating costs for the industry's model would be considerably higher than estimates made using the Agency's model. The associated equipment costs would also be higher than the Agency's costs for the same equipment since the equipment in the industry's model would have to be larger to treat the higher wastewater volume. Based upon the demonstrated flow rate used to develop the model BAT treatment system, the Agency believes its cost estimates are appropriate. The industry also included over $1 million of site specific costs in its estimates for demolition of an old blast furnace to make room for the BAT treatment facilities. The Agency believes that other sites may be available at this plant and that such high site specific costs would not be incurred. In any event, the Agency believes that the demolotion of old blast furnaces to make room for BAT treatment facilities is not required across the industry. The Agency believes that its cost estimates based upon its model treatment systems are accurate and appropriate for estimating industry-wide costs. As demonstrated in the previous comment, the Agency's estimates compare favorably with industry costs for Plant CCOG40 ------- 0860B. Moreover, as presented in the Volume I and in the i'ronmaki subcategory report of the Development Document, the Agency h compared its estimates with actual costs incurred at sever ironmaking facilities within the industry. This comparison furth demonstrates that the Agency's estimates are reasonable, and in fac exceed costs reported by the industry. 000041 ------- D. STEELMAKING 1. BOF-OPEN COMBUSTION a. COMMENT The industry commented that effluent limitations should be established for suspended solids only, since blowdown treatment for toxic metals has not been demonstrated for BOF-Open Combustion operations; the industry also commented that the Agency's proposed limitations for toxic metals are not achievable with the model BAT treatment technology. RESPONSE The model treatment system upon which the final BAT limitations are based -is lime precipitation followed by sedimentation in clarifiers. The model treatment system upon which the proposed BAT limitations are based included the above components and filtration of the clarified effluent. The Agency made this change in the model treatment system because available data show that filters do not perform substantially better than clarifiers with respect to toxic metals removal after precipitation and sedimentation has occurred. The final BAT limitations and standards are based upon a treatment technology which is well demonstrateds on a full-scale basis at BOF-Suppressed Combustion and Open Hearth-Wet operations and on a pilot-scale at an Electric Arc Furnace operation. The wastewaters from operation in these steelmaking subdivisions have characteristics similar to wastewaters from BOF-Open Combustion operations. In fact, as set out in the development document and in the response to Comment D°46, Electric Arc Furnace wastewaters contain much higher levels of toxic metals than any of the other steelmaking operations. The concentrations of toxic metals used to develop the BAT effluent limitations are based upon data from the EAF system. As a result, the application of the model treatment technology to wastewaters from BOF-open combustion operations will produce the same or better effluent quality. The high levels of toxic metals in the BPT recycle system blowdowns for wet steelmaking operations (the wastewaters after treatment to achieve the BPT limitations) justify the need for treatment at the BAT level. Zinc was found in the sampled effluents at levels ranging from 0.32 mg/1 to 2.8 mg/1; chromium in the range from 0.01 mg/1 to 30.1 mg/1; and lead in the range of 0.04 mg/1 to 13.6 mg/1. The Agency considers toxic metals at these levels to be significant and at treatable levels. BAT limitations are established for only lead and zinc based on achievable concentrations of 0.30 mg/1 and 0.45 mg/1, respectively. The Agency believes that it is appropriate to establish specific limits for these toxic metals and that limitations based upon these levels can be achieved at all steelmaking operations. Limitations based upon suspended solids alone will not effectively control the discharge of toxic metals in steelmaking wastewaters since these metals are in both the dissolved and particulate forms. It CGG6£2 ------- should be noted that if the commenter is claiming that the levels o toxic metal pollutants are found below the established BAT limitation and standards (and the Agency believes that this is not the case a many plants), then no additional treatment beyond that necessary b achieve the 3PT limitations would be necessary. b. COMMENT The industry commented that the model flow of 65 gal/ton for BOF-opei combustion operations should be reevaluated because the plant (0584F at which this flow is achieved is unique. The industry noted that th< use of fuel oil is used to fire waste heat boilers at this plant coul< affect the quality of the scrubber water to the extent that highei recycle rates could be achieved. RESPONSE The industry supplied no information or data to support theii contention that the use of fuel oil at this plant could affecl scrubber water to the point higher recycle rates could be achieved, The Agency does not believe this practice would significantly affecl the ability to recycle EOF wastewaters. Nevertheless, the Agencj reevaluated flow data for BOF-Open Combustion operations and found th< applied flow rate at plant 0584F is substantially lower than the mode] treatment system applied flow rate (265 gal/ton vs 1100 gal/ton), anc the recycle rate at this plant is only 75%. Since this flow is not it line with the model applied flow, the Agency evaluated all BOF-Oper Combustion systems with recycle rates of 90% or greater and founc these plants to be representative of the industry and practicing gooc wastewater treatment. Thus, the model treatment system effluent flov rate was established at 110 gal/ton. This flow is being achieved at 20% of the BOF-Open Combustion operations and can be achieved at al] BOF-Open Combustion plants with properly designed and operated recycle systems. C. COMMENT One commenter stated that the Agency did not properly evaluate treatec effluent data for BOF wet-open combustion steelmaking operations, citing the Agency's use of central treatment plant data. Th€ commenter noted the BOF effluent at Plant 0020B is diluted anc therefore the data are not valid; that the BOF discharge at plant 0112D receives further treatment which the Agency did not consider ir its analysis; and, for plants 0856B and 0868A, the Agenci misrepresented the quantity of toxic pollutants to be removed by the application of the proposed BPT and BAT limitations. RESPONSE The Agency disagrees with the commenter and believes that its analysis of the data used to determine raw waste loadings is proper. However, the Agency discovered an error in the data used to represent the rav wastewater pollutant loads for Plant 0868A. Mistakenly, the quality COGC£3 ------- of .the .make-up water was used instead of the actual raw wastewater quality. This has been corrected. This error resulted in an understatement of the effluent reductions achieved at BPT, in that the raw waste loads were significantly understated. The raw waste data for the other plants (0020B, 0112D and 0856B) are representative of raw wastewater discharges from EOF wet-open combustion systems. The Agency also believes that its analysis of the treated effluent data is proper. Samples for all of these plants were taken at the blowdown frcr. the recycle systems. The effluent quality from those plants is representative of the effluent from BPT systems. The only exception is the effluent load total suspended solids at Plant 0112D, which exceeded the BPT limitations. Increased recycle will not affect the effluent quality with respect to the limited pollutants since the concentration of these pollutants is reduced in the thickeners, which perform independently of wastewater recycle. Thus, the effluent data are representative of the discharge from BPT systems and are appropriate for calculating effluent reductions. The treated effluent at Plant 0020B includes wastewater discharges from a cupola. The effluent quality for the BOF discharge was therefore calculated from a proportional share of the effluent load attributable to the BOF. The load was apportioned on the basis of relative wastewater volumes. Although the pH values measured at Plants 0856B and 0112B are higher than the prescribed maximum of 9.0 standard units, the concentration of toxic metals will remian unchanged even if the pH is lowered. The toxic metals were measured as total metals, and are unaffected by pH alone. Therefore, the toxic metals data are representative of effluents from BPT systems. The Agency believes that its analysis of the data is proper and that it has not misrepresented the amount of toxic metal pollutants removed at BPT and BAT. 2. STEELMAKING-BOF-SUPPRESSED COMBUSTION COMMENT The industry commented that blowdown treatment for metals is not justified since the treatment system installed at the exemplary plant (Plant 0684F) does not remove any metals. Effluent limitations should therefore, be established for suspended solids only. RESPONSE Plant 0684F was not used as the exemplary plant upon which the proposed BAT limitations were based. Lime precipitation and clarification, the model BAT treatment system, is installed at this plant to treat the blowdown from a BPT recycle system. The Agency notes that toxic metals were not being removed during its sampling survey across the blowdown treatment system installed at plant 0684F GGOCS4 ------- due to the low levels of toxic metals in the influent to 'the 'blowdow treatment system. The toxic metals in this wastewater were bein removed prior to blowdown treatment because of the operation of th recycle system. Lime precipitation is practiced on the total flow o the recycle system rather than on the small blowdown as included i the Agency's BAT model treatment system. The high pH of the ra wastewater at plant 0688F results in the precipitation an sedimentation of the toxic metals in the primary BPT treatment system The effluent from the BPT treatment system installed at this plan complies with the final BAT limitations. Treatment of toxic metals in this subdivision is justified since thes metals are present at treatable levels. The 30-day averag concentration basis for zinc is 0.45 mg/1 and for lead 0.30 mg/1. A noted above, these concentrations are based upon a pilot stud; conducted on wastewaters from a wet EAF operation which ii representative of such operations. Wet EAF wastewaters typicall; contain toxic metals at levels much higher than contained ii wastewaters from other steelmaking operations. Limitations on tota suspended solids alone will not effectively control toxic metals since these metals are present to some extent in the dissolved state As noted above, if the commenter is claiming that the levels of toxii metals in the BPT effluent at a particular plant are in compliance with the BAT limitations, then additional treatment facilities beyon< that required to achieve the BPT limitations are not required. 3. STEELMAKING-BOF-SEMI-WET a. COMMENT The industry commented that effluent limitations based upon reasonabl< blowdown rates should be established in lieu of the proposed (BPT an< BAT) zero discharge limitations since achievement of zero discharg< through the application of the model treatment technology has not beet demonstrated. RESPONSE The model treatment technology to achieve zero discharge has beer modified to conform to the system installed at Plant 0432A, which is in compliance with the zero discharge limitation. The performance at this plant is the basis for the final BPT and BAT limitations, However, the model treatment technology used as the basis for th« proposed limitations included wastewater treatment and sludge handlinc equipment more sophisticated than installed at Plant 0432A. That model technology included vacuum filters which minimize water loss through the sludge as opposed to drag out tanks used with most semi-wet gas cleaning systems. The water loss as moisture in sludge is not considered a discharge. This water loss, however, serves as blowdown from the system and prevents dissolved solids from increasing to levels at which scaling would occur. Thus, zero discharge can be achieved by attention to water application rate and sludge handlingg. The Agency recognizes, however, that there may be unique, plant OGDOS5 ------- specific, factors which could not be taken into account in this regulation which may limit the owner or operator's ability to achieve zero discharge at certain semi-wet steelmaking operations. In such cases the owner of that facility may pursue alternative limitations at the permit writing stage based upon this fundamentally different factor. Reference is made to Section IV of the steelmaking subcategory report of the development document for additional information. b. COMMENT One comrnenter recommended that three additional BOF semi-wet plants be sampled in order to determine whether this segmentation of the BOF subdivision is proper. RESPONSE The Agency believes that sufficient information is available to justify segmenting the BOF subdivision to separately regulate the semi-wet plants. The fact that semi-wet operations include water use primarily for conditioning and cooling the gases prior to dry gas cleaning clearly distinguish these plants from those where the gases are cleaned in wet scrubbers. The information submitted by industry and the sampling data collected by the Agency demonstrate that the water application rates and untreated wastewater contamination at semi-wet plants are an order of magnitude less than at wet plants; and, that recycle to extinction is feasible at semi-wet plants where water is used for gas conditioning purposes. Zero discharge cannot be achieved at plants with wet scrubbers due to scaling problems. 4. STEELMAKING - EAF a. COMMENT The industry commented that the flow basis for the EAF-Wet subdivision should be reevaluated, since the two plants identified as achieving the 50 gal/ton model flow rate actually discharge at higher levels. RESPONSE Data used by the Agency to develop the model flow rate of 50 gal/ton for the proposed BAT limitations were submitted by the industry in response to questionnaires. The Agency has corrected the data base for EAF plants based upon more detailed information submitted by the owners. The model treatment system flow rate has been increased to 110 gal/ton, which represents the average of those plants that achieve a recycle rate greater than or equal to 90 percent. For the reasons set out in the steelmaking subcategory report, the Agency believes that this is an appropriate flow rate upon which to base the BAT limitations. GGOC£6 ------- b. COMMENT The industry commented that effluent limitations should be establishe for suspended solids alone, since the need to limit toxic metals an the validity of the underlying treatment technology has not bee justified. In its comments, the industry presented concentrations o toxic metals determined from ratios of concentrations of suspende solids and toxic metals to indicate that higher toxic metal limitations are justified. The industry also commented that th Agency did not present dissolved metals data for its pilot plant stud to support its view that much of the toxic metals loading is, in fact in the form of dissolved metals. RESPONSE As for the other steelmaking subdivisions, the proposed BA limitations are based upon lime precipitation followed b; clarification and filtration. The final BAT limitations are, however based upon lime precipitation and clarification. Filtration has bee deleted from the model treatment system since the incremental remova of toxic metals after lime precipitation and clarification is no significant. Pilot studies were conducted on wastewaters from an EAF-wet operation This plant (0612) is representative of other wet EAF plants, and has discharge close to the model flow rate. The data from this stud clearly indicate that a large portion of the toxic metals found i steelmaking wastewaters are present in the dissolved state, and lim precipitation followed by clarification effectively removes thes metals. Filtration or other technologies that remove suspended solid alone are not-effective for dissolved metals removal. The dissolve metals data were in the record at proposal; and, have been included i the development document. The Agency has evaluated the methodolog used by the industry (ratio of suspended solids to toxic metal effluent levels) and finds it to be erroneous since, as noted above, considerable portion of the toxic metals in EAF wastewaters ar dissolved toxic metals, and a ratio of total suspended solids b dissolved metals is meaningless. The levels of toxic metals present in BPT system effluents justify th need for treatment beyond the BPT level. Effluent data collecte during the Agency's sampling surveys and other data submitted b industry show that zinc levels range from 3.2 mg/1 to 48 mg/1, an lead from 1.0 mg/1 and 25 mg/1. These data demonstrate that EA wastewaters contain the highest level of toxic metal pollutants. Th pilot plant study noted above demonstrated that the model BA treatment technology can remove lead and zinc to levels of 0.3 mg/ and 0.45 mg/1 on a 30-day average basis, respectively. As note earlier, the Agency used these data as the basis for the BA limitations for all wet steelmaking operations. The Agency believe that since EAF wastewaters are the most highly contaminate steelmaking wastewaters with respect to toxic metals, it i appropriate to base effluent limitations and stanadards for the les * Onr«f>r n u U b £ i ------- contaminated steelmaking wastewaters upon treatability and performance data developed for EAF operations. c. COMMENT The industry commented that effluent limitations should be established for the EAF semi-wet subdivision in lieu of the zero discharge standards/ since zero discharge is no longer achieved at the plant upon which this standard was based, and zero discharge is not achieved at other plants in this subdivision. RESPONSE Plant 0432C was one of the models for the zero discharge standard for EAF semi-wet operations. The gas conditioning system at this plant was converted to once-through discharge as a result of scaling experienced at the spray nozzles, in the gas conditioning system after several years of operation at zero discharge. The Agency found that Plant 0584A operates in a zero discharge mode, despite the fact that provision for discharge is included in the design of the facility. Information recently submitted by the company indicate that wastewater discharge at this plant occurs only inadvertently when leaks develop in the spray towers, or an imbalance in the flow system occurs. These discharges are reported to occur on an infrequent basis. The Agency considers these infrequent and inadvertant discharges to be upsets which are not precluded under the zero discharge standard. The Agency believes the achievability of the zero discharge standard is demonstrated at this plant. As noted above, this technology is also demonstrated in the EOF semi-wet subdivision in the same type of application. In the Agency's opinion, the demonstration of zero discharge at EOF semi-wet plants is applicable to EAF semi-wet operations. The Agency recognizes, however, that there may be unique, plant specific factors which could not be taken into account in this regulation which may limit the owner or operator's ability to achieve zero discharge at certain semi-wet steelmaking operations. In such cases, the owner of that facility may pursue alternative limitations at the permit writing stage based upon this fundamentally different factor. Reference is made to Section IV of the steelmaking subcategory report of the Development Document for additional information. 5. STEELMAKING-OPEN HEARTH a. COMMENT The industry commented that the open hearth semi-wet segment should be deleted since the single plant covered by this segment has wet gas cleaning systems. RESPONSE In response to this comment, the Agency reviewed available information for Plant 0864A and found that wet air pollution control systems are ------- installed on the open hearth steelmaking operations at this plant. Accordingly, the open hearth-semi-wet segment has been deleted,and th« plant is now listed as an open hearth-wet operation. b. COMMENT The industry commented that effluent limitations should be established for suspended solids only, since the model BAT treatment technology has not been demonstrated for open hearth-wet operations and the toxic metal effluent limitations cannot be consistently achieved because of fluctuations in raw waste loads. RESPONSE As for the other steelmaking operations, the model treatment technology used to establish the proposed BAT limitation included filtration of the effluent from a lime precipitation and clarificatior system. The model treatment technology used for the final BAT limitations is lime precipitation and clarification. This technology is demonstrated at Plant 0864A, as well as for the other steelmakinc subdivisions. At Plant 0864A, lime is added in the primary BP1! recycle loop upstream of the clarifiers. In the model BAT treatment system lime precipitation and clarification is performed on the blowdown from the BPT recycle system. Nonetheless, the same effluent concentrations with respect to toxic metals are achievable in both systems. This is also demonstrated at Plant 0684F (see Response tc Comment D-2). The effluent at Plant 0864A is in compliance with the BAT limitations. These limitations were established on the basis of c pilot plant study conducted at Plant 0612. As noted in the response to Comment D-4b EAF operations have the highest levels of toxic meta] contamination. The Agency has determined it is appropriate to base the BAT limitations upon those data for all wet steelmakinc operations. Fluctuations in influent loads to the BAT treatment system at oper hearth operations should not affect the effluent quality of well designed treatment facilities. In the Agency's opinion, properly designed and operated treatment facilities are capable of treating varying raw waste loadings to a level which achieves the BAT limitations. Moreover, the BPT recycle systems installed at these facilities serve to equalize and dampen the fluctuations in the loads discharged to the blowdown treatment system. If such fluctuations are unavoidable at a particular plant, surge capacity for the blowdown car be installed prior to the BAT treatment system at low cost to achieve the desired blowdown rate and the applicable effluent limitations. Establishing effluent limitations for suspended solids will not adequately control the discharge of toxic metals since the toxic metals are present, to a large extent, in the dissolved state. The need for treatment of toxic metals is justified since these pollutants are present at treatable levels. Zinc has been found at levels ranging from 4.4 mg/1 to 26 mg/1. Although lead was found belov treatable levels in open hearth wastewaters, limitations have beer COOG49 ------- established for this pollutant to facilitate co-treatment with other compatible wastewaters. 6. STEELMAKING-GENERAL a. COMMENT A commenter stated that the Agency in reviewing the alternative BAT treatment technologies for steelmaking wastewaters, did not consider high gradient magnetic separation. RESPONSE The Agency agrees that high gradient magnetic separation may be a promising wastewater treatment technology for removal of iron-bearing particles. However, the Agency has no data to demonstrate how this technology would perform with respect to removal of dissolved toxic metals, and lacks sufficient data to confidently project the reliability and cost of such systems. As a result, this technology was not considered. b COMMENT The same commenter stated that in-plant control measures for reducing wastewaters from steelmaking operations should be given more consideration. RESPONSE Aside from recycling of wastewaters, the Agency is not aware of other in-plant controls that could be used at all steelmaking facilities to reduce the discharge of wastewaters. Recycle is a major component of the model treatment systems evaluated by the Agency. c. COMMENT One commenter believes that sulfide precipitation, rather than lime precipitation should have been selected as the model BAT and NSPS treatment systems, since this technology is less costly and should remove toxic metals to lower levels. RESPONSE Theoretically, sulfide precipitation should remove toxic metals to lower levels than lime precipitation. However, the study conducted by the Agency on steelmaking wastewaters demonstrate that lime, sulfide and carbonate precipitation reduced metals to equivalent levels. The Agency concluded that it was appropriate to base the BAT limitations on lime precipitation since this technology is widely used in the industry and the studies conducted by the Agency demonstrate similar performance with other precipitation systems. OOOC50 ------- d. COMMENT One commenter contends that the retrofit of lime precipitatioi technology in the model BPT recycle treatment system, rather thai using it for blowdown would reduce costs. The commenter stated thai the installation of plate settler packs in existing clarifiers anc thickeners would be standard engineering practice. RESPONSE The Agency balieves that placing tube plate settler packs in a full flow treatment sytsem and providing the requisite chemical additioi would be substantially more costly than providing separate chemica! addition and sedimentation for a substantially reduced effluent flow The Agency also believes that there would be substantial retrofil problems implementing this technology at most plants. Notwithstanding the above, the regulation does not preclude this method of operation. e COMMENT The commenter recommends that the Agency collect additional data foi fluoride in steelmaking wastewaters and reconsider the need t< regulate fluoride discharges in the steelmaking subcategory. This commenter cited three specific examples of high fluorid* concentrations in raw wastewaters (one EAF-semi-wet and two oper hearth operati ons). RESPONSE The Agency agrees that fluoride is present in EAF and open heartl furnace steelmaking wastewaters at treatable levels. However, th« Agency believes that the model treatment system used to establish th« BAT effluent limitations for toxic metals will also effectively control fluoride. Lime precipitation is a commonly used technology tc remove fluoride. Those operations with high fluoride concentrations were also observed to have low raw wastewater pH and high toxic metals concentrations. Therefore, lime addition sufficient to achieve th« level of control specified for the limited toxic metal pollutants wil] also achieve effective removal of fluoride. The Agency does not consider the expected discharge levels of fluoride to be higher thai treatability levels and thus, does not believe that limitations an< standards for fluoride are appropriate. f. COMMENT One commenter recommended that EPA eliminate pelletizing am associated credits from the cost estimate for the steelmakinc subcategory since steelmaking sludges are not frequently re-used. C00051 ------- RESPONSE The Agency re-evaluated steelmaking sludge credits and agrees with the commenter. Although recovery of steelmaking sludges is practiced at two plants, the Agency has concluded that such practices are not applicable on an industry-wide basis. Thus, credit for sludge recovery has been deleted from the cost estimates for this subcategory. 000052 ------- E, VACUUM DEGASSING 1. COMMENT In response to the Agency's solicitation for comments on the feasibility of establishing a BAT limitation of zero discharge for vacuum degassing operations, one commenter recommended that zero discharge be adopted. RESPONSE While zero discharge has been reported for two vacuum degassing operations, the Agency does not believe that zero discharge can be achieved at all vacuum degassing operations unless costly evaporative technologies are used. The Agency believes that a small blowdown may be necessary to prevent the build-up of dissolved salts in the recycle systems. The Agency has concluded that the incremental pollutant removal between the promulgated BAT limitations based upon 98% recycle of vacuum degassing wastewaters and zero discharge does not justify the high cost involved. To the extent that zero discharge can be achieved at low cost to attain compliance with the appropriate limitations and standards, the Agency encourages the industry to do so. 2. COMMENT A commenter contends that the Agency should evaluate the use of coagulant aids prior to filtration in the Vacuum Degassing subcategory. The commenter states that when used for gas scrubbing purposes waters should contain no more than 200 mg/1 of TSS, that low suspended solids loadings would permit complete recycle and eliminate the need for a discharge. RESPONSE While the use of coagulant aids can can enhance filter performance in certain cases, consideration must be given to the nature of the wastewater being filtered. In this case, the nature of the wastewaters (i.e., discrete particulate matters, etc.) do not warrant coagulant aid addition. In fact, the model raw wastewater suspended solids concentration is 60 mg/1, much lower than found in other steelmaking wastewaters. The sampled plant monitoring data demonstrate that high rate recycle can be achieved at vacuum degassing operations without the use of coagulant aids and filtration. The Agency does not believe filtration would allow complete recycle of vacuum degassing operations. As noted above, the Agency did not establish a zero discharge standard for these operations, because it believes zero discharge can only be achieved universally with costly evaporative technologies. 000053 ------- 3. COMMENT ' , , The commenter states that the Agency should have considered hig gradient magnetic separation for the removal of fine iron particulate from vacuum degassing scrubber wastewaters. The commenter states tha such a device is capable of producing an effluent with less than 2 mg/1 of TSS. RESPONSE Filtration, which is a component of the BAT model treatment system will achieve similar effluent TSS levels. Filtration has th significant advantage of being demonstrated in this subcategory. I: addition, filtration offers significant investment and operating cos benefits as well. C00054 ------- FV.. CONTINUOUS CASTING 1. COMMENT The industry commented that the BAT limitations should be set equal to the BPT limitations since toxic metals are not contributed by the process in significant amounts nor are they removed by the proposed BAT treatment technology (filtration). RESPONSE The Agency believes that it is appropriate and feasible to reduce the discharge of toxic metals from continuous casting operations. Available data clearly show that chromium and zinc are present in the untreated continuous casting wastewaters and in BPT effluents in the 1 to 2 mg/1 range. Lead is also present at treatable levels. Consequently, the Agency has promulgated BAT limitations that are more stringent than the BPT limitations (which limit conventional pollutants only). Filtration of the BPT recycle system blowdown was used as the BAT model treatment system to develop the proposed BAT limitations. In response to the above comment, the Agency reevaluated available monitoring data and found that a considerable portion of the toxic metals found in continuous casting wastewaters are in a dissolved state. The Agency believes that some of the dissolved metals may originate in chemical additives used in the high rate recycle systems at the sampled plants or, are actually fine particulate metals measured as dissolved metals by the analytical methodology. The Agency agrees that filtration does not effectively control these metals. Accordingly, the Agency has selected lime precipitation and sedimentation as the model BAT technology. This technology is effective for treating both dissolved and fine particulate toxic metals. The Agency used data on achievable toxic metal concentrations obtained from pilot plant studies at electric furnace operations to develop the BAT limitations for continuous casting operations. As explained in the development document, the Agency believes it is appropriate to rely on the data to establish the BAT limitations for continuous casting operations. Moreover, the limitations and standards for continuous casting, vacuum degassing, and all wet steelmaking operations are based upon the same treatment technology and concentrations. Co-treatment of compatible wastewaters from these subcategories is feasible. 2. COMMENT In response to the Agency's solicitation of comments on whether zero discharge would be appropriate as BAT for continuous casting operations, the industry commented that zero discharge is not possible due to comingling of other extraneous wastewaters and the need for blowdown to control levels of dissolved solids in the recycled water. 000055 ------- RESPONSE The final BAT limitations are not based upon zero discharge becaus the Agency believes zero discharge can only be universally achieve through the use of costly evaporative technologies. However, th Agency notes that zero discharge has been reported for several plants and, to the extent zero discharge can be achieved to attain complianc with the appropriate limitations and standards, the Agency encourage the industry to continue this practice. 000056 ------- G. HOT FORMING 1 . COMMENT The industry commented that the Agency should not promulgate BAT limitations for hot forming operations because toxic metals are not contributed by hot forming processes to its wastewaters. The industry also commented that BAT limitations for suspended solids and oil and grease should be established at a level no more stringent than BPT. Others commented that the BAT limitation for hot forming operations should be zero discharge. RESPONSE In response to these comments, the Agency reviewed its existing data for the hot forming subcategory and conducted additional extensive sampling programs at fifteen hot forming operations in cooperation with the industry. These data clearly demonstrate that significant quantities of toxic metals are generated by hot forming operations, are present in hot forming raw wastewaters, and, are also present in the wastewaters discharged from the primary scale pits used to recover mill scale. These data also demonstrate that toxic metals are removed to very low levels at plants with the model BPT treatment system installed (i.e., primary scale pit, partial recycle, secondary settling, and filtration). The average gross effluent concentration of all toxic metals in the wastewaters of these plants after treatment is about 0.07 mg/1. The Agency believes that, at these levels, the toxic pollutants have been effectively controlled and that the substantial cost (more than $300 million on an industry-wide basis) of full scale (96 percent) recycle of these wastewaters to further reduce the discharge of toxic metals is not justified. While zero discharge is reported to be achieved at some hot forming operations, the Agency found that many of these systems do, in fact, have small discharges. The Agency does not believe that zero discharge can be achieved at all hot forming operations without the use of costly evaporative technologies. The data for several hot forming operations demonstrate that wastewater recycle rates of up to 99% are achievable on a long term basis. Based upon these factors, the Agency has not promulgated BAT limitations for the hot forming subcategory. As explained in greater detail in the development document, the final BPT limitations were revised from those proposed to take into account actual performance of the BPT technology with respect to suspended solids, oil and grease, and flow. The Agency has maintained high rate recycle (96%) as the basis for NSPS since this technology is well demonstrated throughout the industry and will substantially reduce the total pollutant loading discharged from the process. 000057 ------- 2. COMMENT . . •, The industry commented that the Agency should retain its definition oj "carbon" steels from the March 1976 development document and adopt c new definition of "specialty" steels. RESPONSE In response to this comment, the Agency has reviewed both th< definition of "specialty" steels contained in the proposed regulatior and the definition suggested by the commenter. The Agency believes the commenter's suggested definition, being consistent with industry usage, is more appropriate and has adopted that definition oJ "specialty" steels. 3. COMMENT The industry recommended that the Agency reevaluate its toxic metal discharge loadings from the hot forming subcategory, notably witt respect to concentrations reported as being less than the detectable limit of the analytical methodology. RESPONSE The toxic metal loading data for all subdivisions of the hot forminc subcategory were reviewed and revised accordingly. All loading dat< are now presented as long term averages as opposed to 30 day average: based upon the effluent limitations. Concentrations reported as less than the analytical level of detection have been considered as zero, The Agency believes that treatment of the data in this fashion ii appropriate. 4. COMMENT The industry commented that the pollutant loading data for the hoi forming subcategory are biased because production weightec concentrations were not used in developing the loading estimates. Th< industry contends the overall loadings are overly influenced by small plants with poor treatment. RESPONSE The Agency has analyzed the data and concluded that it would b< inappropriate to average concentrations on a production weighte< basis. Effluent quality is unrelated to production and is, in fact, related primarily to the performance of the wastewater treatmenl facilities. Since the concern is with the pollutant loading.' discharged from a facility, the appropriate method for computin< weighted averages, if necessary, would be on a flow weighted basis The Agency has computed the flow weighted averages for the exampl< presented by AISI in its comment (Table 12, p. 167). The following comparison of the methods for calculating the averages demonstrate; C00058 ------- that differences between the flow weighted method and the arithmetic average method used by the Agency are not significant. EPA Average (Arithmetic) EPA Average (Flow Weighted) AISI Average (Production Weighted) Flow, gal/ton TSS Oil and Grease Lead Nickel Zinc Total Toxic Metals 6,590 1.47 0.28 0.0011 0.0058 0.0015 0.0084 6,590 1.69 0.26 0.0007 0.0073 0.0013 0.0093 6,419 0.78 0.24 0.0011 0.00092 0.0015 0.0035 000059 ------- In any event, the issue of computing toxic metal loadings for h forming operations is not particularly relevant, since the Agency h not promulgated toxic metal limitations and standards for hot formi operations. 5. COMMENT The industry commented that not all sources of wastewater flow we considered for hot forming pipe and tube operations at Plants 068 and 0948A; that some of the data for Plants 0060R and 0684A we: misinterpreted or incorrect and, that there are no seamless tul operatons at Plant 0856C. RESPONSE The Agency reevaluated the data submitted by the industry for Planl 0060R and 0684A, and made appropriate corrections to its data bas< For Plant 0856C, the Agency found that operations at this plai include the manufacture of pressure vessels by seamless pipe methoc and has kept data for this plant in the data base. The own* classified the operation as a seamless tube hot forming plant and tl Agency believes the operation should be classified accordingly becaus of the manufacturing process used. With respect to Plant 0684H, tl Agency's contractor could not quanitfy the flow at this plant durii the sampling survey. However, data reported for this plant by tl owner were used by the Agency. Reference is made to Table X-12, ( the hot forming subcategory report in the draft development documer and to Table IX-9 in the hot forming subcategory report in the fin; development document. In response to the comment regarding the seamless tube finishing ar« flows for Plant 0948A, the Agency reevaluated the flow data reporte by the owner. The Agency did not include the applied flow rate associated with the seamless tube finishing operations at this plar (quenching, tempering, and upsetting) in its determination of th average applied flow for all seamless pipe and tube operations Because of the inordinately high applied flow rates at this plant fc these operations, the Agency does not believe it is appropriate t bias the average rate for all mills with data for a one mill wit ancilliary operations. Since such finishing operations are practice at only a few plants and the flow rates at those plants are variable the Agency has decided that case-by-case determinations should be mac for those facilities at the permit writing stage. 6. COMMENT The Agency solicited comments as to whether the carbon and specialt steel hot forming operations should be subdivided to a greater degre to account for the differing levels of toxic metal contributed fc either type of operation. In response, one commenter stated tha further subdivision is not warranted, since the data showed tha carbon steel operations occassionally discharged higher loadings c GOOC60 ------- toxic metals, and the toxic metal levels in the discharge from both carbon arid specialty steel operations are similarly treatable. RESPONSE The Agency agrees with the commenter. In addition, available data indicate that after application of the model BPT treatment technology, the levels of toxic metals in the discharge from both types of operations are the same. As a result the Agency, has not further subdivided the hot forming subcategory. 7. COMMENT One commenter suggested that the Agency use sulfide precipitation for toxic metals removal from hot forming wastewaters as the model BAT and NSPS treatment systems. RESPONSE The Agency considered sulfide precipitation as an alternative treatment technology for toxic metals removal. However, this technology was not selected as part of the BAT model treatment system since the Agency concluded that toxic metals are effectively controlled by the BPT model treatment system and, therefore, BAT limitations are not necessary. 8. COMMENT The same commenter suggested the Agency did not adequately consider the transfer of wastewater demineralization technology used to treat continuous casting wastewaters for the treatment of wastewaters from hot forming operations. The commenter implies that demineralization technology could be used to reduce or eliminate the discharge from hot forming wastewaters. RESPONSE The Agency believes demineralization technology is neither appropriate nor necessary for the treatment of hot forming wastewaters. As noted above, the Agency has not promulgated BAT limitations or NSPS for toxic metals for hot forming operations. Demineralization is not demonstrated for treatment of hot forming wastewaters. Based upon widespread application in the industry, the Agency found that sedimentation, clarification, and filtration systems produce water of sufficient quality for recycle rates of up to 99 percent. Thus, the application of dimineralization to hot forming wastewaters provides no significant benefits in terms of effluent quality. 9. COMMENT The industry commented that the Agency should not use comingling factors (factors used to adjust the costs of separate treatment facilities for combined treatment of hot forming wastewaters) to 000061 ------- estimate the cost of compliance with the proposed BAT limitations fo: hot forming operations, because the economies of scale realized witi comingling factors may be offset by site-specific costs. The industr also commented that its estimated investment costs for industry-widi compliance with the proposed BAT limitations is higher than tin Agency's estimate by a factor of 1.4. In making this comment, th< industry cited estimates prepared by Bethlehem Steel for one plant ai the basis for its industry-wide estimate. The industry furthei commented that the Agency's annual cost estimtes are likely to be loi because the industry believes the cost of capital, depreciation an< operation and maintenance is likely to be 27% vs. 20% used by th< Agency for these factors; and, because the Agency overstates mil! scale credits. RESPONSE As noted -above, the Agency has decided not to promulgate the propose* BAT limitations for hot forming operations. Comingling factors wer< not used to estimate the cost of compliance with the final BP' limitations or with NSPS. Reference is made to the hot forming subcategory report of th< development document for a detailed cost comparison of actual industrj expenditures and Agency model based estimates for 24 hot formim treatment systems. This comparison clearly demonstrates the Agency's estimated costs for treatment of hot forming operations accurately reflects actual costs incurred by the industry including site-specifi< and retrofit costs. With respect to annual costs, the Agency has revised the operating cost credits allocated to recovery of mill scal< and modified the capital recovery factor used to estimate annualizec costs of capital. The revised factor is set out in Volume I of th< development document and was used to determine annual costs. Th< Agency believes the use of this factor is appropriate. 10. COMMENT The industry commented that the cost comparisons for BCT treatment systems considered for nearly all hot forming operations would nol pass a BCT cost test based upon $0.27/lb of conventional pollutant removed. RESPONSE As noted in the development document, the Agency has promulgated BC limitations for hot forming operations that are the same as th< respective BPT limitations. 11. COMMENT One commenter questioned the Agency's specification of filtratior systems for oil and grease removal. RESPONSE D062 ------- The model treatment technology for hot forming operations includes filtration for suspended solids and oil and grease removal. Most of the oil removed from hot forming wastewaters is removed at primary scale pits or in secondary settling systems where oil skimmers are used. The filters included in the BPT model treatment systems are capable of removing much of the oil remaining after oil skimming operations. The Agency agrees with the commenter that filtration systems cannot be used as a primary oil removal system, particularly for hot forming wastewaters with high oil levels. Reference is made to the development document for filter performance data for oil and grease removal. 000063 ------- H. SALT BATH DESCALING 1. COMMENT The industry commented that model treatment system flows for bo Kolene (oxidizing) and Hydride (reducing) descaling operatioi operations should reflect the distinction between the type of produi or operating mode, i.e., batch and continuous operations. RESPONSE As set out in detail in the Development Document, the Agency hi reevaluated the data and found the revised rinsewater flow f< different products and operating modes are appropriate. Tl limitations and standards for descaling operations are based up< these revised flow rates. 2. COMMENT The industry commented that flow rates used to establish the effluei limitations must account for the fact that process waters used fc rinsing the descaled products are also used concurrently for produ< cooling. RESPONSE Since actual rates reported by the industry were used to establi! model treatment system flow rates and the effluent limitations ai standards, all uses of the process waters have been taken into accoul The Agency believes the revised model flow rates are sufficient 1 accomodate concurrent rinsing and cooling of the product. The Agent does not have any data which demonstrates a need for additional fl< allowances beyond that provided by the revised flows noted above. 3. COMMENT The industry commented that the flow data for the only continuoi hydride operation (Plant 0176) were excluded from the data base. Th« contend these data should be included and scrubber water flows at thi plant should also be considered. RESPONSE The reducing (hydride) subdivision has been segmented into batch ai continuous operations. As described in the development document, tl flow data for Plant 0176 were used as the basis for the model fl< rate for continuous hydride operations. The scrubber waste at thi plant was not included in the data base for descaling operations sin< the scrubber in question is associated with a combination aci pickling operation the Agency has included the scrubber data in tl data base for the acid pickling subcategory. 000064 ------- 4. COMMENT The industry commented that the effluent limitations and standards for scale removal operations should be based upon data for treatment systems specific to scale removal operations, rather than on central treatment plant systems that do not include scale removal operations. RESPONSE The proposed limitations were based upon data from several steel finishing operations. In response to industry comments, the Agency based the final effluent limitations and standards upon performance data for a wastewater treatment facility at the Armco Steel - Butler Works that is used to treat wastewaters from descaling and combination acid pickling operations. The performance data were submitted as part of industry's comments, and subsequently supplemented with additional data submitted by the company at the request of the Agency. Hence, the basis for the descaling effluent limitations and standards reflect combined treatment of descaling and combination acid pickling wastewaters, which is common practice in the industry. The agency considers wastewaters from these operations to be compatible for purposes of co-treatment. 5. COMMENT An industry commenter noted that the Agency did not properly use central treatment plant data to demonstrate that the proposed BPT limitations are achievable. This commenter cited the use of data from Plant 139 as an example of the improper use of such data. RESPONSE The Agency agrees that data from Plant 139 are not appropriate to justify the BPT limitations, because the wastewaters at this plant are not properly treated. Only a crude treatment system is installed at this plant. Data for this plant are no longer used to justify the limitations. However, the Agency has continued to use central treatment plant data to establish and justify the promulgated limitations and standards. The Agency believes that effluent data from properly designed and operated central treatment systems for compatible wastewaters are suitable for this purpose. As explained throughout the development document, these treatment systems are common in the industry. The Agency has structured the final regulations to facilitate co-treatment of compatible wastewaters by limiting common pollutants in those subcategories with compatible wastewaters. 000065 ------- I. ACID PICKLING 1. COMMENT The industry commented that the model flow rate for each acid picklinc subdivision, (i.e., sulfuric, hydrochloric and combination acid), should be reevaluated to consider discharge rates associated witl different products and that the subcategory should be furthei segmented to account for these variations. RESPONSE In response to this comment, the Agency reevaluated available flov data and determined that rinsewater flows are related to product type. Accordingly, the Agency has resegmented each of the acid picklinc subdivisions. Separate effluent limitations and standards art established for the following groups of products: (1) rod, wire anc coil; (2) bars, billet and blooms; (3) strip, sheet and plate; and (4) pipe, tube and other products. The model flow rates better reflect actual rinsewater requirements by product type than did the model flov rates used to develop the proposed limitations. As discussed in the development document these model flows were developed using the production weighted method and included nearly all of the reportec flow data. 2. COMMENT The industry commented that the cost and feasibility of retrofittinc cascade rinse systems to existing pickling lines should be reevaluated. RESPONSE In light of the information submitted by the industry, the Agency has increased model costs for retrofitting cascade rinse systems. Ir addition, the Agency has determined that space limitations and the configuration of certain pickling lines may require major reconstruction of some lines to permit retrofitting of cascade rinse systems. This would result in prohibitive retrofit costs. Cascade rinse systems were, therefore, not selected as the basis for BAT limitations. The Agency considers retrofit of cascade rinse systems at acid pickling lines substantially different than retrofitting end- of-pipe pollution control systems. Cascade rinse systems are essentially process modifications which substantially alter process water usage, whereas end-of-pipe treatment systems, including those with internal and end-of-pipe recycle, do not affect the interna] workings of the production processes to any great extent. As noted ir the development document, less expensive rinsing systems now beinc marketed should provide the opportunity to achieve rinsewater flov reduction at some pickling lines at less cost than conventional flov reduction methods. However, because these systems are relatively nev and sufficient information is not available, the Agency did not use this technology as model flow reduction systems for BAT at this time. 000066 ------- As a .result, the BAT limitations are the same as the BPT limitations. However, 'cascade rinse systems are included in the NSPS and PSNS model treatment systems, since cascade rinse systems can be designed into new pickling lines without retrofit problems. 3. COMMENT The industry commented that the fume scrubber flow allowances should be reevaluated and flow allowances should be determined on a site-specific basis at the permit writing stage, since these flows are independent of production rates. RESPONSE The Agency has reevaluated fume scrubber flow data for all acid pickling operations and concluded that the flow rates are independent of production, scrubber type, or the air flow rate through the scrubbers. Fume scrubber wastewaters are commonly recycled to a high degree. Based upon this review, a model flow rate of 15 gpm (which represents a blowdown of 15% from recycled fume scrubber systems) was established. This model flow rate is used as the basis for the daily mass effluent limitations and standards separately established for fume scrubbers. The Agency believes it is more effective to establish uniform limitations in this regulation rather than on a site-specific basis at the permit level, because the data demonstrate that recycle of fume scrubbers is feasible at all plants and there is no need to defer this issue for case-by-case determinations at the permit level. 4. COMMENT The industry commented that effluent data from carbon steel operations should not be used to establish toxic metals limitations and standards for specialty steel operations. The industry suggested the Agency use data for the Armco Steel-Butler Works as a basis for the appropriate limitations and standards. RESPONSE Based upon this comment, additional effluent data from the Armco Steel - Butler Works (a specialty steel operation) were obtained. These data were used to establish toxic metals limitations and standards for specialty steel operations (i.e., combination acid pickling and salt bath descaling operations). Effluent data for carbon steel operations are no longer considered with data from specialty steel operations. 5. COMMENT The industry commented that the model flow rates for new sources improperly assumes that flows can be reduced (beyond the rate for existing sources) by using dirty fume scrubber blowdown as make-up to the cascade rinse system. 000067 ------- RESPONSE Based upon this comment, the Agency has changed its NSPS mode treatment system to provide for separate mass-based discharges fo fume scrubber recycle system blowdowns. The Agency no longer include use of this water as make-up to the cascade rinse system included i the NSPS model treatment system. The Agency believes, however, tha the fume scrubber recycle system blowdown can be used, at least on a intermittent basis, as make-up to the acid tanks, thus minimizing th discharge. 6. COMMENT The industry recommended that pickle line wastewater flows should b reevaluated to develop allowances for flows from wet looping pits The industry cited a wet looping pit at Plant 0384A with a wastewate discharge of 108 gpm as demonstrating a need for such an allowance. RESPONSE The Agency has not established separate allowances for discharges froi wet looping pits. Available data indicate that discharges fro: looping pits are uncommon. The Agency contacted representatives o Plant 0384A to obtain additional information regarding wet looping pi flows at this plant. These representatives reported that the flow o 108 gpm for these wet looping pits is unrealistically high and tha the four wet looping pits at Plant 0384A are now operated on a batci basis. Water is added to replace water lost through drag-out on thi product. They also reported that the pits are periodically bate! dumped. Both the water make-up rate and the frequency of dumping th< pits were reported to be unknown. The Agency believes that separate allowances for wet looping pits are not appropriate in most cases since the discharge rates appear to be minimal in relation to the higl volume acid pickling rinsewater flows. To the extent additiona. allowances may be necessary, this should be addressed at the permil writing stage as a fundamentally different factor variance issue. 7. COMMENT Two commenters stated that the Agency did not adequately evaluat< process requirements that affect rinsewater rates for combination aci< pickling operations. The commenters site such factors as line speed strip width, strip gauge and multiple strand arrangements that cai cause wide variations in rinsewater rates at a single process. RESPONSE The Agency agrees that these process requirements can affecl rinsewater rates. However, the Agency believes that all of th< significant factors were considered in establishing the final effluenl limitations and standards. The Agency's consideration of thes< factors resulted in the subdivision and segmentation of the aci< pickling subcategory as well as in estalishing appropriate flow rates, GOQG68 ------- As explained in the development document, the subdivision takes into account the different types of acids used and the process differences between carbon and specialty steel operations. Segmentation of the subdivisions takes into consideration the different water usage rates associated with the various products and processes. The flow variations that may occur within a particular segment or a specific pickling line are taken into account by the method used to establish the model flow rates. All of the flow data reported by the industry were used to establish the model flows for each segment. The data submitted by the industry are typical flows which include flow variations at a single process. Additionally, since all of the flow data were used to establish the model flow rates, a broad range of process variations are encompassed (e.g., line speed, strip gauge) and taken into account. The Agency believes that appropriate consideration has been given to the factors that significantly affect rinsewater rates. A more detailed discussion of this issue is presented in the acid pickling subcategory report. 8. COMMENT Two commenters stated that the Agency did not adequately take into account process differences that affect the amount of acid used per ton of steel processed. The commenters cited such factors as the type of acid, and temperature, alloy type and process intended, (i.e., removal of scale and surface defects vs. brightening to remove tarnish.) RESPONSE The Agency agrees that process factors including those cited by the commenters affect the amount of acid used. The Agency has taken these factors into account. The model spent pickle liquor discharge rates directly account for the differences in acids and are based upon the operation that consumes the largest amount of acid. This provides for conservative spent acid flow rates. The difference in acids has been addressed in the subdivision of the subcategory by acid type and different spent pickle liquor flow allowances established for the three acid subdivisions. The data used to establish the spent pickle liquor allowances include only those operations where scale and surface defects are removed. Much lower spent pickle liquor generation rates for light pickling operations, such as brightening were not used. The other process factors are taken into account by the fact that all flows (with the exception of those from light pickling operations) reported by the industry were used to establish the model flow rates. The Agency believes that the data base is broad enough to encompass the process variations raised by the commenters. The Agency also believes that the model flow rates are sufficiently generous to account for relatively minor variations that result from other factors, including acid temperature and the type of steel pickled. GGGG69 ------- 9. COMMENT A commenter stated that the method in which the Agency apportioned th loads from central treatment plants to demonstrate achievability o effluent limitations for the acid pickling and scale remova subcategories is inappropriate. The commenter suggested that tota effluent loads from a central treatment plant should be compared wit the aggregate of the BPT limitations for the contributing sources. RESPONSE The Agency believes that the method it has used to apportion the tota effluent load from a central treatment plant is appropriate an provides an indication of the effluent loads attributable to th contributing sources. The Agency agrees with the commenter tha comparing the total effluent load from a central treatment plant wit the aggregate BPT limitations for the contributing sources is als appropriate. The Agency has done this for central treatment system which co-treat compatible steel industry wastewaters and for whic adequate production data are available to compute the aggregat effluent limitations. Reference is made to the development documen for examples. These data indicate the limitations and standards ar achievable with central treatment systems. 10. COMMENT The industry recommended that the Agency not include cascade rins systems in the model treatment systems used to develop the limitation and standards for combination acid pickling operations. According t this industry, the technology has not been clearly demonstrated a combination acid pickling operations. RESPONSE The Agency disagrees with this comment. Cascade rinse systems hav< been installed at combination acid pickling operations at Plant 02561 (4 lines). The Agency considers this plant representative of th< industry. The Agency also notes that the industry's comments indicate that cascade rinse systems have been installed on the combination aci< pickling operations at Plant 0060. Although the Agency has no flo< data for these plants, the Agency believes that the model flow rate: are achievable by the use of cascade rinsing. The Agency also note: that the model flow rates are being achieved at other plants in th' combination acid pickling subdivision. Thus, although the Agency hai used cascade rinsing as the model technology for flow reduction, othe methods are available to the industry. Furthermore, cascade rinsing is well demonstrated for both sulfuri< and hydrochloric acid pickling operations and the technology ai applied to combination acid pickling operations is not different Based upon the widespread use of this technology, the Agency believe: that equal or better product quality can be maintained. As noted ii the development document, other acid pickling rinse systems with OOG070 ------- discharge, rates can be applied to new sources. Accordingly, the Agency based the NSPS and PSNS upon model treatment systems that include cascade rinse systems. As noted above, the Agency has not based the limitations and standards for existing sources upon this technology. 11. COMMENT One commenter stated that the data from one of the plants (Plant U) should not have been used to demonstrate the achievability of the BPT effluent limitations for metals since the pH of the discharge was 10.4 standard units. RESPONSE The Agency disagrees with the commenter. The Agency does, however, agree that the pH does exceed the allowable range of 6.0 - 9.0, and the discharge will have to be acidified to achieve compliance. This will have no effect on the levels of toxic metals present in this discharge, since the sample measurements are made for total metals. The effluent limitations for metals are also established on the basis of total metals. Acidification may change the relative proportion of particulate and dissolved metals. However, the level of total metals will remain unchanged. 12. COMMENT One commenter stated that effluent limitations should not be established for fluorides at combination acid pickling operations. The commenter further noted that additional treatment may be needed at certain central treatment plants to comply with the proposed fluoride limitation, and that the benefits of minimal incremental removal would not justify additional treatment. RESPONSE The Agency has not established effluent limitations for fluorides, as it believes that the limitations established for toxic metals will effectively control the discharge of fluorides. The same treatment technology (lime precipitation) used to remove toxic metals, will also remove fluorides. 13. COMMENT A commenter stated that the Agency was incorrect in identifying certain plants (Plants 121, 0 and C) that did not support the BPT limitations as having inadequate treatment. The commenter noted that the information presented in the Development Document indicated that these plants do have adequate treatment. RESPONSE 0071 ------- The Agency agrees with the commenter that the treatment compohent installed at Plants 121, 0 and C are adequate, in'that'they ar consistent with the model treatment system. However, the Agenc believes that these treatment systems are not properly operated, ar thus the wastewaters are not adequately treated. In the case of Plar C it is clear from the plant diagram in Section VII that the aci rinsewaters were by-passing the neutralization/precipitation step c the treatment system. The effluent data in Section VII demonstrat the discharge was not being properly treated. The effluent was acidi (average pH of 5.0) and as a result contained high levels of toxi metals. At Plant 0 the sampling conducted by the Agency showed highe levels of chromium (2.66 mg/1) and copper (0.11 mg/1) in the effluen than in the influent to the treatment system. Additionally, samplin conducted at this same plant at subsequent dates to acquire data fc salt bath descaling operations show much lower levels of chromium i the effluents, despite the much higher influent concentrations. Thus the Agency does not believe that the data in Section VII of the aci pickling subcategory report for this plant are representative of th capability of this treatment facility. The same discrepency i effluent quality was observed at Plant 121, during two separat surveys. 14. COMMENT One commenter claimed that the use of caustic in fume scrubbers t achieve state air pollution requirements could result in fouling o plugging problems if high fume scrubber recycle rates are practiced. RESPONSE The Agency believes that the limitations and standards for fum scrubbers can be achieved at all plants including those operated wit caustic. However, to the extent a state air pollution requiremen would require operating practices that would preclude the attainmen of the fume scrubber limitations and standards, the owner or operate; could apply for a "fundamentally different factors" variance on tha1 basis. 15. COMMENT One steel company commented that excess quench water from < combination acid pickling operation was not considered by the Agenc; in developing the limitations and standards for those operations. RESPONSE The Agency re-evaluated the information submitted by the company foi this plant and found that all reported wastewater flows were includec in the development of the limitations and standards. However, th< company did not specifically list excess quench flows as a process wastewater flow at this plant. Nevertheless, if there are process wastewater flows not considered by th- ' Agency in developing th« regulation, the discharger may seek allowances for these flows at th€ 000072 ------- NPDES permit level through a "fundamentally different factors" variance.' G00073 ------- J. COLD FORMING 1 . COMMENT The industry commented that flow data for one-stand cold rolling mill should not be included in the data base for multi-stand mills, sine the one-stand flow rates are much lower. The industry requested separate subcategory for one-stand cold rolling mills. RESPONSE In response to this comment, cold rolling flow data were reviewed an the recirculation and direct application subdivisions have bee segmented to separately account for the one-stand operations. Sine combination mills necessarily have more than one-stand, no separat segment has been established for this subdivision. 2. COMMENT The industry commented that the BPT and BAT model flow rates fo application mills have been established at such low levels tha production of certain cold rolled products may be discontinued as result. RESPONSE The Agency evaluated all of the information provided by the industr on this issue. Unfortunately, the Agency did not receive any detaile information or data from the industry during the comment perio despite a specific request for data and documentation of the data (4 FR 1874). Aside from that request for information, the Agency sent supplemental request to the American Iron and Steel Institute whic was responded to by Bethlehem Steel. That response indicates tha Bethlehem Steel may have problems achieving the model flow rates a two plants with direct application mills, primarily because of th thickness reduction achieved on these mills and the volume of solutio required for product cooling and cooling of the work rolls. As se out in the development document, the Agency compared the thicknes reduction obtained at several mills with the respective flow rates a those mills. This comparison led the Agency to conclude that th model discharge flows for cold rolling operations are appropriate an that they can be achieved at most, if not all plants, without produc quality related problems. The high flows experienced at some mills are not always related t product requirements, but instead result from the continuous discharg of wastewater during periods when products are not being rolled. I addition, cold rolling mills are not devoted to the production of single product. The product can vary on a day-to-day basis, and eve within shifts on a given day. Therefore, if the water/oil applicatic rates are related to the type of product being rolled as the industr contends (the data available to the Agency does not support thi contention), the discharge rates will vary over the same time period 000074 ------- As a,result the high flows associated with one product will be offset by low flows associated with another product. Nevertheless, should a particular mill or product requirement necessitate continuous use of higher volumes of water or oil solutions, such unique situations are more appropriately addressed on a case-by-case basis in a "fundamentally different factor" variance proceeding at the permit writing stage. \ 3. COMMENT The industry commented that toxic organic pollutants should not be limited since those pollutants appeared at levels higher than those used to develop the proposed limitations in the effluent from only one plant. Another commenter recommended that the Agency sample additional cold rolling operations to better quantify the presence and magnitude of toxic organics in the discharge from these operations. RESPONSE The Agency sampled raw wastewaters, and treated and partially treated effluents at 26 different cold rolling and cold worked pipe and tube mills. The cold rolling plants included recirculation, combination and direct application mills. The resulting data demonstrate pervasisive contamination of waste oil solutions and effluents by toxic organic pollutants. Thirty different toxic organics were found at significant and treatable levels at the 26 mills sampled. These pollutants were present at varying levels and diversity among the mills. The waste oils from only two operations (an electric weld tube mill and a plant that contract hauled its waste oil and had no discharge) showed no contamination. These data clearly demonstrate the widespread nature and diversity of toxic organic pollutant contamination and the need for control of these pollutants. Limitations were promulgated for two toxic organic pollutants (naphthalene and tetrachloroethylene) for each cold rolling sudivision (i.e., recirculation, combination and direct application), rather than the four toxic organic pollutants included in the proposed regulation for the recirculation subdivision. Naphthalene and tetrachloroethylene are common in most cold rolling and cleaning solutions. Naphthalene is the most commonly found toxic organic pollutant. It was found in the wastewaters at 50% of the plants sampled at levels greater than 0.10 mg/1, which is the concentration basis for the effluent limitations. Levels up to 165 mg/1 were found. Tetrachlorethylene is a solvent used for cleaning the oil systems at cold rolling mills. It was found in the wastewaters at one-third of the plants. The limitations for tetrachloroethylene (concentration basis of 0.15 mg/1) are established to control the indiscriminate dumping of cleaning solutions. Due to the wide variation in toxic organic pollutants the Agency does not believe that naphthalene and tetrachloroethylene can adequately serve as indicators for other toxic organic pollutants found in these 000075 ------- wastewaters. Rather, the Agency has excluded the other toxic ; organi pollutants from this regulation pursuant to Paragraph VIII of th Consent Decree. This will allow permit writers to establis site-specific limitations for toxic organic pollutants on a case h case basis. NPDES permit writers are advised to completely revie toxic organic pollutants associated with cold rolling operations on site-specific basis prior to finalizing NPDES permits/ ar periodically thereafter, to ensure adequate control is provided fc all toxic organic pollutants 4. COMMENT The industry commented that BAT limitations more stringent than BE limitations should not be promulgated since toxic organic pollutant were found at high levels at only one plant and the proposed BA treatment technology does not effectively remove toxic metals. RESPONSE The Agency has promulgated BAT limitations which are the same as th BPT limitations for toxic pollutants. The BPT model treatmer technology is the same as used to develop the proposed limitations Contrary to the comment and as noted above, toxic organic pollutant were found in the wastewaters at many plants at treatable levels Through extensive sampling at a plant that has the BPT model treatmen technology installed, the Agency determined that this technolog provides adequate control for the toxic organic pollutants for whic limitations have been established. As a result, no treatment beyon BPT is required for these pollutants. Site-specific effluen limitations may be established for other toxic organic pollutants tha may be present in these wastewaters as explained above. 5. COMMENT The industry commented that the data base used to establish the zer discharge requirement for cold worked pipe and tube operations usin water improperly includes mills that use soluble oil rather tha water. RESPONSE Those mills using soluble oils have been deleted from the data bas for mills using water. However, zero discharge is achieved at six ou of the remaining 15 mills using water. THe zero discharge mill account for 40% of those mills using water for which flow data wer reported. 6. COMMENT The industry commented that due to the extreme variation of proces flow rates, the zero discharge requirement is not appropriate for col worked pipe and tube operations using water, and this subdivisio should be further segmented on a flow basis. 000076 ------- RESPONSE The process flow rate should not by itself affect the ability to recycle the wastewater. The Agency received flow data for 15 mills; zero discharge was reported for six mills. The Agency believes these zero discharge plants have good water management practices. The nine plants that discharge wastewaters have wide variations in flow. The highest flows are associated with plants that are operated in a once-through mode. Partial recycle is practiced at other plants. The Agency has determined there are no factors that distinguish these plants from those that have higher rate recycle and achieve zero discharge. The Agency believes that zero discharge can be achieved at those plants with discharges. Hence, the Agency believes it is not appropriate to further segment the cold worked pipe and tube subdivision tc accomodate those operations. 7. COMMENT The industry commented that the proposed BAT limitations which were based upon filtration of wastewaters from cold rolling mills are based upon inadequate data, and additional sampling of other cold mill wastewater filtration systems are necessary. RESPONSE Filtration is no longer used as the model BAT treatment technology for cold rolling operations. The BAT limitations are the same as the BPT limitations, which are based upon a model treatment system that includes dissolved gas flotation. 8. COMMENT The industry commented that new source requirements should be established for each type of cold rolling mill (i.e., recirculation, combination and direct application), rather than restricting all new source cold rolling operations to recirculation mills. RESPONSE The Agency has established NSPS and PSNS for each type of cold rolling mill. This will provide industry the flexibility to install facilities it believes is best suited for the intended purposes. The model treatment technology is the same as the model BPT and BAT technology. However, the model flow rates are based upon the better operated recirculation, combination, and direct application mills. 9. COMMENT One steel company commented that two of its cold worked pipe and tube operations were incorrectly classified as hot forming operations. 000077 ------- RESPONSE In response to this comment, the designation of the mills in questioi has been changed to indicate that they are cold worked pipe and tub* operations. 10. COMMENT Another steel company commented that two of its cold roll in; operations were incorrectly classified as recirculation mills when ii fact they are direct application mills. RESPONSE As a result of this comment, the cold rolling data base has bee) revised to reflect the reclassification of these two cold rollin< operations. 11. COMMENT One commenter suggested that EPA encourage the use of "clean oils (oil solutions free of the toxic organic compounds) for cold formini operations. RESPONSE As indicated in the responses to previous comments, the Agency foum that most rolling solutions are highly contaminated with toxic organii pollutants. The Agency continues to encourage the use of rollim solutions that are free of contamination of toxic organic pollutants to the extent possible. However, the Agency did not promulgate limitations and standards on the basis of substituting clean rollim solutions for contaminated solutions at all mills because it does no have sufficient information and data to determine that "clean solutions can be substituted for those solutions formulated with toxii organic pollutants. As a result, the Agency has promulgated effluen limitations and standards for certain toxic organic pollutants base< upon emulsion breaking and dissolved gas flotation of cold rollim wastewaters. The limitations and standards for these pollutants, an< those for other toxic organic pollutants that may be established a the permit level may be achieved through the use of "clean" rollim solutions. 12. COMMENT One commenter indicated that EPA did not consider sulfid precipitation as a BAT option for cold forming operations. Th commenter stated that lower solubilities of metal sulfides, as oppose to hydroxides, would result in better removal of toxic metals. RESPONSE 000078 ------- The Agency has not considered sulfide precipitation as an alternative BAT' treatment system since the toxic metals found in cold forming wastewaters are principally present as metal oxides. Other forms of toxic metals are found when wastewaters from pickling operations are used to break the oil emulsions. In subsequent treatment of the oily-wastewater, lime is added to neutralize the wastewater prior to dissolved gas flotation. As a result, toxic metals are precipitated as metal hydroxides. The Agency has determined that in treating acid pickling wastewaters, sulfide precipitation does not result in substantially more removal of toxic metals than precipitation with lime. This finding is applicable to this subcategory since the toxic metals amenable to precipitation generally originate in the acid pickling wastewaters used to treat cold forming wastewaters. 13. COMMENT One commenter contended that the Agency did not consider magnetic separation as an alternate BAT technology for cold rolling operations. RESPONSE The Agency did not consider magnetic separation as a alternate cold rolling wastewater treatment technology since emphasis was placed on those technologies for which adequate performance data are available. The technologies considered by the Agency are capable of removing toxic metals to low levels. The Agency limited its review in this fashion to maintain a manageable list of alternate treatment technologies. The Agency is aware that magnetic separation is used at some recirculation mills to remove the scale {iron oxide particles) from the oil solutions prior to reuse. However, since toxic metals are not magnetic, these pollutants will be removed only to the extent that they are bound with the iron oxides. As a result, it is unlikely that magnetic separation will remove toxic metals to a greater degree than achieved by the alternate treatment technologies considered by the Agency. 14. COMMENT The industry commented that the limited data presented in the development document for the proposed regulation show that wastewater from combination mills do not contain any organic or metallic priority pollutants. Therefore, the industry recommends that BAT be set equal to a "proper" BPT. RESPONSE As pointed out above, additional sampling at several cold rolling mills was conducted after the proposed regulation was issued to provide an expanded data base on the presence of toxic pollutants. Six additional combination operations were surveyed by the Agency. Data gathered during these surveys confirm that untreated wastewaters from combination mills contained high levels of toxic organic pollutants and toxic metals. Concentrations of toxic organic OOGC79 ------- pollutants as high as 26.2 mg/1 were detected in the raw wastewaters Additionally, toxic metals were detected in the wastewater at elevate levels. Limitations and standards have been promulgated for certai toxic pollutants at the BPT, PSES, PSNS, and NSPS levels of treatment The ability to control toxic pollutants common in cold rollin wastewaters is demonstrated for the model treatment technologies. 15. COMMENT The industry disagreed with the zero discharge standard proposed fo cold worked pipe and tube operations using oil solutions. Th commenter states that this limitation ignores the future effect o RCRA regulations on the disposal of oily wastes. RESPONSE The Agency has retained the zero discharge requirement for cold worke pipe and tube operations using oil. The model treatment system fo these operations includes a recycle system for the soluble oil with blowdown of 0.5 gal/ton. This blowdown is stored and periodical!; hauled off-site for disposal, so there will be no discharge ti navigable waters from these operations. The Agency has taken int< account the costs for disposing of these wastewaters by contrac hauling. These costs are included in the annual operating costs fo this subdivision. Approximately 79% of the cold worked pipe and tub using soluble oils presently have spent oil solutions hauled off sit for disposal. As described in the development document, the Agency evaluated a alternate treatment system based upon treatment and discharge of thes wastewaters. The capital and annual costs for this alternat treatment system are significantly higher than the costs for achievin the zero discharge standard. Moreover, sludge with characteristic similar to the oily waste is produced as a result of treatment Disposal of this sludge requires the same considerations as disposa of the oily wastes. Hence, the commenters concerns would not b alleviated by providing for treatment and discharge of wastewater: from cold worked pipe and tube operations. 16. COMMENT The industry commented that the Agency should consider establishin limitations and standards on the basis of the surface area o products. RESPONSE The Agency considered this comment and found that the necessary dat are not available to establish limitations and standards for col' rolled or coated products in the steel industry. The industr; generally does not keep detailed surface area records and the Agenc; OOGG80 ------- believes it would be burdensome for both the industry and the Agency to keep and track such data. ooocei ------- LL. ALKALINE CLEANING 1. COMMENT The industry commented that the BPT model flow rate of 50 gal/ton is inconsistent with the data base, which contains flows up to 20 times that amount, particularly, since flow reduction systems are not included in the model treatment systems. RESPONSE The Agency has reevaluated all flow data for alkaline cleaning operations. The subcategory has now been separated into batch and continuous subdivisions to better reflect the rinsewater flow differences due to operating modes, and indirectly, the different products. The model flow rates used as the basis for the limitations are 250 gal/ton and 350 gal/ton for batch and continuous operations, respectively. These flows are the averages for all plants in the respective subdivisions with flow rates less than 1000 gal/ton. Based upon its review of the flow rates reported for different products and modes of operation, the Agency concluded that at lines with flows higher than 1000 gal/ton, water conservation is not practiced to any significant degree and is not representative of plants employing good water conservation practices. In batch operations, 27 lines have reported flow rates ranging from 0 to 8000 gal/ton with an average of 1067 gal/ton. Lines with flows less than 1000 gal/ton (20 lines; 75%) have an average flow of 236 gal/ton. A flow rate of 250 gal/ton was used as the basis for the limitations. Thirteen of the lines (48% of all lines) have reported flows of less than 250 gal/ton. In continuous operations 84 lines have flow rates ranging from 1 to 16,899 gal/ton with an average of 114^0 gal/ton. Lines with flows less than 1000 gal/ton (62 lines> 75%) have an average flow of 351 gal/ton. A flow rate of 350 gal/ton was selected for continuous operations. Thirty-four lines (40%) have reported flows of less than 350 gal/ton. The Agency believes the selected flows can be achieved at all lines with proper attention to water application rates; and, based upon those batch and continuous lines operated at flows less than 250 gal/ton and 350 gal/ton, respectively, product quality will not be adversely affected at those flows. 2. COMMENT The industry commented that the effluent limitations should be based upon a concentration of 25 mg/1 for total suspended solids and that there should be no restriction on flows, since toxic pollutants are not discharged from alkaline cleaning operations. 000082 ------- RESPONSE The Agency agrees that the quantities of toxic pollutants added t process wastewaters from these operations are not significant. Th Agency has concluded that it is appropriate to base the 30-day averag mass effluent limitatiupons upon 30 mg/1 for total suspended solid (and 10 mg/1 for oil and grease) and the model flow rates describe above. The model total suspended solids concentration was set at 3 mg/1 to conform to the limitations for other finishing operations. Wastewaters from nearly all nearly all alkaline cleaning operation are treated jointly with wastewaters from other steel finishin operations in central treatment systems. Large uncontrolled volume of wastewaters from this source would dilute the wastewaters fro other sources, potentially resulting in increased discharges of toxi metal pollutants from central treatment systems. Thus, the Agenc believes it is appropriate to establish mass-based effluen limitations and standards for alkaline cleaning operations. OOOC83 ------- L. HOT COATING 1. COMMENT The industry commented that the BAT model flow, which is based upon cascade rinsing and fume scrubber recycle to reduce the discharge volume, has not been demonstrated. Consequently, it suggests that BAT model flow be set at the same level as the BPT model flow. RESPONSE As it did for pickling operations, the Agency reevaluated the cost and feasibility of retrofitting cascade rinse systems at existing hot coating operations. The Agency has concluded that unlike all end-of- pipe model treatment systems, cascade rinse systems are actually process modifications. The space limitations and configurations at some hot coating lines, may preclude the installation of cascade rinse systems at all existing lines without major reconstruction. For that reason, the Agency believes that the cost of installing the system would be substantially higher than originally estimated. The Agency adjusted its costs for cascade rinse systems based upon data submitted by the industry, but the Agency has no basis to estimate the significantly higher reconstruction costs that may be required at some facilities. These considerations lead the Agency to delete cascade rinsing as a basis for the BAT limitations. The final BAT limitations are the same as the BPT limitations for those hot coating lines without fume scrubbers. These limits are based upon once-through flows for rinsewaters. NSPS are, however, based on the use of cascade rinsing or other demonstrated flow reduction technologies. The Agency promulgated separate limitations and standards for fume scrubbers, since these dischargers are independent of production rate, scrubber type and gas flow through the scrubbers. These allowances, which are established as the quantity of pollutant allowed to be discharged per day, are to be added to the limitations for other wastewaters from hot coating lines when the NPDES permit is being written. The BPT model treatment system is based upon once-through flow, while at BAT, the model treatment system includes 85% recycle of these scrubber wastewaters. Recycle of fume scrubbers at that rate is demonstrated at several hot coating operations, as well as at many pickling operations. The BAT limitations for hot coating operations with fume scrubbers reflect this flow reduction. 2. COMMENT The industry commented that the Agency's model cost estimate for cascade rinse systems is understated. RESPONSE The Agency has reviewed its cost for cascade rinse and agrees that the costs used for the proposed regulation are low. As noted above, the Agency evaluated the cost data submitted by the industry, and, based 000084 ------- upon those costs, the model costs for cascade rinse systems wer increased. 3. COMMENT The industry commented that the Agency has not presented informatio demonstrating cascade rinse systems for hot coating operations; tha product quality considerations may preclude the use of cascade rins systems; that the Agency should establish the BAT model treatmen system flow rate equal to the model BPT flow rate; and the Agenc should base the limitations and standards on published solubility dat for toxic metals. RESPONSE As noted above, the Agency promulgated BAT limitations that are th same as the respective BPT limitations for those hot coatin operations without fume scrubbers. Recycle of fume scrubbe wastewaters is the model BAT technology for those hot coatin operations with fume scrubbers. As set out in the developmen document, this technology is well demonstrated in the hot coatini subcategory. For new sources, the Agency included rinsewater flo' reduction in the model treatment systems. As set out in th< development document, rinsewater flow reduction to the level specifier by the Agency is well demonstrated in the industry for all produc types. Thus, product quality considerations evidently do not affec the ability to operate at the NSPS model flow rates or less. Fo costing purposes, the Agency developed alternative BAT and NSPS mode treatment systems and BAT industry-wide costs on the basis of cascad rinse systems. The Agency believes it has developed conservativ costs in this manner. With 'respect to the effluent quality used to develop and demonstrat the achievability of the limitations, the Agency believes the us central treatment plant data is appropriate provided that the centra treatment plants are treating compatible wastewaters (as set out ii the preamble to the regulation), and the treatment facilities ar< properly designed and operated. For reasons set out in the preamble the Agency has determined that the limitations and standards must b< based upon total rather than soluble metals, and that publisher solubility data are not representative of industry performance an< thus are not appropriate for developing effluent limitations an standards. Based upon widespread demonstration in the industry, th Agency believes the limitations and standards are achievable at plant; that are properly designed and operated. Proper operation include minimization of dragout from pickling and hot coating operation through proper maintenance of wringer rolls, etc. OOG085 ------- GENERAL COMMENTS 1. COMMENT The Agency received several comments regarding the use of "indicator" pollutants in the proposed regulation. The industry commented that the use of indicator pollutants should be expanded and offered the following specific examples: (a) Phenols (4AAP) should be used as an indicator for all toxic organic pollutants found in cokemaking wastewaters. (b) Total suspended solids should be used as an indicator for toxic metal pollutants in several subcategories. Environmental groups, on the other hand, suggested the Agency limit more, or in some cases, all of the toxic metal and toxic organic pollutants found in steel industry wastewaters to insure adequate control of those pollutants. One industry commenter requested all of the methodologies and associated correlation data and statistical analyses used by the Agency in developing its proposed use of indicator pollutants. RESPONSE The Agency carefully considered these comments and has determined that its general approach with respect to the use of indicator pollutants in the proposed and final regulations is appropriate. The Agency relied heavily upon its engineering judgment in establishing the indicator pollutants. This engineering judgment included consideration of the nature and chemical properties of the pollutants present in the wastewaters, the treatability of these pollutants, and the model treatment system involved. For example, where toxic metals were found at treatable levels, the Agency established limitations for two of the toxic metals. The limitations for these metals will require the installation and proper operation of the necessary treatment systems, which in turn ensures that other toxic metals, as well as other pollutants amenable to the same treatment are effectively removed. In selecting and using indicator pollutants, the Agency gave highest consideration to insuring that adequate control is provided for toxic organic and toxic metal pollutants found in steel industry wastewaters. As set out in the development document and in response to several comments, this cannot be done by using suspended solids as an indicator. Instead, the Agency established limitations for certain toxic pollutants with characteristics similar to other toxic pollutants. Thus, the Agency believes the toxic pollutants not directly limited will be adequately controlled. Consideration was also given to developing a common list of limited pollutants for those subcategories with compatible wastewaters to facilitate more cost effective co-treatment, where appropriate; and finally, the Agency restricted the number of limited toxic pollutants to foster 000086 ------- development of practical monitoring programs for the industry that cai be implemented through NPDES permits at reasonable costs. The Agency used indicator pollutants for the regulation in th< following instances: a. Cokemaking Operations Phenols (4AAP) is used as an indicator for the acid fractioi toxic organic pollutants found in cokemaking wastewateri Benzene, and benzo(o)pyrene and naphthalene are used a: indicator pollutants for volatile and base neutral toxi< organic pollutants, respectively. The Agency consideret whether or not phenols (4AAP) would be an appropriat< indicator for all toxic organic pollutants found ii cokemaking wastewaters. However, available data for th< model BAT biological treatment facility show no correlatioi between the effluent levels of phenols (4AAP) and th< volatile and base/neutral toxic organic pollutants However, those data do show a relationship between the thre< limited toxic organic pollutants and other pollutants ii their respective classes. Thus, the Agency does not believ< that phenols (4AAP) can serve as an effective indicator foi all toxic organic pollutants found in cokemakini wastewaters. b. Toxic Metals in Other Subcategories Lead and zinc are used as indicators for toxic metals foi all but the specialty steel finishing operations. For thos< operations, chromium and nickel are indicators for the othei toxic metals. The Agency believes these metals ar< effective indicators as demonstrated by the monitoring dat< presented in the development document. The Agenq considered total suspended solids as an indicator for toxi< metals but found that total suspended solids is a pooi indicator for toxic metals, notably when these metals an present in the dissolved state or as fine particulates. The Agency believes its approach to indicator pollutants is consisten with the requirement to effectively regulate toxic pollutants, and yet provide for reasonable limitations and monitoring requirements Alternatively, the Agency would have to specifically limit all toxii pollutants, placing an unmanageable monitoring burden on industry and in some cases, restricting co-treatmant of compatible wastewaters The Agency suggests that it would be appropriate for permit writers t< require dischargers to conduct confirmatory monitoring for a brie: period of time to ensure that there are no unique plant-specifL factors which would prevent the effective use of indicator pollutant: at individual plants. While the Agency is confident that it: "indicator" policy effectively controls the discharge of all treatabL toxic pollutants found in subcategory wastewaters, it also believe: that this confirmatory analysis is appropriate. OOOG87 ------- 2. • COMMENT One commenter recommended that the Agency closely review the validity of the statistical formula used to determine the daily maximum variability factor which is used to establish the daily maximum effluent limitations. The commenter was unable to derive the formula. RESPONSE The Agency has reviewed the statistical formula in question and believes it is valid for determining the daily maximum varibility factor. The techniques used to define the formula for the daily maximum variablity factors are based upon well known and widely applied statistical methodologies. The derivation of the formula which was referenced in the development document, can be found in Appendix XII-A1 (pp. 415-417) in the Development Document for Existing Source Pretreatment Standards for the Electroplating Point Source Category, EPA 440/1-79/003, August 1979. 3. COMMENT One commenter questioned the use of different methods to calculate the daily variability factor; why 100 observations was chosen as the criterion for different methods of analysis; how well the statistically calculated 99th compares with the observed 99th percentile for plants with greater than 100 observations; and, if there are noticeable differences in this comparison, what is the Agency's rationale for using the nonparametric technique to establish the daily maximum limitations as opposed to the statistical method. RESPONSE The points raised in this comment are discussed in Appendix A of Volume I of the development document. For plants with over 100 observations the nonparametric technique of the empirical distribution function was used to estimate daily limitations. The empirical 99th percentile used to obtain the daily limits was calculated according to the following definition given by J. Gibbons.* The qth percentile is the estimated effluent concentration of rank r (ranked from smallest to largest such that r = n x q if (n x q) is an integer {(n x q) + 1} if (n x q) is not an integer where { } means to take the largest integer not exceeding the quantity in the brackets and n is the total number of observed effluent concentrations. For example, if n = 100 and q = 0.99, r = (100)(0.99) = 99 and the 99th percentile is estimated by the 99th largest (of the 100) value. If n = 225 and q = 0.99, r = {(225H0.99) + 1) = {222.75 + 1 } » {223.75} = 223 and the 99th percentile is estimated by the 223rd largest (of the 225 values). Using this definition a plant would require at least 100 effluent observations for the empirical OOOC88 ------- 99th percentile not to be the largest of the observations. Therefore 100 observations were considered the minimum number to be used i: estimating the daily variability factor using nonparametrii techniques. When the number of observations were less than 100, a parametric mode (in this case, the lognormal) was used to estimate the 99tl percentile. It has been shown that the assumption that the pollutan effluent data are lognormally distributed is reasonable {see page 26 and Figures A-l through A-4 of the development document as well a: Appendix A of the development document for Electroplatim Pretreatment, EPA 440/1-79/003). This model has been used ' an< supported in the development of several categorical standards and ha: been generally accepted by industry. In response to this comment, the Agency completed a compaison betweei the two methods used to calculate the 99th percentile for plants witl more than 100 observations. For most plants, the two methods compar< favorably. At several plants the actual 99th percentile is lesi stringent than the calculated values, while at the remaining plant: the 99th percentile value is more stringent than the calculate* values. Since the comparison showed there was no bias to eithe; method, the Agency has continued to use the 99th percentile value fo: plants with more than 100 observations. The agency believes that thi: nonparametric statistical estimation technique is a valid an* appropriate method for developing achievable concentration levels. *Gibbons, Jean, Nonparametric Statistical Inference, McGraw Hill, 4. COMMENT The same commenter stated the Agency has made no effort to rationaliz its selection of the 99th percentile for calculating daily maxima an< 95th percentile for calculating 30-day averages. RESPONSE The selected percentiles have been used by the Agency in setting man; of the categorical limitations and standards, and, in fact have bee recommended and used by the industry for NPDES permits. Th justification for using the 99th and 95th percentiles are presented i Appendix A of the development document. OOOG89 ------- 5.. COMMENT Several commenters were received from the industry that the Agency's solid waste disposal cost of $5.00/ton is understated, notably with respect to disposal of solid wastes considered hazardous under RCRA. The industry presented several alternative estimates ranging from $13/ton to $200/ton for disposal. RESPONSE In response to these comments, the Agency reevaluated solid waste disposal costs and determined that a cost of $5/ton is a representative cost for disposal of non-hazardous solid wastes for large industries. The Agency agrees, however, that a disposal cost of $5/ton for hazardous solid wastes as defined by RCRA is understated. Accordingly, the Agency evaluated information submitted by the industry and material prepared by the Agency's Office of Solid Wastes. The Agency based its hazardous solid waste disposal cost estimates ($18/ton) upon information developed by the Agency's Office of Solid Waste and by information submitted by the industry, particularly information submitted for Plant 0320, which the Agency found to be representative of steel industry operations. As set out in the development document, the Agency reevaluated solid waste generation rates for each subcategory, and made revisions to its estimates, where appropriate. 6. COMMENT One commenter indicated that the equation used to describe sulfide precipitation presented in Volume I of the draft development document is incorrect. RESPONSE The Agency agrees. The appropriate corrections have been made in the development document. 7. COMMENT One commenter states that because the proposed PSES are identical to the proposed BAT, there is no reason for indirect discharges to continue discharging to POTW systems; that POTW operations could fall below optimum efficiency due to loss of hydraulic loading; and, some POTWs could lose revenue from the indirect dischargers that would no longer discharge to the POTWs. The commenter states that these lost revenues would have to be made up by local residents. RESPONSE The Agency has promulgated PSES that are the same as the BAT limitations for all steel industry operations except for cokemaking, where the PSES are based upon the same type of pretreatment the industry provides for its on-site biological treatment systems. As G8G030 ------- set out in the development document, the Agency has determined tha these PSES will prevent pass through of toxic pollutants at POTWs to , significantly greater degree than would occur if steel industr wastewaters were discharged to POTWs untreated. In certain cases indirect dischargers may find it less costly to discharge directly an< comply with the applicable BAT limitations than to comply with th PSES and continue discharging to POTWs. However, the Agency note: that indirect dischargers will be able to obtain credits for th pollutant removals experienced at POTWs and may therefore, find i less costly to be discharged to POTWs. Based upon the numbers am types of indirect steel industry discharges, the Agency does no expect POTW operations to fall below optimum efficiency because of th< lack of hydraulic loading from the steel industry. If anything, les: hydraulic loading would be a benefit at many POTWs, notably those tha are being operated at or beyond their design capacity and those witl combined sewerage systems. While the Agency cannot argue that no POT1 may lose revenues because of less steel industry indirect discharges, this would not affect the Agency's decision on promulgating PSES thai minimize pass through of toxic pollutants at POTWs. The Agency note; that the company which raised this point discharges partially treate< cokemaking wastewaters to a POTW that is experiencing operating problems and is passing through pollutants associated with cokemakint operations. 8. COMMENT One commenter indicated the Agency's discussion on sedimentatioi presented in Volume I of the draft development document is no' correct. The commenter points out that overflow rates (rate o: particle settling) is the primary factor which governs suspendei solids removal. He also states that tube plate settlers do nol actually increase the effective surface area but increase th< effective sludge collection area. RESPONSE The Agency agrees with these comments and has revised the discussioi of sedimentation in Volume I accordingly. 9. COMMENT The same commenter stated that the data presented in Table VI-1 ii Volume I of the draft development document are not confirmed by dati presented in "Carbon Adsorption Isotherms for Toxic Organics," (EPA- 600/8-80-02). RESPONSE The data presented in Table VI-1 of the draft development document foi those toxic organic pollutants associated with cokemaking operation: were obtained from the full scale activated carbon treatment syster installed at Plant 0684F. The Agency believes that full scal< demonstration of the technology on the specific wastewaters bein< OOOC91 ------- regulated provides more representative data than a reference based primarily on adsorption studies on single compound systems. Nonetheless, the reference cited by the commenter indicates that activated carbon can be used to achieve the limitations for toxic organic pollutants where the Agency has included activated carbon in the model treatment system. 10. COMMENT The same commenter also questioned the design procedures used to determine the area requirements and the costs of the treatment facilities presented in the draft development document. RESPONSE The Agency determined the area requirements for the model treatment facilities on the basis of the area required for each component (e.g., scale pits, clarifiers, filters, aeration basins). The area for each component is based upon the size of the component necessary to process the volume of wastewater for the model treatment system. For scale pits, clarifiers, and thickeners, the overflow rate is the primary factor influencing the size of the equipment. The area requirements for other equipment items were determined from engineering cost references or based upon typical installations found in the industry. With respect to the Agency's cost estimates, reference is made to Volume I of the development document for a review of these estimates and how they compare with actual industry costs. 11. COMMENT One commenter implied that the Agency did not adequately address the difference between large and small mills. The commenter stated that the smaller specialty steel mills may have to incur additional wastewater treatment costs due to different minimum solubility of the various metals; the actual process, operation, constraints and pollutants at specialty steel mills are different than at the larger iron and steel plants, although the steelmaking processes are basically the same; and, sulfuric acid recovery at specialty steel mills would be cost intensive, whereas it any be cost effective at large iron and steel plants. RESPONSE The Agency believes it has adequately addressed the differences between the larger iron and steel mills and the smaller specialty steel mills, and that the water pollution control costs incurred at specialty steel mills would be similar to the costs incurred at iron and steel mills. The Agency has established separate effluent limitations for specialty steel operations where process, flow, or raw wastewater or effluent quality indicated separate limitations are appropriate. For example, certain hot forming subdivisions have been segmented to separately cover specialty steel operations; and the acid pickling subcategory has been subdivided to separately account for OOuG92 ------- combination acid pickling which is essentially a specialty stee operation. Moreover, the concentration bases for the ' toxic meta effluent limitations for combination acid pickling and salt bat descaling operations are different than those used for the othe pickling subdivisions, which are generally associated with larger iro and steel mills. Thus, the Agency has taken into account th different solubilities of the toxic metals in specialty stee operations. On the issue of sulfuric acid recovery, the Agenc disagrees that the cost effectiveness would be substantially differen between large and small plants. Such systems are installed at smal plants (e.g., Plants 0476A and 01121) and large plants (e.g., Plan 0112C). In any event, sulfuric acid recovery is not required fo compliance with the regulation. 12. COMMENT One commenter stated the Agency's cost for filtration systems include in the model treatment systems used to develop the propose limitations and standards are not consistent when the costs per uni volume of wastewater filtered are considered, even after adjustment were made for economies of scale. The commenter also noted that are requirements for filters were not consistent. RESPONSE In response to this comment, the Agency reevaluated its costs and are requirements for filtration systems and, as described in the preamble also refined its costing methodology to address the problems note above. The data presented below demonstrate that the filtration cost and area requirements used for the final regulation are generall consistent. The increases in unit costs ($/gpm) in the 300 to 500 gp range result from interpolation. OOOG93 ------- Filter Cost Comparison Flow (GPM) 6 21 24 67 257 292 334 500 750 3306 5160 €814 12889 Capital Cost (Dollars) 15,400 32,000 35,400 105,400 246,700 285,500 401,000 513,400 539,300 1,660,100 2,168,500 2,392,000 2,857,500 Cost ($/GPM) Land (Ft«) 2566, 1523, 1475, 1573, 959, 977, 1200, 1026, 719, 502, 420. 351 , 221 . 7 8 0 1 9 7 6 8 1 1 3 0 7 * 3520 5300 8800 *Land area of 1700 ft2 specified. 13. COMMENT One commenter suggested that intensive sampling surveys similar to the Agency's intensive sampling survey conducted with the industry at several hot forming operations should be completed for other subcategories as well. The commenter contends the data base is not adequate in other subcategories and the results from the hot forming surveys allowed the Agency to have a complete data base and make proper interpretations of the data for that subcategory. RESPONSE The Agency has not conducted intensive sampling surveys for other subcategories because it believes its existing data base for all subcategories obtained through extensive monitoring of the industry, responses to Agency questionnaires, NPDES permit records, and data submitted during the comment period is adequate. With respect to the hot forming subcategory, the additional data obtained from the joint sampling survey with industry are not different than the data available prior to the joint survey. The Agency did, however, reevaluate the hot forming data and reached different conclusions regarding the discharge of toxic pollutants at different levels of treatment. Long term average discharges were evaluated in selecting the model treatment technologies for the final regulation, rather than discharges based upon regulated levels of the limited pollutants which were evaluated for the proposed regulation. Also, for the final regulation, the Agency considered concentrations of pollutants reported less than detectable levels as not present (or zero); whereas, for the proposed regulation, those concentrations were considered to be present at the detectable levels. The Agency made 000094 ------- the above changes for all subcategories and believes its-evaluation the data for all subcategories is appropriate. 14. COMMENT Several commenters noted that the Agency had not completed regulatory impact analysis for the proposed regulation pursuant Executive Order 12291. RESPONSE The Agency had not conducted a Regulatory Impact Analysis (RIA) fi the proposed regulation because Executive Order 12291 was not issu until after this regulation was proposed. However, the Agency h. completed an extensive Regulatory Impact Analysis for the fin. regulation. The RIA includes a cost-effectiveness analysis of tl model treatment technologies including an evaluation of the coi effectiveness of treatment beyond the current level of discharge limited water quality analyses of about 30 stream segments with ste< industry discharges; detailed water quality analyses for three streai highly affected by steel industry operations; an assessment of tl potential benefits associated with steel industry compliance with t) final regulation for those three stream segments; and, a rou< assessment of the aggregate benefits of industry compliance with ti regulation. The industry participated in the selection of the stre< segments studied by the Agency and had considerable correspondeni with the Agency during the conduct of the associated benefil analyses. The Agency has determined that the RIA supports the fine- regulation, and, to the extent allowed by law, the informatic contained in the RIA was considered by the Agency in developing tl final regulation. 15. COMMENT The Agency received several comments from industry recommending the the limitations and standards be promulgated on a "net" basis; the is, to allow for full credit or pass through of the levels of tl limited pollutants in the intake waters. RESPONSE The Agency has not promulgated net limitations and standards. Th Agency specifically considered whether or not such standards should t developed and applied on a net or gross basis, and determined the gross limitations and standards are appropriate. As set out in eac subcategory report of the development document, the Agency found the the levels of the limited pollutants found in make-up waters do nc significantly add to the raw waste loadings at most plants, and thi do not affect the industry's ability to comply with the limitations c a gross basis using appropriate pollution control technologies Accordingly, the agency has promulgated the regulation with r OGOG95 ------- provision for net credits, and has determined that the limitations and standards' should be applied on a gross basis, except to the extent provided by 40 CFR Part 122.63(h). 16. COMMENT The Agency received comments from operators of POTWs suggesting that PSES and PSNS be promulgated on the basis of concentrations rather than as mass-based standards. The commenters cited the difficulty of monitoring for compliance with mass-based PSES and PSNS where both flow monitoring and frequent solicitation of industrial production records would be required. RESPONSE The Agency considered promulgating PSES and PSNS on the basis of concentration only, but did not do so because it believes that pass through of toxic pollutants from steel industry discharges at POTWs can more effectively be regulated with mass-based PSES and PSNS. The commenters appear to have some misconceptions about how to apply the mass-based PSES in their pretreatment programs. These standards would be applied in the same way the limitations and standards are applied for direct dischargers in NPDES permits. That is, the production capacity of the facility in question, or a production rate representing high production operations, is used to determine the mass-based standards in terms of kg/day or Ibs/day. Once the pretreatment standards are fixed, there would be no need to monitor or solicit additional industrial production data. However, the standards would have to be modified to take into account any new capacity additions or retirements. The flow of the steel industry discharge to the POTW and the concentrations of the limited pollutants would be monitored to determine compliance. The Agency believes these are reasonable requirements. 17. COMMENT One commenter stated that the Agency has used engineering judgment to interpret information without defining the criteria used to make that judgment. The commenter noted that since engineering judgment is not necessarily objective, it was difficult for the commenter to fully evaluate some of the data presented by the Agency. RESPONSE The Agency has used engineering judgment to identify plants which it believes have state-of-the-art treatment systems and are representative of other similar operations. The Agency has also used its judgment to analyze operating data, discharge flow rates, and effluent data to identify well designed and operated treatment facilities which it used to establish the effluent limitations. The Agency recognizes that engineering judgment is not always objective. However, the Agency does not believe that a universally applicable set of objective criteria can be established due to the wide variations of OOGG96 ------- conditions that must be evaluated. The Agency has therefor appropriately used the expertise of its staff and its consultants t exercise engineering judgment on a case-by-case basis. 18. COMMENT One commenter, while agreeing that the 0.6 factor is a reasonab] means of estimating costs for different sizes of similar wastewat« treatment facilities, stated that the method is not universal] applicable. The commentor was particularly concerned that the Agenc used production rates rather than wastewater volumes to scale tt costs. RESPONSE The 0.6 factor is a commonly applied method for scaling costs c identical facilities for different sizes. This method is used in bot the public and private sector to estimate costs, as indicated by U industry's comments on costs. The commenters concern regarding tl Agency's use of production rather than flows for scaling is unfoundec The Agency has determined that flows and production rates are relate< Thus, on the assumption that the model treatment technologies at tl model flow rates will be installed by the industry to achiei compliance with the effluent limitations, scaling costs on the bas: of production or flow rates will yield the same result. The Agency : well aware that in actual practice different treatment technologi< will be used, and different discharge rates will be attained 1 achieve compliance with the same limitations. Some dischargers wi! attain lower discharge rates than the model flow rates, while othei will have higher discharge rates. It is well beyond the ability < the Agency to perform its cost estimates on the basis of the actu; treatment technologies and flows that are and will be used at ea< plant, Moreover, the Agency has previously compared (see Volume I < the Development) cost estimates made by scaling model costs on tl basis of production and flow rates with site specific engineering co; estimates. This comparison clearly showed that the estimates usii either production or flows for scaling compare favorably with si specific cost estimates, and in the aggregate, the estimates made < the basis of production more closely approximated the site specif costs. The Agency has also compared its cost estimates with actui costs for over ninety wastewater treatment facilities reported by t industry. This comparison also demonstrates that the Agency's meth of developing cost estimates is appropriate. 19. COMMENT A commenter pointed out that the equation for the capital recove factor shown in Volume I is incorrect. RESPONSE The commenter is correct in identifying the typographical error in t Development Document. It should be noted, however, that the Agen OOGC97 ------- has .revised the method used for annualizing capital costs. This is discussed in detail in Section VII of Volume I of the Development Document. 20. COMMENT A commenter expressed concern that insufficient consideration has been given to treatment of toxic pollutants/ listed in Appendix B of the preamble to the proposed regulation as "not treatable" and "regulation considered" which the Agency excluded from the proposed regulation. The commenter stated that more stringent treatment requirements are needed at the point of discharge to eliminate the possibility, that multiple discharges to a receiving water used as a source of drinking water will raise the levels of toxic pollutant to the point where more expensive and difficult removal at potable water treatment facilities will be necessary. The commenter concurred with the use of appropriate indicator pollutants, but recommended that a complete analysis of the discharge be made on some infrequent basis to ensure that no change has ocurred in the wastewater characteristics. RESPONSE The Agency has regulated toxic pollutants wherever toxic pollutants were present at treatable levels. The Agency accomplished this by directly limiting certain toxic pollutants and using these toxic pollutants as indicators of the presence and treatment of other toxic pollutants found in the wastewaters. The Agency believes that removal of the indicator pollutants will result in comparable removal of other toxic pollutants found in the same wastewaters. Moreover, the treatment technologies used to establish the effluent limitations removes toxic pollutants to levels at which only marginal incremental removal can be achieved by other state-of-the-art treatment technologies. The Agency believes it has given sufficient consideration to treatment of toxic pollutants on an industry-wide basis. The Agency recognizes that in certain instances local water quality or drinking water considerations could warrant more stringent treatment requirements. These considerations are, however, more properly addressed at the local level, and where warranted more stringent treatment requirements may be imposed through NPDES Permits. The toxic pollutants which the Agency has identified as "not treatable" were found in steel industry wastewaters at concentrations at or below those achievable by state-of-the-art technology. The Agency expects that the levels of these pollutants will remain at or near these concentrations. Those toxic pollutants which the Agency considered but did not establish effluent limitations, were present at or near treatability levels or are otherwise controlled by indicator pollutants. Hence, the Agency believes that the concentration of those toxic pollutants which were not specifically limited will be present in steel industry discharges only at or near treatability levels. Thus, in most cases, no further treatment except costly evaporative and recycle technologies could be used to further reduce the discharge of these pollutants. GQOC98 ------- With regard to the recommendation to establish a monitorinc program to completely analyze discharges for toxic pollutants, th< Agency does not believe that it is appropriate to establish that typs of program in this regulation. It should be noted, however, thai complete analyses of discharges for toxic pollutants are performed ii conjunction with the filing of NPDES permit applications. 21. COMMENT Two commenters stated that the Agency has not recognized that centra! treatment facilities treat wastewaters from sources other than thos< covered by the guidelines. One of the commenters recommended that th< Agency include in the regulation guidance and reference sources to b< used to determine allowances for these other sources. RESPONSE The Agency has established effluent limitations for those operation: in the steel industry which are the primary sources of pollutants The Agency is aware that wastewaters from other production 01 ancillary operations are discharged from steel plants. Thos< operations generally contain lower levels of pollutants or are nol widely used in the industry. The treatment and discharge of thes< wastewaters with steel industry wastewaters is recognized throughoul the Development Document. The Agency believes that it would be mor< effective to establish the effluent limitations for these operation: on a case-by-case basis at the permit level. The Agency, however does not believe that it would be appropriate to set forth guidance ii the regulation on this issue. 22. COMMENT One commenter stated that although the annual electric powe: consumption estimated by the Agency for compliance with the proposei regulation amounts to only 3.6 percent of the electric powe consumption of the industry, and only 0.6 percent of the total energ; consumed by the industry, his experience at one plant is that electri power amounted to 14 percent of the energy consumed, but accounted fo 39.2 percent of the total energy cost. On this basis, the commente concludes that the actual energy cost to industry is higher tha indicated by the Agency. RESPONSE The Agency believes that its cost estimates for electric powe consumption necessary to comply with the regulation are accurate; and as set out in the economic impact analysis, the Agency has accounte for escalation of power costs and other energy costs over the perio of time covered by the economic impact analysis. Differences in cost for power and fuel noted above by the contractor were also accounte for in the economic impact analysis. The Agency notes that the powe COG099 ------- consumption associated with compliance with the final regulation is about one- third less than that for the proposed regulation. Most of the difference is attributed to the Agency's decision not to promulgate BAT Limitations based upon high rate recycle systems for hot forming operations. 23. COMMENT The Agency received comments from a manufacturer of water pollution control equipment recommending that a specific technology be considered as the best available technology. The commenter states this technology could be used to achieve the BAT limitations for toxic metals at less cost than with chemical reduction or ion exchange treatment. RESPONSE The Agency reviewed the information submitted by the commenter and believes that this technology is one of several that may be used by the industry to comply with the limitations and standards for toxic metals. However, the Agency based the limitations and standards for toxic metals upon classic chemical reduction and lime precipitation technologies that are well demonstrated in the steel industry. As noted in the development document, the industry may use any wastewater treatment technology to achieve the limitations, including that suggested by the commenter. 24. COMMENT Two commenters noted that the Agency did not consider technologies transferrable from foreign industry to establish the effluent limitations. The commenters did not endorse these technologies, but argued they should have been evaluated and considered. RESPONSE The Agency did not consider any technologies for which it did not have sufficient operating and performance data for establishing effluent limitations. In some cases, the foreign technologies could not be fully evaluated to confidently project costs, reliability and achievable effluent levels, and to determine its effects or acceptability from the perspective of energy, air pollution and solid waste. Based upon limited information available through the Agency's Office of Research and Development which evaluated foriegn technologies, the Agency believes that the American steel industry is at least as advanced as foreign steel makers in the field of wastewater treatment. 25. COMMENT One commenter stated that for some subcategories and treatment options the effluent data presented in the draft development document are insufficient for confidently predicting statistical variability. The 000100 ------- commenter identified specific pollutants for certain treatment option in six subcategories (cokemaking, ironmaking, steelmaking, ho forming, pickling and alkaline cleaning) which contained less than 2 observations. RESPONSE The Agency believes that, where effluent limitations and standard have been promulgated, a sufficient quantity of high quality data ar available to develop and support the limitations and standards. Th Agency believes that the data so used are representative of th discharge, and therefore, sufficient for evaluation of the process an to establish the limitations and standards Nearly all of the dat cited by the commenter were not relied upon to establish effluen limitations for most of the pollutants. For example, the phenol (4AAP) data for pickling wastewaters, and phenols (4AAP), cyanide an ammonia data for hot forming wastewaters indicate these pollutant were present in the make-up water supply at levels found in th wastewaters. Effluent limitations or standards for iron have not bee established for any subcategory and toxic metals have not bee directly limited at hot forming operations. In other instances, th treatment technologies identified by the commenter were not selecte as basis for the effluent limitations. Effluent limitations have been established for several of th pollutants identified by the commenter, i.e., naphthalene, benzo-a pyrene and benzene for cokemaking operations; and, lead for ironmakir operations. The Agency believes that the data for these pollutant are representative of the operation of the treatment systems and th discharge from such operations. Thus, the Agency used these data t establish effluent limitations. The Agency is confident that th limitations it has established are reasonable and appropriate. 26. COMMENT The same commenter questioned the possible inadequacy of the data bas used to develop the effluent limitations. The commenter stated tha while the data may be adequate, not enough information was presente in the Development Document to make a proper evaluation. Th commenter was concerned that the facilities sampled were no adequately characterized to determine whether the facilities an pollutants found are representative of the industry. RESPONSE The Agency believes that the facilities sampled and the pollutant found during these surveys are representative of the industry. Th toxic sampling survey was designed and conducted to produc representative information. Initially, the Agency selecte representative plants (10 steelmaking and 11 forming and finishin plants) on the basis of its knowledge and experience for screenin surveys to characterize the wastewaters from operations in eac subcategory. The Agency then reviewed the information provided by th C001C1 ------- iridustry. in response to the DCPs to identify representative operations with treatment facilities in-place. Verification sampling was then conducted at these facilities, which were not the same facilities at which the screening surveys were performed. Additional sampling was also conducted at many hot and cold forming operations. In all, verification sampling was conducted at 21 steelmaking and 113 forming and finishing plants. The effluent data from the screening and verification sampling surveys were similar with respect to the pollutants found and the levels at which they were present in the wastewaters. As a result, the Agency did not distinquish the data from the screening surveys from that obtained during the verification surveys. All of these data are presented in the respective subcategory reports of the development document. In addition, each subcategory report provides descriptions of each of the facilities sampled. The basic information on the production processes/ wastewater treatment facilities and discharge modes are presented in Section III, while further description of the wastewater treatment facilities as they were operated at the time of the sampling inspections are provided in Section VII along with diagrams of the wastewater sources and treatment facilities. More detailed information on the production and treatment facilities, and operating modes as reported by the industry are contained in the DCPs and D-DCP which are in the record. Additional information acquired during the sampling surveys is presented in the volumes of trip reports which are also in the record. 27. COMMENT The industry commented that the regulation must be reproposed for additional public comment after the Agency completed its determination of what the final limitations and standards should be. One industry coinmenter indicates that the Agency's data gathering efforts were still underway during the comment period and the industry would not have an opportunity to comment on the Agency's final conclusions. RESPONSE The Agency obtained information and data from the industry during the comment period and after it was closed, particularly financial information concerning plants which might be adversely affected by the regulation. The information and data obtained by the Agency after the public comment period was closed was obtained in direct response to certain industry comments that were unclear, or for other comments, where the points raised by the industry required the Agency to obtain additional information to complete its evaluation. The supplemental information so obtained by the Agency is generally corroberative of information at hand at the time of proposal. The Agency believes it was neither feasible nor appropriate to repropose its findings and conclusions on this regulation before promulgation. The Agency believes that industry and the public have had more than ample time and opportunity to make their views on the regulation known to the Agency. Draft contractor's reports were COG102 ------- distributed for public comment in October 1979; the Agency held < public meeting in May 1980 to receive comments on these reports; th< public comment period on the proposed regulation was extended twice a1 the request of the industry to a total of 120 days and, the industry has participated heavily in the process of completing the Regulator^ Impact Analysis. 28. COMMENT One industry commenter, when discussing the issue of watei consumption, stated that there are inconsistencies between th< Agency's estimates of evaporation rates in the iron and steel drafi development document,, and the estimates contained in the steal electric generating development document. The commenter noted tha' the data in the steam electric document indicate that water loss ii cooling towers is about twice that of once-through in stream cooling whereas the discussion in the steel document implies a nearly equa water loss for both systems. RESPONSE The Agency has reviewed the water consumption discussion in the Steai Electric Development Document and has not found any significan inconsistencies between the two methodologies. In fact certai; portions of the methodology used in Steam Electric were included i the Agency's water consumption analysis for the Iron and Stee Industry. The Agency's review of the Steam Electric documents shows that bot approaches present the same relative evaporation rates for differen types of cooling systems. For example, the steam electric data show that a mechanical draft wet cooling tower will result in 2.25 time the amount of water evaporated in a once-through system. Th evaporation rate presented in the steel industry document for we cooling towers is 2.2 times the once-through rate. Based upon the above, the Agency has concluded that its estimates o water consumption for the steel industry are appropriate an consistent with the approach used in the Steam Electric study. 29. COMMENT One commenter suggested that the Agency establish in this regulatio some reference points or standards for which the design and th adequacy of the treatment facilities can be measured against upsets The commenter stated that the definition of upset in NPDES regulatio and pretreatment standards are overly broad. RESPONSE The Agency believes that it is neither appropriate nor possible t establish reference points or standards against which upsets can b measured. The events and conditions under which upsets can occur ar 000103 ------- numerous and highly site-specific. The Agency believes that the upset provision contained in the NPDES regulation at 40 CFR 8122.60 is adequate. 30. COMMENT A commenter requested that EPA continue the stay of the effective data of amendments to the general pretreatment regulations (40 CFR Part 403) promulgated on January 28, 1981 (46 Fed. Reg. 9404); stay the general pretreatment regulations promulgated on June 26, 1978 (43 Fed. Reg. 27736); review and reconsider the entire pretreatment program pursuant to Executive Order 12291; and, make major changes to the pretreatment program. RESPONSE These comments were responded to in the Agency's action deferring the effective data of certain protions of the amendments to the general pretreatment regulations. See, 47 Fed. Reg. 4518 (February 1, 1982). 31. COMMENT A commenter requested that the categorical pretreatment standards for this point source category be stayed pending review of the general pretreatment program. RESPONSE Under Section 307(b) of the clean Water Act, categorical pretreatment standards are required if EPA determines that the introduction of pollutants from this point source category would interfere with, pass through or otherwise be incompatible with the publicly owned treatment works. The data contained in this rulemaking record establish that categorical pretreatment standards are appropriate and necessary to prevent pass through of pollutants. Accordingly, EPA has established these pretreatment standards. 32. COMMENT Commenters requested clarification of the deadline for obtaining a category determination under 40 CFR 403.6(a) and a fundamentally different factors variance under 40 CFR 403.13 of the general pretreatment regulations. RESPONSE This comment was responded to in a letter sent to one of the commenters by the Assistant Administrator for Water. This letter is included in the record of this rulemaking. 33. COMMENT 000104 ------- Several commenters suggested that the Agency not establish categorica pretreatment standards for steel industry operations for a variety o reasons including: the purported lack of water quality benefit fo: receiving waters; that certain POTWs achieve a level of toxL pollutant removal comparable to that achieved by PSES and PSNS (am the Agency's purported failure to account for that removal); and, tha Agency's failure to compare the minimization of the pass through o: toxic pollutants through POTW as it relates to the incrementa removals achieved through the BAT limitations. RESPONSE As discussed in detail in the subcategory reports in the developmen document, the Agency has determined that the PSES and PSNS in th< regulation will prevent pass through of toxic pollutants at POTWs to i significantly greater degree than would otherwise occur without sucl standards. The Agency reached these conclusions after comparing thi toxic pollutant removal achieved by compliance with PSES and PSNS wit! the percentage of toxic pollutant removal achieved at POTWs. Thi! comparison revealed that PSES and PSNS are appropriate to prevent thi pass through of those pollutants. In the unlikely event that an individual POTW achieves the same level of toxic pollutant removal at PSES and PSNS, this can be accomodate* through the removal credits provisions of the general pretreatmenl regulation. The Agency believes, therefore, that the PSES and PSN! contained in this regulation are appropriate. 34. COMMENT One commenter said that it was inappropriate for the Agency t< establish pretreatment standards based upon limitations of POTW sludg< disposal alternatives. RESPONSE The Agency has established the pretreatment standards contained ii this regulation to minimize the pass through of toxic metal pollutant* through POTWs and, in once case, to prevent interference with POTf operations. It did not base its pretreatment upon possibl< limitations of POTW sludge disposal alternatives. The Agency determined that the metals pass through POTWs and that pretreatmenl standards (with one exception) should be analogous to BAT level treatment because the model treatment systems remove a greatei percentage of the toxic metals found in steel industry wastewaters than well operated POTWs achieving secondary treatment. 35. COMMENT Several commenters noted that the projected cost of the regulatioi contained in the draft development was different than the drafl economic analysis. 000105 ------- RESPONSE • • As explained in greater detail in the economic analysis report, the Agency could not use identical cost projections for both the technical development document and the economic analysis. The Agency did, however, reduce the difference between these costs as much as possible. The remaining differences are not significant in terms of the economic impact of the regulation. 36. COMMENT One commenter suggested that the Agency's economic analysis include a consideration of the following: the effects of enforcement of the trigger price mechanism; the expiration of the governments anti- inflation program; and other capital investments required of the steel industry to satisfy governmental requirements. RESPONSE The Agency's economic analysis includes these factors. With respect to capital investments necessary to satisfy governmental requirements, the analysis included those investments when they could be determined witb a reasonable degree of certainty. For example, in the case of OSHA requirements, the costs were not included because they could not be determined with a reasonable degree of certainty. 37. COMMENT The industry contends the Agency used flow data from plants with the lowest flows, and concentration data from plants with the lowest concentrations to develop the limitations and standards. The industry states that plants with low flow rates invariably have higher pollutant concentrations in the wastewaters than do plants with lower flows. RESPONSE The Agency disagrees. In all cases, the Agency believes it has established the model treatment flow rates at levels that can be achieved by the industry. Where recycle systems are included in the model treatment systems, the Agency selected model treatment system blowdown flow rates on the basis of actual performance in the industry at representative plants, i.e., plants with applied water rates generally in the range of the model treatment system applied flow rates. For those subcategories where recycle is not part of the model treatment system, the Agency established the model treatment flow rates at levels that can be achieved with good water management practices. The pollutant concentrations used to establish the limitations and standards are based upon performance of treatment systems at plants which have representative untreated wastewaters. Thus, as noted above, the Agency believes it has used representative data to establish the limitations and standards. OOulOG ------- 38. COMMENT "^™""~^^™"' • • The industry commented that when the Agency establishes effluen limitations or standards based upon the "average of the best" plants about half of the best plants would not be able to comply with th limitations. RESPONSE The Agency disagrees. The "average of the best" concept, as used b the Agency, does not mean that arithmetic averages of the bes effluent loads were used as basis for the effluent limitations an standards. The effluent limitations and standards were developed o the basis of model flow rates and effluent concentrations. The mode flow rates were determined from the "average of the best" plants which generally included a large proportion or all of the flow dati reported by the industry. The exceptions were for situations when the model discharge flow rates were based upon the recirculation o: the wastewaters. In these instances a smaller data base was use< since not all plants are operated to minimize the discharge froi recycle systems. In any event, as presented in each subcategor? report of the development document, the model flow rates ar< demonstrated to be achievable by all plants in the respectiv< subcategories. The effluent concentrations were developed froi available effluent data. These data were statistically analyzed an< the effluent concentration bases for the effluent limitations an< standards were projected at the 95th percentile level for the 30-daj average effluent concentration and the 99th percentile level for th< daily maximum. These effluent concentrations are achievable a1 properly designed and well operated treatment systems. Thus, sinc< both the model flows and effluent concentrations are demonstrated tc be achievable. The Agency believes the effluent limitations anc standards established on this basis are achievable by all plants tc which the limitations and standards apply. 39. COMMENT For several subcategories, the industry commented that the Agency die not consider the chemical and energy effectiveness of the selectee model treatment technologies including indirect energy consumption, water losses, and other indirect factors associated with manufacture of chemicals, power, and other items required to operate the mode] treatment systems. In some cases, the industry commented that th€ chemical dosages specified by the Agency are not adequate. RESPONSE As noted in the subcategory reports and in responses to other comments, the Agency reevaluated the chemical dosage requirements for the model treatment systems and made adjustments as appropriate. Th€ Agency has determined that the use of treatment chemicals and the expenditure of energy to operate the treatment systems to achieve the effluent limitations and standards is appropriate and justified. With) CGulO? ------- respect .to indirect energy consumption to produce the treatment chemicals, indirect water losses associated with the generation of power to manufacture the chemicals, and other indirect impacts, the Agency believes it is neither appropriate nor possible for it to evaluate each and every indirect factor associated with the regulation. 40. COMMENT One commenter suggested that the Agency did not adequately consider the adverse air quality impacts associated with industry compliance with this regulation. RESPONSE As noted in the development document, the Agency specifically considered the adverse air quality impacts associated with the alternative treatment systems considered by the Agency for selection as model treatment systems. In addition, the Agency concluded that adverse air quality impacts associated with industry compliance with this regulation are justified by the effluent reduction benefits. 41. COMMENT Several cornmenters objected to the Agency's use of "indicator" pollutants in conjunction with the "alternative effluent limitations" (40 CFR Part 423.03) because it would result in the discharge of an greater amount of toxic pollutants than would occur without the alternative effluent limitations. RESPONSE The Agency disagrees. In developing the alternative effluent limitations, the Agency analyzed the nature of the wastewaters of the various steel industry operations. It believes that if dischargers satisfy the requirements associated with 40 CFR 423.03, there will be no significant increase in the amount of toxic pollutants than would have occured without the application of those alternative limitations. 42. COMMENT Several commenters said that the provisions for alternative effluent limitations contained in 40 CFR 423.03 is illegal and inappropriate. RESPONSE The Agency disagrees. As expalined in the preamble to the regulation, the alternative effluent limitations provide a discharge with an alternative means of achieving the same level of effluent reduction as required by 40 CFR Part 423 Parts A-L, but at a reduced cost. The Agency believes this is an appropriate approach to implement the requirements of the Clean Water Act. ------- 43. COMMENT ~"~ r~~ ~ 4 v One commenter claimed that it and others in the industry have achievei the BPT limitations using non-standard technologies, and that it ma; cost substantially more than the Agency estimates for the commente: and others to achieve the BAT limitations. RESPONSE The Agency believes that its model-based costing methodology ii appropriate for developing industry-wide costs. The Agency hai verified its costing methodology by comparing model based cos estimates with actual industry costs (see Volume I). The Agenc believes that most of the problems cited by the commenter ar' associated with central treatment facilities. The Agency hai addressed this problem to the maximum extent possible by structurini the regulation to facilitate co-treatment of compatible wastewater: and by separately addressing central treatment problems at certai: plants. Reference is made to the preamble for a complete discussio: of this issue. 44. COMMENT The industry commented that the Agency does not have the authority t< regulate flow and that attainment of the flows used by the Agenc; might result in process changes for certain operations or produc quality problems. RESPONSE The Agency believes it appropriate to establish mass-based limitation and standards based upon flow reduction and good water managemen practices. As set out in the development document, the Agenc believes the model treatment system flow rates used to establish th limitations and standards are achievable at all plants without proces changes; and, that product quality will not be adversely affected. 45. COMMENT One commenter stated that the Agency should undertake a more complet analysis of the impact of solid waste disposal costs and problems. RESPONSE The Agency believes that it has adequately considered costs an problems associated with solid waste. Where the RCRA regulation lists certain solid wastes as hazardous, and the solid waste i produced as a result of the wastewater treatment, the Agency ha included appropriate costs ($18/ton) for disposal of these soli wastes. Other solid wastes have been addressed as non-hazardou wastes with appropriate sludge disposal costs ($5/t.on). These cost include site considerations for minimizing or eliminating any advers environmental effects that may result from the disposal of thes CGul09 ------- wastes, e.g./ proper lining of the disposal site. The Agency does not presently have data which would allow it to precisely determine or project which other wastes, if any, might be considered hazardous under RCRA. ------- LIST OF COMMENTERS IRON AND STEEL INDUSTRY PROPOSED REGULATION Comment No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 (46 FR 1858— Due May Commenter AM. Water .W. Serv. Company Armco, Inc. Anaco, Inc. National Steel Armco, Inc. Jones & Laugh 1 in Steel Jones & Laugh 1 in Steel Northwestern Steel & Wire Company Armco, Inc. United States Steel Corporation Kolene Corporation Midwest Steel And co American Water Works Service Company, Inc. (Duplicate) Alabama By-Products Corporation LaClade Steel Company Jones & Laugh 1 in Steel Rooks, Pitts, Fullagar and 8, 1981) Author D. L. Kelleher J. E. Barker J. E. Barker H. R. Wood J. E. Barker D. H. Miller D. H. Miller J. E. Barker J. C. Moniot D. S. Shoemaker K. L. Armour Joseph G. Duffey Daniel L. Kelleher Wm. C. Jones Dale L. Elsenraich David H. Miller James T. Harrington Comment Dated 2/11/81 2/24/81 M 3/4/81 2/26/81 2/27/81 M 3/2/81 3/5/81 3/13/81 3/13/81 3/16/81 3/13/81 3/26/81 2/17/81 3/2/81 2/23/81 2/11/81 4/3/81 4/6/81 4/8/81 4/10/81 19 Poust Colt Industries R. H. Wills, Jr. 4/8/81 cooni ------- LIST OF COMMENTERS IRON AUD STEEL INDUSTRY PROPOSED REGULATION PAGE 2 Commenter Comment No. 20 Carpenter Technology Corporation 21 Koppera 22 U.S. Si.ee! Corporation 23 County Sanitation District of Los Angeles County 24 Natural Resources Defense Council, Inc. 25 Jones & Laughlin Steel 26 Donald Caless 27 Arkansas Science Information Exchange 28 Bass Anglers Sportsman Society 29 National Steel Corporation 30 William V. Peterson 31 CF & I Steel Corporation 32 CF & I Steel Corporation 33 Welborn, Dufford, Cook & Brown 34 United States Steel Corporation 35 Citizens for a Better Environraent 36 Jones & Laughlin Steel 37 J. A. Buzzelli Author Harold W. Miller Charles P. Brush Stephan K. Todd Jay G. Kremer Craig Koralek Donald Caless John S. Miller, Ph.D Bob Barker Ralph W. Purdy William V. Peterson Billy D. Egley John C. Winkley William C. Robb J. D. Moniot Michael E. Belliveau David H. Miller J. A. Buzzelli Comment Dated 4/7/81 4/7/81 4/13/81 4/16/81 4/29/81 4/29/81 5/8/81 5/4/81 5/4/81 5/6/81 5/2/81 5/7/81 5/13/80 9/11/80 5/8/81 5/7/81 5/7/81 5/2/81 000)1? ------- r>« »rr ------- LIST OF COMMENTERS . IRON AND STE'EL INDUSTRY PROPOSED REGULATION PAGE 3 Comment No. 38 39 40 41 42 43 44 45 46 47 48 Coinmenter Author Rooks, Pitts, Fullagar and Poust Bethlehaa Steel Corporation Inland Steel Republic Steel Group Against Smog and Pollution (GASP) Sierra Club General Counsel of the United States Department of Commerce American Iron & Steel Institute Pickands Mather Northwestern Steel & Wire Company Ford Motor Company James T. Harrington David M. Anderson D. C. Lang W. L. West Patricia B. Pelkofer Martha E. Ture Gerald C. lannelli E. F. Young, Jr. T. J. Manthey Dale R. VanDeVelde A. B. M. Houston Comment Dated 5/8/81 5/6/81 4/28/81 5/6/81 5/6/81 5/6/81 5/8/81 5/8/81 5/8/81 5/6/81 5/7/81 GGulI? ------- |