United States Environmental Protection Agency Hazardous Waste Engineering Research Laboratory Cincinnati OH 45268 Research and Deveiopment EPA/600/S2-87/099 Jan. 1988 <>ERA Project Summary Technical Resource Document: Treatment Technologies for Corrosive-Containing Wastes, Volume II Lisa Wilk, Stephen Palmer, and Marc Breton This Technical Resource Document (TRD) for wastes containing corrosives is one in a series of five documents which evaluate waste management alternatives to land disposal. In addition to this TRD for corrosive wastes, the other four TRDs in the series address land disposal alternatives for the fol- lowing waste categories: dioxins; solvents; nonsolvent halogenated organics; and metals/cyanides. The purpose of these documents is to provide a comprehensive source of information that can be used by envir- onmental regulatory agencies and others in evaluating available waste management options, which include waste minimization and recycling as well as treatment. Emphasis has been placed on the collection and interpre- tation of performance data for proven technologies. However, all potentially viable technologies are identified and discussed. When possible, cost and available capacity data are provided to assist the user of the TRDs in assessing the applicability of technologies to specific waste streams. This Project Summary was devel- oped by EPA's Hazardous Waste Engi- neering Research Laboratory, Cincin- nati, OH, to announce key findings of the research project that is fully doc- umented in a separate report of the same title (see Project Report ordering information at back). Background Corrosive acids and alkalis are widely used by all segments of American industry and result in the generation of approximately 40 percent of all RCRA- regulated hazardous wastes.1 Improper management of these wastes can result in altered pH of surface waters to the detriment of aquatic organisms. Land disposal of these wastes can also lead to the solubilization of toxic (e.g., heavy metals) constituents of co-disposed wastes, thereby enhancing the potential for their transport into the environment.2 To combat the potential negative effects associated with current disposal practi- ces, the 1984 RCRA Amendments directed EPA to ban corrosive wastes from land disposal to the extent required to protect human health and the environment. The land disposal ban excludes acidic corrosive wastes (pH less than or equal to 2.0) from land disposal units(excluding underground injection), effective July 8, 1987. Treatment standards for corro- sives which are currently managed through underground injection will be promulgated on August 8, 1988. Finally, alkaline corrosive wastes (pH greater than 12.5) will be banned from disposal effective May 8, 1990. In addition, treatment standards for hazardous con- stituents which are commonly present in corrosive wastes, such as heavy metals and toxic organics, are also being pro- mulgated under the 1984 RCRA Amend- ments. Thus, prior to land disposal, corrosive wastes will also have to meet these standards as they are promulgated. In fiscal year 1986, the U.S. EPA Hazardous Waste Engineering Research ------- Laboratory (HWERL) began developing a series of technical resource documents (TRDs) which evaluate waste manage- ment alternatives to land disposal. These documents are intended to serve a two- fold purpose. First, they provide technical support for current EPA efforts to identify available alternative waste management capacity and to evaluate the technical feasibility of meeting proposed treatment standards. Secondly, the documents provide a single, comprehensive source of technical data to assist waste gener- ators and regulatory agencies in evaluat- ing available waste management options. To date, in addition to the Corrosives Technical Resource Docu- ment, three other TRDs have been completed covering the following waste categories: dioxins, solvents (halogen- ated and non-halogenated), and non- solvent halogenated organics. Scope This summary of the Corrosives Tech- nical Resource Document provides envir- onmental regulatory agencies and hazardous waste generators with a source of technical information describ- ing corrosive waste management alter- natives. These options include waste minimization (i.e., source reduction, recycling, waste exchange), and treat- ment and disposal of waste streams. Emphasis is placed on the collection and interpretation of performance data for neutralization and recovery technologies which have demonstrated both technical and economic feasibility for handling corrosives. Table 1 summarizes potentially appli- cable corrosive waste management alternatives for various waste character- istics and management objectives. With the exception of recycled or reused wastes, all corrosive liquids and sludges will require some form of neutralization prior to ultimate disposal. Pretreatment requirements are generally limited to phase separation, equalization, cyanide destruction, and chromium reduction. Post-treatment (i.e, post-neutralization) requirements vary with contaminant types and concentrations and selection of neutralization reagent. Contaminants of particular concern in residual streams include heavy metals and toxic organics which exceed effluent limitations (e.g., NPDES, POTW) or land dipsosal treat- ment standards. Determination of the overall applica- bility and availability of these technolo- gies for managing corrosives required an understanding of the nature of current waste management practices. Analysis of these practices served to identify available methods which have proven to be both technologically and economically capable of treating corrosive wastes. To a significant extent, waste management alternatives which will permit industry to meet EPA disposal requirements (e.g., neutralization, metals precipitation, organic removal techniques) have already been implemented. This occurred in response to increased regulatory requirements and the improved eco- nomic viability of waste minimization and treatment options. The latter resulted from increased disposal costs and liabil- ity, and advances in waste processing technology. Determining the applicability of alter- native technologies also required an in- depth understanding of the nature of corrosive wastes. Data requirements included the range and variability in corrosive waste physical, chemical, and flow (i.e., rate, periodicity) characteristics which, in turn, required an understand- ing of corrosive waste industrial origins. Available data were summarized on a national basis to assist EPA efforts in evaluating the existence of available alternative treatment capacity to manage wastes which will be excluded from land disposal. However, these data were found to be limited. In particular, waste characteristics from industries other than the Chemical and Allied Products Industries (SIC 28) need to be compiled on a national basis. Available data on corrosive waste generation, characteristics and current management practices are briefly sum- marized below. This is followed by a discussion of potential waste manage- ment alternatives which have been categorized as either neutralization (with appropriate pretreatment and post- treatment) or recycling processes. Emphasis is placed on identifying pro- cess design and operating parameters, and waste characteristics which affect overall process applicability. This discus- sion concludes with a summary of technical and economic factors which should be considered in the selection of an optimal waste management system. Corrosive Waste Generation, Characteristics, and Management Practices The most comprehensive source of data regarding corrosive waste genera- tion and management was a study1 based on the results of the EPA's National Survey of Hazardous Waste Generators and Treatment, Storage and Disposal Facilities(TSDFs) Regulated Under RCRA in 1981.3 Highlights of the survey results are as follows:1 • The total quantity of corrosive waste (D002 and K062; corrosives and spent pickle liquor from steel finishing operations) generated in the United Statesin 1981 was21.8to25.6billion gallons. This represents approxi- mately 40 percent of all hazardous waste generation. However, it includes mixtures of corrosive and non-corrosive wastes which signifi- cantly inflates the total estimate. • The number of generators of D002 corrosive wastes was 4,705 which represents over one-third of all RCRA waste generators. These wastes were handled at 513 TSDFs in 1981. In addition, 64 TSDFs handled K062 corrosive wastes. • The total quantity of corrosive waste that was reportedly land disposed, and thus affected by the proposed land disposal ban, was 3.6 to 4.2 billion gallons. • Nearly 95 percent of land disposed corrosives were liquid acidic wastes. • Disposal by deep-well injection accounted for 87 percent of land disposed corrosives with another 6 percent disposed in surface impound- ments and 5 percent in landfills. Waste generation estimates provided by the National Survey compare favor- ably with more recent, but less compre- hensive, projections.4'5 However, data indicate that these estimates include large quantities of corrosive waste mixtures; i.e., corrosives mixed with other wastes or nonhazardous mate- rials.6 Thus, actual waste volume at the point of production (i.e., excluding the effects of mixing or treatment) may be lower by 40 percent or more.1'6 The primary industrial applications for acids and bases which result in gener- ation of corrosive wastes are: (1) use as chemical intermediates in the inorganic and organic chemical manufacturing industries; (2) use as a metal cleaning agent in metal production and fabrication industries; and (3) use in boiler blow- down and stack gas treatment, primarily in electricity generating facilities. Other ------- Table 1. Waste Management AIternatives to Land Disposal Waste Management Objective Applicable Waste TypefsJ Potential Waste Management Alternative Waste minimization Source reduction Recycling All Concentrated inorganic liquids (e.g.. plating, etching solutions) Raw material substitution Process redesign Product reformulation Waste segregation Crystallization Ion exchange Evaporation/distillation Electrodialysis Solvent extraction Thermal decomposition Dilute inorganic liquids (e.g., plating rinses) Concentrated organic liquids (e.g., solvents with acid/alkali) Ion exchange Electrodialysis Reverse osmosis Donnan dialysis/ coupled transport Neutralization followed by recovery such as distillation, evaporation, steam stripping, or use as a fuel. Waste exchange Pretreatment Concentrated liquids Dilute inorganic liquids Liquid with solids Liquid—two-phase Liquid or sludge with cyanide Recycling Mutual neutralization Screening Distillation Centrifugation Decanting Extraction Cyanide destruction through chlorination Reuse in process with lower raw material specifications Sedimentation Flotation Equalization Flotation Distillation Mutual neutralization Filtration Settling Centrifugation Equalization Liquid or sludge with hexavalent chromium Chromium reduction Sludge Bulky solids Vacuum filtration Other dewatering Shredders Filter press Hammermills Centrifugation Crushers Neutralization Acidic waste Alkaline waste All Limestone Sulfuric acid Mutual neutralization Lime Hydrochloric acid Caustic soda Carbonic acid (COi) Post-treatment Metal-containing liquid Trace organic-containing liquids Precipitation and clarification Adsorption Dilute organic-containing liquid Concentrated organic liquid Inorganic sludges and solids Biological treatment Air stripping Distillation Extraction Incineration Solidification Chemical oxidation Incineration Steam stripping Supercritical fluids Use as a fuel Encapsulation Ozonation Evaporation Wet air oxidation Landfill Organic sludges and solids Incineration Wet air oxidation ------- significant corrosive waste sources include refining processes in the petro- leum industry and pulping liquor in the paper industry. A summary of corrosive waste quantity handled by various industrial classification codes (SIC) is provided in Table 2.1 The majority of corrosive wastes are handled in onsite wastewater treatment facilities which ultimately discharge treated effluents to POTWs or to surface waters under NPDES permits.1'6 How- ever, approximately 16.5 percent of all corrosives were reportedly land disposed in 1981 in methods which would be affected by the land disposal restric- tions.1 A summary of these waste management practices is provided in Table 3. As shown, 87 percent of land disposed corrosives are managed through deep well injection.1 More recent data suggest that deep well injected waste volumes may have decreased significantly (24 perecent) since the National Survey data was collected.8 However, other quantities presented in Table 3 are expected to adequately approximate current waste management practices. Waste charcteristics of land disposed corrosives are less well defined. The vast majority are acidic (82 percent), inorganic (82 percent), and characterized as dilute (94.3 percent, liquids only).1 Deep well injection wastes have a high tendency to contain toxic organics,6 whereas landfilled wastes are likely (38 percent) to contain heavy metals at concentra- tions which exceed proposed land dis- posal restrictions.9 Detailed characteri- zation data for the Chemical and Allied Products Industries, currently being compiled by the EPA,6 will enable the majority of deep well injected wastes to be characterized. Approximately 60 percent of landfilled wastes are accounted for by spent pickle liquor from the iron and steel industry (K062) which has also been adequately characterized. However, data are limited for the remainder of land disposed corrosives. These data will be required for EPA to assess the availability of alternative waste management options when cor- rosive wastes become prohibited from land disposal. Neutralization Neutralization processes are the most commonly applied methods for managing corrosive wastes. Adjustment of waste pH is typically required prior to subse- quent treatment processes to limit corrosion of processing equipment or to enhance treatment; e.g., metals precip- itation or biological degradation of toxic organics. Alkaline reagents commonly used to neutralize strongly acidic waste streams (greater than 5,000 mg/L of mineral acid strength) include high calcium lime and caustic soda.1 For the treatment of dilute acidic waste streams (5,000 mg/L or less), limestone treatment may also be economically feasible.10 Mineral acids such as sulfuric or hydrochloric are the primary reagents used for the neutral- ization of corrosive alkaline waste streams.11 However, alkaline waste streams which have flow rates of over 100,000 gpd or require greater than 200 tons of reagent per year, may also be economically treated by liquid carbon dioxide.12 Pretreatment requirements prior to neutralization typically consist of gross solids removal (i.e., filtration), flow equalization, or treatment of individual waste streams prior to combination with other process wastes. These treatments of segregated wastes result in economic benefits from reduced reagent costs and smaller equipment sizing. Common pretreatment processes include cyanide destruction, chromium reduction, metals precipitation from highly chelated wastes, and oil removal. Post-treatment of neutralized wastes which do not contain metals or organics typically consists of liquid/solid separa- tion (e.g., clarification) to precipitate insoluble salts, followed by sludge dewatering (e.g., filter press) and dispo- sal in a secure landfill. Post-treatment of corrosives with metals or toxic organ- ics depends primarily on their concentration.13'14 Neutralized waste streams containing trace organics (less than 500 ppm) would require additional post-treatment through technologies such as carbon or resin adsorption or air stripping.13 Dilute organic waste streams (500 to 10,000 ppm) are most often economically treated via biological degradation followed by filtration and polishing; e.g., activated carbon.14 Concentrated organic waste streams usually undergo phase separa- tion (e.g., dissolved air flotation) follow- ing neutralization.14 The concentrated organic phase can be recovered through distillation, steam stripping, solvent extraction, or thin film evaporation.13 Table 2. Corrosive Waste Quantity Handled by Industrial Classification (million gallons/ year) SIC Code 28 49 29 33 26 36 35 32 34 37 20 Industry Description Chemicals and allied products Electric, gas and sanitary services Petroleum refining Primary metals Paper and allied products Electric and electronic machinery, equipment and supplies Machinery, except electrical Stone, clay, glass, concrete Fabricated metals Transportation equipment Food and kindred products Other industries Total: Waste High 18,337 2,305 1,150 1,143 1.126 581 417 190 183 136 27 50 25,645 Quantity Handled" Low Percent 15.590 1,960 978 972 957 495 354 162 156 115 23 42 21.803 71 5 9.0 45 4.5 4.4 23 1.6 0.7 0.7 05 0.1 0.2 1000 'Includes O002 andK062 only. Source: National Survey, Reference 1. ------- Table 3. Management Practice Summary for Corrosive Wastes National Estimates (million gallons) High Quantity Estimate' Low Quantity Estimate" Handled0 Disposed0 Injection well Landfill Land treatment Surface impoundment Other Treated0 Tanks Surface impoundment Incineration Other Stored0 Tanks Containers Surface impoundment Waste piles Other Recycled" Onsite: Generator TSDF Offsite: Generator TSDF Corrosive Waste D002 24.596 3,970 3,635 85 18 206 26 15.912 7,040 5,614 6 3.252 10.094 1.542 9 6,530 6 2.007 373 330 42 288 43 14 29 Spent Pickle Liquor K062 1.048 236 28 131 56 20 218 139 39 40 265 211 47 7 354 34 6 28 320 170 150 Total 25,644 4,206 3,663 217 18 262 46 16.031 7,180 5.653 6 3,292 10.360 1,754 9 6,577 13 2.007 727 364 48 316 363 184 179 Corrosive Waste D002 20,912 3.375 3,090 73 15 175 22 13,528 5,986 4,773 5 2,764 8.582 1,311 8 5,552 5 1,706 327 280 35 245 36 11 25 Spent Pickle Liquor K062 891 200 24 112 48 17 185 118 33 34 226 180 40 6 301 30 6 24 272 143 129 Total 21,803 3,576 3,114 185 15 223 39 13,714 6.104 4.806 5 2.799 8.809 1.491 8 5.592 11 1.706 618 310 41 269 308 154 154 °1.235 x base data. "1.05 x base data. cSource of base data: Reference 1. "Source of base data: Reference 7. The aqueous phase will be treated through wastewater treatment methods as previously discussed. Sludges con- taining significant concentrations of toxic organics (e.g., greater than 20 percent) must be incinerated or otherwise treated through processes which will destroy or detoxify organic compounds; e.g., pyrol- ysis, and wet air oxidation.13 Solidifica- tion/encapsulation technologies have not been adequately developed for wastes with high organic content such that land disposal treatment standards can be achieved.13 Metals containing aqueous wastes generally undergo precipitation followed by sludge consolidation. Solidification or encapsulation of the sludge product will be required prior to disposal in a secure landfill if the leachate exceeds EPtoxicity standards for heavy metals. Unlike fixation of organics, this technology is demonstrated and widely available.13 A key consideration in the use of neutralization technologies is selection of the most appropriate reagent. Table 4 summarizes the most commonly used reagents, applicable waste types, resid- uals generated, and system costs. Neu- tralization reagents and acid/alkali waste combination are discussed in more detail below. Mutual Neutralization Acid/alkali mixing (mutual neutraliza- tion) is often the most economical method of neutralization available, particularly m cases where compatible wastes are present in the same plant.1 The primary advantage of waste combi- nation is reduced operating costs since neutralizing reagent requirements are minimized. The main disadvantage is that mixing two waste streams, each with its own variability in composition and flow, may require more conservative system design; i.e., larger equalization and neutralization tanks and back-up neutral- ization reagent systems. Additionally, care must be exercised when combining waste streams or accepting wastes from another firm to prevent any hazardous products or releases during the neutral- ization reaction. Limestone Neutralization Limestone treatment is a well- developed and established technology for the neutralization of dilute acidic waste streams. However, limestone (CaCO3) is limited in its ability to achieve neutral- ization endpoints over pH 6.0 or to neutralize wastes with acid conentra- ------- Table 4. Summary of Neutralization Technologies Applicable Waste Stage of Process Streams Development Acid/ alkali mutual neutralization Limestone Lime Caustic soda Suit uric acid Hydrochloric acid All acid/ alkali compatible waste streams except cyanide. Dilute acid waste streams of less than 5.000 mg/L mineral acid strength and containing low concentrations of acid salts. All acid wastes. All acid wastes. All alkaline wastes except cyanide. All acid wastes. Well developed. Well developed. Well developed. Well developed. Well developed. Well developed. but rarely applied due to high reagent cost. Performance Generally slower than comparable technologies due to dilute concentrations of reagents. May evolve hazardous constituents if incompatible wastes are mixed. Requires stone sizes of 0.074 mm or less. Requires 45 minutes or more of retention time. Can only neutralize acidic wastes to pH 6.0. Must be aerated to remove evolved CO* Requires 15 to 30 minutes of retention time. Must be slurried to a concentration of 10 to 35% solids prior to use. Can under- (below pH 7) or over- (above pH 7) neutralize. Requires 3 to 15 minutes of retention time. In liquid form, easy to handle and apply. Can under- or over- neutralize including pH 13 or 'higher. Requires 15 to 30 minutes of retention time. In liquid form, but presents burn hazard. Highly reactive and widely available. Requires 5 to 20 minutes of retention time. Liquid form presents burn and fume hazard. More reactive than sulfuric. Residuals Generated Variable. dependent on quantity of insolubles and products contained in each waste stream. Will generate voluminous sludge product when reacted with sulfate-containing wastes. Stones over 200 mesh will sulfonate. be rendered inactive. and add to sludge product. Will generate voluminous sludge similar to limestone. Reaction products are generally soluble, however. sludges do not dewater as readily or as easily as lime or limestone. Will generate large quantities of gypsum sludge when reacted with calcium-based alkaline wastes. Reaction products are generally soluble. Cost Least expensive of all neutralization technologies. Most cost- effective in treating concentrated wastes. May be cost-effective in treating dilute acidic wastes. More expensive than crushed limestone (200 mesh). Most expensive of all widely used alkaline reagents (five times the cost of lime). Least expensive of all widely used acidic reagents. Approximately twice as expensive as sulfuric on a neutralization equivalent basis. ------- Table 4. Continued Process Carbonic acids. liquid carbon dioxide Applicable Waste Stage of Streams Development All alkaline wastes Emerging except cyanide. technology. Performance Retention time 1 to 1 Viminu1.es. In liquid form, must be vaporized prior to use. Can only neutralize alkaline wastes to pH 8.3 end point. Residuals Generated Will form calcium carbonate precipitate when reacted with calcium-based alkaline wastes. Cost Approximately 3 to 4 times as expensive as sulfuric. Therefore, limited to applications using more than 200 tons of reagents per year or with flow rate greater than 1 00.000 gpd. tions greater than 5,000 mg/L10 The primary advantage of limestone neutral- ization is that limestone is a low cost and widely available reagent. It can be used in an upflow expanded bed mode or as a pretreatment in combination with lime. In the latter case, the pH is raised to approximately 3.0 to 6.0 with lime addition completing the process of neutralization.15 However, in the pres- ence of concentrated acidic wastes, limestone particles will become coated with precipitate, rendering them inactive and adding to already voluminous sludge product. Lime Neutralization Lime slurry treatment of acidic waste streams is analogous to that of limestone in that both are calcium-based rea- gents.18 Lime (CaO) is typically hydrated (slaked) and slurried with water to a 10 to 35 percent solids concentration prior to use.17 Slurried lime (Ca(OH)2) reacts more rapidly than limestone, typically requiring only 15 to 30 minutes retention time versus 45 minutes or more for limestone. The ability of lime slurry to treat a wide variety of manufacturing waste streams has been well demon- strated in bench, pilot, and full-scale systems. Lime slurry treatment is more versatile than limestone since it can effectively neutralize both dilute and concentrated acidic waste streams to pH endpoints ranging from 6.0 to 12.4. However, when reacted with sulfate- containing wastes (e.g., sulfuric acid), lime (and limestone) will form a volumi- nous calcium sulfate (gypsum) sludge product. Sodium Hydroxide Neutralization After lime, sodium hydroxide (NaOH) is the second most widely used alkaline reagent for the neutralization of both dilute and concentrated acidic waste streams. Its chief advantage over lime slurry neutralization is that as a liquid reagent, it is easier to store and handle, will rapidly dissociate into solution, and has minimal hold-up time.18 As a result, retention times are typically 5 to 20 minutes19 with a corresponding reduc- tion in feed system and tankage require- ments. In addition, sodium hydroxide is highly caustic (can neutralize to a 14.0 pH endpoint), and as a sodium-based reagent, it generates reaction products which are usually soluble. The main disadvantage of sodium hydroxide are burn dangers from splash- ing and a 500 percent increase in reagent costs on a neutralization equivalent basis as compared to lime. Thus, in high volume applications where reagent expenditures constitute the bulk of operating expenses, lime is generally the reagent of choice. In low volume appli- cations where low space requirements, soluble end-products, and rapid reaction rates are important factors in reagent selection, caustic soda becomes superior. Mineral A cid Neutralization Mineral acid treatment is the most widely used and demonstrated technol- ogy for the neutralization of corrosive alkaline waste streams. Both sulfuric (H2SCu) and hydrochloric(HCI) acids have very high dissociation constants, so that quantities required for neutralization are relatively low in comparison to other acids 1 Consequently, reactor volumes and handling/storage facilities are smaller. Sulfuric acid, being the most widely available and lowest in cost on a neutralization equivalent basis, is the most prevalent acidic reagent.12 It is typically used in combination with an alkali reagent to control pH fluctuations in both the acidic and alkaline ranges. Hydrochloric acid is generally used in situations requiring rapid reaction rates and soluble reaction products. The primary disadvantage in the use of mineral acid reagents is the generation of potentially hazardous sludge (sulfuric acid), and acid mist, or toxic/hazardous fumes (hydrochloric acid). The highly corrosive nature of mineral acids pres- ents a burn hazard to personnel, and increases the likelihood of a possible catastrophic release during bulk trans- port or storage. Carbonic Acid Neutralization Carbonic acid (H2C03> treatment, using liquid carbon dioxide as a neutralizing agent, is a relatively new and emerging technology. Currently, applications are limited to waste streams with flow rates greater than 100,000 gpd or facilities using more than 200 tons of reagent per year.12 Since liquid carbon dioxide is vaporized prior to use and applied as extremely fine (15 microns or less) bubbles, capital requirements are min- imal (e.g., sparger system) and reaction times are typically only 1 to 11/2 minutes. However, liquid CC>2 can only neutralize to a pH 8.3 endpoint.12 In addition, it costs two to three times as much as sulfuric acid and will form an insoluble calcium carbonate precipitate when reacted with calcium-based alkaline waste streams. Recovery/Reuse Technologies As an alternative to conventional neutralization treatment, recovery/ reuse technologies may be employed. Certain recovery technologies have been established as being cost-effective for specific applications. Additional research has shown the technical and potential economical feasibility of a number of ------- other emerging technologies. With the implementation of the land disposal ban and the resulting increases in costs for sludge disposal, it is anticipated that recovery/reuse will be cost-effective for an increasing number of corrosive wastes. Crystallization and evaporation/distil- lation involve the use of temperature changes to effect a separation of con- taminants and recovery of corrosive solutions. Ion exchange methods are based on the use of an anionic or cationic selective resin to remove ionic contam- inants (i.e., metal ions) from corrosive wastes. Electrodialysis, reverse osmosis, donnan dialysis, and coupled transport processes involve the use of a membrane to separate contaminants from corrosive solutions. The driving force of the membrane separation is an electric current for electrodialysis, hydraulic pressure (generated by a pump) for reverse osmosis, and a concentration gradient (between spent corrosive solu- tion and a metal stripping solution) for donnan dialysis and coupled transport. Solvent extraction uses the differential distribution of constituents between the aqueous phase waste and an organic solvent to separate constituents from a mixed solution of metal salts and acid wastes. Thermal decomposition involves decomposing metal salts, present in spent acid wastes, in a roaster and collecting vaporized acid in a condenser. In general, recovery/reuse process selection will be limited to wastes possessing specific chemical, physical, and flow characteristics. A summary of the overall performance, applicable waste streams, residuals generation, and status ot development for the corrosive recovery/reuse technologies is provided in Table 5. A brief description of these processes and their current status is presented below. Evaporation/Distillation Evaporation/distillation techniques can be used to recover a variety of plating and other process chemicals. They are most commonly used in metal finishing and electroplating industries to recovery plating solutions, chromic acid and other concentrated acids, and metal cyanides by evaporating water from the dilute rinse solution and concentrating the corrosive solution for return to the concentrated bath.1'20'21 Water recovered from the distillation (condensation) process is of high purity and can be reused in process waters. Evaporation systems used to recover corrosive plating rinses are cost- competitive with conventional neutrali- zation and disposal technologies. Greater cost savings are realized with larger operations. However, the use of evapo- ration/distillation systems to recovery concentrated streams directly from the spent bath solution is limited. Pilot-scale evaporation/distillation systems for recovery of nitric/hydrofluoric acid pickling liquors have been tested at facilities in Europe.22'23 However, cost- effective systems for direct recovery of spent solutions via evaporation/distilla- tion have not been developed at the commercial-scale for application in the United States. Crystallization Crystallization is a recovery technique whereby metal contaminants in a spent corrosive solution are crystallized and removed by settling or centrifugation. It is a demonstrated and commercially available technology for the recovery of acid pickling liquors and caustic etching solutions.24'25'2*27 The use of crystallization techniques for the recovery of sulfuric acid pickling liquors and caustic aluminum etching solutions is limited by economics. This is due to the small quantities of these solutions used by individual manufactur- ers, the costs for plant modifications, and the varying demand for the crystal product.1'28 Nitric-hydrofluoric acid pic- kling liquors are used in larger quantities by individual manufacturers in the steel industry than sulfuric acid pickling liquors. Therefore, crystallization tech- niques would have wider application for this waste type. Despite these limita- tions, these processes are currently being used in the metal finishing industry in specialized applications. Ion Exchange Ion exchange has been used to recover acids, bases, and process wastes from the metal finishing, electroplating, and fertilizer manufacturing industries by removing metal contaminants and rec- ycling the treated solution.1'29 Ion exchange techniques involve the use of an anionic or cationic selective resin to remove ionic contaminants (i.e., metals) from solution. Three types of ion exchange configurations can be used: cocurrent, countercurrent (reverse flow) fixed bed, and countercurrent (reverse flow) continuous. Cocurrent ion exchange systems are generally not employed for direct treat- ment of corrosive wastes. Cocurrent systems using weak exchangers have inefficient exchange capacities in the corrosive pH ranges. Thus, they are generally used as polishing systems following other treatment operations. Corrosive systems using strong exchangers are not cost effective because of the high costs for column regeneration. However, reciprocating flow ion exchange (RFIE) systems have been shown to be effective in the treatment of corrosive wastes. These may be more cost-effective for the treatment of corrosives than conven- tional neutralization, particularly when enactment of land disposal restrictions increase costs associated with land disposal of residuals. Chemical recovery systems using fixed bed RFIE have been used to recover chromic acid and metal salts, and to deionize mixed-metal rinse solutions for recovering process water and concen- trating the metals for subsequent treat- ment. °'31 Commercial units are available from several vendors. Acid purification systems using con- tinuous RFIE have been used to remove aluminum salts from sulfuric acid anod- izing solutions, to remove metals from nitric acid rack-stripping solutions, and to remove metals from sulfuric and hydrochloric acid pickling solutions.30 Acid purification systems are most cost- effective for removing high concentra- tions of contaminants relative to other ion exchange systems. Electrodialysis Electrodialysis (ED) uses an electric field and a semipermeable ion-selective membrane to concentrate or separate ionic species in a water solution.32'33 Its primary application in the treatment of corrosive wastes is recovery of corrosive plating solutions, pickling solutions, and etchants by removing contaminant metal ions. Three types of configurations may be used in the design of ED units: concentrating-diluting, ion-substituting, and electrolytic. Currently, electrodialysis has a limited area of application in the recovery/reuse of corrosive wastes. Concentrating- diluting and ion transfer ED units have been successful in the recovery of chromic acids from dilute solutions.34'35 Electrolytic ED units have demonstrated the ability to recover concentrated acid solutions by removing metal ion contam- 8 ------- Table 5. Summary of Recovery/ Reuse Technologies for Corrosive Wastes Applicable Waste Stage of Process Streams Development Performance Evaporation/ distillation Crystallization Ion exchange Electrodialysis Metal plating rinses; acid pickling liquors HiSOt pickling liquors; HNOa/HF pickling liquors; caustic aluminum etch solutions. Plating rinses; acid pickling baths; aluminum etching solutions; HiSOt anodizing solutions; rack- stripping solutions (HF/HNOsl. Recovery of chromic/ sulf uric acid etching solutions. Recovery of plating rinses (particularly chromic acid rinse water). Recovery ofHNOs/ HF pickling liquors. Well-established for treating plating rinses. 20 to 25 systems currently in operation (fewer applications for caustic recovery). Several RFIE units in operation for treatment of corrosives. Units for direct treatment of acid bath only available fromECO-TEC, Ltd. Units currently being sold, but limited area of application. 5 in operation. Several in operation. Marketed, none in operation to date. Plating solution recovered for reuse in plating bath. Rinse water can be reused. 97-98% recovery f or HsSOt (80-85% metal removal) 99% HN03 and 50% HF recovered. 80% recovery of NaOH Cocurrent systems not technically feasible for direct treatment of corrosives, can be used in conjunction with neutralization technologies to lower overall costs RFIE units show good results. Conventional RFIE performs best with dilute solutions APU performs best with high metal concentration (30 to 100g/L) 85% recovery of etching solution. 45% copper removal. 30% zinc removal Works best when copper concentrations are in the 2 to 4 oz/ gal usage. 3 M HF/HN03 recorded. Residuals Generated Impurities will be concentrated. therefore. crystallization/ filtration system may be required Ferrous sulf ate heptahydeate crystals lean be traded or sold). Metal fluoride crystals (can recover additional HF by thermal decomposition) Aluminum hydroxide crystals (can be traded or sold). Cocurrent process generates spent regenerant, which is also corrosive Recovered metals which can be reused, treated. disposed, or marketed Metals which can be treated. disposed, or regenerated for reuse Chromic acid can be returned to plating bath, rinse water can be reused. 2 M KOH Soln which can be recycled back to the pretreatment step for this ED application. Cost Can be cost- effective for recovering corrosive plating solutions from rinse waters Cost-effective if treating large quantities of waste RFIE and APU are cost-effective. Cost-effective for specific applications (chromic/ sulf ate acid etchantsl Low capital investment; cost- effective for specific application (chromic acid rinses) Cost-effective for large quantity generator. ------- Table 5. (Continued) Applicable Waste Process Streams Reverse osmosis Plating rinses. Donnan dialysis/ Plating rinses; coupled transport potentially applicable to acid baths. Solvent extraction HN03 /HF pickling liquors. Thermal Acid wastes. decomposition Stage of Development Corrosive waste membranes marketed by four companies. RD module systems applicable to corrosives available from two companies. Donnan analysis only lab-scale tested. Coupled transport lab and field tested. Coupled transport system is currently being marketed. Commercial-scale systems installed for development purposes in Europe and Japan. No commercial- scale installations in U.S. Well-establshed for recovering spent pickle liquors generated by steel industry. Pilot-scale stage for organic wastes. Performance 90% conversion achieved with cyanide plating rinses. Data not available for Donnan analysis (further testing required). Coupled transport has demonstrated 99% recovery of chromate from plating rinses. Other plating rinses should be applicable, but not fully tested. 95% recovery of HNO3;70% recovery of HF. 99% regeneration efficiency for pickling liquors. Residuals Generated Recovered plating solution returned to plating bath (after being concentrated by an evaporator). Rinsewater reused. Data not available for Donnan analysis. For chromate plating rinse applications. sodium chromate is generated; can be used elsewhere in plant or subjected to ion exchange to recover chromic acid for recycle to plating solution. Metal sludge (95% iron can be recovered by thermal decomposition). 98-99% purity iron oxide which can be reused, traded. or marketed. Cost Cost-effective for limited applications. Development of a more chemically resistant membrane would make it very cost- effective for a wider area of application. No cost data available for Donnan analysis. Average capital cost for plating shop is $20,000. Can be cost- effective for specific applications. Not available. Expensive capital investment. Only cost-effective for large quantity waste acid generators. inants; e.g., removing copper ions from spent chromic acid/sulfuric acid brass etchants and bright dipping solutions.36 Another recently developed application uses electrodialysis in conjunction with neutralization to recover spent hydrofluoric-nitric acid pickling liquors.37'38 Current research in the application of electrodialysis to the treatment of cor- rosive wastes is directed at using the electrolytic ED configuration. The U.S. Bureau of Mines is currently investigat- ing techniques for the removal of iron from nitric-hydrofluoric acid pickling liquors.39'40 In addition, Ionics, Inc. is currently developing improved ED mem- branes for use with corrosive wastes. However, their research is currently limited to bench-scale studies and preliminary results have not yet been released.41 Reverse Osmosis RO involves passing the wastewater through a semipermeable membrane at a pressure greater than the osmotic pressure caused by the dissolved mate- rials in the solvent.42 Thus, the osmotic flow, defined as the flow from a concen- trated solution to a dilute solution, is reversed due to the increase in pressure applied to the system. The technology has been applied in the metal finishing industry to recover plating chemicals from rinsewater, permitting reuse of both plating chemicals arid rinsewaters.29'43 Reverse osmosis systems are currently available for recovering corrosive waste- water streams; e.g., plating rinses. However, cost-effective use of RO sys- tems for corrosive waste applications is generally limited due to reduced mem- brane lifetime and high costs for mem- brane cleaning and replacement. How- ever, future development of membranes which are able to withstand corrosive 10 ------- and oxidizing solutions is expected.32 If membrane lifetimes are increased, reverse osmosis would be a very cost- effective alternative to conventional treatment technologies. Excluding mem- brane cleaning and replacement costs, the only significant operating cost is the electricity required for operation of the pump. However, current systems are limited in the degree of attainable concentration in the recovered corrosive solution. Thus, many applications may also require the use of an evaporator in conjunction with the RO unit. This combined system is generally more cost- effective than evaporation alone for dilute solutions. Donnan Dialysis and Coupled Transport Donnan dialysis and coupled transport are similar processes in that both employ a concentration gradient to drive ions from a spent solution across a membrane into a metal stripping solution. The major difference between these processes is the type of membrane and transport mechanism employed. The coupled transport membrane is highly selective and, therefore, has more specific process applications, whereas the donnan dial- ysis membrane is applicable to a wider variety of solution constituents. How- ever, greater purity can be achieved using the coupled transport membrane. Donnan dialysis has not been tested on a pilot-scale. Much of the research that has been performed to date has concentrated on membrane develop- ment.44 However, preliminary research performed by the Southwest Research Institute has encouraged them to develop a pilot-scale unit.45 Pilot-scale testing is needed to determine if sufficient solution concentrations can be achieved with the process. Bend Research Corporation has per- formed most of the development work for coupled transport technology and has a patent pending on the process.46 Although the process is applicable to the treatment of several metal-containing solutions, the most developed application is for the treatment of hexavalent chro- mium in plating rinses. The process was recently licensed to Concept Membrane, Inc. for marketing and sales purposes. However, commercial units are not currently available for purchase.46 Both membrane technologies show good potential as cost-effective alterna- tives to conventional neutralization and disposal practices. In addition, donnan dialysis and coupled transport offer potential economic advantages over other membrane technologies, due to lower energy requirements. The large hydraulic pressures required for reverse osmosis and the large electric current flow required by electrodialysis are not required for these technologies.44'46 Solvent Extract/on Solvent extraction is a separation technique utilizing the differential distri- bution of constituents between the aqueous phase and an organic solvent phase to separate constituents from a mixed solution. It is widely used as an analytical chemistry technique and for the recovery of metals in the field of hydrometallurgy. Recently, research has also shown applications for solvent extraction in the recovery of spent nitric- hydrofluoric acid pickling liquors gener- ated by the steel industry. Commercial- scale systems have been tested in both Sweden and Japan but none have yet been employed in the United States.47'48 Of the four solvent extraction pro- cesses developed for acid waste recov- ery, the Kawasaki (or Solex) process has shown the most promising results. Commercial-scale testing of the Kawa- saki process has demonstrated 95 per- cent recovery of nitric acid and 70 percent recovery of hydrofluoric acid.48 In addition, 95 percent of the iron in the waste solution was recovered for reuse.48 Kawasaki intends to eventually market the process.48 However, although the technology has been demonstrated to be technically feasible, limited eco- nomic data are available to assess its economic viability. Thermal Decomposition Thermal decomposition is an effective but capital intensive regeneration pro- cess which has been used to recover both free and bound acids from wastes. The process involves precipitating and decomposing metal salts in a roaster, and collecting the vaporized acid in a con- densor. Several steel manufacturers use the thermal decomposition process for the recovery of hydrochloric acid from spent pickling liquors. Although there are currently no other commercial-scale applications, research has demonstrated the technical feasibility of using thermal decomposition to regenerate waste sulfuric acid effluents from spent pickling liquors and organic chemical industry corrosive wastes. The thermal decomposition process has the advantage of being able to recover bound, as well as free acid from waste, which distinguishes it from the previously mentioned recovery technol- ogies. More than 99 percent of the hydrochloric acid equivalents in waste pickle liquor can be regenerated, and an estimated 93 to 96 percent of sulfuric acid equivalents can potentially be regenerated by thermal decom- position.28'49 However, capital costs for thermal decomposition will be prohibitive for small volume generators. Although the total quantity of waste sulfuric acid generated by the steel industry is greater than the amount of hydrochloric acid generated, the latter is generated by a small number of large quantity genera- tors. Combined with the higher purchase price of hydrochloric acid, HCI regener- ation systems may be more economically viable than sulfuric acid regeneration systems in the steel industry. However, large quantities of waste sulfuric acid are generated by individual organic chemical manufacturing plants and, therefore, acid regeneration may have a wider application for this industry. With increasing costs for disposal, and increasing development of the technol- ogy for other waste types, thermal regeneration systems are likely to find wider application in corrosive waste treatment. Selection of Optimal Waste Management Alternative Waste management options have been summarized previously in Table 1. These include source reduction, recycling, use of a neutralization treatment system or some combination of these waste han- dling practices. Selection of the optimal management alternative will ultimately be a function of regulatory compliance, economics, and availability of onsite and offsite processing systems and equip- ment. Economic considerations include processing (including pretreatment and post-treatment) and disposal costs, value of recovered products, and potential adverse effects on product quality or process equipment resulting from waste minimization or reuse of recovered products. Additional consideration in system selection must be given to factors such as safety, public and employee acceptance, liability, and degree of 11 ------- uncertainty in cost estimates and ability to meet treatment objectives. References 1. Camp, Dresser & McKee, Inc., Boston, MA. Technical Assess- ment of Treatment Alternatives for Wastes Containing Corrosives. Prepared for USEPA under Con- tract No. 68-01-6403. September 1984. 2. USEPA. Identification and Listing of Hazardous Waste Under RCRA, Subtitle C, Section 3001—Corro- sivity Characteristics (40 CFR 261.22). U.S. Environmental Pro- tection Agency, Washington, D.C. PB81-184319. May 1980. 3. Deitz, S. et al., Westat, Inc. National Survey of Hazardous Waste Gener- ators and Treatment, Storage, and Disposal Facilities Regulated Under RCRA in 1981. Rockville, MD. U.S. EPA/OSW. April 1984. 4. U.S. Congressional Budget Office. Hazardous Waste Management— Recent Changes and Policy Alter- natives. CBO Congress of the United States. May 1985. 5. Noll, K. E. et al. Recovery, Recycle and Reuse of Industrial Wastes. Lewis Publishers, Inc., Chelsea, Ml. 1985. 6. Science Applications International Corporation. Industry Studies Data Base. August 1985. 7. DPRA, Inc. Written Communication to M. Arienti, GCA Technology Division, Inc., regarding analysis of Recycling Data from the National Survey Data Base. Data Request No. M850415W. June 10, 1985. 8. ICF, Inc. Survey of Selected Firms in the Commercial Hazardous Waste Management Industry: 1984 Update. Prepared for U.S. EPA Office of Policy Analysis. September 1985. 9. Radimsky, J. et al. Recycling and/ or Treatment Capacity for Hazard- ous Wastes Containing Dissolved Metals and Strong Acids. California Department of Health Services. October 1983. 10. Gehm, H. W. Neutralization of Acid Wastewaters with Upflow Expanded Limestone Bed. Sewage Works Journal 16:104-120. 1944. 11. Capaccio, R. S., and R. Sarnelli. Neutralization and Precipitation. Plating and Surface Finishing. September 1986. 12. Ponzevik, D. Liquid Air Products. Telephone conversation with Ste- phen Palmer, GCA Technology Division, Inc. September 6, 1 986. 13. Breton, M. et al., GCA Technology Division, Inc. Technical Resource Document: Treatment Technolo- gies for Solvent-Containing Wastes. Prepared for USEPA HWERL under Contract No. 68-03- 3243. August 1986. 14. Warner, P. H. et al. Treatment Technologies for Corrosive Hazard- ous Wastes. Journal of the Air Pollution Control Federation. April 1986. 15. Arthur D. Little, Inc. Physical, Chemical, and Biological Treat- ment Techniques for Industrial Wastes. U.S. EPA SW-148. November 1976. 16. Kirk-Othmer Encyclopedia of Chemical Technology. Volume 14, 3rd Edition. John Wiley & Sons, New York, NY. 1981. 17. Cushnie, G. C. Removal of Metals from Wastewater. Neutralization and Precipitation. Pollution Tech- nology Review No. 107, Noyes Data Corporation. 18. Kirk-Othmer Encyclopedia of Chemical Technology. Volume 1, 3rd Edition. John Wiley & Sons, New York, NY. 1981. 19. Mabbett, Cappacio & Associates. Industrial Wastewater Pretreat- ment Study: Preliminary Engineer- ing Design Report. January 1982. 20. Stephenson, J. B., J. C. Hogan, and R. S. Kaplan. Recycling and Metal Recovery Technology for Stainless Steel Pickling Liquors. Environ- mental Progress, (3)1:50-53. Feb- ruary 1984. 21. Chacey, K., L. Mellichamp, and W. Williamson. Chrome Electroplating Waste BAT. Pollution Engineering. April 1983. 22 Solderman, J. New Method for Recovery of Spent Pickling Acids. In: Third International Congress on Industrial Wastewaters and Wastes, Stockholm, Sweden. Feb- ruary 6-8, 1980. 23. Delu, H., L. Xiuchung, and W. Chingwen. The Regeneration of Nitric and Hydrofluoric Acids from Waste Pickling Liquor. In: Sympo- sium on Iron and Steel Pollution Abatement Technology for 1980 held in Philadelphia, Pennsylvania. November 18-20, 1980. 24. Peterson, J. C., Crown Technology, Inc., Indianapolis, Indiana. Tele- phone conversation with L. Wilk, GCA Technology Division, Inc. Re: Sulfuric Acid Recovery System. July 10, 1986. 25. Luhrs, R. Acid Recovery Systems, Inc., Lenexa, Kansas. Telephone conversation with L. Wilk, GCA Technology Division, Inc. Re: Sul- furic Acid Recovery System. Sep- tember 4, 1986. 26. Smith, I., G. M. Cameron, and H C. Peterson. Chemetics Interna tional Co., Toronto, Ontario, Can ada. Acid Recovery Cuts Wast< Output. Chemical Engineering February 3, 1986. 27 Krepler, A. Total Regeneration o the Waste Pickle Liquor for Stain less Steel. Ruthner Industrieanla gen Aktiengesellschaft Technica Report No. 3, Vienna, Austria 1980. 28. Versar, Inc. National Profile Reportfor Recycling/A Prehminar Assessment. Draft Report Prepare* for the U.S. EPA, Waste Treatmen Branch, under EPA Contract Nc 68-01 -7053, Work Assignment Nc 17. JulyS, 1985. 29. U.S. EPA, Office of Research an Development, Washington, DC Treatability Manual, Volume II Technologies for Control/Remove of Pollutants. EPA/600/8-80 042c. July 1980. 12 ------- 30. Fontana, C. Eco-Tech, Ltd., Picker- ing, Ontario, Canada. Telephone conversation with L. Wilk. August 21, 1986. 31. U.S. EPA Industrial Environmental Research Laboratory, Cincinnati, Ohio. Summary Report: Control and Treatment Technology for the Metal Finishing Industry—Ion Exchange. EPA/625/8-81/007. June 1981. 32. Higgins, T. E. CH2MHill. Industrial Proceses to Reduce Generation of Hazardous Waste at DOD Facili- ties—Phase 2 Report, Evaluation of 18 Case Studies. Prepared for the DOD Environmental Leadership Project and the U.S. Army Corp of Engineers. July 1985. 33. Radimsky, J., D. I. Daniels, M. R. Eriksson, and R. Piacentini. Califor- nia Department of Health Services. Recycling and/or Treatment Capacity for Hazardous Wastes Containing Dissolved Metals and Strong Acids. October 1983. 34. Eisenmann, J. L. Membrane Pro- cesses for Metal Recovery from Electroplating Rinse Water. In: Proceedings of the 2nd Conference on Advanced Pollution Control for the Metal Finishing Industry, co- sponsored by the American Elec- troplaters Society and the U.S. EPA; held in Kissemee, Florida, February 5-7, 1979. EPA/600/8- 79/014. May 1979. 35. Pouli, D. Innova Technology, Inc. Clearwater, Florida. Telephone conversation with L. Wilk, GCA Technology Division, Inc. August 26, 1986. 38. Basta, N. Use Electrodialytic Mem- branes for Waste Recovery. Chem- ical Engineering. March 3, 1986. 39. Horter, G. L. U.S. Bureau of Mines, Rolla, Missouri. Telephone conver- sation with L. Wilk, GCA Technol- ogy Division, Inc. August 29,1986. 40. Horter, G. L., J. B. Stephenson, and W. M. Dressel. Permselective Membrane Research for Stainless Steel Pickle Liquors. In: Proceed- ings of the International Sympo- sium on Recycle and Secondary Recovery of Metals; sponsored by the metallurgical Society of AIME, Warrendale, Pennsylvania; held in FortLauderdale, Florida. December 1-4,1985. 41. Jain, S. M. Ionics, Inc. Telephone conversation with J. Spielman, GCA Technology Division, Inc. August 12, 1986. 42. U.S. EPA. Sources and Treatment of Wastewater in the Nonferrous Metals Industry. Prepared by Radian Corporation for the U.S. EPA, Industrial Environmental Research Laboratory, Cincinnati, Ohio, under EPA Contract No. 68- 02-2068. EPA/600/2-80/074. April 1980. 43. U.S. EPA, Office of Research and Development, Cincinnati, Ohio. Handbook for Remedial Action at Waste Disposal Sites. EPA/625/6- 85/006. October 1985. 44. Hamil, H. F. Southwest Research Institute, San Antonio, Texas. Project Summary: Fabrication and Pilot-Scale Testing of a Prototype Donnan Dialyzer for the Removal of Toxic Metals from Electroplating Rinse Waters. EPA/600/S2-85/ 080. August 1985. 47. Rydberg, J., H. Reinhardt, B. Lunden, and P. Haglund. Recovery of Metals from Stainless Steel Pickling Bath. In: Proceedings of the 2nd Annual International Sym- posium on HydroMetallurgy, Chi- cago, Illinois. February 25-March 1, 1973. 48. Watanabe, T., M. Hoshimo, K. Uchimo, and Y. Nakazato. A New Acid and Iron Recovery Process in Stainless Steel Annealing and Pickling Line. Kawasaki Steel Tech- nical Report No. 14, pp. 72-82. March 1986. 49. Wadhawan, S. C. Perox, Inc., Pitts- burgh, Pennsylvania. Letter to J. Spielman, GCA Technology Div- ision, Inc. August 7, 1986. 36. Gary, S. Scientific Control, Inc., Chicago, Illinois. Telephone conversation with L. Wilk, GCA Technology Division, Inc. August 29, 1986. 37. Rodgers, B. Aquatech Systems, Bethel, New Jersey. Telephone conversation with J. Spielman, GCA Technology Division, Inc., August 11, 1986. 45. Hamil, H. F. Southwest Research Institute, San Antonio, Texas. Telephone conversation with L. Wilk, GCA Technology Division, inc. September 24, 1986. 46. Friesen, D. Bend Research Corpo- ration, Bend, Oregon. Telephone conversation with L. Wilk, GCA Technology Division, Inc. Sep- tember 25, 1986. 13 ------- Lisa Wilk. Stephen Palmer, and Marc Breton are with Alliance Technologies Corporation, Bedford, MA 01730. Harry M. Freeman is the EPA Project Officer (see below). The complete report, entitled "Technical Resource Document: Treatment Technologies for Corrosive-Containing Wastes, Volume II," (Order No. PB 88-131 289/AS; Cost: $38.95) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Hazardous Waste Engineering Research Laboratory U.S. Environmental Protection Agency Cincinnati, OH 45268 ------- W ^2. W 7 3 00 2 8 C 8 $ CO 8 MO OJ O o mxi —» 00 m OB O X) m O at m X) (V o m 9 CO en ------- |