United States Environmental Protection Agency National Risk Management Research Laboratory Cincinnati, OH 45268 Research and Development EPA/600/SR-95/120 August 1995 &EPA Project Summary Demonstration of Alternative Cleaning Systems Dean M. Menke, Gary A. Davis, Lori E. Kincaid, and Rupy Sawhney This report represents the first dem- onstration of cleaner technologies to support the goals of the 33/50 Program under the EPA Cooperative Agreement No. CR821848. It focuses on substi- tutes for solvent degreasing processes that eliminate the use of chlorinated organic solvents. The substitute tech- nologies were 1) an aqueous wash sys- tem; 2) a no-clean technology; and 3) a hot water wash system. Technical, en- vironmental, and economic evaluations were performed to determine the mer- its of the substitutes as they were implemented by Calsonic Manufactur- ing Corporation, the project's industry partner. A national environmental im- pact evaluation was also performed to estimate the potential impacts on the nation's environment if entire indus- trial sectors were to implement the sub- stitutes. The demonstration strongly supports the implementation of the alternative technologies. The implementation of the cleaning process alternatives either improved or did not affect the perfor- mance of subsequent process steps or the quality of the products. The aque- ous wash system reduced cleaning cycle times by 50% and part reject rates by nearly 77% with improved cleaning characteristics. The no-clean alterna- tive had no effect on either production or part reject rates. The substitutes sig- nificantly reduced the quantity of toxic chemicals used and released. The tra- ditional processes released 1,1,1- trichloroethane (TCA) to the air, as well as generated a TCA hazardous waste stream; the substitutes generate either a non-hazardous wastewater discharge (aqueous and hot water wash systems), or a volatile organic compound air emission (no-clean technologies). Each alternative offered significant financial advantages as compared to the tradi- tional solvent degreasing systems when the economics were evaluated using activity-based cost accounting. The national environmental impact evaluation compared the life-cycle en- vironmental impacts of traditional chlo- rinated solvent systems to the alternatives. The evaluation suggests that significant reductions in life-cycle chemical emissions will occur with the implementation of alternative cleaning systems. Generally, for the aqueous wash systems, the shift would mean increased wastewater loads and oily pollutant discharges to POTWs. The nation's POTW infrastructure, in aggre- gate, can handle these increased loads. The shift in waste stream composition, however, must be evaluated on a case- by-case basis. This Project Summary was developed by EPA's National Risk Management Research Laboratory, Cincinnati, OH to announce key findings of the research project that is fully documented in a separate report of the same title (see Project Report ordering information at back). Introduction The "Cleaner Technology Demonstra- tions for the 33/50 Chemicals" project is a cooperative agreement between the U.S. ------- Environmental Protection Agency (EPA), National Risk Management Research Laboratory (NRMRL, formerly Risk Re- duction Engineering Laboratory) and the Center for Clean Products and Clean Tech- nologies (Center) of The University of Ten- nessee. The research of this project supports the voluntary pollution preven- tion initiatives of the 33/50 Program, while having applications within a broad range of industries. This report represents the first demonstration project to be completed under the EPA NRMRL project. Objectives The overall objective of this project was to evaluate substitutes for the 33/50 chemi- cals in order to encourage reductions in their use and release. This report focuses on substitutes for solvent degreasing pro- cesses that eliminate the use of the 33/50 chlorinated organic chemicals. In this study the Center worked directly with an indus- try partner, Calsonic Manufacturing Cor- poration (CMC) of Shelbyville, TN, to demonstrate substitute feasibility. To meet the project objective, technical, environmental, and economic evaluations of solvent degreasing substitutes were evaluated. A fourth evaluation, a national environmental impact evaluation, was per- formed to estimate the impacts to the nation's environment if entire industrial sectors were to implement similar alterna- tives to solvent degreasing. Within each evaluation, the following objectives were established: 1. Technical Evaluation • evaluate the effect of a substitute on process and product perfor- mance as compared to the 33/50 chemicals 2. Environmental Evaluation • evaluate the potential for reduction in releases and off-site transfers of the 33/50 chemicals in the produc- tion process or product stage • compare the overall life-cycle en- vironmental attributes of the substi- tute as compared to the 33/50 chemicals 3. Economic Evaluation • evaluate the total cost of the sub- stitute as compared to the 33/50 chemicals 4. National Impact Evaluation • evaluate the national environmen- tal impact of replacing the 33/50 chemicals with the substitute Methodology Data required to perform the technical, environmental, and economic evaluations were collected through data request tables, site visits, and interviews with CMC em- ployees. Data request tables, completed by CMC and during site visits, allowed for the collection of process information in- cluding capital costs, operating and main- tenance costs, utilities consumption, and production data. Similar data were re- quested for both the solvent degreasing systems (historic data) and alternative sys- tems (current data). Questions concern- ing generation rates and disposal costs of waste (hazardous and non-hazardous) and waste water accompanied the data re- quest tables, as well as questions con- cerning permitting requirements and costs. These questions were also directed at op- erations both before and after the process changes. Site visits and interviews allowed Cen- ter staff to become familiar with the op- erations of CMC, ask specific questions to complete and clarify the data request tables, and to maintain a working contact with CMC. An extended site visit near the completion of this project was conducted to observe the day-to-day operations of the process lines under investigation in order to extend the traditional economic evaluation by using activity-based cost accounting. The national impact evaluation utilized the knowledge of CMC's process changes to identify and evaluate potential changes on a national scale if entire industrial sec- tors were to implement similar solvent degreasing alternatives, to CMC's. Toxic Release Inventory (TRI) data and infor- mation from various literature sources were used to develop a life-cycle evaluation of chlorinated solvent degreasing and its al- ternatives. CMC'S Chlorinated Solvent Substitutes Program CMC is located in Shelbyville, TN, with several sister companies throughout the U.S. and the world. CMC employs ap- proximately 800 persons, and has more than 430,00 ft2 of manufacturing area di- vided between two sites, three buildings. CMC manufactures automotive parts, in- cluding heaters, blowers, cooling units, motor fans, radiators, auxiliary oil coolers and exhaust systems. To meet internal protocols to eliminate 1,1,1-trichloroethane (TCA) from its manu- facturing processes, CMC initiated a num- ber of changes to eliminate solvent degreasing applications. These changes included an aqueous wash system, a no- clean process which employs an evapora- tive lubricant to eliminate the need for solvent degreasing, and the application of a hot water wash to remove forming oils. Technical, environmental, and economic evaluations were performed for the aque- ous wash and no-clean alternatives to de- termine their merits. The merits of the hot water wash system were presented as supplemental information to the aqueous wash alternative. An introduction to these process changes, and the manufacturing lines which utilize them, is presented be- low. The Radiator Line and Aqueous Wash System Radiators are designed to hold a large volume of water and antifreeze in proxim- ity to a large volume of air to allow effi- cient heat transfer from the fluid to the air. CMC manufactures the tube-and-fin type of radiator core, consisting of a series of long tubes extending between a top tank and bottom tank of the radiator. In this type of configuration, fins are placed be- tween the tubes; air passes between the fins and around the outside of the tubes, absorbing heat from the fluid in the tubes. CMC manufactures the tubes and fins of the radiator core from aluminum stock. Tubes are formed from aluminum rolls at a tube-forming station with the assistance of a forming/cooling fluid, cut to length, and sent to assembly. To form the fins, rolls of aluminum are lubricated with a forming (napthenic) oil, fed through fin corrugators, cut to length, and sent to assembly. The tubes, fins, and prefabri- cated endplates are assembled in a jig to complete the radiator core. Following assembly, the cores are cleaned by a conveyor aqueous wash sys- tem to remove the forming oils, cutting oils, coolant, and other soils. The aque- ous wash process begins with a water wash, intended to remove the majority of the contaminants, followed by a heated detergent bath, and completed by a hot water rinse. Effluent from the aqueous wash process is sent to a wastewater treatment plant at the facility for pretreat- ment prior to discharge to the local sewer system. After the aqueous wash, the ra- diator cores continue on the conveyor for flux application, drying, and brazing. Final assembly includes nylon fluid tanks and leak testing. The current aqueous wash system was adapted in 1991. Previously, five batch vapor degreasers were used to clean the assembled radiator core, one located at each fin corrugation and assembly sta- tion. Under this scheme the radiator core was an assembly of corrugated fins (pro- cess above) and prefabricated tubes and endplates supplied by another company. These assemblies were then cleaned in one of the five vapor degreasers, using 1,1,1-trichloroethane as the degreasing ------- solvent. The use of TCA resulted in re- leases of TCA to the air from the process, releases to water (wastewater) from sol- vent carry over on parts to subsequent process units, and a hazardous waste stream of spent TCA. CMC sent this haz- ardous waste stream to an off-site recy- cling facility. To eliminate these waste streams and improve the cleaning pro- cess, CMC implemented the aqueous wash system. The Condenser Line and No- Clean Technology CMC manufactures condensers for use in automobile air conditioning systems. The condenser consists of a serpentine tube on which fins have been mounted. Com- pressed vapor passes through the tube; air passing around the fins and between the tubes removes heat from the com- pressed vapor. The cooled vapor con- denses and runs into a receiver-dryer. CMC manufactures the fins from rolls of aluminum, and bends and cuts the tubes from rolled aluminum-tube stock. In 1993 CMC converted its fin manufac- turing process from a conveyor solvent degreasing process using TCA to an "evaporative" oil, no-clean process. In this no-clean system, rolls of aluminum are lubricated with a low-boiling-point oil and fed through a fin corrugator. The fin then passes through fin driers to evaporate the oils. CMC operates four fin corrugator sta- tions in the condenser line. In the current system the corrugated fin is conveyed through the now empty vapor degreasing chambers, then cut to length and sent to assembly. The Converter Line and Hot Water Wash System Catalytic converters are automobile ex- haust units which consist of a ceramic substrate and wire mesh encased in a metal shell. CMC assembles converters from shells, flanges, ceramic substrates, and wire mesh separators supplied by other manufacturers. After receiving these materials, CMC cleans the metal shell halves and flanges in a conveyor hot wa- ter wash system to remove cutting and lubricating oils left by the manufacturer. The wash system consists of a hot water spray zone, followed by a second hot wa- ter spray (rinse) zone and a drying oven. After cleaning, the ceramic substrate and wire mesh separator are inserted in the two shell halves, which are then welded together with the flanges, to form the con- verter unit. Each catalytic converter is leak- tested using an air-based pressure-decay system. The converters then continue along the process train to be incorporated into the exhaust system. Until December 1993, CMC used a con- veyor vapor degreaser with TCA as the degreasing solvent. The current equipment used in the hot water wash system was converted by CMC from an obsolete muf- fler washing system and a defunct paint spray booth and curing oven. Results of the Technical, Environmental, and Economic Evaluations Over the last four years CMC has imple- mented a number of changes to eliminate TCA from its cleaning processes. Efforts to accomplish this goal included the in- stallation of an aqueous wash system (de- tergent) which replaced five solvent degreasers on a radiator manufacturing line, the replacement of a petroleum-based lubricant with an evaporative lubricant that does not require cleaning for subsequent processing on a condenser manufacturing line, and the installation of a hot water wash system to replace a solvent degreaser on a catalytic converter manu- facturing line. These changes, along with similar changes on other process lines, eliminated the use of TCA as a cleaning solvent within CMC's manufacturing facil- ity. Total elimination of TCA from cleaning processes was accomplished by Novem- ber, 1994. The technical, environmental, and eco- nomic evaluations performed in this study were completed using CMC's historic records, information obtained from site vis- its and interviews with CMC employees, the on-line TRI data base, and literature searches. The radiator and condenser manufacturing lines were the main focus of the research. The merits of the hot water wash system were presented as supplemental information to the aqueous wash alternative. The environmental analy- sis of CMC was expanded to evaluate the national environmental impacts if entire industry sectors were to implement similar process changes. Technical Evaluation The technical evaluation analyzed the merits of the alternative cleaning systems (both the aqueous wash and the no-clean, evaporative lubricant systems) by com- paring the rates of production (i.e., cycle time required to clean one part) and the part reject rates between the old and new processes. Both historic data and inter- views with CMC quality control staff es- tablished the results shown in Table 1. A significant decrease in cycle time was experienced with the implementation of the aqueous wash system in the radiator line; cycle time to clean one radiator unit was decreased by 50%. The process bottleneck, which was the solvent degreasing application, has now shifted away from the cleaning operation, and employee attentions can be focused upon other operations to further optimize the manufacturing process. A significant decrease in the parts re- ject rate for the radiator line was also experienced after the implementation of the aqueous wash system. This decrease, over 76%, is predominantly attributed to the improved cleaning characteristics of the aqueous wash system. The produc- tion and part reject rates for the condenser line, though not statistically evaluated due to data limitations, were evaluated through employee interviews. These interviews established that the implementation of the no-clean process alternative had little ef- fect on either rate. Environmental Evaluation The changes in chemical releases and transfers to the environment from CMC's manufacturing facilities due to the imple- mentation of the alternative processes in- cluded the following: 1. elimination of TRI reporting require- ments of TCA hazardous waste emissions, from each process line; 2. the creation of a state-regulated VOC air emission for the condenser line; and 3. the creation of a waste water stream for the radiator line. These changes are summarized for the radiator and condenser manufacturing lines in the following table (Table 2). It is as- sumed that air releases and hazardous waste transfers are the only TCA emis- sions from CMC processes. Therefore, Table 1. Summary of the Technical Evaluation Results Line Cycle Time Part Reject Rate Radiator 50% decrease was experi- enced after aqueous wash implementation Condenser no significant change 76% reduction in part reject rate due to aqueous wash system no significant change ------- Table 2. Summary of Environmental Evaluation Results Line Total Waste Generation per Year Solvent Degreasing Operations Alternative Systems Operations Radiator 171, 500 Ib 114,900 Ib 56,600 Ib TCA consumed TCA haz. waste transfers TCA air releases (1990) 22,1 00 Ib 2.0 million gal 1 0,800 Ib 64,780 Ib detergent consumed wastewater generated non-haz., oily waste transfers non-haz. wastewater treatment solids transfers (1992) Condenser 121, 500 Ib 14,400lb 1 '5,400 Ib 46, 100 Ib (1992) TCA consumed petroleum lub. consumed TCA haz. waste transfers TCA air releases 1 2,200 Ib 1 2,200 Ib evap. lub. consumed VOC air releases (1994) based on TCA consumption rates and line- specific hazardous waste generation esti- mates, the air releases were estimated. Other line-specific information was drawn directly from purchasing records. Though eliminating the use and hazard- ous waste disposal of TCA, the hot water wash system of the converter line was not quantitatively evaluated in this analysis. However, a qualitative evaluation of this system is presented throughout the evalu- ations of the report. Though the aqueous wash system of the radiator line generates two million gal- lons of wastewater per year, overall chemi- cal consumption, when compared to the solvent degreasing system, has greatly decreased. The consumption rate of 2,640 gal/yr of detergent is minimal when com- pared to the 15,840 gal/yr (171,700 Ib/yr) of TCA previously consumed. The evapo- rative lubricant system of the condenser line has similar advantages; the release of 12,200 Ib/yr of VOC-lubricant is an or- der of magnitude less than the 121,500 Ib/yr of TCA released by the degreasers. These data clearly show the trade-off issues that must be considered when choosing between alternative cleaning sys- tems. For the radiator line, releases of the toxic, ozone-depleting chemical TCA were eliminated, but a larger volume, low-toxic- ity wastewater stream was generated. Al- though hazardous waste management requirements have been eliminated for this line, permitted discharge requirements set by the local publicly owned treatment works (POTW) must still be met. For the condenser line, hazardous waste and TCA were once again eliminated. Air releases decreased substantially, suggesting less potential employee exposure; complete data on the relative toxicity of TCA and the mineral-spirit-based VOCs emitted by the evaporative lube, however, are not available. This is one of the reasons CMC is now switching to a non-petroleum based evaporative lube. Economic Evaluation Two economic evaluations were com- pleted for the analyses of the alternatives. The first evaluation used a traditional method focusing on direct costs. The sec- ond method utilized activity-based costing to more accurately allocate overhead costs to the appropriate products and processes. Finally, a hybrid of these methods was used to more accurately represent the costs and benefits of the alternatives. Tables 3 and 4 summarize the results of traditional and hybrid economic analyses for the radiator and condenser manufac- turing lines, respectively. Table 3 shows that the hybrid method identified additional direct costs associ- ated with the solvent degreasing units of the radiator line that would have been part of an overhead cost factor in a more traditional analysis. These results illustrate very clearly that traditional cost analyses are not adequate to fully estimate the ben- efits of pollution prevention projects. By properly allocating through ABC that would normally be part of an overhead factor, this study demonstrates the costs-benefits of the aqueous wash system, benefits be- yond traditional costing techniques are re- alized. The results of the economic analysis for the condenser line did not change the final conclusions since the evaporative lube system had clear advantages even with traditional cost methods. By using the hy- brid approach, however, the cost savings due to the implementation of this alterna- tive were even greater. National Environmental Impact Evaluation The environmental evaluation of CMC's process changes was used to estimate the potential environmental impacts of the alternatives to solvent degreasing if entire industrial sectors were to implement simi- lar changes. This evaluation utilized the life-cycle concept to evaluate the potential environmental impacts which could result throughout the life cycle of the chemicals used in the traditional and alternative pro- cesses. The elimination of chlorinated sol- vents from materials and parts degreasing could significantly impact the national emis- sions of these chemicals from their produc- tion, use and disposal. The implementation of the alternative systems, though having associated releases and transfers of other chemicals, could significantly decrease the environmental impacts now associated with the life cycle of solvent degreasers and the solvents used. Replacing chlorinated solvent degreas- ers could substantially reduce the use of approximately 499.9 million Ib of chlori- nated chemicals in materials and parts degreasing applications. In addition to the direct use and disposal emissions that would be reduced, an estimated 460,000 Ib of solvent emissions from production facilities could also be reduced. This 460,000 Ib estimate is based on the quan- tity of the chlorinated solvents currently produced, the emissions from these pro- duction processes, and the distribution of the chemicals to solvent degreasing appli- cations. ------- Table 3. Comparison of Hybrid and Traditonal Analyses-Radiator Manufacturing Line Hybrid Analysis Tradition, Direct Cost Analysis Analysis Solvent System Aqueous Wash System Solvent System Aqueous Wash System Payback NPV (5-yr) NPV (10-yr) NPV (15-yr) $2,584,150 $5,725,530 $9,547,510 2.4 yr $1,514,260 $3,073,640 $4,762,870 $660,580 $1,464,270 $2,442,090 11.6yr $808,280 $1,508,720 $2,147,930 Notes: 1. i = interest rate/period = 4%. 2. the capital investment of the aqueous wash system was depreciated (straight-line) over seven yr. 3. assumptions: inflation rate of zero and equal costs/yr. 4. dollar values represent costs. Table 4. Comparison of Hybrid and Traditional Analyses-Condenser Manufacturing Line Hybrid Analysis Tradition, Direct Cost Analysis Analysis Solvent System Evaporative Oil System Solvent System Evaporative Oil System Payback NPV (5-yr) $1,089,550 0.27 yr $219,660 $619,750 0.45 yr $99,930 Notes: 1. i = interest rate/period = 4%. 2. the capital investment of the aqueous wash system was depreciated (straight-line) over 7 yr. 3. assumptions: inflation rate of zero and equal costs/yr. 4. dollar values represent costs. The implementation of an aqueous wash alternative has unique emissions of its own. Detergents, a mixture of surfactants, builders, chelators, and other ingredients, have associated chemical production re- leases and transfers. Emissions from pro- duction of commonly used ingredients (e.g., ethoxylated alcohols, alkylbenzene sulfonates, EDTA, and tetrapotassium py- rophosphate) include ethylene, ethylene glycol, benzene, glycol ether, and a vari- ety of acids. An estimate of the quantity of detergent ingredients applied to industrial applications was not available, and there- fore an estimate of the production releases which could be allocated to the industrial use of detergents was not possible. How- ever, order-of-magnitude calculations show that life-cycle releases and transfers could be significantly reduced with the imple- mentation of the aqueous alternative. A second issue to address when con- sidering the life-cycle attributes of aque- ous wash systems is the proper management of the water waste stream. Pretreatment of the wastewater from aque- ous systems may be required to ad- equately remove oils, greases, biological oxygen demand (BOD), and suspended solids. The conclusions from the national environmental impact evaluation indicated that the infrastructure of wastewater treat- ment facilities is sufficient to handle the increased wastewater flow and load if en- tire industry sectors shifted from solvent to aqueous systems. Conclusions The demonstration strongly supports the implementation of the alternative technolo- gies. The implementation of the cleaning process alternatives either improved or did not affect the performance of subse- quent process steps or the quality of the products. The aqueous wash system re- duced cleaning cycle times by 50% and part reject rates by nearly 77% with im- proved cleaning characteristics. The no- clean alternative had no effect on either production or part reject rates. The substi- tutes significantly reduced the quantity of toxic chemicals used and released. The traditional processes released 1,1,1- trichloroethane (TCA) to the air, as well as generating a TCA hazardous waste stream; the substitutes generate either a non-hazardous wastewater discharge (aqueous and hot water wash systems), or a volatile organic compound air emis- sion that is much less no-clean technol- ogy. Each alternative offered significant financial advantages as compared to the traditional solvent degreasing systems when using activity-based cost account- ing and compared to the traditional sol- vent degreasing systems. The national environmental impact evaluation compared the life-cycle envi- ronmental impacts of traditional chlorinated solvent systems versus the alternatives. The evaluation suggests that significant reductions in life-cycle chemical emissions will occur with implementation of alterna- tive cleaning systems. Generally, for the aqueous wash systems, the shift would mean increased wastewater loads and oily pollutant discharges to POTWs. The nation's POTW infrastructure, in aggre- gate, can handle these increased loads, however, the shift in waste stream com- position must be evaluated on a case-by- case basis. ------- Dean M. Menke, Gary A. Davis, Lori E. Kincaid, and Rupy Sawhney are with the University of Tennessee, Knoxville, TN 37996-0710 Diana R. Kirk is the EPA Project Officer (see below). The complete report, entitled "Demonstration of Alternative Cleaning Systems,1 (Order No. PB95-255741; Cost: $27.00, subject to change) 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: National Risk Management Research Laboratory U. S. Environmental Protection Agency Cincinnati, OH 45268 United States Environmental Protection Agency Technology Transfer and Support Division (CERI) Cincinnati, OH 45268 Official Business Penalty for Private Use $300 BULK RATE POSTAGE & FEES PAID EPA PERMIT No. G-35 EPA/600/SR-95/120 ------- |