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Solvent Alternatives Guide
Alkaline Aqueous

Case Studies

Martin Marietta Astronautics had been using a 1,1,1-trichloroethane (TCA) vapor degreaser to clean large fabricated rocket components. After researching six aqueous cleaners they decided upon Daraclean 282 from W.R. Grace. This cleaner is cost effective because it can be reused after filtering and skimming to eliminate contaminants. The aqueous cleaner is biodegradable, has no known health risks, and cleans the aluminum components better than TCA. Research and implementation costs totalled $270,000. Martin Marietta Astronautics is saving $200,000 annually on materials, operating, maintenance, and waste disposal costs. Additionally, ozone depletion taxes which accompanied TCA usage would have cost $400,000 through 1995. Since 1988 Martin Marietta Astronautics has reduced its consumption of TCA by 98 percent.

Dykema, Kevin J., and George R. Larsen. 1993. Shifting the Environmental Paradigm at Martin Marietta Astronautics, Pollution Prevention Review, Spring: 201-202.

A decorative plating company switched from perchloroethylene vapor degreasers to an automated aqueous system. The new system includes an alkaline prewash, spray rinse, alkaline wash, three successive rinses in deionized water, followed by air-knife blowoff, and finishing with an oven dry. The system was put into operation in 1991, eliminating perchloroethylene usage.

Willis, Dennis G. 1992. Decorative Plater eliminates Vapor Degreasers, presented at the 13th AESF/EPA Conference on Environmental Control for the Surface Finishing Industry, Orlando, Florida.

Washington Scientific Industries (WSI) is a precision machining company that had been using TCA vapor degreasers at 20 work stations. Initially one aqueous cleaning system using a mild alkaline detergent with a rust inhibitor sprayed at high-pressure was put into service. This unit replaced one vapor degreaser that required the purchase of 1,000 gallons of TCA annually and generated 200 gallons of waste. The cost was $7,000 and the first year's savings were $6,500. Subsequently, other workstations have been switched to high-pressure aqueous cleaning.

DeWahl, Karl, and Donna Peterson. 1992. Waste Reduction in Solvent Cleaning; Process Changes Versus Recycling, Pollution Prevention Review, Winter: 74.

A Connecticut manufacturer of precision steel components needed to eliminate the use of two TCA vapor degreasers. The degreasers were centrally located and used to clean parts at various stages of the production process. After evaluating the cleaning needs of the factory, several changes were made. Cleaning was eliminated for parts that were in transit from one machining process to the next. Cleaning was decentralized, allowing alternate methods for a department's specific needs to be developed. Aqueous methods were substituted for the TCA vapor degreasers in 95% of the cleaning applications. Several systems were developed using emulsifying alkaline solutions, nonemulsifying alkaline solutions, rust inhibitors, ultrasonics, and immersion cleaning. Some of the clients of this manufacturer required lubricants that could not be removed by aqueous chemistries. A small TCA degreaser was kept for this fraction (5%) of "special" cleaning.

Elliott, Bradley T. 1991. Solvent Waste Reduction Through Process Substitution, presented at the Environmental Technology Expo '91, Chicago, Illinois.

The Ross Gear plant in Greeneville, Tennessee manufactures fluid power components which are extremely sensitive to contamination. To remove the soils produced during the lapping operation, Ross Gear had been using a trichloroethylene vapor degreaser. Ross Gear discontinued the use of trichloroethylene in the Greeneville plant in 1987. The plant now cleans with an aqueous system using an alkaline solution and ultrasonics. The plant eliminated health hazards associated with trichloroethylene use, reduced overall hazardous waste by 50%, and realized significant savings in material and waste disposal costs.

Hartman, Frank, and Rad Clanton. 1988. The Elimination of a Trichloroethylene Vapor Degreasing Operation, Governor's Award for Excellence in Hazardous Waste Management, WRATT, University of Tennessee.

At the Department of Energy's Y-12 nuclear-weapons plant in Oak Ridge, Tennessee, ultrasonic cleaning with aqueous detergents has replaced about 95 percent of the vapor degreasing with chlorinated solvents. The Y-12 plant has many small ultrasonic cleaners and five large automated systems. The initial cost of these systems ranges from $10K to $150K. Martin Marietta Energy Systems, Inc., who manages the Y-12 plant, found that ultrasonic cleaning with aqueous detergents works as well or better than vapor degreasing with chlorinated solvents. NST (Oakite Products Inc., Berkeley Heights, NJ) is used for nonferrous materials cleaning. Micro (International Products Corp., Burlington, NJ) is used for cleaning ferrous parts. While most ultrasonic cleaners operate at 40 KHz, Martin Marietta has found that 20 KHz ultrasonics is more effective at removing tenacious oils. Aqueous detergent can usually be discharged to the sewer where it readily biodegrades.

Vaccari, John. 1993. Ultrasonic Cleaning with Aqueous Detergents; A Government Plant Has Almost Entirely Replaced the Use of Chlorinated Solvents, and Cleaning Performance Is At Least As Good As Before, American Machinist, 137(4):41-42.

Crown Equipment Corporation in New Bremen, Ohio, manufactures lifting equipment and has production facilities worldwide. Crown-New Bremen started investigating aqueous cleaning in the mid-80s. A major portion of their cleaning was done with TCA, either in cold tanks or vapor degreasers. After investigating various alternatives, Crown-New Bremen first replaced the TCA in the cold cleaning tanks with aqueous solutions. Satisfied that aqueous cleaning was as good or better than TCA for cold cleaning, Crown turned its attention to the two large TCA vapor degreasers. In restructuring their entire cleaning process(es) Crown was able to eliminate some of the interim parts cleaning completely. The remainder of the parts fell into two categories: small parts which needed cleaning and deburring; and larger parts of various sizes which needed cleaning only. The smaller parts are now cleaned and deburred in one operation which consists of a vibratory cleaner with an aqueous cleaning solution. The larger parts are immersed in a heated, agitated, alkaline cleaning solution. After an initial rinse, some parts receive an additional rinse in a rust inhibitor. All parts are then dried with forced air. Crown has eliminated the annual purchase of 17,000 gallons of TCA.

Alternatives to Solvents Degreasing for the '90s, Solid and Hazardous Waste Education Center, University of Wisconsin-Extension, Madison, WI.

The United States Air Force Materiel Command at Newark AFB, Ohio, maintains inertial guidance and navigation systems. Various metals, plastics, and epoxies are subject to precision cleaning on the base. Prior to 1988 the Aerospace Guidance and Metrology Center was using 2,000,000 lb of CFC-113 annually. Small quantities of methyl chloroform, CFC-12, and trichloroethylene were also being used. Several changes were instituted to reduce/eliminate CFC usage at the base. Installation of centralized aqueous precision cleaning centers eliminated nearly all the vapor degreasers on base. Additionally they are using air and nitrogen for cooling, supercritical CO2, perfluorocarbon flushing, and fluorocarbon/surfactant blends for cleaning. Payback on new equipment cost is about 2 years. The Aerospace and Guidance Center anticipates that it will have a 90% reduction in ozone-depleting solvents by October 1993.

Hunt, Don. 1992. How One of the Largest Air Force Users Is Getting Out of CFC'S, Proceedings of the 1992 International CFC and Halon Alternatives Conference, pp. 547-556.

A filter manufacturer cleaned filter canisters contaminated with an animal-fat-based stamping lubricant in an open area with floor drains. The cleaning was done by an operator wearing a rubber suit who washed each canister individually. An aqueous chemistry power washer was built to accommodate wire pallets of canisters. The new system slashes the cost of cleaning materials by 90%, takes up less floor space, and gives a better quality product. Savings in labor alone paid for the new system in 8 months. Since the new system has been in place the accident rate for cleaning has fallen to zero per year, down from 3 per year. Noise levels have also been reduced. The cleaning operator is very happy with the new system.

Nouri, Steven M. 1991. Aqueous Clean Does Work, Proceedings of the 1991 International CFC and Halon Alternatives Conference, Baltimore, MD, p. 62.

Modern Windows and Awning Company (MOCO) uses a six stage power washer to clean metal storm and screen doors prior to powdercoating. The power washer has alkaline aqueous wash, followed by water rinse. The final rinse contains a corrosion inhibitor. Cleaning is followed by oven drying and powder coating. The powder coating process yields a high quality finish on the windows and doors and has very little waste. The dry powder overspray is collected and reused. Fixtures used in the spray booth collect very little of the powder and are cleaned occasionally by burning off the paint buildup. The entire cleaning/finishing process uses no ozone-depleting solvents.

Powder Coating is Finish of Choice, Plating and Surface Finishing, 80(7):8-9, 1993.

FMC Corporation, Naval Systems Division, has eliminated its use of 1,1,1 -trichloroethane in manufacturing naval weapons handling systems. Alkaline detergents are now used for much of the cleaning. Isopropyl alcohol replaced TCA in foundry operations. Steam degreasing and semiaqueous cleaners are now used in the plating operations. Elimination of the TCA resulted in a net savings of $29,000 per year from 1991 levels. Isopropyl alcohol also replaced CFC-113 in the wave solder cleaning of printed circuit boards, reducing the purchase of CFC-113 by 5,500 lbs annually, and saving FMC $15,000 in chemical purchases.

Douglas L. Hildre, Environmental Control Manager, FMC Corporation, Naval Systems Division, 4800 East River Road, Fridley, MN, 55421 MnTAP, 1993 Governor's Awards for Excellence in Pollution Prevention.

Digital Equipment Corporation (DEC) has replaced CFC cleaning systems at its Colorado Springs, Colorado and Kaufbeuren, Bavaria, Germany facilities. The alkaline aqueous system it installed at these locations consists of one cleaning, three rinsing, and two drying stations. The cleaning station consists of a heated ultrasonic tank filled with an alkaline detergent-surfactant. Cleaning is followed by a rough spray rinse, immersion in a high purity water ultrasonic tank, and finally a spray rinse with high purity water. Drying is accomplished in two stages. First, excess water is blown off the parts using pressurized clean, dry air. Infrared radiation then heats the parts surface to 160 F to speed up evaporative drying. The system incorporates a water purification and reclamation system. Waste water is nonhazardous and can be sent directly to sewer, provided the parts being cleaned contain no hazardous contaminant. The aqueous system surpasses the CFC system in removing particulates and is at least equal to the CFC system in overall efficiency.

Vosper, Fred C. and Vickers, David J. Developing Precision Aqueous Cleaning of Hard-Disk Electromechanical Components, Microcontamination, 10(10): 31-34, 1992.

A Toshiba Corporation plant in Japan cleans CRT's, printed circuit boards, and formed metal parts. In 1986, 1100 tons of CFC-113 and 1200 tons of 1,1,1-trichloroethane were used. Alternatives include filtered compressed air to blow off the CRT's, volatile stamping oils for metal forming, and alkaline aqueous cleaning for the PCB's. Toshiba Corporation has developed silicone based detergents for cleaning components sensitive to water. By 1992 the use of ozone depleting solvents had been cut in half. Toshiba has found alkaline aqueous cleaning yields a cleaner product than CFC-113.

Matsui, Shigeo/ Toshiba, Toshiba"s Actions to Reduce Use of CFC's and methyl chloroform in Electronics Cleaning, 1992 International Conference on CFC and Halon Alternatives, Washington, DC, pp 429-430.

The Engine Division of Caterpillar, Inc. in Pontiac, Illinois has eliminated nearly all its vapor degreasers by switching to alkaline aqueous cleaning of diesel fuel systems. Previously, Freon TMC, TCA, and Stoddard solvent had been used to clean the fuel systems of oil, coatings, and machining coolants.

Eggenberger, Gary and Wear, B. Ross/Caterpillar, CONNTAPP, Ozone Layer Protection Conference, September 1993.

American Etching and Manufacturing in Pacoima,CA manufactures precision sheet metal parts, solar cell wafers, and satellite dish components from stainless steel and nickel. Photoresist coatings and cleaners are now water-based as opposed to solvent based. Alkaline aqueous cleaners are also replacing methanol, reducing the flammability of the waste generated. American Etching reduced its waste from 683 tons in 1988 to 548 tons in 1989.

American Etching and Manufacturing, Case Studies in Waste Minimization, Government Institutes, Inc., Rockville, MD, October 1991.

Emerson Electric Company in Murphy, NC, is a manufacturer of power tools. Solvent degreasing has been replaced by alkaline detergent and steam degreasing.

Hunt, Gary, et al, eds., Process Modification and Material Recovery at Power Tool Plant, Case Summaries of Waste Reduction by Industries in the Southeast, North Carolina Department of Natural Resources and Community Development, July 1989, p. 43.

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Last Update: 29 December 1998