POLLUTION PREVENTION INTERIM PROJECT REPORT
The Pierce Company, Inc. initiated a joint project with the Indiana Pollution Prevention and Safe Materials Institute to investigate measures the company could take to reduce hazardous chemical use as well as to reduce its hazardous chemical regulatory reporting burdens. The joint project quickly focused on the vapor degreasing operation employed by the company for cleaning its pre-assembled fuel pump products as well as other automotive parts.
The Pierce Company is located in Upland, Indiana, and produces a diversified product line for the automotive and industrial markets. The company machines, stamps, and assembles automotive fuel pumps, water pumps, oil pumps, governors, and manufactures gasoline-powered electric generators. The company employs approximately 160 people.
The vapor degreaser is used to clean and degrease all of the company's automotive parts assemblies. The parts are cleaned in a standard vapor bath chamber using trichloroethylene. The parts dry almost immediately and are moved to an in-process goods area for press assembly. The press-assembled parts are then moved to a brazing station where brazing paste and/or copper grommets are placed over key areas of the assembly. The assembled parts are then conveyed through a brazing oven which operates at 2000(F with a residence time of approximately 25 minutes. Upon exit from the oven, each part is inspected for proper flow and "fill out," characteristic of a quality brazing seal.
Trichloroethylene (CAS 79-61-6) is a halogenated cleaning solvent. Its use in a cleaning/degreasing unit, in concentrations greater than 5% (by weight), qualifies the cleaning process to be regulated under the National Emissions Standard for Hazardous Air Pollutants (NESHAP). This regulation subjects the company to a variety of reporting and operating regulations.
The vapor degreasing process is responsible for trichloroethylene air emissions of approximately 1 ton per year and hazardous waste off-site transfers of approximately 3 tons per year.
The cost of virgin trichloroethylene is currently $9.89 per gallon. However, these costs are expected to rise as the product will continue to be regulated, making its use more expensive.
The current cost of disposal is approximately $0.89 per gallon, which is also expected to rise dramatically in the near future.
The Pierce Company entered into a joint project with the Indiana Pollution Prevention and Safe Materials Institute to investigate pollution prevention opportunities which would reduce the company's regulatory and environmental liability with regard to the trichloroethylene cleaning solvent NESHAP. The Institute set up a testing program to screen various aqueous-based, degreasing cleaning solutions. Five separate candidate aqueous cleaners were selected and typical production parts were cleaned under a variety of temperatures and pH conditions. The cleaned parts were then processed side by side with traditionally cleaned parts.
The investigation was performed as a double-blind test using fuel pump parts cleaned with the five different cleaners in order to determine how effectively the aqueous system cleaned the subject parts. The test samples were denoted A, B, C, D, and E and represented each of the five cleaners tested. The cleaned part which achieved the best flow characteristics of the brazing compound would then designate the best cleaner.
Prior to the testing, Pierce Company operation managers were asked their opinions of the cleaned parts. All of the cleaned parts were inspected and viewed as acceptable with regard to the removal of the processing oil. Some of the parts contained rust spots, which were judged unsatisfactory. Therefore, rust preventatives will be investigated. Observation test results concluded that samples B and C were considered the best, based on appearance (lack of rust) and feel (lack of oils), prior to testing.
The brazing test was performed in conjunction with the manufacturing process. First, the cleaned parts were assembled by pressing or crimping the fittings into the housings. The samples were then "brazed" with the application of brazing paste or a brazing ring and heated in the brazing oven at 2000(F for 25 minutes.
The results were extremely promising. All of the parts had an acceptable flow of the brazing compound and were judged to be of acceptable quality. The Pierce Company personnel gave the following rankings with regard to the flow of the brazing compound: B was considered the best, followed by A, with C, D, and E following closely behind.
Sample B, a Grace aqueous cleaning product--Daraclean(r)--was judged the best of all the candidates for cleaning and offered a further advantage of operating at a nearly neutral pH. One last laboratory test--lead leaching--was performed on the Grace product candidate. The Hazardous Waste Research and Information Center (HWRIC) in Champaign, Illinois, performed the original material/candidate cleaning tests and agreed to perform the lead leaching test. The Pierce/IPPI team wanted to be certain that the potential use of the new aqueous cleaning would not cause leaching of heavy metals and produce a costly hazardous waste. The lab data from HWRIC showed that there was little-to-no lead leaching from the metal parts into the cleaning solution.
In mid-March of 1996, Pierce will begin a plant pilot test using a specially designed bench top aqueous cleaning unit. The pilot test will allow the Pierce/IPPI team to delineate the following:
1. Load factor of Grace cleaner:
The team will be able to estimate the quantity of oil-laden parts which can be cleaned per gallon of aqueous cleaner.
2. Dilution factor: The current test water-to-cleaner dilution ratio is 5:1 for the Grace cleaner. The pilot study will allow this ratio to be confirmed or optimized. Increasing the dilution factor could produce savings.
3. Characterize the spent aqueous cleaner's BOD (biochemical oxygen demand) level:
The goal will be to release the material to the public sewage treatment works. The BODs, FOG (fats, oils, and grease), and SS (suspended solids) will all have to be characterized before any POTW will consider consent-to-release to the sewer.
4. Rinse factor: The pilot test will allow the team to optimize the rinse phase and conserve water usage.
POTENTIAL ENVIRONMENTAL AND COST BENEFITS
Currently, the team's objective is to use/adapt the current equipment to the new cleaner. If the pilot test proves successful, costs will depend upon the outcome of the four points above.
The team is hopeful that the current vapor degreasing machine can be adapted to function as the aqueous cleaning tank because this adaptation would dramatically reduce the cost of the company's conversion to the aqueous cleaning system. The pilot study and the spent aqueous cleaner characterization should be completed by mid-May of 1996. 4 (c) Purdue Research Foundation, 1996.