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ENVIRONMENTAL RESEARCH BRIEF: WASTE MINIMIZATION ASSESSMENT FOR A MANUFACTURER OF PRINTED CIRCUIT BOARDS
Citation:
Kirsch, F. W. AND G. P. Looby. ENVIRONMENTAL RESEARCH BRIEF: WASTE MINIMIZATION ASSESSMENT FOR A MANUFACTURER OF PRINTED CIRCUIT BOARDS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/M-91/022 (NTIS 91-234542), 1991.
Impact/Purpose:
information
Description:
The U.S. Environmental Protection Agency (EPA) has funded a pilot project to assist small- and medium- size manufacturers who want to minimize their generation of hazardous waste but lack the expertise to do so. Waste Minimization Assessment Centers (WMACs) were established at selected universities and procedures were adapted from the EPA Waste Minimization Opportunity Assessment Manual (EPA/625/7-88/003, July 1988). The WMAC team at Colorado State University inspected a plant producing printed circuit boards — a plant that already had taken steps to control its hazardous wastes. Producing a circuit board involves many major processes and subprocesses: preparing the board; depositing copper en the board by electroless plating; applying dry film; electrolytically plating copper; electrolytically plating tin; etching and stripping; applying solder; and, perhaps, plating gold on connectors. Each of these steps produces hazardous wastes, e.g., electrolytic copper plating results in acid soap dumps, copper and tin drag-out, and sulf uric acid. The main sources of metallic contamination (copper [both dissolved and metallic], tin, lead, gold) are the rinses after scrubbing, plating, and etching. Although the greatest amount of waste can be reduced by reusing effluent from the MEMTEK f (with some further treatment), the greatest dollar savings can be found by changing the dry film developer. The present brand adheres strongly to the unexposed film and requires an aggressive acid soap; a less aggressive, nonhazardous soap could be used with a less-adhering dry film developer. This Research Brief was developed by the principal investigators and EPA's Risk Reduction Engineering Laboratory, Cincinnati, OH, to announce key findings of an ongoing research project that is fully documented in a separate report of the same title available from the authors.