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CHROMATE RECOVERY FROM CHROMATING RINSEWATER IN THE METAL-FINISHING INDUSTRY
Citation:
Gavaskar, A., R. Olfenbuttel, AND E. Drescher. CHROMATE RECOVERY FROM CHROMATING RINSEWATER IN THE METAL-FINISHING INDUSTRY. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/R-95/087 (NTIS PB95243044), 1995.
Description:
The recovery system evaluated in this study combines various aspects of vacuum evaporation and flash distillation. t provides a continuous supply of good quality rinsewater to the chromating line at QRD. ecirculation prevents nearly 450,000 gal of water from going to waste every year. ontaminants removed from the circulating water include chromium, zinc, and other dissolved solids. ontaminants are concentrated in a smaller wastestream (approximately 200 gal/yr) and disposed. ecause QRD uses three different chromate formulations on a single chromating line, this concentrate could not be reused. t plants that use a single formulation, reuse may be possible, provided that the levels of zinc and iron do not increase to the point that chromating quality is affected. ecause wastewater (requiring treatment) is not generated, the recovery system leads to a reduction in waste water treatment costs. verall operating cost reduction depends on the individual user's expected wastewater treatment costs. t QRD, the return on investment was sufficient for the initial capital outlay to be recovered in approximately 4 years.
