ABSTRACT
Electroplating and other metal finishing operations discharge their spent process water to either waterways or publicly owned treatment works (POTWs) and they comprise more individual wastewater discharges than any other industrial category. The pollutants contained in these discharges are potentially toxic; therefore, to comply with the Clean Water Act, the water must be treated186 before being discharged to a waterway or a POTW. The regulations require oxidation of cyanide, reduction of hexavalent chromium, removal of heavy metals, and control of pH.
Sulfide precipitation is one among many methods available for removing metals from metal finishing process wastewater. This chapter presents information on various technologies that have been demonstrated. By providing process descriptions, advantages and disadvantages, and economic characteristics of each system, this chapter can facilitate the evaluation of effective means of pollution control by those involved in metal finishing wastewater pollution control.
