ABSTRACT
When the Environmental Protection Agency (EPA) developed the pretreatment standards for the metal finishing industry, the Agency defined neutralization, flocculation, and clarification as the Best Available Technology (BAT). In this process, the metals are removed from the wastewater in the form of a metal hydroxide sludge. This chapter presents a case history of a printed circuit board manufacturer who meets the federal discharge standards without generating hazardous sludge. The system was designed with two electrolytic recovery units; one for copper and one for lead. The copper and lead have been separated in order to avoid contamination of the copper treatment tank with fluoboric acid. The tin-lead plating solution is a fluoboric acid-based system. Fluoboric acid will attack the anodes in the electrolytic cell and destroy them within approximately two weeks. Therefore, the lead is handled by itself in a manner that allows special anodes to be used which are more resistant to the acid.
