DESTRUCTION OF POLLUTANTS IN INDUSTRIAL RINSE WATERS BY ADVANCED OXIDATION PROCESSES

Recycling process water is a growing need for a variety of industries faced with increasing water costs and environmental constraints. Metal finishing activities such as printed circuit board (PCB) manufacturin g generate large volumes of rinse water slightly contaminated with ino rganic chemicals and organic additives. While the former can be remove d with proven technologies, there is a need for effective processes fo r elimination of trace organics in order to allow recycling of rinse w ater without negative impact on process bath quality. A cooperative re search project started recently to study a water recycling process ada pted to this need, able to remove 95% of the Chemical Oxygen Demand (C OD) of the rinse water by combining proven membrane separation with an innovative chemical oxidation. Two types of advanced oxidations based on the conjunction of heterogeneous catalysts with oxidants will be s pecifically investigated. In a preliminary stage of the project, the e xperimental tests were performed with a set of model compounds, select ed from among the chemicals most frequently used in the plating proces ses, namely chelating agents, surfactants and corrosion inhibitors. Th ese compounds were oxidized comparatively by ozone and catalytic ozona tion. The differences between standard oxidation and catalytic oxidati on are presented and discussed. (C) 1997 IAWQ. Published by Elsevier S cience Ltd.