A NOVEL PROCESS FOR THE CLOSED-LOOP REUSE OF RINSE WATERS FROM THE ELECTRONIC INDUSTRY

摘要

The electronic industry uses large amounts of rinse water for the production of printedrncircuit boards (PCBs) and semiconductors. As water and wastewater treatment costsrnare increasing steadily, recovery and reuse of rinse waters which are only slightlyrncontaminated with inorganic chemicals and organic additives become more and morernattractive options from both the economical and environmental point of view. Whilerninorganic compounds such as heavy metals, acids and bases can be removed withrnproven technologies, there is a need for effective processes that would reduce orrneliminate the traces of organic compounds that could have a detrimental effect onrnprocess baths and on the final products. The development of a new water recyclingrnprocess based on advanced oxidation was studied within a European ResearchrnProject coordinated by Anjou Recherche.rnThe primary goal of the project was to evaluate the suitability of using catalyticrnozonation followed by biological degradation for the treatment of typical organicrncompounds found in rinse waters from printed circuit boards (PCB) production. Thernmain variables studied in laboratory scale experiments on a synthetic rinse watersrnmimicking either those found in PCBs or semiconductors production plant were ozonernconcentration, hydraulic retention time and pH. In our study, ozone alone as well asrnozone in combination with hydrogen peroxide did not lead to any significant TOCrnremoval. Ozonation in presence of a transition metal supported catalyst allowed a 25%