A pilot plant study using ceramic membrane microfiltration, carbon adsorption and reverse osmosis to treat CMP (chemical mechanical polishing) wastewater

Abstract

Currently, most semi-conductor plants adopt the conventional chemical coagulation and sedimentation process to treat chemical mechanical polishing (CMP) wastewater. This treatment process consumes a large quantity of coagulants, and its optimum pH operation range is rather narrow. This treatment process produces huge amounts of sludge and is hard to operate due to the unstable characteristics of the abrasive slurry of CMP wastewater. The purpose of this research is to establish a pilot plant which consists of chemical pretreatment, ceramic membrane microfiltration, carbon filtration and reverse osmosis system, which will allow the reclamation of the CMP wastewater. Actual CMP wastewater was sampled and treated in the pilot plant. The results of the pilot tests demonstrated the viability of the treatment scheme and provided data for scale-up calculations. Cost per ton of CMP wastewater reclaimed was calculated using the operating data established, and compared with the conventional chemical coagulation and sedimentation process.