Degradation Efficiency of Textile and Wood Processing Industry Wastewater by Photocatalytic Process Using In Situ Ultrafiltration Membrane

The hybrid membrane photocatalytic reactor (MPR) in this study was constructed by submerging a flat polyethersulfone membrane module into a ZnO or TiO2 slurry photocatalytic reactor for raw wastewater treatment. The short and long term MPR performance was investigated for the degradation of textile and wood processing industry wastewater. The different operational parameters such as the catalyst type, catalyst loading, initial wastewater concentration, light type, and semiconductor powder type affecting the performance of the reactor were initially evaluated using a batch system without a membrane module. After the optimization of the operating conditions, the long term studies were performed by the MPR. Nearly 100% color and 30-55% chemical oxygen demand (COD) removal could be reached at a hydraulic retention time of 6 h for both wastewater effluents. Moreover, reverse osmosis experiments were applied on MPR ultrafiltration effluent for further COD removal and up to 88% COD removal efficiency could be obtained. The color and organic matter degradation efficiency showed that the catalyst can be reused effectively in MPR. In this hybrid design, the membrane module served also as a separator which is very advantageous in keeping catalyst powder in suspension during the operation. The results indicated that the effluent water can be used as process water in the industry.