Selection of pretreatment process and reverse osmosis membrane for a wastewater reclamation system for the industrial water use

Abstract

Wastewater reclamation offers an attractive solution to water stress problems these days. Because of health concerns in the reclaimed wastewater as drinking water, most of water reuse projects are focusing on the industrial water use. The key water quality constraint to the industrial water reuse is ionic constituents from nearby industrial complexes. Therefore, the reverse osmosis (RO) process must be the main process for a wastewater reclamation system for the industrial water use. The most important target for the design of an RO-based wastewater reclamation system is to minimize membrane fouling. This study focuses on the selection of pretreatment process and RO membrane to minimize the fouling in the RO process. Since raw water is the wastewater treatment plant effluent, high-quality pretreatment and low-fouling RO membrane should be considered for the design of the whole system. A short-term field test for microfiltration (MF) and ultrafiltration (UF) was carried out to see which process showed better performance in terms of the process stability and the pre-treated water quality. Both MF and UF produced the pretreated water of the similar quality, while UF showed more stable transmembrane pressure data than MF. In addition, a short-term field RO-fouling test was introduced to select the best RO membrane among the three tested membranes in terms of the fouling resistance.