Using Chlorine Dioxide to Remove the Fouling of Ultrafiltration Membrane and Control Disinfection By-Products

Abstract

Ultrafiltration (UF) can remove natural organic matter (NOM) effectively. Moreover, chlorine dioxide (ClO 2 ) has been an alternative disinfectant as it forms fewer disinfection by-products with NOM than chlorination does. Therefore, combining ClO 2 with UF may improve conventional purification processes. In this study, feed water containing humic acid with 4.07 mg/L total organic carbon (TOC) was dosed directly with various amounts of ClO 2 (0, 2, 5, 10, and 15 mg/L) before being filtered through a 5-kDa UF membrane. With a low dose (2 mg/L ClO 2 ), UF removed humic acid effectively, as TOC was not detected in the permeate, and the permeate flux increased to about 80% of the initial permeate flux by cross flow. Moreover, the concentrations of ClO 2 ― , ClO 3 ― , and trihalomethanes in the permeate were below the United States Environmental Protection Agency guidelines.