Biofouling control by UV/H2O2pretreatment for brackish water reverse osmosis processElectronic supplementary information (ESI) available. See DOI: 10.1039/c8ew00183a

UV applied with H2O2is a well-known advanced oxidation process (AOP) for degradation of trace organic compounds. However, the UV/H2O2process has scarcely been documented as a disinfection method for brackish or seawater applications or particularly as a potential reverse osmosis (RO) biofouling control tool in varied treatment scenarios. The objective of this paper is to evaluate the potential of medium-pressure (MP)-UV/H2O2as a pretreatment step to control brackish water RO (BWRO) biofouling caused by indigenous microorganisms. UV/H2O2pretreatment significantly reduced total heterotrophic counts. Consequently, the quantity of biofilm cells and extracellular polymeric substances (EPS) following UV/H2O2pretreatment was significantly lower than that obtained after the control and the singular UV pretreatment steps. This is attributed to the additive or synergistic effect of MP UV light, H2O2and OH radicals. Hence, UV/H2O2has a high potential as a biofouling control tool in BWRO desalination systems. Higher H2O2concentrations may achieve improved biofouling control due to enhanced radical formation and higher H2O2residual effect.