Investigating the performance of a UV/H₂O₂ integrated flow-through system followed by free chlorine

Ultraviolet (UV) irradiation is an emerging technique for drinking water disinfection due to effective removal of enteric pathogens without generation of disinfection by-products (DBPs). In order to overcome the drawback of UV irradiation the integration of UV disinfection with sequential disinfectant was proposed. Among all the possible combinations and sequences, a UV/H₂O₂-Cl₂ integrated system has proven to be effective in many previous studies. In this study, a UV/H₂O₂ flow-through system followed by free chlorine was built and studied. MS-2 coliphage, as a model for a waterborne virus, were inactivated to evaluate the disinfection capacity. Assimilable organic carbon (AOC) tests and an Ames assay using Salmonella typhimurium TA98 and TA100 on such a proposed integrated system were also performed to determine re-growth potential of bacteria and genotoxicity, respectively. Briefly, such a proposed flow-through system was effective in removal of MS-2 coliphage and no genotoxic potential was detected according to the results; however, an increase of AOC may raise concerns of bacterial re-growth along the subsequent distribution system.