Effects of coexisting anions on removal of bromide in drinking water by coagulation

Bromo-DBPs (disinfection by-products) are generated by bromide and disinfectant in drinking water disinfection, which have adverse effects on human health. In this study, effects of coexisting anions on removal of bromide by aluminium coagulation were investigated. It was observed that bromide was removed of 62.1-87.0% in raw water, while the removal efficiency of bromide was achieved 82.8-99.2% in deionized water through the combination of Br− with Al(III) in various pathways. The coexisting anions in raw water significantly affected the removal of bromide. Removal efficiency decreased by 11.5, 21.2, 14.6, 8.0 and 40.8% with the addition of HCO3−, SO42−, Cl−, NO3− and H2PO4−, respectively, for their affinities with Al(III) or accelerating the formation of Al(OH)3(am). These results demonstrated that bromo-DBPs in drinking water could be controlled though removing bromide by enhanced coagulation.