Inhibition of bromate formation during drinking water treatment by adapting ozonation to electro-peroxone process

This study investigated bromate formation during drinking water treatment by conventional ozonation and electro-peroxone (E-peroxone) processes. The E-peroxone process combined conventional ozonation with electrolysis processes and used a carbon-based cathode to electrochemically convert O-2 in the sparged ozone generator effluent (O-2 and O-3 gas mixture) to H2O2, which can then react with sparged O-3 to yield (OH)-O-center dot (i.e., the peroxone reaction). Results show that ozonation of bromide-containing water (Br- of 150 mu g/L) produced significant amounts of bromate (e.g., similar to 60-120 mu g/L) in the effluent. In contrast, by applying a small current (e.g., 60-100 mA) to electrochemically generate H2O2 from sparged O-2, the E-peroxone process can decrease bromate to <10 mu g/L and significantly increase natural organic matter (NOM) removal. The results indicate that the E-peroxone process may provide a simple and effective way to improve existing ozonation process for controlling bromate formation and removing NOM during drinking water treatment. (C) 2014 Elsevier B.V. All rights reserved.