MEMBRO3X, a Novel Combination of a Membrane Contactor with Advanced Oxidation (O3/H2O2) for Simultaneous Micropollutant Abatement and Bromate Minimization

Ozonation is a water treatment process for disinfection and/or micropollutant abatement. However, ozonation of bromide-containing water leads to bromate (BrO3-) formation, a potential human carcinogen. A solution for mitigating BrO3- formation during abatement of micro pollutants is to minimize the ozone (O-3) concentration. This can be achieved by dosing ozone in numerous small portions throughout a reactor in the presence of H2O2. Under these conditions, O-3 is rapidly consumed to form hydroxyl radical ('OH), which will oxidize micropollutants. To achieve this goal, a novel process (MEMBRO3X) was developed in which ozone is transferred to the water through the pores of polytetrafluoroethylene (PTFE) hollow fiber membranes. When compared to the conventional peroxone process (O-3/H2O2), the MEMBRO3X process shows better performance in terms of micropollutant abatement and bromate minimization for groundwater and surface water treatment. For a groundwater containing 180 mu g/L bromide, a 95% abatement of the ozone-resistant probe compound p-chlorobenzoic acid yielded <0.5 mu g/L BrO3-, whereas in the conventional peroxone process, 8 mu g/L BrO3 was formed. In addition, the efficacy of the MEMBRO3X process was demonstrated with river water and lake water.