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 micropollutants is to minimize the ozone (O₃) concentration. This can be achieved by dosing ozone in numerous small portions throughout a reactor in the presence of H₂O₂. Under these conditions, O₃ is rapidly consumed to form hydroxyl radical (^<b>•</b>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 (O₃/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 μg/L bromide, a 95% abatement of the ozone-resistant probe compound <i>p</i>-chlorobenzoic acid yielded <0.5 μg/L BrO₃^–, whereas in the conventional peroxone process, 8 μg/L BrO₃^– was formed. In addition, the efficacy of the MEMBRO₃X process was demonstrated with river water and lake water