P97: Biological Bromate Removal By Denitrifying Fixed-Bed Column Reactor

Carcinogenic bromate (BrO^-₃) can be present in drinking water as a result of its formation from bromide (Br-) during ozonation. A long term performance of a fixed-bed column reactor (FBCR) containing sulfur and limestone was evaluated for  the removal of bromate by denitrification process. The reduction of bromate by mixed bacterial populations was studied under laboratory conditions. The column reactor was operated in continuous up-flow mode at 28-30 °C in a temperature controlled room. Long term tests were examined the impact of  hidraulic retention time on the process performance. A mixed culture FBCR reduced 100 µg/L bromate to below 10 µg/L at different hidraulic retention times. Bromate was reduced cometabolically by nitrate denitrifying microorganisms. Nitrate concentration was 50 mg/L in feed solution of fixed-bed column reactor. Bromate reduction in excess of 90 % in FBCR demonstrates that the process is sustainable.