Effect of operating conditions on Bromate Removal Efficiency in BAC filters

This study examined the use of biologically active carbon (BAC) filters for microbial reduction of bromate to bromide. In these filters, abiotic reduction by the activated carbon did not play a significant role in bromate removal. Bromate removal in a BAC filter decreased by 30% after a system perturbation, suggesting that filter history affects bromate removal. Although 25 and 51 mm (1 and 2 in.) inner‐diameter BAC filters provided comparable bromate removals for the tested contact times, the larger filter exhibited nitrite production; therefore, system performance must be monitored to prevent such undesirable compounds from entering the water. The mass of bromate removed increased as the influent bromate concentration increased, whereas bromate removal did not change after backwashing. Experimental evidence indicated that increased regrowth would not be observed in the distribution system following BAC filtration with a low influent dissolved oxygen concentration (2 mg/L) in the tested water.