Removal of bromate ion from water using granular activated carbon

Abstract

This study investigated the feasibility of using granular activated carbon (GAC) to remove bromate ion (BrO 3 −) from drinking water through a rapid small-scale column test (RSSCT) method and a pilot-scale study. Results from RSSCT tests indicated that the GAC capacity for BrO 3 − removal was carbon-specific and dependent on the source water quality and empty bed contact time (EBCT). The presence of dissolved organic carbon (DOC) and anions, such as bromide, nitrate, and sulfate, resulted in poor BrO 3 − reduction. On the other hand, BrO 3 − removal was improved by increasing EBCT. The reduction capacity of spent GAC could be completely recovered by thermal regeneration. Under RSSCT conditions, the results showed that preloading with natural water significantly decreased the capacity of GAC for BrO 3 − removal; whereas in the pilot plant study, a GAC column (operating with 20-min EBCT) preloaded for 110 days achieved a BrO 3 − removal ranging from 57 to 92% for at least 98 days, and the BrO 3 − amount removed was found to be proportional to the influent BrO 3 − concentration. These limited data suggest that if suitable GAC is used, GAC performed in the biological mode may achieve a longer bedlife for BrO 3 − removal.