Removal of bromate and assimilable organic carbon from drinking water using granular activated carbon.
This study investigated the feasibility of using granular activated carbon (GAC) to remove bromate ion (BrO3-) and assimilable organic carbon (AOC) from drinking water through a rapid small-scale column test (RSSCT) method and a pilot-scale study. Results from RSSCT indicated that the GAC capacity for BrO3- removal was dependent on the GAC type, empty bed contact time (EBCT), and source water quality. The GAC with a high number of basic groups and higher pHpzc values showed an increased BrO3- removal capacity. BrO3- removal was improved by increasing EBCT. The high EBCT provides a greater opportunity for BrO3- to be adsorbed and reduced to Br- on the GAC surface. On the other hand, the presence of dissolved organic carbon (DOC) and anions, such as chloride, bromide, and sulfate, resulted in poor BrO3- reduction. In the GAC pilot plant, a GAC column preloaded for 12 months achieved a BrO3- and AOC removal range from 79-96% and 41-75%, respectively. The BrO3- amount removed was found to be proportional to the influent BrO3- concentration. However, the BrO3- removal rate apparently decreased with increasing operation time. In contrast, the AOC apparently increased during the long-term operation period. This may be a result of the contribution due to new GAC being gradually transformed into biological activated carbon (BAC), and the bacterial biomass adsorbed on GAC surface hindering BrO3- reduction by GAC either by blocking pores or adsorbing at the activated sites for BrO3- reduction.
Huang
W J
WJ
Department of Environmental Engineering, HungKuang University, Sha-Lu, Taichung, Chinese Taiwan. huangwj@sunrise.hk.edu.tw
Peng
H S
HS
Peng
M Y
MY
Chen
L Y
LY
D000327:Adsorption; D018533:Biomass; D001959:Bromates / Q000737:chemistry / Q000302:isolation & purification*; D002244:Carbon / Q000737:chemistry / Q000302:isolation & purification*; D009930:Organic Chemicals / Q000302:isolation & purification*; D010126:Ozone / Q000737:chemistry; D013997:Time Factors; D018508:Water Purification / Q000379:methods*; D014881:Water Supply
D001959:Bromates; D009930:Organic Chemicals; D010126:Ozone; D002244:Carbon