Biological activated carbon (BAC) filtration is vital for the abatement of micropollutants in drinking water. However, limited information is available on contaminant removal in BAC filters with aged media (e.g., >
6 year) which are commonly operated at water treatment plants, and mechanistic insights into linkages among media age, microbial community, and contaminant removal still lack. In this study, the effects of media age on the abatement of eight micropollutants with various functional groups were investigated. The abatement of micropollutants decreased with increasing media age. Pseudo-first-order rate constants for contaminant removal in 6- and 15-year BAC were (0.3-3.1) × 10