AbstractOrganic removal rates achieved in the aerobic BAC process were comparable to rates typically reported for traditional aerobic fixed‐film systems. When operated at organic loading rates lower than 0.03 g COD/g GAC‐d and air as the oxygen source, greater than 90 percent COD removal and 99 percent phenol removal was achieved. At higher organic loading rates, oxygen limitations resulted in less than optimal performance. Observed oxygen limitations were mitigated by the use of pure oxygen. Long‐term stability of operation of the BAC process was excellent with one aerobic BAC column operated under the same conditions in excess of 260 days. During that time, consistent column performance was achieved without the need to provide supplemental carbon or carbon regeneration. System biomass yields ranged from 0.05 to 0.30 g VSS/g COD removed and increased with effluent COD concentration.