Removal of sulfamethazine antibiotics by aerobic sludge and an isolated Achromobacter sp. S-3.

Removal characteristics of sulfamethazine (SMZ) by sludge and a bacterial strain using an aerobic sequence batch reactor (ASBR) were studied. Operating conditions were optimized by varying the reaction time and sludge retention time (SRT). An Achromobacter sp. (S-3) with the ability to remove SMZ was isolated from the ASBR. The effects of different operating parameters (pH and temperature) on the biodegradation of SMZ by S-3 were determined. The results indicate that, between 0.5 and 4 hr, reaction time of the ASBR had a significant effect on the SMZ removal efficiency in the system. The SMZ removal efficiency also increased from 45% to 80% when SRT was prolonged from 5 to 25 days, although longer SRT had no impact on SMZ removal. The SMZ adsorption rate decreased with increasing temperature, which fitted Freundlich isotherm well. The removal of SMZ in the ASBR was due to the combined effects of adsorption and degradation, and degradation played a leading role.