The degradation of antibiotic amoxicillin in the Fenton-activated sludge combined system

The present study investigated the removal efficiency of amoxicillin by the Fenton process, individual activated sludge process and Fenton-activated sludge combined system. For the antibiotic at 1 g L-1, the optimal conditions of the Fenton process included: 4 mL FeSO4 center dot 7H(2)O solution (20.43 g L-1), 6 mL H2O2 solution (3%) and 40 degrees C. Under the optimal conditions, the removal rate of amoxicillin achieved up to 80% in 70 min. In addition, the impact of amoxicillin on microorganism limited the removal capacity of the activated sludge process. When the concentration of amoxicillin was less than 350 mg L-1, 69.04-88.79% of the antibiotic was removed. However, the antibiotic could not be treated by the activated sludge when the concentration increased up to 650 mg L-1. On the other hand, ifamoxicillin was pretreated partly by the Fenton process it was then degraded completely by the same activated sludge. Thus, the combined system included two steps: 80% amoxicillin was degraded in step I and was removed completely in the cheaper biological treatment (step II). Our result showed that compared with the individual activated sludge process, the Fenton process improved the removal capacity of the subsequent activated sludge process in the combined system.