Carbamazepine degradation by gamma irradiation coupled to biological treatment

Carbamazepine is an emerging contaminant and resistant to biodegradation, which cannot be effectively removed by the conventional biological wastewater treatment processes. In this study, the combined gamma irradiation and biodegradation was employed to remove carbamazepine from wastewater. The effect of dose on the removal of carbamazepine was studied at different doses (300, 600 and 800 Gy). The results showed that the removal efficiency of carbamazepine increased with dose increasing during the irradiation process. The maximum removal efficiency was 99.8% at 800 Gy, while the removal efficiency of total organic carbon (TOC) was only 26.5%. The removal efficiency of TOC increased to 79.3% after the sequent biological treatment. In addition, several intermediates and organic acids were detected. The possible degradation pathway of carbamazepine during the integrated irradiation and biodegradation was proposed. Based on the overall analysis, the combined gamma irradiation and biological treatment process can be an alternative for removing the recalcitrant organic pollutants such as carbamazepine from wastewater. (C) 2016 Elsevier B.V. All rights reserved.