In this study, the performance of an integrated technology, combining biological treatment with advanced oxidation process in sequence, was evaluated for the degradation of sulfolane in aqueous media. In addition, the impact of biological process on AOP was also studied by assessing residual sulfolane, nutrient and total suspended solids (TSS) concentrations. The integration of activated sludge process with UVC/H2O2 resulted in more than 81% of sulfolane degradation in less than 24 h. It was observed that mineralization was much faster in biological system compared to AOP. Mechanistically, the process of degradation is different in the two processes as various by-products were identified during UVC/H2O2 but not during the biological process. The impact of residual sulfolane concentration on UVC/H2O2 was significant beyond a concentration of 30 mg L−1, while below 30 mg L−1 the rate of degradation was independent of sulfolane concentration. Residual nutrients from biological systems did not impact AOP performance. Nevertheless, presence of TSS >44 mg L−1 had a negative impact on the performance of UVC/H2O2 by reducing UV transmittance which led to retardation of sulfolane degradation. The application of UVC/H2O2 after biological treatment was an advantage as UVC/H2O2 could perform dual roles of oxidant and disinfectant.
