A Step Closer to Real Practice: Integrated Tandem Photocatalysis-Activated Sludge Process Towards Degradation of Crude Oil

Intimately coupled photocatalysis and biodegradation (ICPB) systems are promising wastewater treatment technology, how to implement ICPB systems for the treatment of real oil spills is a pressing issue. In this study, ICPB system consisting of BiOBr/M-CN and biofilms is manufactured for the treatment of oil spills. The results show that ICPB system could degrade 89.08 ± 5.36 % of crude oil within 48 h, which outperformed the single photocatalysis and biodegradation and achieved the rapid disposal of oil spills. The BiOBr/M-CN formed a Z-scheme heterojunction structure with reinforced redox capacity. The holes combined with the negative charge on the surface of biofilms, which promoted the separation of electrons and holes and accelerated the degradation of crude oil. Furthermore, ICPB system maintained an excellent degradation ratio after three cycles and its biofilms progressively adapted to the adverse effects of crude oil and light. The microbial community structure remained stable during the degradation of crude oil, and Acinetobacter and Sphingobium were the dominant genera of biofilm. The proliferation of Acinetobacter genus seemed to contribute the primary reason for promoting the degradation of crude oil. Our work demonstrates that integrated tandem strategies perhaps represent a feasible pathway toward practical photocatalytic degradation.