Fates of antibiotic resistance genes during upgrading process of a municipal wastewater treatment plant in southwest China

Abstract

This study comprehensively analyzed the fates of antibiotics, antibiotic resistance genes (ARGs) and microbial community during upgrading process of municipal wastewater treatment plant (MWTP) of Anaerobic/Anoxic/Oxic-membrane bioreactor (A2/O-MBR) from regulation to stable operation phase. The factors most affecting ARGs profile were investigated, and the potential hosts for ARGs were further determined. Results showed that the removal rate of total antibiotics and the reduction of ARGs increased by 10.49% and 1.37 logs in A2/O-MBR during upgrading process, respectively. The most prevalent ARG was sul1 in both water and sludge phase. Mobile genetic elements (MGEs) and microbial community were the most significant factors affecting ARGs distribution in water phase and sludge, respectively. Notably, the abundance of potential antibiotic resistance bacteria (ARB) was significantly decreased during upgrading process. Therefore, sul1and intI1 proliferation as well as microbial community succession should be emphasized in ARGs pollution management and control. This study expected to provide a theoretical basis for the application of MBR process to remove antibiotics and ARGs in upgrading of MWTPs.