Removal of antibiotic resistance genes and pathogenicity in effluent from municipal wastewater treatment plant by plasma oxidation

Abstract

Municipal wastewater treatment plants (MWTP) are the main gathering places for antibiotic resistance genes (ARGs) and pathogenic bacteria. In this study, plasma oxidation was applied to remove the ARGs and inhibit pathogenicity in the effluent. The experimental results demonstrated that approximately 1.32 log, 1.34 log, 2.39 log, and 2.80 log of aac(3)-II, blaTEM-1, TetW, and TetC were removed within 25 min of the plasma treatment, respectively. OH, 1O2, O3, H2O2, NO2−, and NO3− all contributed to ARG removal. Coexisting dissolved organic matter was also oxidized, which was positively related to ARG removal. Plasma oxidation led to a decrease in the diversity and richness of microbial communities; Parcubacteria and Proteobacteria were the main potential hosts of ARGs and mobile genetic elements. Integron gene IntI1 decreased by 2.46 log after plasma treatment, which was positively related to ARG removal. Gene expression related to ATP binding, DNA repair, gene transfer, and the cell membrane was reduced after plasma treatment, resulting in effective ARG removal. Furthermore, pathogenic genes related to lumpy skin disease, Niemann-Pick disease, polycystic kidney and hepatic disease were all down-regulated by plasma treatment. Overall, the plasma treatment inhibited the transmission risks of ARGs and pathogenicity in the effluent of MWTP.