Removal of antibiotic resistant bacteria by the coupled system of ferrous ion activated peroxymonosulfate (PMS) and sodium percarbonate (SPC): Performance and mechanisms

Abstract

Antibiotic resistance has turned into a focus of universal public health concern. Wastewater treatment plants are considered as reservoirs of antibiotic resistant bacteria (ARB) and antibiotic resistant genes (ARGs), which can be transmitted to the environment. In this research, an effective method for inactivating Escherichia coli DH5α (E. coli DH5α) carrying resistance genes was developed utilizing dual oxidant system of peroxymonosulfate (PMS) and sodium percarbonate (SPC) in the presence of ferrous ions (Fe(II)). The results indicated that E. coli DH5α could be inactivated 6.36 log under the conditions of 0.50 mM PMS, 0.50 mM SPC and 0.50 mM Fe(II) after 30 min. Besides, the removal of different types of ARB and pollutants could also be achieved by Fe(II)/PMS/SPC system. The quenching experiment and EPR analysis demonstrated that reactive species (•OH, SO4•−, O2•−, 1O2 and CO3•−) involved in the inactivation of E. coli DH5α. Bacterial damage mechanisms were systematically studied in terms of cell structure and morphology, enzyme activity, malondialdehyde and intracellular reactive oxygen species levels. The inactivation of E. coli DH5α in complex water matrix (including coexisting of anions and natural organic matter) and real wastewater was inhibited. The abundance of intracellular ARGs decreased by 1.15 log, whereas extracellular ARGs increased by 0.32 log. This research supplied a prospective approach for inhibiting the dissemination of antibiotic resistance.