Efficient control of antibiotic resistance in wastewater by UV/peracetic acid treatment: Unveiling distinct mechanisms behind the elimination of various contaminants

The abuse of antibiotics has led to an increase in contamination by antibiotics, antibiotic-resistant bacteria (ARB), and antibiotic resistance genes (ARGs) in the environment, especially in wastewater treatment plants, which are the main treatment sites for antibiotic contaminants. In this study, we demonstrated that the combined ultraviolet (UV)/peracetic acid (PAA) process effectively removes coexisting antibiotics, ARB, and ARGs simultaneously by removing 96 % of ampicillin (AMP, with an initial concentration of 10 mu M) in 8 min and completely inactivating super-resistant Escherichia coli (E. coli) NDM-1 (i.e., achieving 7.44-log reduction) in just 3 min (PBS, pH=7.0). These bacteria did not proliferate during the 86-h bacterial regrowth test. The analysis of radical quenching and electron paramagnetic resonance revealed that reactive species, such as hydroxyl radicals (& sdot;OH) and carbon-centered organic radicals (R-C & sdot;), played dominant roles in AMP removal, whereas UV irradiation was crucial for ARB inactivation. Furthermore, the ARGs fragments were efficiently damaged, as demonstrated by gel electrophoresis analysis, leaving few intact sequences. This strategy effectively reduced the horizontal transfer frequency of ARGs. Subsequent evaluations of the stability and efficiency of UV/PAA for pollutant removal in real wastewater further affirmed the broad applicability of the UV/PAA process. This study revealed that UV/PAA system has the potential to alleviate the burden of antibiotic resistance and contribute to a better comprehension and application for novel technology to control antibiotic resistance spread.