Inactivation of antibiotic-resistant bacteria in hospital wastewater by ozone-based advanced water treatment processes.

The emergence and spread of antimicrobial resistance (AMR) continue on a global scale. The impacts of wastewater on the environment and human health have been identified, and understanding the environmental impacts of hospital wastewater and exploring appropriate forms of treatment are major societal challenges. In the present research, we evaluated the efficacy of ozone (O)-based advanced wastewater treatment systems (O, O/HO, O/UV, and O/UV/HO) for the treatment of antimicrobials, antimicrobial-resistant bacteria (AMRB), and antimicrobial resistance genes (AMRGs) in wastewater from medical facilities. Our results indicated that the O-based advanced wastewater treatment inactivated multiple antimicrobials (>99.9%) and AMRB after 10-30 min of treatment. Additionally, AMRGs were effectively removed (1.4-6.6 log) during hospital wastewater treatment. The inactivation and/or removal performances of these pollutants through the O/UV and O/UV/HO treatments were significantly (P < 0.05) better than those in the O and O/HO treatments. Altered taxonomic diversity of microorganisms based on 16S rRNA gene sequencing following the O-based treatment showed that advanced wastewater treatments not only removed viable bacteria but also removed genes constituting microorganisms in the wastewater. Consequently, the objective of this study was to apply advanced wastewater treatments to treat wastewater, mitigate environmental pollution, and alleviate potential threats to environmental and human health associated with AMR. Our findings will contribute to enhancing the effectiveness of advanced wastewater treatment systems through on-site application, not only in wastewater treatment plants (WWTPs) but also in medical facilities. Moreover, our results will help reduce the discharge of AMRB and AMRGs into rivers and maintain the safety of aquatic environments.