Using photocatalyzed-peroxonization to disinfect and denature genetic material of bacterial plasmids present in hospital wastewater

Abstract

The literature reports the presence of multiresistant microorganisms in wastewater discharged from municipal and hospital wastewater treatment plants (WWTPs). This has led to questions concerning the disinfection efficiency of the treatments applied. Thus, this study aimed to assess the efficiency of different chemical oxidation methods to disinfect and to degrade bacterial plasmids present in hospital wastewaters, to avoid the dispersion of antibiotic resistance genes in the environment. The methods tested were UV_254nm alone or associated with an Ag or Ti-photocatalyst in photo-peroxonization (UV_254 nm/H₂O₂/O₃/Ag₂O/Ag₂CO₃@PU or UV_254 nm/H₂O₂/O₃/TiO₂@PU) under different pH conditions (4, 7, and 10). The application of plasmid DNA electrophoresis to hospital wastewater treated using an advanced oxidation process (AOP) achieved the total structural denaturation of microorganism plasmids at the three pH values tested. Also, UV_254 nm alone was partially efficient in the disinfection of hospital wastewater. AOPs performed with the two functionalized catalysts resulted in 100% disinfection after 10 min at the three pH values tested. No intact plasmids were observed after 20 min of treatment with photocatalysis. This study could contribute to the development and improvement of wastewater treatment aimed at mitigating the spread of multiresistant microorganisms in the environment.

Keywords:

• Wastewater disinfection
• plasmid denaturation
• photocatalysis oxidation
• polyurethane support
• environmental impact

Acknowledgements

The authors thank FAPESC (project 2021TR000549) for the financial support. C.M. Radetski gratefully acknowledges the CNPq - Brazil (Process 302124/2019-5) for the grant awarded. A. Dal Conti-Lampert and R. Ariente-Neto acknowledge CAPES – Brazil for the Doctorate and Post-Doctorate degree scholarships.

Disclosure statement

We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome, apart from the grants funding listed in the acknowledgements.

Availability of data and materials

The datasets used and/or analyzed during the current study are available from the corresponding author upon reasonable request.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.