Reduction of antibiotic resistance determinants in urban wastewater by ozone: Emphasis on the impact of wastewater matrix towards the inactivation kinetics, toxicity and bacterial regrowth

I C Iakovides; K Manoli; P Karaolia; I Michael-Kordatou; C M Manaia; D Fatta-Kassinos

doi:10.1016/j.jhazmat.2021.126527

Reduction of antibiotic resistance determinants in urban wastewater by ozone: Emphasis on the impact of wastewater matrix towards the inactivation kinetics, toxicity and bacterial regrowth

J Hazard Mater. 2021 Oct 15:420:126527. doi: 10.1016/j.jhazmat.2021.126527. Epub 2021 Jun 29.

Authors

I C Iakovides¹, K Manoli¹, P Karaolia², I Michael-Kordatou², C M Manaia³, D Fatta-Kassinos⁴

Affiliations

¹ Department of Civil and Environmental Engineering, School of Engineering, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus; Nireas-International Water Research Centre, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus.
² Nireas-International Water Research Centre, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus.
³ Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua de Diogo Botelho 1327, 4169-005 Porto, Portugal.
⁴ Department of Civil and Environmental Engineering, School of Engineering, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus; Nireas-International Water Research Centre, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus. Electronic address: dfatta@ucy.ac.cy.

PMID: 34329111
DOI: 10.1016/j.jhazmat.2021.126527

Abstract

This study investigated the impact of bench-scale ozonation on the inactivation of total cultivable and antibiotic-resistant bacteria (faecal coliforms, Escherichia coli, Pseudomonas aeruginosa, Enterococcus spp., and total heterotrophs), and the reduction of gene markers (16S rRNA and intl1) and antibiotic resistance genes (qacEΔ1, sul1, aadA1 and dfrA1) indigenously present in wastewater effluents treated by membrane bioreactor (MBR) or conventional activated sludge (CAS). The Chick-Watson model-predicted ozone exposure (CT) requirements, showed that higher CT values were needed for CAS- than MBR-treated effluents to achieve a 3-log reduction of each microbial group, i.e., ~30 and 10 gO₃ min gDOC^-1 respectively. Ozonation was efficient in inactivating the examined antibiotic-resistant bacteria, and no bacterial regrowth was observed after 72 h. The genes abundance decreased significantly by ozone, but an increase in their abundance was detected 72 h after storage of the treated samples. A very low removal of DOC was achieved and at the same time phyto- and eco-toxicity increased after the ozonation treatment in both wastewater matrices. The gene abundance, regrowth and toxicity results of this study may be of high environmental significance for comprehensive evaluation of ozone and may guide future studies in assessing these parameters for other oxidants/disinfectants.

Keywords: Disinfection; Ecotoxicity; Genes; Ozonation; Phytotoxicity.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Anti-Bacterial Agents / toxicity
Bacteria / genetics
Drug Resistance, Microbial / genetics
Kinetics
Ozone*
RNA, Ribosomal, 16S
Waste Disposal, Fluid
Wastewater*

Substances

Anti-Bacterial Agents
RNA, Ribosomal, 16S
Waste Water
Ozone