title: Ozonation and UV254nmradiation for the removal of microorganisms and antibiotic resistance genes from urban wastewater.
abstract: Conventional wastewater treatment has a limited capacity to reduce antibiotic resistant bacteria and genes (ARB&ARG). Tertiary treatment processes are promising solutions, although the transitory inactivation of bacteria may select ARB&ARG. This study aimed at assessing the potential of ozonation and UV254nmradiation to inactivate cultivable fungal and bacterial populations, and the selected genes 16S rRNA (common to all bacteria), intI1 (common in Gram-negative bacteria) and the ARG vanA, blaTEM, sul1 and qnrS. The abundance of the different microbiological parameters per volume of wastewater was reduced by ∼2 log units for cultivable fungi and 16S rRNA and intI1 genes, by∼3-4 log units, for total heterotrophs, enterobacteria and enterococci, and to values close or below the limits of quantification for ARG, for both processes, after a contact time of 30min. Yet, most of the cultivable populations, the 16S rRNA and intI1 genes as well as the ARG, except qnrS after ozonation, reached pre-treatment levels after 3days storage, suggesting a transitory rather than permanent microbial inactivation. Noticeably, normalization per 16S rRNA gene evidenced an increase of the ARG and intI1 prevalence, mainly after UV254nmtreatment. The results suggest that these tertiary treatments may be selecting for ARB&ARG populations.
authors.affiliation: LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: José M
authors.initials: JM
authors.lastname: Sousa
authors.affiliation: Universidade Católica Portuguesa, CBQF-Centro de Biotecnologia e Química Fina-Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal.
authors.forename: Gonçalo
authors.initials: G
authors.lastname: Macedo
authors.affiliation: Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: Marta
authors.initials: M
authors.lastname: Pedrosa
authors.affiliation: LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal; Universidade Católica Portuguesa, CBQF-Centro de Biotecnologia e Química Fina-Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal.
authors.forename: Cristina
authors.initials: C
authors.lastname: Becerra-Castro
authors.affiliation: Adventech-Advanced Environmental Technologies, Centro Empresarial e Tecnológico, Rua de Fundões 151, 3700-121 São João da Madeira, Portugal.
authors.forename: Sérgio
authors.initials: S
authors.lastname: Castro-Silva
authors.affiliation: Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: M Fernando R
authors.initials: MFR
authors.lastname: Pereira
authors.affiliation: Laboratory of Separation and Reaction Engineering-Laboratory of Catalysis and Materials (LSRE-LCM), Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal.
authors.forename: Adrián M T
authors.initials: AMT
authors.lastname: Silva
authors.affiliation: LEPABE-Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto, Portugal. Electronic address: opnunes@fe.up.pt.
authors.forename: Olga C
authors.initials: OC
authors.lastname: Nunes
authors.affiliation: Universidade Católica Portuguesa, CBQF-Centro de Biotecnologia e Química Fina-Laboratório Associado, Escola Superior de Biotecnologia, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401 Porto, Portugal.
authors.forename: Célia M
authors.initials: CM
authors.lastname: Manaia
mesh_terms: D001419:Bacteria / Q000235:genetics; D058491:Bacterial Load; D002947:Cities; D004269:DNA, Bacterial / Q000187:drug effects / Q000235:genetics / Q000528:radiation effects; D004203:Disinfection; D004352:Drug Resistance, Microbial / Q000235:genetics* / Q000528:radiation effects*; D010126:Ozone / Q000737:chemistry*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D014466:Ultraviolet Rays; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry*; D014871:Water Microbiology
chemical_list: D004269:DNA, Bacterial; D010126:Ozone; D012336:RNA, Ribosomal, 16S; D062065:Wastewater
keywords: Antibiotic resistance genes; Microbial inactivation; Microbial regrowth; Synthetic wastewater; Urban wastewater