title: Photocatalytic ozonation of urban wastewater and surface water using immobilized TiO2 with LEDs: Micropollutants, antibiotic resistance genes and estrogenic activity.
abstract: Photocatalytic ozonation was employed for the first time in continuous mode with TiO2-coated glass Raschig rings and light emitting diodes (LEDs) to treat urban wastewater as well as surface water collected from the supply area of a drinking water treatment plant (DWTP). Different levels of contamination and types of contaminants were considered in this work, including chemical priority substances (PSs) and contaminants of emerging concern (CECs), as well as potential human opportunistic antibiotic resistant bacteria and their genes (ARB&ARG). Photocatalytic ozonation was more effective than single ozonation (or even than TiO2 catalytic ozonation) in the degradation of typical reaction by-products (such as oxalic acid), and more effective than photocatalysis to remove the parent micropollutants determined in urban wastewater. In fact, only fluoxetine, clarithromycin, erythromycin and 17-alpha-ethinylestradiol (EE2) were detected after photocatalytic ozonation, by using solid-phase extraction (SPE) pre-concentration and LC-MS/MS analysis. In surface water, this treatment allowed the removal of all determined micropollutants to levels below the limit of detection (0.01-0.20 ng L(-1)). The efficiency of this process was then assessed based on the capacity to remove different groups of cultivable microorganisms and housekeeping (16S rRNA) and antibiotic resistance or related genes (intI1, blaTEM, qnrS, sul1). Photocatalytic ozonation was observed to efficiently remove microorganisms and ARGs. Although after storage total heterotrophic and ARB (to ciprofloxacin, gentamicin, meropenem), fungi, and the genes 16S rRNA and intI1, increased to values close to the pre-treatment levels, the ARGs (blaTEM, qnrS and sul1) were reduced to levels below/close to the quantification limit even after 3-days storage of treated surface water or wastewater. Yeast estrogen screen (YES), thiazolyl blue tetrazolium reduction (MTT) and lactate dehydrogenase (LDH) assays were also performed before and after photocatalytic ozonation to evaluate the potential estrogenic activity, the cellular metabolic activity and the cell viability. Compounds with estrogenic effects and significant differences concerning cell viability were not observed in any case. A slight cytotoxicity was only detected for Caco-2 and hCMEC/D3 cell lines after treatment of the urban wastewater, but not for L929 fibroblasts.
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; 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: Nuno F F
authors.initials: NFF
authors.lastname: Moreira
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: CBQF-Centro de Biotecnologia e Química Fina-Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, 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: Ana R
authors.initials: AR
authors.lastname: Ribeiro
authors.affiliation: UCIBIO, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
authors.forename: Luisa
authors.initials: L
authors.lastname: Barreiros
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: 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: Joaquim L
authors.initials: JL
authors.lastname: Faria
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: 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: UCIBIO, REQUIMTE, Departamento de Ciências Químicas, Faculdade de Farmácia, Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313, Porto, Portugal.
authors.forename: Marcela A
authors.initials: MA
authors.lastname: Segundo
authors.affiliation: CBQF-Centro de Biotecnologia e Química Fina-Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Arquiteto Lobão Vital, Apartado 2511, 4202-401, Porto, Portugal. Electronic address: cmanaia@porto.ucp.pt.
authors.forename: Célia M
authors.initials: CM
authors.lastname: Manaia
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: 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. Electronic address: adrian@fe.up.pt.
authors.forename: Adrián M T
authors.initials: AMT
authors.lastname: Silva
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D001419:Bacteria / Q000302:isolation & purification; D001426:Bacterial Proteins / Q000235:genetics; D018938:Caco-2 Cells; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D004352:Drug Resistance, Microbial / Q000235:genetics; D006801:Humans; D008027:Light; D010126:Ozone / Q000737:chemistry*; D010782:Photolysis; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D052616:Solid Phase Extraction; D053719:Tandem Mass Spectrometry; D014025:Titanium / Q000737:chemistry*; D062065:Wastewater / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods*; D001618:beta-Lactamases / Q000235:genetics
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D010126:Ozone; D012336:RNA, Ribosomal, 16S; D014025:Titanium; D062065:Wastewater; D014874:Water Pollutants, Chemical; D001618:beta-Lactamases; C009495:titanium dioxide
keywords: Antibiotic resistance genes; Cytotoxicity; LEDs; Microbial inactivation and regrowth; Organic micropollutants; Photocatalytic ozonation