title: Performance of aerobic granular sludge in a sequencing batch bioreactor exposed to ofloxacin, norfloxacin and ciprofloxacin.
abstract: A granular sludge sequencing batch reactor (SBR) was operated for 340 days for treating a synthetic wastewater containing fluoroquinolones (FQs), namely ofloxacin, norfloxacin and ciprofloxacin. The SBR was intermittently fed with FQs, at concentrations of 9 and 32 μM. No evidence of FQ biodegradation was observed but the pharmaceutical compounds adsorbed to the aerobic granular sludge, being gradually released into the medium in successive cycles after stopping the FQ feeding. Overall COD removal was not affected during the shock loadings. Activity of ammonia oxidizing bacteria and nitrite oxidizing bacteria did not seem to be inhibited by the presence of FQs (maximum of 0.03 and 0.01 mM for ammonium and nitrite in the effluent, respectively). However, during the FQs feeding, nitrate accumulation up to 1.7 mM was observed at the effluent suggesting that denitrification was inhibited. The activity of phosphate accumulating organisms was affected, as indicated by the decrease of P removal capacity during the aerobic phase. Exposure to the FQs also promoted disintegration of the granules leading to an increase of the effluent solid content, nevertheless the solid content at the bioreactor effluent returned to normal levels within ca. 1 month after removing the FQs in the feed allowing recovery of the bedvolume. Denaturing gradient gel electrophoresis revealed a dynamic bacterial community with gradual changes due to FQs exposure. Bacterial isolates retrieved from the granules predominantly belonged to α- and γ-branch of the Proteobacteria phylum. The capacity of the system to return to its initial conditions after withdrawal of the FQ compounds in the inlet stream, reinforced its robustness to deal with wastewaters containing organic pollutants.
authors.affiliation: CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal; CEQUIMED-UP, Laboratório de Química Orgânica e Farmacêutica, Dep. Ciências Químicas, Faculdade de Farmácia da Universidade do Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal. Electronic address: camorim@porto.ucp.pt.
authors.forename: Catarina L
authors.initials: CL
authors.lastname: Amorim
authors.affiliation: CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal; Cooperativa do Ensino Superior Politécnico e Universitário (CESPU), Centro de Investigação em Ciências da Saúde (CICS), Instituto Superior de Ciências da Saúde-Norte (ISCS-N), Rua Central de Gandra 1317, 4585-116 Gandra, Portugal. Electronic address: alexandra.a.maia@gmail.com.
authors.forename: Alexandra S
authors.initials: AS
authors.lastname: Maia
authors.affiliation: CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal; Laboratory of Hydrobiology, Institute of Biomedical Sciences Abel Salazar (ICBAS) and Institute of Marine Research (CIIMAR), Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal. Electronic address: rmesquita@porto.ucp.pt.
authors.forename: Raquel B R
authors.initials: RB
authors.lastname: Mesquita
authors.affiliation: CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal. Electronic address: arangel@porto.ucp.pt.
authors.forename: António O S S
authors.initials: AO
authors.lastname: Rangel
authors.affiliation: Department of Biotechnology, Delft University of Technology, Julianalaan 67, 2628BC Delft, The Netherlands. Electronic address: M.C.M.vanLoosdrecht@tudelft.nl.
authors.forename: Mark C M
authors.initials: MC
authors.lastname: van Loosdrecht
authors.affiliation: CEQUIMED-UP, Laboratório de Química Orgânica e Farmacêutica, Dep. Ciências Químicas, Faculdade de Farmácia da Universidade do Porto, Rua Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal; Cooperativa do Ensino Superior Politécnico e Universitário (CESPU), Centro de Investigação em Ciências da Saúde (CICS), Instituto Superior de Ciências da Saúde-Norte (ISCS-N), Rua Central de Gandra 1317, 4585-116 Gandra, Portugal. Electronic address: elizabeth.tiritan@iscsn.cespu.pt.
authors.forename: Maria Elizabeth
authors.initials: ME
authors.lastname: Tiritan
authors.affiliation: CBQF - Centro de Biotecnologia e Química Fina, Laboratório Associado, Escola Superior de Biotecnologia, Universidade Católica Portuguesa/Porto, Rua Dr. António Bernardino Almeida, 4200-072 Porto, Portugal. Electronic address: plcastro@porto.ucp.pt.
authors.forename: Paula M L
authors.initials: PM
authors.lastname: Castro
mesh_terms: D000332:Aerobiosis; D001419:Bacteria / Q000378:metabolism; D061249:Batch Cell Culture Techniques / Q000295:instrumentation*; D057919:Biological Oxygen Demand Analysis; D019149:Bioreactors / Q000382:microbiology*; D002939:Ciprofloxacin / Q000302:isolation & purification*; D016000:Cluster Analysis; D058645:Denaturing Gradient Gel Electrophoresis; D009584:Nitrogen / Q000302:isolation & purification; D009643:Norfloxacin / Q000302:isolation & purification*; D015242:Ofloxacin / Q000302:isolation & purification*; D010710:Phosphates / Q000302:isolation & purification; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012722:Sewage / Q000382:microbiology*
chemical_list: D010710:Phosphates; D012336:RNA, Ribosomal, 16S; D012722:Sewage; D002939:Ciprofloxacin; D015242:Ofloxacin; D009643:Norfloxacin; D009584:Nitrogen
keywords: Aerobic granular sludge; Fluoroquinolones; Microbial community; Nutrients removal