title: Role of ammonia-oxidizing bacteria in micropollutant removal from wastewater with aerobic granular sludge.
abstract: Nitrifying wastewater treatment plants (WWTPs) are more efficient than non-nitrifying WWTPs to remove several micropollutants such as pharmaceuticals and pesticides. This may be related to the activity of nitrifying organisms, such as ammonia-oxidizing bacteria (AOBs), which could possibly co-metabolically oxidize micropollutants with their ammonia monooxygenase (AMO). The role of AOBs in micropollutant removal was investigated with aerobic granular sludge (AGS), a promising technology for municipal WWTPs. Two identical laboratory-scale AGS sequencing batch reactors (AGS-SBRs) were operated with or without nitrification (inhibition of AMOs) to assess their potential for micropollutant removal. Of the 36 micropollutants studied at 1 μg l(-1) in synthetic wastewater, nine were over 80% removed, but 17 were eliminated by less than 20%. Five substances (bisphenol A, naproxen, irgarol, terbutryn and iohexol) were removed better in the reactor with nitrification, probably due to co-oxidation catalysed by AMOs. However, for the removal of all other micropollutants, AOBs did not seem to play a significant role. Many compounds were better removed in aerobic condition, suggesting that aerobic heterotrophic organisms were involved in the degradation. As the AGS-SBRs did not favour the growth of such organisms, their potential for micropollutant removal appeared to be lower than that of conventional nitrifying WWTPs.
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering (ENAC), Ecological Engineering Laboratory, Station 2, 1015 Lausanne, Switzerland E-mail: jonas.margot@epfl.ch; Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering (ENAC), Laboratory for Environmental Biotechnology, Station 6, 1015 Lausanne, Switzerland.
authors.forename: Jonas
authors.initials: J
authors.lastname: Margot
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering (ENAC), Laboratory for Environmental Biotechnology, Station 6, 1015 Lausanne, Switzerland; Present address: Laboratory of Microbial Ecology and Technology (LabMET), Ghent University (UGent), Coupure Links 653, 9000 Ghent, Belgium.
authors.forename: Samuel
authors.initials: S
authors.lastname: Lochmatter
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering (ENAC), Ecological Engineering Laboratory, Station 2, 1015 Lausanne, Switzerland E-mail: jonas.margot@epfl.ch.
authors.forename: D A
authors.initials: DA
authors.lastname: Barry
authors.affiliation: Ecole Polytechnique Fédérale de Lausanne (EPFL), School of Architecture, Civil and Environmental Engineering (ENAC), Laboratory for Environmental Biotechnology, Station 6, 1015 Lausanne, Switzerland.
authors.forename: Christof
authors.initials: C
authors.lastname: Holliger
mesh_terms: D000332:Aerobiosis; D000641:Ammonia / Q000378:metabolism; D001419:Bacteria / Q000378:metabolism*; D019149:Bioreactors; D058465:Nitrification; D010084:Oxidation-Reduction; D012722:Sewage / Q000737:chemistry*; D062065:Wastewater / Q000032:analysis*; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D000641:Ammonia; D012722:Sewage; D062065:Wastewater; D014874:Water Pollutants, Chemical