title: Influence of humic acid addition on the degradation of pharmaceuticals by biofilms in effluent wastewater.
abstract: The degradation of organic micropollutants in wastewater treatment is suspected to depend on co-degradation i.e. be dependent on concentrations of substrate. This complicates predicting and modelling their fate. The effect of humic acid, as a model for complex organic substrate, was investigated in relation to the biodegradation of pharmaceuticals by suspended biofilm carriers adapted to polishing effluent water from a tertiary sewage treatment plant. Twelve out of 22 investigated pharmaceuticals were significantly biodegradable. The biodegradation rate constants of ten of those compounds were increasing with increased humic acid concentrations. At the highest humic acid concentration (30mgC/L), the biodegradation rate constants were four times higher than the biodegradation rate constants without added humic acid. This shows that the presence of complex substrate stimulates degradation via a co-metabolism-like mechanism and competitive inhibition does not occur. Increases of rate constant per mgC/L are tentatively calculated.
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet 115, 2800 Kgs., Lyngby, Denmark.
authors.forename: Kai
authors.initials: K
authors.lastname: Tang
authors.affiliation: Environmental Science, Århus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
authors.forename: Monica
authors.initials: M
authors.lastname: Escola Casas
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet 115, 2800 Kgs., Lyngby, Denmark.
authors.forename: Gordon T H
authors.initials: GTH
authors.lastname: Ooi
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet 115, 2800 Kgs., Lyngby, Denmark.
authors.forename: Kamilla M S
authors.initials: KMS
authors.lastname: Kaarsholm
authors.affiliation: Environmental Science, Århus University, Frederiksborgvej 399, 4000 Roskilde, Denmark.
authors.forename: Kai
authors.initials: K
authors.lastname: Bester
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Bygningstorvet 115, 2800 Kgs., Lyngby, Denmark. Electronic address: Henrik@ndersen.net.
authors.forename: Henrik R
authors.initials: HR
authors.lastname: Andersen
mesh_terms: D001673:Biodegradation, Environmental; D018441:Biofilms; D006812:Humic Substances; D004364:Pharmaceutical Preparations / Q000032:analysis / Q000378:metabolism*; D014865:Waste Disposal, Fluid / Q000379:methods; D062065:Wastewater / Q000032:analysis / Q000382:microbiology; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D006812:Humic Substances; D004364:Pharmaceutical Preparations; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Biodegradation; Co-metabolism; Dissolved organic carbon; Humic acid; Moving bed biofilm reactor