title: Biodegradation of pharmaceuticals in hospital wastewater by a hybrid biofilm and activated sludge system (Hybas).
abstract: Hospital wastewater contributes a significant input of pharmaceuticals into municipal wastewater. The combination of suspended activated sludge and biofilm processes, as stand-alone or as hybrid process (hybrid biofilm and activated sludge system (Hybas™)) has been suggested as a possible solution for hospital wastewater treatment. To investigate the potential of such a hybrid system for the removal of pharmaceuticals in hospital wastewater a pilot plant consisting of a series of one activated sludge reactor, two Hybas™ reactors and one moving bed biofilm reactor (MBBR) has been established and adapted during 10 months of continuous operation. After this adaption phase batch and continuous experiments were performed for the determination of degradation of pharmaceuticals. Removal of organic matter and nitrification mainly occurred in the first reactor. Most pharmaceuticals were removed significantly. The removal of pharmaceuticals (including X-ray contrast media, β-blockers, analgesics and antibiotics) was fitted to a single first-order kinetics degradation function, giving degradation rate constants from 0 to 1.49 h(-1), from 0 to 7.78 × 10(-1)h(-1), from 0 to 7.86 × 10(-1)h(-1) and from 0 to 1.07 × 10(-1)h(-1) for first, second, third and fourth reactors respectively. Generally, the highest removal rate constants were found in the first and third reactors while the lowest were found in the second one. When the removal rate constants were normalized to biomass amount, the last reactor (biofilm only) appeared to have the most effective biomass in respect to removing pharmaceuticals. In the batch experiment, out of 26 compounds, 16 were assessed to degrade more than 20% of the respective pharmaceutical within the Hybas™ train. In the continuous flow experiments, the measured removals were similar to those estimated from the batch experiments, but the concentrations of a few pharmaceuticals appeared to increase during the first treatment step. Such increase could be attributed to de-conjugation or formation from other metabolites.
authors.affiliation: Environmental Science, Aarhus University, Frederiksborgsvej 399, 4000 Roskilde, Denmark.
authors.forename: Mònica
authors.initials: M
authors.lastname: Escolà Casas
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby, Denmark.
authors.forename: Ravi Kumar
authors.initials: RK
authors.lastname: Chhetri
authors.affiliation: Environmental Science, Aarhus University, Frederiksborgsvej 399, 4000 Roskilde, Denmark.
authors.forename: Gordon
authors.initials: G
authors.lastname: Ooi
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby, Denmark.
authors.forename: Kamilla M S
authors.initials: KMS
authors.lastname: Hansen
authors.affiliation: Department of Chemistry and Biotechnology, Danish Technological Institute, Kongsvang Allé 29, 8000 Aarhus C, Denmark.
authors.forename: Klaus
authors.initials: K
authors.lastname: Litty
authors.affiliation: AnoxKaldnes, Klosterängsvägen 11A, 226 47 Lund, Sweden.
authors.forename: Magnus
authors.initials: M
authors.lastname: Christensson
authors.affiliation: Department of Chemistry and Biotechnology, Danish Technological Institute, Kongsvang Allé 29, 8000 Aarhus C, Denmark.
authors.forename: Caroline
authors.initials: C
authors.lastname: Kragelund
authors.affiliation: Department of Environmental Engineering, Technical University of Denmark, Miljøvej 113, 2800 Kgs. Lyngby, Denmark.
authors.forename: Henrik R
authors.initials: HR
authors.lastname: Andersen
authors.affiliation: Environmental Science, Aarhus University, Frederiksborgsvej 399, 4000 Roskilde, Denmark. Electronic address: kb@envs.au.dk.
authors.forename: Kai
authors.initials: K
authors.lastname: Bester
mesh_terms: D001673:Biodegradation, Environmental; D018441:Biofilms / Q000254:growth & development; D006761:Hospitals; D004364:Pharmaceutical Preparations / Q000032:analysis*; D014865:Waste Disposal, Fluid / Q000379:methods*; D062065:Wastewater / Q000737:chemistry / Q000382:microbiology*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D004364:Pharmaceutical Preparations; D062065:Wastewater; D014874:Water Pollutants, Chemical
keywords: Hospital wastewater; MBBR; Pharmaceuticals; Removal rate constants; X-ray contrast media