title: The effect of redox conditions and adaptation time on organic micropollutant removal during river bank filtration: A laboratory-scale column study.
abstract: This study investigated the redox dependent removal and adaptive behaviour of a mixture of 15 organic micropollutants (OMPs) in laboratory-scale soil columns fed with river water. Three separate pilot systems were used consisting of: (1) two columns, (2) ten columns and (3) twenty two columns to create oxic, suboxic (partial nitrate removal) and anoxic (complete nitrate removal). The pilot set-up has some unique features--it can simulate fairly long residence times (e.g., 45 days using the 22 column system) and reduced conditions developed naturally within the system. Dimethoate, diuron, and metoprolol showed redox dependent removal behaviour with higher biodegradation rates in the oxic zone compared to the suboxic/anoxic zone. The redox dependent behaviour of these three OMPs could not be explained based on their physico-chemical properties (hydrophobicity, charge and molecular weight) or functional groups present in the molecular structure. OMPs that showed persistent behaviour in the oxic zone (atrazine, carbamazepine, hydrochlorothiazide and simazine) were also not removed under more reduced conditions. Adaptive behaviour was observed for five OMPs: dimethoate, chloridazon, lincomycin, sulfamethoxazole and phenazone. However, the adaptive behaviour could not be explained by the physico-chemical properties (hydrophobicity, charge and molecular weight) investigated in this study and only rough trends were observed with specific functional groups (e.g. ethers, sulphur, primary and secondary amines). Finally, the adaptive behaviour of OMPs was found to be an important factor that should be incorporated in predictive models for OMP removal during river bank filtration.
authors.affiliation: Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Water Management, PO Box 5048, 2600 GA, Delft, The Netherlands; Ghent University, Faculty of Bioscience Engineering, Particle and Interfacial Technology Group, Coupure Links 653, B-9000 Ghent, Belgium. Electronic address: c.bertelkamp@tudelft.nl.
authors.forename: C
authors.initials: C
authors.lastname: Bertelkamp
authors.affiliation: Ghent University, Faculty of Bioscience Engineering, Particle and Interfacial Technology Group, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: A R D
authors.initials: AR
authors.lastname: Verliefde
authors.affiliation: Ghent University, Faculty of Bioscience Engineering, Particle and Interfacial Technology Group, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: K
authors.initials: K
authors.lastname: Schoutteten
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: L
authors.initials: L
authors.lastname: Vanhaecke
authors.affiliation: Ghent University, Faculty of Veterinary Medicine, Department of Veterinary Public Health and Food Safety, Laboratory of Chemical Analysis, Salisburylaan 133, B-9820 Merelbeke, Belgium.
authors.forename: J
authors.initials: J
authors.lastname: Vanden Bussche
authors.affiliation: The University of Auckland, Department of Civil and Environmental Engineering, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: N
authors.initials: N
authors.lastname: Singhal
authors.affiliation: Delft University of Technology, Faculty of Civil Engineering and Geosciences, Department of Water Management, PO Box 5048, 2600 GA, Delft, The Netherlands; Strategic Centre, Waternet, Korte Ouderkerkerdijk 7, 1096 AC, Amsterdam, The Netherlands.
authors.forename: J P
authors.initials: JP
authors.lastname: van der Hoek
mesh_terms: D001673:Biodegradation, Environmental; D005374:Filtration; D008956:Models, Chemical; D010084:Oxidation-Reduction; D045483:Rivers / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D014874:Water Pollutants, Chemical
keywords: Adaptation; Biodegradation; Organic micropollutants; Redox; River bank filtration