TY  - JOUR
A1  - Munz, Matthias
A1  - Oswald, Sascha Eric
A1  - Schaefferling, Robin
A1  - Lensing, Hermann Josef
T1  - Temperature-dependent redox zonation, nitrate removal and attenuation of organic micropollutants during bank filtration
JF  - Water research
N2  - River bank filtration (RBF) is considered to efficiently remove nitrate and trace organic micropollutants (OMP) from polluted surface waters. This is essential for maintaining good groundwater quality and providing high quality drinking water. Predicting the fate of OMP during RBF is difficult as the biogeochemical factors controlling the removal efficiency are not fully understood. To determine in-situ removal efficiency and degradation rates of nitrate and OMP indicator substances we conducted a field study in a RBF system during a period of one and a half years incorporating temporally and spatially varying redox conditions and temperature changes typically occurring in temperate climates. RBF was analyzed by means of mixing ratios between infiltrated river water and groundwater as well as average residence times of surface water towards the individual groundwater observation wells. These results were used to calculate temperature dependent first order degradation rates of redox sensitive species and several OMP. Five out of ten investigated OMP were completely removed along RBF pathways. We demonstrate that degradation rates of several OMP during bank filtration were controlled by redox conditions and temperature whereby temperature itself also had a significant influence on the extent of the most reactive oxic zone. The seasonal variations in temperature alone could explain a considerable percentage of the variance in dissolved oxygen (34%), nitrate (81%) as well as the OMPs diclofenac (44%) and sulfamethoxazole (76%). Estimated in-situ degradation rates roughly varied within one order of magnitude for temperature changes between 5 degrees C and 20 degrees C. This study highlights that temporal variability in temperature and redox zonation is a significant factor for migration and degradation of nitrate and several OMPs. (C) 2019 Elsevier Ltd. All rights reserved.
KW  - Pharmaceuticals
KW  - In-situ degradation rates
KW  - Denitrification
KW  - River-groundwater-interaction
KW  - Urban water cycle
Y1  - 2019
U6  - https://doi.org/10.1016/j.watres.2019.06.041
SN  - 0043-1354
VL  - 162
SP  - 225
EP  - 235
PB  - Elsevier
CY  - Oxford
ER  -