Hydrodynamic or hydrochemical aspects of anthropogenic and naturally induced bank filtration - examples from Berlin/Brandenburg

摘要

Bank filtration is the natural or anthropogenically induced process of surface water infiltration into an aquifer. It is of particular importance as a method to gain or pre-treat water for drinking water production. The hydrodynamic and hydrochemical processes during bank filtration were investigated at one rural site in the Oderbruch and at two urban sites in Berlin (Germany). Results show that these sites differ substantially with regard to the characteristics of the hyporheic zone (permeable versus clogged), travel times (decades versus months to decades) and shape of the redox zones (horizontal versus vertical redox succession). The hyporheic zone is a key parameter determining the site characteristics. Since the surface water in Berlin contains a proportion of treated sewage, a number of wastewater-bound substances (e. g. pharmaceutical residues) have been detected in the surface water. Most of them were, however, fully or partly removed during bank filtration. The redox conditions are an important key parameter with regard to the elimination (or persistence) of a number of organic trace compounds (e. g. phenazone, sulfamethoxazole, clindamycin), whose elimination depends on the prevailing redox environment.