Within the scope of the interdisciplinary NASRI research project (Natural and Artificial Systems for Recharge and Infiltration) dealing with river bank filtration processes at Berlin water works, a semi-technical column experiment is ongoing since January 2003 to simulate river bank filtration. Here a 30 m long ensemble of 6 soil columns is operated by surface water sampled from Lake Tegel (Berlin, Germany). In April 2004, oxic conditions in the column ensemble were forced to change in anoxic by gassing the flushing solution supply with nitrogen gas. The objective of reactive transport modelling was to (i) identify the main biogeochemical processes and the governing redox conditions within the soil column system during flushing as a conceptual model for river bank filtration and to (ii) verify the observed hydrochemistry of the pore water.