Modelling Assessment of an in situ Oxygen Sparging Remediation of an Ammonium Contamination - Pilot Plant BIOXWAND Berlin

Abstract

Reactive transport modelling is demonstrated by assessing the remediation of an Ammonium contamination plume originating from sewage field management over decades and situated close to the Friedrichshagen water works in Berlin. As remediation method, an in situ nitrification of the aquifer by injection of Oxygen gas and Air close to the production wells will be performed. In order to assess the kernel process itself (the nitrification), but also its impact on the hydrochemical composition of the raw water to be pumped from water works production wells, reactive transport modelling was performed. First, principal aspects of the coupling of hydrodynamic transport and reactive software tools are presented. In order to assess the remediation by in situ nitrificaton a site and problem adapted reaction network has to be deduced, followed by the mathematical formulation and by the incorporation of reactive terms into a reactive transport solver. Two model versions result from these steps: (1) a generic regional model set up to evaluate the long-term reaction zoning to expect due to permanent Oxygen gas injection, and (2) a verification of the monitored hydrochemistry during a first field test to estimate reaction parameters for further field tests planned in future closely to the well fields.