Reduced nitrate degradation in groundwater and its consequences – model-based assessment

In many water catchment areas, degredation processes in aquifers used for water management ensure a reduction in nitrate pollution. The reaction capacity of aquifers is mainly linked to organic carbon compounds and pyrite. The latter is particularly favoured for denitrification. However, pyrite is a finite resource that is depleted by continuous nitrate inputs. In principle, this leads to the advance of reaction fronts in the aquifer and potentially also to increasing concentrations in the managed groundwater. Model calculations are used to illustrate various dispersion mechanisms and the decisive role of pyrite in regard to the amount of nitrate in the groundwater.