Mobility and removal of nitrate in heterogeneous Eocene aquifers

n a study of the principles of lateral and vertical nitrate mobility and removal in unconfined heterogeneous fine sandy Eocene aquifers by long-term observation, no significant nitrate reduction could be observed over short distances (90 m) in the lateral flow direction. Decreasing oxygen contents and limited flow velocity in a downward direction (caused by clay lenses and layers) resulted in a more efficient but incomplete nitrate removal with increasing depth. Chemo-organotrophic and chemo-lithotrophic denitrification coexist in the aquifers. Recharge input of organic matter and the reactivity of sedimentary organic sources, as well as the amounts of pyrite and Fe2+-bearing minerals, control which microbiologically catalysed process finally occurs. Sharp boundaries between different redox zones do not exist due to locally changing availability of organic and inorganic electron donors used for nitrate reduction. Furthermore, preferential flow paths result in a wide spread occurrence of low concentrations of nitrate below the main denitrification zone

Mobility and removal of nitrate in heterogenous Eocene aquifers

In a study of the principles of lateral and vertical nitrate mobility and removal in unconfined heterogeneous fine sandy Eocene aquifers by long-term observation, no significant nitrate reduction could be observed over short distances (90 m) in the lateral flow direction. Decreasing oxygen contents and limited flow velocity in a downward direction (caused by clay lenses and layers) resulted in a more efficient but incomplete nitrate removal with increasing depth. Chemo-organotrophic and chemo-lithotrophic denitrification coexist in the aquifers. Recharge input of organic matter and the reactivity of sedimentary organic sources, as well as the amounts of pyrite and Fe2+-bearing minerals, control which microbiologically catalysed process finally occurs. Share boundaries between different redox zones do not exist due to locally changing availability of organic and inorganic electron donors used for nitrate reduction. Furthermore, preferential flow result in a wide spread occurrence of low concentrations of nitrate below the main denitrification zone

Supporting the Flemish groundwater policy with respect to nitrate pollution

The Laboratory for Applied Geology and Hydrogeology of Ghent University is executing a project commissioned by the Ministry of the Flemish Community, concerning the spread of nitrates in the groundwater of Flanders. The distribution of nitrate is studied as a function of the aquifer characteristics. The project will lead to the development of a nitrate specific model that will be used by the Ministry for policy development and as a management toot to calculate nitrate distribution in groundwater, starting from an input nitrate concentration at the water table. The results of the project will contribute to a better foundation for the definition of "nitrate-vulnerable zones" as a function of aquifer characteristics in general, and more specifically, advective transport velocity and nitrate reduction capacity