Water-Sediment Interactions: Column Design for Ammonium Adsorption-Desorption Experiments

Theresa Frommen1, Maike Gröschke2, Laura Krömer1, Gesche Grützmacher3, Andreas Winkler1, Michael Schneider1
1 FU Berlin
2 Kompetenzzentrum Wasser Berlin / FU Berlin
3 Kompetenzzentrum Wasser Berlin

P 6.13 in Grundwasser-, Boden- und Oberflächenwasser-Interaktionen



The fate and transport of ammonium during riverbank filtration at a study site in Delhi, India, is of significant importance due to the resulting pollution of drinking water production wells. In order to understand the behaviour of ammonium and to assess the future development of ammonium concentrations, column experiments were conducted with representative sediment samples from the floodplain aquifer in Delhi.

The experiments were conducted under oxic as well as under anoxic conditions, which prevail in the aquifer. In order to achieve conditions in the lab representative of the study site, the following set-up of the experiments was used: the model water was adjusted for the main ions in order to be comparable to the original groundwater. Anoxic conditions were established by using argon balloons to create an oxygen free atmosphere and by using glass or gas-tight tubes in order to inhibit gas exchange at the connections. The redox conditions were monitored with chemical optical oxygen sensor spots (PreSens) at six points during the entire duration of the experiments: in the model water vessel, at the inlet of the columns, at two points in the columns, at the outlet of the columns and in the sampling flasks. A peristaltic pump maintained a flow rate of ~0.17 ml/min. Measurements of pH and redox potential were conducted by connecting pH- and OPR-probes at the outlet of the columns.

This set up allows the procedure of column experiments in an oxygen free atmosphere. With the methods described above it is possible to control the redox conditions within the columns. This work contributes to the successful development of subsequent adsorption- desorption experiments.

Letzte Änderung 28.01.2014