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Geophysics in sand filters

3D mapping of ochre in sand filters (3D-FIL)

In Denmark and several other countries, drinking water originates from groundwater treated in open sand filters. For optimal performance, the open sand filters must be backwashed periodically to prevent clogging. However, often the waterworks has insufficient knowledge about the performance of the backwash processes. In this project, a geophysical method based on DC/IP principles is being developed for continuous geoelectrical measurements on the upper 30 cm of the open filter, where clogging occurs mainly due to iron oxidation. Based on the geophysical measurements it is possible to optimise the backwash process with respect to frequency and duration, and thus increase the lifetime of the filters, save water and energy at the waterworks and ensure higher drinking water quality.

The collaboration partners are VIA University College Horsens, Niras and Lemvig Vand og Spildevand, whom provide access to one of their active filters.

  • ERT/IP
  • ABEM Terrameter LS
  • Remote control unit
  • Custom electrodes
  • Lemvig Vand og Spildevand
  • VIA University College Horsens
  • Niras
  • HGG, Department of Geoscience, Aarhus University