In order to prevent the spread of mercury or chrome 6 in the groundwater, we reduce and immobilise the metals in the soil.
  These processes can be performed biologically or chemically:
    - Biologically by reduction of      the soil matrix and sulphide formation.
   - Chemically by adding sulphide complexes      to the soil.
  
  In cooperation with Ghent Dredging, for OVAM in Belgium a pilot project was started to evaluate both techniques on a practical scale.