In the past, two industrial sites (metal processing plant/laundry) in the city of Walldorf were subject to a considerable discharge of CFCs (tri-, tetrachloroethene) into the soil and subsequently into the groundwater. The CFCs that penetrated the subsoil led to the formation of a pollutant plume that is currently approx. 1,700 m long and approx. 200 m wide and extends over the Upper Aquifer and the Middle Aquifer.

Four remediation plants with currently 9 remediation wells are operated throughout the city of Walldorf. Depending on the remediation configuration, up to 150 m³/h of water is extracted and purified using activated carbon.

Remediation monitoring: Sampling and key date measurements at over 100 control levels, plant control, analysis, documentation of the remediation process, preparation of groundwater levelling plans

Regular remediation optimisations based on monitoring and investigation campaigns:

• Isotope content determinations
• Trace gas analysis
• Studies on mass transfer OGWL / MGWL
• Investigation of the biodegradation of the pollutants (incl. own laboratory tests)

Further procedure for the optimisation of GW extraction and the investigation of the interaction between OGWL and MGWL:

• Construction of deep wells
• Depth-horizontal power pumping tests
• Tracer trials
• Creation of a 3D groundwater model