Soilremediation by “Enhanced Vapour Extraction”

The contaminants, mainly volatile halogenated hydrocarbons (VHHC) and volatile aromatic hydrocarbons (BTEX), were found in the unsaturated zone of the sandstone layer and in the seeping water. Since 1991 a remediation system was in operation, using standard methods of soil vapour extraction and pump and treat technique. In the beginning these methods had been quite efficient. But during the further progress of the remediation, the amount of extracted pollutants declined. The hydraulic remediation is limited because there are only small amounts of water to be pumped off. To reinforce the remediation, CEA GmbH developed the alternate system of “Enhanced Vapour Extraction”(EVE). This method corresponds to the common soil vapour extraction but it’s combined with an injection of air.