Groundwater remediation - Stierli site, Zurich-Seebach

Groundwater remediation of chlorinated solvents using anaerobic dechlorination

The subsoil of this industrial site contains highly-chlorinated hydrocarbons (tetrachloroethene) contamination. The pollutants extend all the way down into the groundwater-saturated zone (8-17 m and deeper). Due to the depth of the contamination, it was decided that it would be preferable to use in-situ remediation.

Taking the site characteristics into account, the final choice was anaerobic dechlorination. A co-substrate (in this case molasses) was injected as a carbon source via injection wells. This made the anaerobic dechlorination of the tetrachloroethene possible.

The measure was monitored via groundwater sampling throughout. The groundwater-saturated zone was successfully remediated. The unsaturated substrate at a depth between 0-8 m and deeper will be remediated by excavation as part of a construction project.

Ecosens AG conducted a preliminary and detailed investigation into the contaminated site before planning a remediation project and carrying out a pilot test. During the remediation phase, Ecosens AG coordinated all third-party services (remediation company, drilling company, laboratory, etc.) and is responsible for the evaluation of the data, continuous changes to the remediation procedure and the presentation of the data to the customer and the authorities (AWEL).


Your contact person:

Corinne Blum

Deputy Departmental Manager for Contaminated Sites and Construction Sites