Clean-up of a chemical dry cleaning facility
One of Sweden's most publicised soil remediation projects has been underway in Värnamo since 2011. The complex project is carried out by RGS Nordic and requires a number of new techniques.
The subsoil in Värnamo was heavily polluted with perchlorethylene (PCE) from the Värnamotvätten company, which ran a chemical dry cleaning facility there from 1938 to 1989. The pollution covered an area of 1200 m2, and extended deep into the subsoil.
RGS Nordic was commissioned to handle the remediation project, which was launched in 2011 after several years of initial studies. The task was complex due to difficult geological conditions in the area, and it was urgent because PCE was found in one of the nearby aquifers that supply the city’s residents with drinking water.
The first part of the project was launched in 2011 with multi-phase extraction (MPE) across the entire contaminated zone at a depth ranging from approx. 2 to 10 metres. Feasibility studies estimated a total amount of pollution around 800 kg, but 850 kg was removed during the MPE work alone, and control measurements showed that a large amount of pollution remained underground.
New techniques implemented
After three years of MPE, we could take the next step. In the saturated zone, at a depth of 8-14 metres, we injected HRC Primer, HRC and HRC-X – for the first time in Sweden. HRC stimulates reductive dechlorination using natural microorganisms, and the combination of the three HRC products gave us an active clean-up time of up to five years.
The HRC products were introduced into the subsoil via direct injection. Again, we had to develop new methods, as it was not possible to carry out the traditional vertical drilling close to a steep and unstable slope. We chose to use directional drilling – a first in Europe.
Excellent results - and it gets even better
After two years of control measurements, we could see that dechlorination had reached 50%. The tests also showed that the favourable environment for reductive dechlorination remained, so the degradation process could continue.
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With our experience from Värnamo and other complex remediation tasks, we are among the most competent pollution fighters in Scandinavia. We are ready to offer a non-binding proposal of how your challenge can be solved in the best possible way.