Thimm, K., O. Syllwasschy, H. Lassnig, and S. Westhus.
NORDROCS 2018: 7th Joint Nordic Meeting on Remediation of Contaminated Sites, 28 slides, 2018

The K20 contaminated site, a former industrial landfill (1926-1981), is situated in the lower part of the Gurktal valley in Austria. The landfill is separated into two sections that contain calcium carbide, chlorinated hydrocarbons (CHCs), and mercury-contaminated wastes. The CHCs are mainly PCE, TCE, hexachlorobutadiene, hexachloroethane, and hexachlorobenzene. In 2009, a notice was issued to remediate the high-priority site through the complete removal of all waste material for reuse, treatment, or disposal; however, clearance of the site was discontinued when significant hexachlorobenzene contamination was detected in 2014. Securing the material on site was determined the next best option. To prevent emissions from the remaining materials, new physical safeguard measures were installed: an innovative, multifunctional surface-sealing system consisting of an 11 kg/m² calcium bentonite geosynthetic clay liner; an active geo-composite mat with 2 kg/m² activated carbon; an LDPE membrane with integrated aluminum layer; and a drainage element. This system is a strong barrier for volatile CHCs. The activated carbon mat was installed below the membrane to reduce CHC concentrations at the interface of the membrane and thereby reduce the driving force for diffusion. Soil vapor extraction pipes installed below and above the sealing system allow for both treatment and continuous monitoring. For long-term stability of the whole sealing system, two layers of geogrids were installed to provide adequate stability against slip parallel to the slope. https://www.intersol.fr/download/28032018/download.php?f=Intersol_2018_6-Kristof_Thimm_Huesker.pdf