Construction of multi-layer geosynthetic containment systems to mitigate groundwater contamination

Abstract

This paper presents the construction of multi-layer geosynthetic containment systems as part of improvements to a stormwater management system to mitigate groundwater contamination at a coal combustion residual landfill in southeastern USA. The improvements consisted of lining the perimeter ditch and sedimentation pond to contain ash sediments and minimize infiltration into the groundwater. A composite liner comprised of HydroTurf synthetic turf system (i.e., a 1.5-mm thick high-density polyethylene (HDPE) textured geomembrane overlain by a synthetic turf that is covered with an infill/ballast material) underlain by a geosynthetic clay liner (GCL) was selected for the perimeter ditch. For the sedimentation pond, a 150-mm thick reinforced concrete layer underlain by a 1.5-mm thick HDPE textured geomembrane-GCL composite liner was selected to facilitate cleaning of the pond. The selection, construction, and lessons learned of the multi-layer geosynthetic containment systems are discussed.