Thompson Engineering was selected as a subcontractor to perform third party construction quality control services for Mississippi Power’s Plant Watson Ash Pond Closure-In-Place (CIP).The project involved placement of earthen structural fill and ash fill, a perimeter road, storm drainage structures (42-inch HDPE discharge pipes and cast-in-place headwalls), AZ19 sheet piles, and the installation of a ClosureTurf® cover system for a 112-acre ash pond closure and a 26-acre coal storage area, more than 6-million square feet in total.
The cover system included 50-mil linear low-density polyethylene (LLDPE) Super Gripnet® geomembrane liners, engineered turf, sand ballast, and ArmorFill™ glue.
Thompson’s Construction Inspection and Materials Testing technicians performed inspection and testing of the fill materials (field density and moisture content). Our certified Geosynthetic Certification Institute (GCI) technicians inspected the installation of geomembrane liners and geocomposites; seaming operations (trial, fusion and extrusion welds); non-destructive (vacuum, air pressure, and spark tests), and destructive (peel and shear) testing; and the installation of the engineered turf and infill.
The installation of the final cover system for the landfill was constructed in accordance with the Mississippi Department of Environmental Quality (MDEQ) regulations for solid waste.