CCR Surface Impoundment Closure & Site Restoration

This project involved retiring a 2,250-megawatt (MW) 3-unit coal-fired power plant, which included the decommissioning and demolition of power-generating structures such as the Power Block and Catenary Railroad System. It also entailed the consolidation and closure of salt ponds, the closure of Solid Waste and Coal Combustion Residual (CCR) Landfills, and the restoration of over 670 acres of the site.
 
Forgen was awarded two major contracts: CWP-05 CCR Landfill Closure and CWP-06 Salt Consolidation, Pond Closure, and Site Restoration.

The project began in August 2021, with a completion target set for 2023. Forgen started salt pond consolidation and closure in September 2021, following site setup and mass dewatering of multiple salt ponds. After dewatering each pond, we excavated and transported approximately 850,000 cubic yards of salts, liners, and selenium-impacted soils to the CCR Landfill.

We also removed existing sumps, pipes, utilities, and embankment soils from the ponds, placing them in the CCR Landfill. At pond 35-5, we removed the borrow soil stockpile, imported around 1 million cubic yards of fill, and graded the pond, coal yard, and power block areas. For the Solid Waste Landfill closure, we installed over 400,000 square feet of HDPE liner and about 35,000 cubic yards of cover soils, supplemented by an erosion control blanket, hydromulch, and specified seed mix.

We excavated borrow areas within the project limits to maintain positive drainage away from their entrances. Before excavation, we installed erosion and storm control measures to prevent stormwater entry and manage accumulated stormwater. We graded the borrow areas to eliminate sudden grade changes such as depressions and furrows.

After installing stormwater controls and haul road entrances/exits, we used a PC 1250 Excavator and a CAT 800 Excavator to load approximately 15 total haul trucks that consisted of 777 haul trucks, 775 haul trucks, and 740 haul trucks. These trucks transported and placed around 1 million cubic yards of borrow material, which we used to finish the former salt ponds area and cover the CCR Landfill’s 60-mil HDPE liner.

We managed dust control and soil conditioning with four 8,000-gallon water trucks. All borrow materials were tested and approved according to project specifications before placement.

We began CCR landfill activities in October 2021 and conducted them concurrently with pond closure activities until their completion. These activities were completed in October 2023. We excavated the stormwater management/sediment control ponds and placed and graded 1.4 million cubic yards of subgrade soil.

We, along with our subcontractors, installed over 23.5 million square feet of geomembrane and geocomposite liners, including a bentonite seal layer against the native sandstone and rip rap runoff dissipation aprons, over the CCR Landfill. Concurrently, we placed 900,000 cubic yards of protective cover and constructed landfill runoff management channels and bench toe drains, including check dams in upper landfill channels. Final activities included permanent stabilization, revegetation using a drill seed method, and the removal of all temporary erosion controls.

The project met all regulatory requirements and project specifications, resulting in the safe retirement of the power plant, effective environmental remediation, and restoration of over 670 acres of the site. Forgen’s expertise in managing complex environmental projects, commitment to regulatory compliance, and dedication to community safety and environmental stewardship were key factors in the project’s success.