AIKEN, S.C. – EM and the Savannah River Site (SRS) management and operations contractor saved nearly $9 million after consolidating more than 430,000 cubic yards of coal ash and associated soil that workers had excavated from 90 acres of land.
Crews completed the work more than a year ahead of schedule, resulting in two huge mounds of ash and soil, each with a water-shielding, protective cover in place.
The majority of the cost savings resulted from use of a low-cost, highly effective geosynthetic material for the mound covers. The same subcontractor was used for both project phases, which meant lower costs to mobilize and demobilize the work sites. The project's early finish also greatly reduced the project cost.
"Without visiting the remediated site, it's hard to grasp just how big of a project this was," DOE-Savannah River Federal Project Director Karen Adams said. "Working closely with DOE and their primary subcontractor, Savannah River Nuclear Solutions (SRNS) has taken what originally appeared to be several large ponds connected by marsh-like areas, and converted it all into grass-covered fields, eliminating environmental hazards from the ash. The contrast between the before-and-after photos is impressive."
Crews cleaned up basins used to manage ashes from the D-Area Powerhouse, which provided steam and electricity for SRS missions for more than 59 years. SRS shut down the powerhouse in 2012 and launched an innovative technology that burns forest debris, agricultural waste, and scrap lumber to generate steam and power.
Workers met the goal to safely and cost effectively protect the environment, including the nearby Savannah River, according to SRNS Project Manager Susan Bell.
"We were pursuing performance excellence and timely completion with this multi-year project, and those goals were not just met, but exceeded," Bell said.
In the five-year project’s first phase, crews consolidated over 130,000 cubic yards of ash and impacted soil into an existing 21-acre ash landfill adjacent to the excavation site, forming the first of two protected areas. SRNS received an award from the Project Management Institute for its work in this phase.
In the second phase, workers combined almost 300,000 cubic yards of ash, coal fines, and associated soil from two basins and adjacent wetlands into a second protected area. Like the landfill, it was capped with the geosynthetic material and a thick earthen cover consisting of fill dirt and grass-covered topsoil.
“The geosynthetic, polyethylene-based system used ensures rainwater runs off, eliminating erosion and the possible migration of contaminants to the groundwater,” said Bell.
Approximately 1.8 million square feet of geosynthetic material, covering approximately 20 acres, was installed over the second area.
“The key is layers of protection,” Bell added. “Each layer has its own purpose, all working together.”
The work was challenging from the start due to the removal of about 80 million gallons of water from the original basins before excavation could begin, Bell noted.
The project resulted from a closure strategy approved by federal and state environmental regulatory agencies, DOE-Savannah River, and SRNS.