Coal Combustion Residuals – Landfill Siting, Engineering, and Permitting for Coal Combustion By-Products Landfill, Pelzer, South Carolina

Duke Energy’s Lee Steam Station is a 400-MW coal-fired power generation facility. SCS Engineers was retained to permit and design a new landfill for the disposal of coal combustion by-products.

SCS Engineers Coal Combustion Residuals
Lee Steam Station

SCS completed preliminary hydrogeological and geotechnical investigations, and then prepared the landfill design, permit application report and construction plans and specifications. SCS also completed a quality-assurance plan for the landfill.

Geotechnical Investigation

The landfill was designed over a closed 18-acre, 35-foot deep retired ash basin. Because of the complexities of constructing a new landfill atop the retired ash basin, SCS conducted a geotechnical evaluation to establish engineering properties of the underlying ash and the perimeter berm.

Our investigation included the following:

  • 18 soil borings (10 along the berm and 8 inside the retired ash basin)
  • Cone penetrometer (CPT) and dilatometer (DMT) tests
  • Field Vane Shear tests
  • Settlement estimates and slope stability analysis
  • Laboratory testing

SCS used the data to determine the anticipated settlement of the new landfill’s base lining system, and the overall slope stability of the developed landfill.

Hydrogeological Investigation. SCS installed eighteen 2-inch piezometers and conducted a hydrogeologic evaluation of the project area to determine the geologic units, depth to groundwater, and direction and rate of groundwater flow.

SCS concluded that the retired ash basin was suitable to site, permit, and design a new Class 3 lined landfill, subject to additional analysis for foundation stability.

Landfill Siting Study. SCS prepared a Landfill Siting Study (LSS) following the guidelines of Regulation 61-107.08 for submission to the South Carolina Department of Health and Environmental Control. The LSS addressed siting restrictions, buffers, and zoning approval, and included the Site Hydrogeological Characterization Report.

Landfill Design and Permit Application. SCS prepared the design and permit application for the landfill, which included the following:

  • Engineering Drawings and Plans
  • Engineering Report
  • Geotechnical Evaluation of the Landfill Embankment and Foundation
  • Operations Plan
  • Groundwater Monitoring Plan
  • Closure Plan
  • Post-Closure Plan
  • Construction Quality Assurance Plan