South Carolina’s Greenwood County Landfill accepts construction, demolition, and land-clearing debris and operates in accordance with South Carolina Department of Health and Environmental Control (SCDHEC) standards. Schnabel performs a variety of services at the landfill, including routine groundwater, surface water, and landfill gas monitoring, statistical analysis, and reporting in compliance with regulations.

Groundwater protection standards were exceeded for tetrachloroethene, trichloroethene, methylene chloride, benzene, and vinyl chloride. Using direct-push technology and a mobile gas chromatograph, we conducted a nature and extent study. Additional studies indicated landfill gas was contributing compounds to the groundwater. An assessment of corrective measures study evaluated pump and treat, slurry walls, permeable reactive barriers, landfill gas (LFG) vapor extraction, air sparging, and monitored natural attenuation has potential remedial alternatives.

Aquifer performance and treatability studies were also conducted. Results suggested that the preferred remedy included landfill gas extraction and monitored natural attenuation (MNA). A passive LFG extraction system was installed first and monitored for improvement in the groundwater quality. Improvement was observed and the passive system was upgraded to an active landfill gas to energy project. Active landfill gas recovery has improved the groundwater quality, and the South Carolina Department of Health and Environmental Control has approved MNA and active landfill gas recovery as the preferred groundwater remedial action.

We also perform landfill gas testing service in response to Greenwood’s Title V air permit for the landfill gas recovery system. Landfill gas monitoring includes monitoring of methane monitoring probes to evaluate system effectiveness, greenhouse gas emissions monitoring, site-specific non-methane organic compound (NMOC) testing, landfill gas emissions modeling (LandGEM), Title V annual compliance certifications, annual point source data reporting, and waste analysis condition evaluation of the landfill gas stream.