Case Study: In Situ Thermal Remediation at Martinsville Landfill
The Martinsville Sanitary Landfill is a closed, unlined, municipal solid waste facility owned and maintained by the City of Martinsville, Virginia.
Starting in the early 1970s and into the early 1980s, there were two solvent pits located upgradient of the landfill which were designated for disposal of liquid chemical wastes, primarily used paints, varnishes, and solvents produced by the local furniture and textile industries. These were unlined open pits into which the local industries would dump their used chemicals, usually several drums at a time. Periodically, the landfill staff would set fire to the liquids in the pits and let them burn.
A plume of groundwater contamination containing numerous VOCs extends under the landfill from the two solvent pits. The facility has been under a groundwater Corrective Action Program involving monitored natural attenuation (MNA) since 2005; however, the soil contamination in the solvent pits was a continuing source feeding the groundwater plume, so the contaminant concentrations were not generally decreasing as hoped and some were increasing over time.
In 2016, at the request of the Virginia Department of Environmental Quality (VDEQ), LaBella Associates conducted further assessment of the solvent pits and investigated remedial alternatives. Soil sampling found total volatile organic compounds (VOCs) as high as 12,675 mg/kg (parts per million) and indicated that there were over 105 tons of VOCs in the soil within the two solvent pits.
LaBella evaluated several potential remedial technologies for the solvent pits for applicability, effectiveness, time required, and cost. The evaluated technologies included:
Excavation and ex situ incineration in an on-site soil burner;
Enhanced bioremediation using injection of chemicals to accelerate natural biodegradation of the contaminants by bacteria in the soil;
Air sparging and soil vapor extraction; and
In situ thermal desorption (ISTD).
LaBella concluded that ISTD would be the most appropriate technology for this site based on the site geology, the size and depth of the pits, and the types and concentrations of contaminants. ISTD was expected to be the fastest as well as the most cost-effective way to remediate the solvent pit soils.
Check out the video to learn more about how LaBella’s team used in situ thermal desorption (ISTD) to remove 116 tons of volatile organic compounds from the soil at the Martinsville, Virginia landfill.