Site Demonstration of Terra-Kleen Response Group's Mobile Solvent Extraction Process

Area of Science:

• Environmental Engineering
• Chemical Engineering
• Soil Remediation Technologies

Background:

• Soil contamination by persistent organic pollutants poses significant environmental and health risks.
• The U.S. Environmental Protection Agency's Superfund Innovative Technology Evaluation (SITE) Program seeks to advance effective remediation solutions.
• Polychlorinated biphenyls (PCBs) and pesticides are common, hazardous soil contaminants requiring efficient removal methods.

Purpose of the Study:

• To evaluate the efficacy of a pilot-scale solvent extraction process developed by Terra-Kleen Response Group (TKRG) for removing organic contaminants from soil.
• To assess the performance of the TKRG solvent extraction technology under field conditions at a contaminated site.
• To determine removal efficiencies for specific organic pollutants, including PCBs and pesticides.

Main Methods:

• Pilot-scale solvent extraction using a proprietary solvent mixture to treat PCB-contaminated soil.
• Homogenization of five tons of soil and processing through five extraction vessels with eleven cycles.
• Full-scale solvent extraction of pesticide-contaminated soil using 19 extractors, each 20 cubic yards, over three cycles.

Main Results:

• Pilot-scale treatment achieved 98.8% removal of PCBs from soil, reducing concentrations from 144 mg/kg to 1.71 mg/kg.
• Hexachlorodibenzofurans (HxCDFs) were reduced to non-detectable levels (<0.117 fxg/kg) after treatment.
• Full-scale treatment removed over 99% of pesticides, achieving residual concentrations below 0.093 mg/kg.

Conclusions:

• The TKRG solvent extraction process is highly effective for removing organic contaminants, including PCBs and pesticides, from contaminated soils.
• The technology demonstrates significant potential for large-scale environmental remediation applications.
• Further optimization may be needed for efficient removal of specific contaminants like Oil and Grease (O&G), where efficiencies were lower (65.9%).