Velsicol / Hardeman County Landfill Superfund Site

The Velsicol Chemical Corporation Hardeman County Landfill Superfund Site is located on Old Toone Road north of Highway 100 in Toone, Tennessee. The Site is a former 24-acre landfill in which about 200,000 to 300,000 drums of pesticide manufacturing waste were disposed in trenches from 1964 to 1973. These wastes contained pesticides including dieldrin, endrin, hexachlorocyclopentadiene, heptachlor, heptachlor epoxide, and volatile organic compounds (VOCs) including carbon tetrachloride and chloroform.
EPA tasked KEMRON with the construction of a soil vapor extraction (SVE) remediation system for the 3-acre Middle Disposal Area (MDA) in accordance with an April 2015 Final Remedial Design Report. The major components of this construction work includes the following:

• Maintenance, refurbishment, and relocation of the Southern Disposal Area (SDA) SVE Treatment System to the MDA. System included condensate recovery, 1,200 scfm utility blower, heat exchanger, granular activated carbon treatment vessels, control panel, interconnection piping, gas analyzer, wireless remote monitoring station and system instrumentation.
• Drilling and installation of nine SVE well couplets to depths of 90 feet using rotosonic drilling techniques in Level B PPE.
• Drilling and installation of three vapor monitoring probe couplets to 90 feet using rotosonic drilling techniques in Level B PPE.
• Installation of 18 precision well heads with orifice plates and to adjust vacuum pressures and measurements of critical well parameters.
• Layout and welding of over 3,000 feet High Density Polyethylene Header (HDPE) transmission pipe to connect the SVE wells to the SVE Treatment System.
• Fabrication and installation of HDPE condensate traps along transmission pipeline.
• Start-up, operation and sampling of SVE treatment system.

KEMRON is also tasked with monthly monitoring and calibration on the 18 newly installed vertical extraction wells to assess effectiveness of vapor capture and balance the amount of vacuum applied to each extraction well. Routine inspection and maintenance to optimize operations. Monitoring of wireless remote monitoring system of critical system measurements such as gas flow, gas temperature and gas concentrations, vapor phase sampling and data collection to achieve a minimum 97% net reduction from baseline conditions of mean VOC soil gas concentrations with a three-year post shut-down rebound of less than 6% from baseline conditions.