Mississippi Dept. of Environmental Quality (MDEQ), 20 pp, 2018

A 24- to 48-hr pilot test of a high-vacuum dual-phase extraction (HVDPE) system is proposed for chlorinated VOCs (CVOCs) found in the southern portion of the former Holley Automotive/Coltec Industries facility. HVDPE is a process that volatilizes sorbed-phase VOCs and removes those compounds from the unsaturated zone while removing liquid-phase contaminants from the underlying aquifer. The specific objectives of the HVDPE pilot test are to demonstrate the ability of HVDPE to facilitate removal of DNAPL (if present) and associated contaminated groundwater, depress the groundwater table, evaporate CVOCs from the dewatered soil matrix, and capture and treat CVOC vapors from the induced vadose zone while extracting contaminated groundwater for ex situ treatment. The project will also identify preliminary site-specific design criteria necessary to implement and operate an effective full-scale HVDPE system. https://www.mdeq.ms.gov/wp-content/uploads/2018/09/2018_04_06_HVDPE-Pilot-Test-Workplan.pdf To further address the plume migrating off the Plant site, in situ chemical reduction (ISCR) injection is proposed for the Plant's northwestern parking lot as part of the site remediation systems. The ISCR workplan details the construction of a reactive curtain (RC) utilizing EHC® and EHC+® reagents in a closely spaced (<15-ft) interval in three lines separated by 15-ft intervals. The total length of the curtain will be ~300 ft. The surface of a dense clay layer varies from about 30 to 40 ft bgs; the overlying sand unit is ~15 ft in thickness. The RC will be screened in the overlying sand unit. Direct-push drilling will be utilized to inject the reagents to the required depth. ISCR workplan: https://www.mdeq.ms.gov/wp-content/uploads/2018/09/2017-12-22-ISCR-Workplan-for-the-Northwest-Parking-Lot.pdf