Soil vapor extraction (SVE) and in situ chemical oxidation (ISCO) for treatment of chlorinated solvents.
AKT Peerless provided environmental remediation services for an industrial facility that experienced a release of chlorinated solvents. The scope of work included a feasibility analysis of four proposed remediation options. Soil vapor extraction (SVE) in combination with in situ chemical oxidation (ISCO) was chosen as the remediation option. Pilot-scale testing to evaluate the feasibility and determine optimal full-scale design parameters was completed before system installation. A full-scale SVE system was designed to treat approximately 240,000 cubic feet of soil. The system included four independently controlled treatment zones with multiple manifolds that can work independently of each other, in some combination with others, or all at once. This control will allow treatment to be focused on one specific area of the plume as necessary or to be applied across the entire plume at once, as dictated by pressure readings, sampling results, soil, and/or groundwater conditions.
ISCO using permanganate injection (the second of two remediation technologies for this facility) is a very effective groundwater remediation technology for the treatment of common chlorinated solvents such as tetrachloroethylene (PCE) and trichloroethylene (TCE). The key benefit of ISCO technology is that it provides significantly enhanced destruction of target contaminants (complete mineralization to carbon dioxide and water is the desired endpoint of an ISCO process) within a relatively short period of time (i.e., months) by comparison with standard pump & treat approaches that require years or even decades to restore groundwater quality. A key benefit of the ISCO approach is that it can accelerate the dissolution of dense non-aqueous phase liquids (DNAPLs) by order(s) of magnitude, which is expected to reduce the time and cost for source remediation by a comparable factor.
Once the contaminant concentration in the extracted soil vapor declines to a near steady-state, chemical injection will be used to treat the groundwater beneath the source area. The goal of this process is to reduce the mass of contamination in the source area, control leaching from the source area, and allow the downgradient groundwater plume to diminish over time.
AKT Peerless’ Feasibility Study and Pilot Tests ensured effective remediation technologies were selected for addressing the chlorinated solvents issues. Following the Pilot Tests, AKT Peerless designed the remediation systems, completed construction oversight and currently conducts operations and maintenance.
AKT Peerless’ maintenance activities for this project include performing routine site and equipment inspections, sampling activities, and reporting documentation. Sampling events to monitor the effectiveness of the SVE systems are required and used to evaluate the concentration of contaminants extracted and the useful remaining life of the carbon columns in order to facilitate carbon change out.
AKT Peerless completed a feasibility analysis, pilot tests, design of the remediation systems, construction oversight and currently conducts operations and maintenance. The SVE systems are expected to operate for 2-4 years for the SVE system. Quarterly groundwater monitoring will continue to be conducted during SVE system operations and for a period of time after (to be coordinated with EGLE). ISCO Injection (two applications) will take place once soil vapor concentrations decline to a relatively steady state.
