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FIELD EVALUATION OF THE TREATMENT OF DNAPL USING EMULSIFIED ZERO-VALENT IRON (DNAPL CONFERENCE)
Citation:
WATLING, M., S. O'HARA, '. KRUG, J. QUINN, N. RUIZ, C. SU, AND R. PULS. FIELD EVALUATION OF THE TREATMENT OF DNAPL USING EMULSIFIED ZERO-VALENT IRON (DNAPL CONFERENCE). Presented at Second International Conference of DNAPL Characterization and Remediation, Niagra Falls, NY, September 24 - 27, 2007.
Impact/Purpose:
Present information at the Second International Conference of DNAPL Characterization and Remediation
Description:
A pilot scale field demonstration of dense non-aqueous phase liquids (DNAPL) treatment using emulsified zero-valent iron (EZVI) is being conducted at Parris Island Marine Corps Recruit Depot (MCRD), Parris Island SC. The demonstration is being conducted by Geosyntec, the National Aeronautics and Space Administration (NASA), the Naval Facilities Engineering Service Center (NFESC) and the United States Environmental Protection Agency (USEPA) National Risk Management Research Laboratory, and funded by the Department of Defense’s Environmental Securities Technology Certification Program (ESTCP) with support from the USEPA. The EZVI technology was developed at the University of Central Florida (UCF) and NASA as a treatment technology for DNAPLs in the subsurface. EZVI consists of a surfactant-stabilized, biodegradable emulsion that forms emulsion droplets composed of an oil-liquid membrane surrounding micro- or nano-scale zero-valent iron (ZVI) particles in water. The emulsion droplets enhance contact between the ZVI and the DNAPL. The ZVI provides rapid abiotic degradation of the DNAPL constituents and the oil provides an immediate sequestration of the DNAPL constituents as well as a long-term electron donor source to enhance further biodegradation. The site of the field demonstration at Parris Island MCRD is a former dry cleaning facility. The demonstration consists of two side-by-side treatment areas to evaluate the performance of nano-scale EZVI to remediate a shallow (<20 ft) tetrachloroethene (PCE) DNAPL source area and to evaluate two injection technologies for EZVI, pneumatic injection and direct injection using a direct push rig. Soil and groundwater samples were collected from the site in June 2005 to assess contaminant distribution within the treatment areas, and a network of performance monitoring wells was installed at the site in June 2006. Groundwater samples were collected prior to EZVI injection to establish baseline conditions for the demonstration. EZVI was injected into the treatment areas in October 2006 and performance monitoring is ongoing. Preliminary results show a decrease in PCE and trichloroethene (TCE) downgradient of the treatment area following EZVI injection, with an increase in degradation products including significant increases in ethene. A description of the pilot test set up and EZVI injection will be presented. The information available to date on the evaluation of the injection technologies and the results of performance monitoring will also be presented.