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Field test on the treatment of source zone chloroethenes using emulsified zerovalent iron
Citation:
SU, C., R. PULS, M. Watling, S. O'Hara, T. Krug, J. Quinn, AND N. Ruiz. Field test on the treatment of source zone chloroethenes using emulsified zerovalent iron. Presented at Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, CHINA, April 21 - 26, 2010.
Impact/Purpose:
The purpose is to determine if EZVI technology at the field scale may offer widespread application to treat DNAPL source areas.
Description:
This talk summarizes the research activities currently underway at the Solid Waste Management Unit 45 (Site 45), Marine Corps Recruit Depot, Parris Island, South Carolina. A pilot field test was initiated in 2005 at this site to evaluate the effectiveness of nanoscale emulsified zero-valent iron (EZVI) injection for treating source zone chlorinated solvents dominated at this site by tetrachloroethene (PCE) and its chlorinated daughter products such as trichloroethene (TCE) and cis-dichloroethene (cis-DCE). In the direct injection plot, 150 gallons of EZVI containing 129 lbs of iron and 491 lbs of corn oil were injected to a test plot 8 ft wide, 8 ft long, and 6 ft thick that contained estimated 155 mg volatile organic carbons (VOCs). In the pneumatic injection plot, 575 gallons of EZVI containing 496 lbs of iron and 1884 lbs of corn oil were injected to a test plot 15 ft wide, 10 ft long, and 12 ft thick that contained estimated 57 kg VOCs. Both direct injection and pneumatic injection methods were found to be able to effectively deliver EZVI within the subsurface. Distribution of injected EZVI was not homogenous. Pneumatic injection showed a radius of influence greater than 5 ft and direct injection greater than 1 ft. Groundwater monitoring results showed decreases in PCE and TCE concentrations with increases in degradation products including significant increases in ethane indicating that EZVI promotes degradation of PCE and its daughter products. Following injection, significant increases in dissolved ferrous iron, dissolved sulfide, volatile fatty acids, and total organic carbon were observed. In contrast, dissolved sulfate and pH were decreased in many wells. The ease of implementation of the EZVI technology at the field scale may offer widespread application to treat DNAPL source areas.