Emulsified Zerovalent Iron for Treating Chlorinated Solvents at a Superfund Site over Six Years
Emulsified Zerovalent Iron for Treating Chlorinated Solvents at a Superfund Site over Six Years
Presented on Monday, March 16, 2015
Groundwater contamination by tetrachloroethene (PCE) occurred from a 1994 spill at the Marine Corps Recruit Depot (MCRD), Parris Island, South Carolina, Superfund site. Containment and treatment of the source zone was critical in controlling the migration of the contaminant plume. Emulsified zerovalent iron (EZVI) was injected into the treatment areas in October 2006, and performance monitoring was conducted until October 2012. The field demonstration consisted of two side-by-side treatment areas to evaluate the performance of EZVI to remediate a shallow (<20 ft) PCE DNAPL source area and to evaluate two injection technologies for EZVI, pneumatic injection and direct injection. In the pneumatic injection plot, 2180 liters of EZVI containing 225 kg of iron (Toda RNIP-10DS), 856 kg of corn oil, and 22.5 kg of surfactant were injected to remedy an estimated 38 kg of CVOCs. In the direct injection plot, 572 liters of EZVI were injected to treat an estimated 0.155 kg of CVOCs. Soil samples were analyzed to evaluate contaminant mass changes. Significant reductions in PCE and trichloroethene (TCE) concentrations were observed in downgradient wells with corresponding increases in degradation products including significant increases in ethene. In the pneumatic injection plot, there were significant reductions in the downgradient groundwater mass flux values for chlorinated ethenes (>58%) and a significant increase in the mass flux of ethene (628%). There were significant reductions in total CVOC mass (78%); an estimated reduction of 23% in the sorbed and dissolved phases and 95% reduction in the PCE DNAPL mass. Significant increases in dissolved sulfide, volatile fatty acids (VFA), and total organic carbon (TOC) were observed and dissolved sulfate and pH decreased in many wells. The effective remediation seems to have been accomplished by a combination of abiotic dechlorination by nanoiron and biological reductive dechlorination stimulated by the oil in the emulsion.
Chunming Su, Ph.D.
U.S. Environmental Protection Agency, Ada, OK
Chunming Su is a Soil Scientist working for USEPA. His research areas are nanotechnology and in situ chemical reduction. He conducts laboratory and field investigations in environmental geochemistry and nanotechnology. Su holds a Ph.D. in Soil Science from Washington State University in Pullman, Washington; an M.S. in Soil Science from the University of Guelph, Guelph, Ontario, Canada; and a B.S. in Soil Science and Agrochemistry from China Agricultural University, Beijing, China.
Robert Puls, Ph.D.
Oklahoma Water Survey, University of Oklahoma, Norman, OK
Robert Puls is Director of the Oklahoma Water Survey and Associate Professor at the University of Oklahoma. He was employed by the USEPA for almost 25 years. Puls was the Technical Lead for the USEPA Study on Hydraulic Fracturing and Drinking Water Resources prior to his retirement in early 2012. As Technical Lead he met with numerous industry representatives, non-governmental organizations, federal agencies, and state agencies responsible for oil and gas regulatory oversight. Puls has a Ph.D. from the University of Arizona as well as degrees from the University of Washington and the University of Wisconsin.
Thomas Krug
Geosyntec, Guelph, ON, Canada
Thomas Krug is an environmental scientist working for Geosyntec.
Mark Watling
Geosyntec, Guelph, ON, Canada
Mark Watling is an environmental engineer working for Geosyntec.
Suzanne O'Hara
Geosyntec, Guelph, ON, Canada
Suzanne O’Hara is an environmental engineer working for Geosyntec.
Jacqueline Quinn
NASA Kennedy Space Center, Kennedy Space Center, FL
Jacqueline Quinn is an environmental engineer working for NASA.
Nancy Ruiz
US Navy, Port Hueneme, CA
Nancy Ruiz is an environmental engineer working for the US Navy.