Field Evaluation of High Voltage Electron Beam Technology for Treating VOC-Contaminated Groundwater. Part II: Acute Toxicity Changes and By-Product Formation

Abstract

AbstractAs part of the Superfund Innovative Technology Evaluation program, the U.S. Environmental Protection Agency evaluated the High Voltage jEnvironmental Applications, Inc. (HVEA), electron beam (E-beam) technology at the U.S. Department of Energy Savannah River Site (SRS) in Aiken, South Carolina. This technology irradiates water with a beam of high-energy electrons, causing the formation of three primary transient reactive species: aqueous electrons, hydroxyl radicals, and hydrogen radicals. Target organic compounds are either mineralized or broken down into low molecular weight organic compounds, primarily by these species. The E-beam system used for the evaluation is housed in an 8- by 48-foot trailer and is rated for a maximum flow rate of 50 gpm. During two different periods totaling 3 weeks in September and November 1994, about 70,000 gallons of SRS M-area groundwater contaminated with volatile organic compounds (VOCs) was treated with the E-beam system. E-beam treatment increased groundwater acute toxicity for fathead minnows but not for water fleas. Although several VOCs were removed, lack of decrease in toxicity appears to be due to formation of toxic by-products, including haloacetic acids and aldehydes, during E-beam treatment of groundwater. An increase in inorganic carbon and chloride concentrations was observed, in the treated groundwater indicating that some VOCs were mineralized during E-beam treatment. Formation of CO