Potable ground-water supplies worldwide are contaminated or threatened by advancing plumes containing radionuclides and metals. Pump-and-treat methods are costly and often ineffective in meeting long-term protection standards (Travis and Doty, 1990; Gillham and Burris, 1992; National Research Council, 1994). Alternative approaches to pump-and-treat methods could have widespread applicability to not only abandoned and active mine sites throughout the United States and other parts of the world, but to various industrial sites as well. Passive in-situ chemical barriers may offer a viable alternative or supplement to pump-and-treat technologies for controlling ground-water contamination. An in-situ chemical barrier is a permeable zone of reactive materials placed in the subsurface that removes ground-water contaminants, thus resulting in clean ground water exiting from the treatment zone. The development of methods for effectively placing chemical or biological barriers and the technology for monitoring their performance will enhance future use of this remediation technology.
Schematic diagram of a reactive barrier. (9K)
In June of 1996 the U.S. Environmental Protection Agency (USEPA), the U.S. Department of the Interior, U.S. Geological Survey (USGS), Bureau of Land Management (BLM), the U.S. Department of Energy, Grand Junction Office (DOE/GJO), and the Utah Department of Environmental Quality (UDEQ) agreed to form a partnership and proceed with demonstrations of in-situ treatment technologies for removing dissolved radionuclides and metals from ground water. The goal of the demonstrations is to determine the technological and economic feasibility of using permeable chemical or biological barriers placed in the flow path for removing dissolved metals and radionuclides from contaminated ground water.
This project will test the performance of selected reactive chemical barriers at the Fry Canyon site, an abandoned uranium upgrader site in southeastern Utah. Anticipated results of the research for each of the chemical barriers tested will include long-term removal efficiencies for uranium and an evaluation of the commercialization potential for each of the barriers. Specific objectives of the field demonstration project include (1) hydrologic and geochemical characterization of the site prior to emplacement of barriers; (2) design, installation, and operation of selected reaction-barrier technologies; and (3) evaluation of barrier(s) performance and commercialization potential. Financial support for this project is provided by the USEPA (Superfund and Office of Radiation and Indoor Air) through an Interagency Agreement with the USGS.