Multi-Site Air Sparging

The Department of Defense DoD is faced with the task of remediating many sites contaminated with a variety of compounds, including petroleum and chlorinated compounds. When a contaminant release occurs, the contaminants may be present in any or all of three phases in the geologic media adsorbed to the soils, in free-phase form, andor dissolved in groundwater. Of the three phases, dissolved contaminants in the groundwater are considered to be of greatest concern due to the risk of human exposure through drinking water. Conventional groundwater treatment technologies typically are expensive and often ineffective. In the past few years, the U.S. Air Force and Navy have been developing in situ remediation technologies that have the potential to remediate sites much less expensively and more effectively than conventional technologies. In particular, air sparging has been intensively studied by the Air Force in cooperation with the Navy at the Naval Base Ventura County NBVC, Port Hueneme site, California, to evaluate proper monitoring techniques for evaluating system performance and to determine critical operating parameters. Air sparging is the process of injecting clean air directly into an aquifer for remediation of contaminated groundwater. In situ air sparging remediates groundwater through a combination of volatilization and enhanced biodegradation. The induced air transport through the groundwater removes the more volatile and less-soluble contaminants by physical stripping. Increased biological activity is stimulated by increased oxygen availability.