PETROLEUM HYDROCARBON REMEDIATION USING AIR INJECTION/VAPOR EXTRACTION, USMC MOUNTAIN WARFARE TRAINING CENTER

摘要

The U.S. Marine Corps’ Mountain Warfare Training Center (MCMWTC), located near the town of Bridgeport, California is a year-round training facility located in the eastern Sierra Nevada. The facility has relied on stored fuel products for heating, transportation, heavy equipment, training operations, and emergency generators. Historic releases of these petroleum hydrocarbons have impacted soil and groundwater and are the primary environmental issue at the base. The highest priority site on MCMWTC encompasses the base gas station with groundwater impacts into a nearby alpine wetland meadow. Petroleum hydrocarbons were detected in soil and groundwater at concentrations great enough to require active remediation to mitigate the site. Technological constraints included high altitude, cold weather climate, low total organic carbon in soil, and complex geologic and hydrogeologic conditions. Air injection with vapor extraction to control the migration of volatilized fuel constituents was the selected remedial alternative. The system was constructed in 1997/1998. Construction challenges included environmental permitting, remote location, equipment and supply logistics, weather impacts, and aesthetic requirements. Since completion of the treatment system in February 1998, the system has been in continuous operation, with brief down periods resulting from power outages and equipment maintenance. The system has removed approximately 135,749 pounds of fuel hydrocarbons, based on vapor extraction and calculated biodegradation rates. Ongoing groundwater monitoring indicates significant concentrations of petroleum hydrocarbons still exist within the source area; however, concentrations of dissolved-phase hydrocarbons outside the source area and within the wetlands have decreased. Treatment time is estimated to end in 2005.