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A BIOVENTING APPROACH TO REMEDIATE A GASONLINE CONTAMINATED SUBSURFACE
Citation:
Kampbell, D., J. Wilson, AND C. Griffin. A BIOVENTING APPROACH TO REMEDIATE A GASONLINE CONTAMINATED SUBSURFACE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-92/220.
Description:
Bioventing is a subsurface process using an air stream to enhance biodegradation of oily contaminants. wo pilot-scale bioventing systems were installed at a field site. rocess operations began in October 1990. he field site is located at an air station. pill in 1969 of about 100,000 kilograms aviation gasoline was caused by a broken underground transfer line. ajor portion of the spilled product still persists as an oily-phase residue in a 80x360 meter plume. he subsurface is a uniform beach sand with the ground water level near five meters. rior to startup of the venting systems, a grass cover was established and a nutrient solution was dispersed throught the unsaturated subsurface. ubsurface air flow patterns are being determined with a tracer gas of sulfur hexafloride. oil gas, core material, and underground water are being monitored to determine the extent of remediation. bjectives of the study are to demonstrate that surface emissions of gasoline are minimal, oily residue will be reduced to less than 100 mg fuel carbon/Kg core material, and the process will be applicable to full-scale remediation. eration systems using injection only and injection, extraction, and reinjection are shown in Figure 1 as north and south plots, respectively. nitial well points presently emit forced air over a depth of 0.15 meter just above the water table. low rate is based on a calculated residence time of 24 hours. il residue changes after three months operation are shown in Tables 1 and 2. urface emissions of fuel hydrocarbons have not exceeded 1 ug/liter soil gas. ield evaluation of the bioventing systems will be completed by December 1991.