| In 1988, the U.S. Air Force initiated a study at Hill Air Force Base (AFB) to examine the potential of bioventing to remediate JP-4 jet fuel-contaminated soils. Bioventing is the process of supplying oxygen in situ to oxygen-deprived soil microbes by forcing air through contaminated soil at low airflow rates. Because bioventing equipment is relatively noninvasive, this technology is especially valuable for treating contaminated soils at military bases, industrial complexes, and gas stations, where structures and utilities cannot be disturbed. Promising results from the Air Force’s initial study prompted the U.S. EPA National Risk Management Research Laboratory (NRMRL) and the Air Force to conduct a field evaluation of bioventing at Hill AFB and at Eielson AFB (see separate fact sheet, EPA/540/F-95/506B). The main objective of the Hill AFB evaluation was to determine the effect of air injection flow rate on the effectiveness of bioventing in stimulating biodegradation while minimizing volatilization. The evaluation also provided an opportunity to gain experience in bioventing large volumes of soil with plumes of fuel that extend deep beneath the surface as well as under roads, underground utilities, and buildings. |