Bioventing pilot test results at the low point drain area, Offutt AFB, Nebraska

The purpose of this paper was to describe the application of bioventing technology at the LPD site at Offutt AFB, Nebraska and present the results of the 15-month pilot test. The preliminary tests indicated sufficient hydrocarbon contamination was present with the necessary soil characteristics to warrant an extended bioventing pilot test. The six month in situ respiration test indicated that progress was being made in reducing the TVH concentrations and biological activity was still occurring. Laboratory analysis of the final soil samples confirmed the reduction in TRPH and BTEX concentrations indicating that the site is close to complete remediation. However, owing to reduced air flow at greater distances from the VW, more biodegradation is still needed near MPB. The reduced biodegradation at MPB could also be due to the high water tables resulting from heavy rains during the summer and fall of 1993. The local water table was above the VW and MP screens for several months. The operation of the blower will continue until the site is completely remediated. The single VW pilot test at the LPD site at Offutt AFB has proven the effectiveness of bioventing in reducing TRPH and BTEX contamination in the subsurface. The installation, operation and maintenance costs were minimal. The effectiveness of this application has resulted in three additional bioventing applications at Offutt AFB including the first, full-scale system located in the state of Nebraska.