Biosparging enhances both aerobic biodegradation and volatilization and is commonly applied to residual hydrocarbon source zone remediation. This technology was applied in pulsed mode to a known source of gasoline contamination in order to quantify the extent of remediation achieved in terms of both mass removed and reduction in mass discharge into groundwater. The gasoline source was created at the groundwater research facility at CFB Borden, Canada. About 40 L of gasoline with 10% ethanol was injected in small volumes from 24 injection points below the water table in 2004. The downgradient plume is still being monitored and the source area was cored in 2007. In 2008, a single-point biosparge system was installed and operated. Water-saturated soils precluded the use of a traditional soil vapor extraction (SVE) system, so an airtight cover was used with soil venting to capture and monitor off-gases. Conservative tracers (He, SF6) and hydrocarbon gas monitoring were intended to assign mass removal to volatilization. CO2 and O2 monitoring in the off-gas confirmed limited biodegradation of hydrocarbons. Post-remediation core analysis and downgradient monitoring of groundwater will be used to define the extent of remediation and decline of mass discharge to the groundwater plume.
Lambert, Jennifer M.; Yang, Tianxiao; Thomson, Neil R.; and Barker, James F.
"Pulsed Biosparging Of A Residual Fuel Source Emplaced At CFB Borden,"
Proceedings of the Annual International Conference on Soils, Sediments, Water and Energy:
Vol. 14, Article 5.
Available at: http://scholarworks.umass.edu/soilsproceedings/vol14/iss1/5