An oil leak was identified at one of the stately homes owned by the National Trust. RSA Geotechnics were contracted to carry out a ground investigation to delineate the extent of the oil leak and to identify any unacceptable risks posed to end users of the development and to controlled waters.
The investigation indicated that soil located within the vicinity of the defect oil pipe had been heavily impacted by hydrocarbon contamination and free product had been identified in the groundwater located beneath the basement floor of the adjoining building, which was subject to flooding during high periods of rain.
Due to the sensitivity and historical nature of the building the typical excavation and removal of contaminated soils was not considered to be a realistic option. Therefore, consideration was given to the available bio-remedial techniques. The bio-remedial products applied included bacteria which use the hydrocarbons as a food source. The bacteria consume the hydrocarbon contamination and chase it back to the edge of the contamination plume. Once the hydrocarbon contamination has been consumed the bacteria returns to normal background levels. The only bi-product of the process is carbon dioxide produced by the bacteria.