A brownfield site in the UK was in the process of being bought by a developer in order to construct a multi-story residential development. Prior to purchasing the site, the developer commissioned a due diligence exercise, to identify any potential environmental liabilities and risks. Following the Phase II investigation, two underground storage tanks were identified as the source of a hydrocarbon plume. The plume posed an unacceptable risk to the environment and remediation was required as part of the pre-construction works under UK planning legislation.

The Remediation Contractor removed the underground storage tanks and treated the most heavily contaminated soils through ex-situ bio piling. These works removed the source of the contamination and addressed the most heavily impacted soils. However, as part of the remediation strategy, it was considered prudent to mitigate against any lateral migration of the petroleum hydrocarbons in the groundwater, especially as this might be aggravated during the piling works.