In-Situ Remediation Soil & Groundwater Treatment

Earth Environmental & Geotechnical have been involved in the In-Situ Remediation Soil assessment of ground conditions on the site for a number of years. The site is a shopping park which is being redeveloped and rejuvenated.

Part of the site was a former fuel retailing facility that ceased trading over thirty years ago. There were no records relating to the operation or decommissioning of the site.

A site investigation found a hydrocarbon impacted benzene plume along the site frontage, though to be associated with a former tank farm.

An In-Situ Remediation Soil Remediation Strategy was developed for the site involving the installation of closely centered wells and the use of in-situ chemical oxidation (filter geosocks impregnated with chemical oxidants) to treat perched water and adjacent soils.

The programme of treatment was in operation for over six months and has proved the reduction in the extent of the plume, with an overall efficiency of 50%.

A Validation Report has been submitted together with a controlled water risk assessment which encompasses revised water quality remediation criteria. These criteria are based on modelling of migrating benzene to a hypothetical well along the hydraulic gradient.