Long term partnership supporting the regeneration of UK land
The Situation
Following detection of petroleum components in water samples from a local public supply well, the client’s site was determined as Contaminated Land under Part IIA of the Environmental Protection Act. Given the limited understanding of the site geology and hydrogeology and thus the associated pollutant linkages at this time, the client commissioned Advisian to undertake more detailed investigation and assessment of the site. All work was undertaken with the approval of the Environment Agency and Local Authority.
Approach
The site investigation works identified historical off-site migration of petroleum product. A potential risk to human health associated with the inhalation of vapours was identified and the client commissioned Advisian to undertake intrusive investigation in the immediate surroundings of the site to assess potential risks to human health.
A remediation strategy was developed following completion of detailed groundwater risk assessment and Cost Benefit Analysis and discussion with key stakeholders. The strategy comprised a combination of source treatment and plume capture through hydraulic containment.
Results
Advisian designed, installed and commissioned two remediation systems focussed on the source areas comprising a total fluids product recovery system combined with soil vapour extraction. In addition, a hydraulic containment system was designed and installed. The three systems have operated successfully since that time recovering hydrocarbon mass from the soil and groundwater in the source area, and successfully preventing further impact to the offsite water supply well.
In addition, Advisian worked closely with the client and academic research organisations on a study focussed on identifying appropriate taste and odour concentrations for MTBE in drinking water. This study is being finalised prior to publication.
Advisian successfully characterised an extremely complex hydrogeological system such that the hydraulic containment system resulted in rapid protection of the offsite water supply well. Within 6 months of commissioning no MTBE impacts were detected in the offsite well.
