The Challenge
An historical leak from an underground fuel farm was impacting an off-site surface water course. The fuel farm was located in the center of a busy mail sorting/distribution facility that needed to remain operational all year round. The underground fuel farm had been decommissioned and replaced with above ground facilities following the incident, however, the tanks and associated lines were identified as a secondary source with significant LNAPL recorded in nearby boreholes.
Our Solution
Soilfix devised and implemented the following remediation solution:
- Decommissioning & removal of four 45,000L underground diesel tanks and associated fuel lines;
- Excavation and removal of gross hydrocarbon contaminated soils from the tank pit and fuel line excavations;
- Pumping and disposal of LNAPL contaminated groundwater from the tank pit excavation and installation of a 300mm sump for ongoing monitoring and recovery;
- Backfill of excavations with a high level of compaction to reduce potential for future settlement. Backfill included chemical amendments to enhance natural attenuation of contamination post remediation;
- Installation of 36nr injection points for chemical oxidation and enhanced natural attenuation of the dissolved phase plume over a 3 month period; and,
- Reinstatement of site surfacing to enable continued use as mail depot.
All works were completed on programme and budget, whilst minimizing disruption to this busy operational depot. All groundwater remediation objectives met to the satisfaction of the EA within the 6-months post-completion monitoring period.
