Groundwater remediation works to address chlorinated hydrocarbon contamination.
Site Overview
The Harmondsworth site occupies an area of approximately 7.5 acres. Extensive contamination was identified with soil and groundwater polluted with chlorinated hydrocarbon.
The site was being developed for commercial / industrial end use.
Objective
The remediation strategy at the Harmondsworth site was designed to address the on-site contamination problems and prevented the potential risk of future contamination of the adjacent site through groundwater migration.
Remediation Strategy
Envirotreat installed an Active Containment System (PRB) comprising both non-permeable and permeable sections
Methodology
The barrier was installed using a Continuous Flight Auger (CFA). The active (permeable) section of the barrier contained modified pillared E-clays designed to remove and chemically immobilise the prime pollutants of concern. The non-permeable (passive) sections of the barrier are composed of a clay and cement mix. Passive barrier sections are used to channel groundwater towards active barrier sections where contamination can be ‘filtered’ out.
The total length of the active barrier was 800m, with an average depth of 7m (the total depth varied with the depth of the underlying clay into which the barrier was keyed into).
Validation
Validation of the barrier installation was undertaken by an independent consultant following completion of the remediation works.
