Ecologia is proud to announce that they are set to commence the final clean-up phase at a site where the deep Chalk aquifer (>25 m below ground level) has been impacted by benzene contamination. The remediation approach will be centred around in-situ thermal remediation using conductive heating.
Several years of groundwater Pump and Treat has been carried-out, which provided effective hydraulic containment and reduction of the initial contamination plume; however, detailed site assessments and the development of a robust conceptual site model concluded that a more aggressive remediation process is now necessary to reduce the high benzene concentrations that persist near the point of loss. Natural attenuation processes are not reducing concentrations at the point of loss – this, coupled with the prevailing fissure flow within the local Chalk aquifer creates an unacceptable residual risk, as without hydraulic containment off-site migration of benzene can occur quickly and unexpectedly with fluctuations in the water table.
Over the next 12 months Ecologia is planning to remove benzene from the aquifer and capillary fringe using a combination of steam injection and conductive heating. A dual-phase extraction system will capture the volatile contaminants stripped from both the groundwater and unsaturated soils, as well as ensuring hydraulic containment within the remediation area. The off-gases will be treated using a combination of GAC filtration and thermal destruction using a CATOX system. A further polishing step using air/ozone sparging will be used to remove any residual contamination following the heat treatment.
Following a positive meeting with the EA permitting team and the Local Authority, the in-situ thermal treatment is set to commence shortly.