Groundwater remediation works by E-Clay PRB to address hydrocarbon contamination.
Site Background & History
The site was located on Old Portsmouth Road, Guildford. The site is bounded by a stream to the south east. The Mill Stream follows the northern boundary of the site and the River Wey lies approximately 150m to the East.
The site had historically been used as a timber yard and (more recently) an industrial estate.
Following decommissioning the site had been earmarked for commercial redevelopment.
Groundwater was confirmed at approximately 1.6m below ground level. Significant contamination issues were identified within the groundwater, namely Polycyclic Aromatic Hydrocarbons (PAHs) and Total Petroleum Hydrocarbons (TPH) believed to be derived from the above ground creosote dipping tanks and historical spillages. The investigation concluded that the contaminated groundwater was migrating north east across the site towards the Mill Stream.
Envirotreat proposed to design and install an E-clay groundwater treatment barrier (Permeable Reactive barrier). The objective to protect both the River Wey and Mill Stream from impact from the identified onsite contamination issues.
Remediation
The groundwater treatment barrier was installed into the soils along the site boundary. The installation was archived using a conventional piling rig and continuous flight auger system.
Validation
Groundwater sampling results from two-year period (post remediation) showed that the installation had effectively minimised the egress of contamination groundwater. Groundwater analysis downstream of the barrier installation was fully compliant with the agreed remediation criteria.
