Envirotreat Technologies Ltd was commissioned by our client (on behalf of Persimmon Homes) to design and install a permeable reactive barrier [PRB] to protect groundwater receptors during the proposed demolition works to the former plating shop at the site in Roade, Northamptonshire – this site is being developed for residential usage by Persimmon Homes. The prime purpose of the barrier was to prevent the migration of highly soluble and mobile hexavalent chromium [Cr VI] contamination within the groundwater – the barrier was also designed to address other metallic species and cyanide pollutants within the groundwater. The reactive medium within the PRB was a highly pillared form of ChromeSorb® (a proprietary form of E-Clay designed to remove the pollutants from the groundwater by chemically sorbing and immobilising both cationic metallic species (trivalent chromium Cr3+, nickel Ni2+ etc) and anionic species (hexavalent chromium typically in the form of chromate CrO42- and cyanide species CN-).
The PRB was installed over a two-week period – the PRB was circa 100m in length and installed to the required depth to intercept contaminated groundwater migrating from the site (keying into the underlying impermeable clay layer). The barrier was installed by in-situ soil mixing techniques using conventional excavators.
The Rolton Group were the environmental consultants for the project.
The photograph shows the PRB installation.