Located in a Southampton suburb, and located on London Clay Formation over Wittering Formation. The site is bounded to the north-east by a former landfill site. Phase 2 bio-gas monitoring demonstrated significant flow levels with elevated Methane concentrations. The client’s development involved the construction of 45 residential properties which was severely compromised due to the highly elevated bio-gas levels.
Extensive investigation by Soils Limited revealed the bio- gas to be migrating through the Whitecliff Formation Sands. The London Clay Formation formed a capping layer above the venting sand, preventing gas migration to the surface across half the site. The remaining half of the site was unprotected; by the absence of the London Clay Formation, thus allowing a pathway for gas to migrate to the surface.
Consultation with peers within the remediation industry allowed Soils Limited to present our client with several active and passive strategies, including pioneering technologies. The safest and most cost effective strategy for client and environment was determined. Soils Limited were able to oversee the implementation and validation of the methods proposed, giving the client full on-site support throughout.