A five acre, former tool manufacturing site in Sheffield, scheduled for re-development was found to be heavily contaminated with Chlorinated Hydrocarbons. Two plumes were identified occupying some 15% of the site, approx 3,500 m³ of sub surface materials, containing Trichloroethene (TCE) and Vinyl Chloride (VC). The site was surrounded by high density housing, and the geological studies indicated an upper layer of made ground, underlain by difficult cohesive clays, silts and sands over dense mudstone.

A Technology Evaluation followed by a Cost/Benefit Analysis indicated that Six Phase Heating (SPH) offered significant benefits in terms of minimising local disruption, reducing remediation timescales, low risk of cost escalation, and overall thoroughness of the remediation process.

During the project, over 70 times more contaminant was removed, than had been envisaged, but despite this, the project was completed some 12 weeks ahead of the original programme.

This was the first full scale use of SPH in the UK and resulted in the removal of some 70 times more contaminant than was originally thought to be present. Despite the much greater volumes of contaminant, overall project costs were contained within the original budget.

Site handover to the client took place 3 months ahead of programme.

This project is the subject of CL:AIRE Technology Demonstration Project Bulletin 26.

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