Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12- 7 - Remediation Contracting Services to the UK Power and Utilities Industry VHE has undertaken a wide portfolio of schemes in the power and utilities sector from the provision of remediation and infrastructure services on the redevelopment of a major power station site to minor remediation and improvement schemes. A large number of projects in this sector have also been carried out under a long term framework agreement with National Grid. This has involved the remediation of a substantial number of urban gas works sites. VHE has been retained on the National Grid Framework since 1996 and successfully delivered over 400 schemes. The projects undertaken by VHE in this sector have involved a wide range of remediation techniques including bioremediation, soil washing and soil stabilisation as well as demolition and in situ or ex situ groundwater treatment, on sites up to 31 hectares in overall size. In addition to power sector projects from fossil fuel generating sources, VHE has also worked in the nuclear power sector on highly challenging decommissioning projects in strictly controlled areas. UTILITIES Neepsend Lane Gasworks Customer: National Grid Property Holdings Value: £10 million VHE has carried out five phases of work on the former Neepsend Lane Gasworks in Sheffield on behalf of National Grid Properties totalling in excess of £10 million. Remedial works undertaken by VHE included screening the overlying construction and demolition wastes, selective excavation, treatment and disposal of contaminated soils associated with the former gas works and groundwater treatment. The overlying construction and demolition materials were excavated and screened to remove waste materials such as paper, plastic, timber and metals in order to render them suitable for re-use as fill on the site. This recovery operation reduced the amount of construction and demolition waste removed from site to around 1.5% of the original tonnage. In common with many former gas works sites, live plant was still present within the site and had to be considered during the design of the works. The principal hazard to be considered during the works was the presence of a live overhead 36” medium pressure gas main, which crossed the site from east to west. This gas main lay approximately 2.5m from the edge of two of the four 15m deep gas holders to be excavated and required significant temporary works measures to be in place to provide additional stability during the works. A total of 17,000 tonnes of contaminated material was sentenced for treatment by bioremediation. Primarily, bioremediation was used to reduce the classification of soils from hazardous to non-hazardous in order to minimise the amount of waste consigned to hazardous waste facilities. In addition, around 4000 tonnes was successfully treated for re-use on site. Hydrocarbon contaminated groundwater was extracted during remediation and pumped to a water treatment area comprising 6 holding tanks and a treatment system. Treatment comprised a 3 stage oleophilic, hydrophobic wired unit feeding a carbon filter pod. All treated waters were discharged under a formal consent agreed with the local water authority. Contact VHE now on 01226 320150 • Visit www.vhe.co.uk • Find us on