The £12.4 million contract with VHE Construction - a subsidiary of Montpellier Group - involves the removal of some 122,000 tonnes of waste tar and contaminated soil and replacement with clean material. Work commenced in January, with disposal due to be completed by July.
Steve Marshall, pre-contracts director at VHE confirms that the pace of the project is driven by the landfill Directive deadline. "There's a big push to complete disposal before July," he says.
From 16 July, the EU waste acceptance criteria will impose a limit of 6% total organic carbon for wastes arriving at hazardous landfill sites. Material from former gas and coking works will therefore no longer be acceptable at landfill without pre-treatment to reduce organic carbon content.
Waste from the Phurnacite works, at Abercwmboi near Aberdare, is being taken by road to a landfill site in north-east England. There are no landfills for hazardous waste in Wales.
Local residents are unhappy with the anticipated 60-70 vehicle movements per day, although operations will not take place outside the hours of 9.30am-3.30pm. Planning consent for a rail head at Abercwmboi was granted in late January, and VHE hopes to be able to shift to rail transfer operations. "Hopefully the rail option will kick in at some stage in the contract," says Mr Marshall.
Supporting the project are waste business Shanks - which acted as waste broker and is arranging the haulage - and hazardous waste landfill operator Impetus. Impetus' landfill at Teesport - a former ICI waste site - has now opened for business with a permit to accept hazardous waste (see p 13 ). Up to 100,000 tonnes of the Abercwmboi waste will go there.
The remediation and reclamation of the 150-acre site will take between four and five years. The works, operated by British Coal subsidiary Coal Products, made smokeless fuels until 1990. The original plant opened in 1942, prior to nationalisation in 1948.
The main process plant was demolished in 1991, but it has taken more than a decade to agree how to clean up the on-site tips. A planning application proposing excavation of the two tips and re-encapsulation in an engineered cell was rejected by Rhondda Cynon Taf Borough Council in 2000.
Faced with stalemate, the WDA approached the Environment Council to embark on stakeholder dialogue. Work to inform the process included site investigations by Golder Associates which confirmed that one tip was up to 9.3 metres deep and the other up to 5 metres. Contamination with tars and related compounds was also found along the entire length of the former batteries, with hotspots of up to 4 metres in depth. Groundwater contamination with ammonia and organic chemicals has also been detected beneath the waste tips and the batteries.
The stakeholder process led to the conclusion that off-site landfilling with rail transportation was the best option for the community. If landfilling proved not to be possible, the next preferred option was thermal treatment.
Plans to clean up another former Coal Products site - the Avenue Cokeworks near Chesterfield - are also progressing. Bids for the remediation work were invited by East Midlands Development Agency last October. Unlike the Phurnacite project, however, EMDA decided against rushing through the project ahead of the landfill Directive deadline. On-site thermal desorption is likely to emerge as the solution to treating the 200,000 tonnes of slurry from effluent lagoons on the site which have total organic carbon content of 18% (ENDS Report 351, pp 3-4 ).
An important factor for EMDA, supporting its preference for on-site treatment, was that it wanted to avoid the impact of lorry movements on the local community. However, another important consideration was that off-site disposal posed challenges in terms of materials handling because of the need to solidify the sludge, and would therefore have been costly.