This scheme was carried out as part of our Term Contract 2002 with National Grid Property Holdings. It was the first phase of works for the environmental improvement works at the former gasworks in Dundee, which still retained live gas storage and distribution plant for the city and surrounding area. As part of an initial treatment exercise an overall volume of 19,215Tonnes of gasworks waste was excavated from within 2 former gasholder bases and taken to landfill. The former gasholder bases extended up to 8m below ground level and it was essential to ensure their stability throughout the project, particularly given the close proximity of live distribution plant. The proximity of live gas mains to the former gasholder bases posed a particular challenge during the operation of the project. Their safe management was ensured through close liaison with local Transco personnel and by paying close attention to the implementation of safe working methods.
The excavations also generated a significant volume of contaminated perched groundwater. An on-site treatment works was established to manage contaminant concentrations in the groundwater. Following chemical analysis and testing, a total of 1250m³ of treated waters were accepted for discharge to the local foul sewer, minimising the need for tanker disposal.
During its operation, the site underwent a total of 3 internal and external audits on quality and environmental matters. The approach that is adopted by the overall project team saw such events as a positive mechanism towards ensuring that project met the objectives and high standards expected of all stakeholders
The relatively long-term nature of projects within the National Grid term contract allows for the development of a strong working relationship between all members of the project team across a number of consecutive projects. Obviously benefiting from this, Dundee was completed on time, and at a cost that was some 25% under the original budget.
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