A team led by CH2M Hill Cos., Denver, is set to be awarded the program management contract for an estimated $4.5-billion sewage interceptor and storage tunnel through London. The project is intended to control discharges from more than 35 combined sewage overflow points that now plague the city.

Sources say losing competitors for the project management role are teams led by Bechtel Group Inc. and Jacobs Engineering Group Inc.

Thames Water Utilities Ltd., the London utility building the 7.2-m-dia Thames Tideway tunnel system, is set to announce the award this week. The project's 32.2-km main bore will run from Hammersmith, west London, to the large eastern Beckton treatment plant, which will be enlarged. The tunnel route will closely follow the River Thames.

Detailed alignment of the Thames tunnel is under review. Site investigations are planned for this year and next. As much as eight years of construction is scheduled to start in 2012.

A 6.9-km northern spur will loop westward from Beckton to the Abbey Mills pumping station. It will capture overflows into the River Lee, which runs through the site for the 2012 Olympic Games.

Thames Water began procuring the Lee tunnel contract in December and expects to make an award next March. A single tunnelling machine will be used, says a utility spokeswoman.

Working in chalk up to 75-m deep, the tunnelling machine will be kept at around eight atmospheres of compressed air to exclude ground water.