As is the case with much of the UK’s water infrastructure, two of Scottish Water’s water treatment works near Edinburgh are showing their age.
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That is why construction is now underway on the brand new £104M Glencorse treatment works. This is a major project for Scottish Water and will eventually allow the two existing Victorian works to be decommissioned.
“The old ones would never have been able to meet water quality requirements going ahead,” says Scottish Water senior project manager Kenny Naylor.
The Glencorse project takes the water treatment away from the city to a greenfield site − with careful planning to ensure the landscape is as undisturbed as possible.
Stakeholder discussions started in 2007 before a design and construct contract was awarded through competitive tender to Black & Veatch, whose first big task was to determine the best location for the project.
A longlist of 25 locations became a shortlist of five, before the final site was chosen − making this the largest such consultation exercise Scottish Water has ever done. Planning permission was granted within 10 weeks of the submission.
The work involves diverting existing mains and constructing a new intake building, a 7,150m² structure housing the treatment processes, a chlorine contact tank and a clear water tank which will act as the holding tank at the head of the network.
Much of the treatment works is concealed underground. Those buildings that are only partially underground have low level green roofs that help them blend in to the surrounding countryside. “It will be landscaped such that it will be very hard to locate it in the surrounding landscape,” says Black & Veatch contracts manager John Marshall.
Black & Veatch design manager Gavin Gibson says the green roofs will be married into the ground by small man-made hills that will round onto the roof. “There are no hard edges, it’s very gentle,” he says.
“By the time we’ve finished here it’ll be hard to tell what we’ve actually done.” The site will boast one of the largest grass roofs in the country.
The water company was keen for the results of the project to be notable for minimising environmental impact. Another obstacle was the discovery of an ancient Roman marching camp on the site. This meant the works had to be relocated slightly from the original plans. “The local archaeologists were delighted,” says Gibson.
One of the advantages of the chosen location is its strategic position adjacent to major existing pipelines running to Edinburgh.
“Because we’re cutting into mains at a strategic point we’re able to use the [hydraulic] head to generate power,” says Marshall. This water turbine will be able to supply roughly 30% of the energy for the construction work.
The location was also carefully chosen to eliminate the need for booster pumps to pump water through the system, allowing gravity to do all the work instead. The result is low operating costs for the new plant.
The project is also notable for the fact that 15km of pipes are being manufactured on site, reducing local traffic disruption and 1,500t of CO2 emissions from vehicles.
The project is now two thirds complete. Construction work started on site in October 2008, and the plant will be operating by the middle of 2011, with landscaping set for completion around three months later. The new treatment works will have a sizeable impact on the area and will serve 450,000 Edinburgh citizens.
Water special case study: The Glencorse water treatment works