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Project Forms Part of Thames Water’s London Tideway Improvements Programme

Project Forms Part of Thames Water’s London Tideway Improvements Programme

Project Name
Mogden Sewage Treatment Works Upgrade
Isleworth, Middlesex, United Kingdom
Thames Water Utilities LTD

Thames Water’s Mogden Sewage Treatment Works is the United Kingdom’s third largest, serving 2 million customers in Greater London. In 2010, work began on an upgrade and expansion project to increase Mogden’s treatment capacity and meet the Environment Agency’s new consent standard.

Working with Thames Water’s Capital Delivery and Operations teams, Black & Veatch was employed as design and build partner for engineering, procurement and construction (EPC) of the new works. The challenge was that under moderate rainstorms, Mogden was unable to fully treat incoming flows. This resulted in more frequent than desirable use of storm tanks and potential discharges of partially treated sewage to the River Thames.

Saving Carbon

Outline design identified that it was essential to increase capacity by 50 percent to fully treat incoming flows and meet more stringent effluent quality standards. Although the existing works is on one of Thames Water’s largest sites, there was very little usable room to construct the new works. Process design evolved to include deeper-than-normal treatment vessels to increase capacity within the same footprint.

A large proportion of the scope required interfacing with the existing plant, with the resulting challenges of integrating old and new equipment while maintaining full treatment capacity.

One of the biggest innovations was the replacement of a 12-metre high concrete reinforced retaining wall with an equally high reinforced earth retaining wall. That saved some 2,300 cubic metres of carbon.

“Working with the Black & Veatch team gives me a real sense of pride in being able to not just deliver a project, but deliver it well, deliver it on time, involve the local community."

Nick Fawcett, Project Manager, Mogden Sewage Treatment Works, Thames Water Utilities

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