Deephams upgrade

Futureproofing one of the UK’s largest sewage works

Deephams upgrade

Meeting future water needs

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Meeting the long-term needs of a growing city without short-term water supply disruptions.

  • Location


  • Client

    Thames Water

  • ACE Member


  • Services

    Project Management

  • Project

  • Delivery date


  • Cost


  • Delivery partners

    AMK (Murphy, Kier)

  • Project length

    3 years

AECOM upgraded Deephams Sewage Treatment Works, meeting the long-term needs of a growing city without short-term water supply disruption.

Deephams Sewage Treatment Works (STW) is one of the UK’s largest sewage treatment works, serving almost a million people – and that number is only set to grow over the coming years. Nested in a busy North London suburb, any expansion of the existing site would be both costly and disruptive.

When AEOCM were commissioned by Thames Water to design a major upgrade for Deephams allowing the plant to serve a larger customer base, as well as reducing odour emissions from the site it was clear that this would be no mean feat.

Working across engineering design disciplines, AECOM worked closely with Thames Water to provide a brand-new sewage treatment solution.

Video - consultancy40Video

Not only were the team at AECOM able to increase the site’s service capacity without infringing on neighbouring property, but their solution in fact required just two-thirds of the existing land.

They were also able to schedule construction and demolition to ensure no disruption to the existing sewage treatment service, and to re-use much of the demolition waste as structural fill. This made for a sustainable sewage treatment solution which did not compromise on the needs of its existing users.



Each day, Deephams deals with more than 200,000 tonnes of waste water, although this can rise to above one million tonnes during periods of heavy rain.

The changes have seen the quality of treated water returned to the River Lea, a tributary of the Thames, significantly improved while there is also a 99 per cent reduction in odour emissions, achieved by covering key parts of the works.

Martin Hoff - consultancy40Quote
We’re all incredibly proud of the upgrade to Deephams. While many of the customers it serves may not have noticed anything while the work was taking place, it is going to make a big difference now and for the future.

Martin Hoff

Thames Water, Head of Major Projects