Award-winning Deephams Sewage Treatment Works upgrade completed

A £250 million project to upgrade Deephams Sewage Treatment Works has now been successfully completed.

What we’ve done

The upgrade means we now serve a population of around one million customers with further development space for the future.

The overall project supports the local environment by increasing the resilience of the site, improving the quality of treated water and achieving a 99% reduction in odour emissions.

The work was done in stages so we could continue to treat sewage while improving the site. Starting in 2015, we began with the refurbishment of the old plant to maximise its capacity. We then improved and rebuilt the streams as shown in the images below.

The project has increased renewable energy generation on-site, from a new combined heat and power plant. This has also reduced the footprint of the works by a third, leaving space for future resilience plans and a growing population.

In June 2019 the newly upgraded site was officially opened by the leader of Enfield Council, councillor Nesil Caliskan alongside Martin Hoff, Thames Water’s Head of Major Projects. 

Benefits to London

  • Improvements to the quality of the final effluent leaving the works helping the downstream river environment and aquatic life
  • Management of invasive species including Japanese knotweed
  • On average two-thirds of the energy for the site is now self-generated using renewable sources
  • Odour has been dramatically decreased as a result of covering the entire inlet works and most sources of odour
  • An education centre has been added to the site which will be run in partnership with Thames Water’s education team support the engagement and education of our current and future customers.
  • Providing training to local people including apprentices
  • The project team provided 5000 hours of volunteering to local causes within the community

As a testament to its success, the project won the prestigious ‘Greatest Contribution to London’ trophy at the ICE London Civil Engineering Awards 2019. A press release about the awards ceremony was sent to local media.