Our proposed upgrade

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We are proposing a major upgrade to our Deephams Sewage Works in Edmonton.

We need to develop an improved sewage treatment process, while continuing to treat the 209,000 tonnes of sewage that arrives at the works each day. This can increase to over 1.3 million tonnes during heavy rainfall – enough to fill 520 Olympic swimming pools.

Following feedback from the first phase of consultation in 2012, we plan to upgrade the treatment works within the boundaries of the existing Deephams Sewage Works site.

Why we need the upgrade

  • To meet new wastewater quality standards set by the Environment Agency
  • To replace the existing treatment plant that is becoming old and worn out
  • To cater for predicted population growth in the area
  • To cope with weather variations that are predicted to occur due to climate change
  • To significantly reduce the odour from the works, at a reasonable cost to all of our wastewater customers

    What will be upgraded

    We need to upgrade most of the existing wastewater treatment facilities at the site, as explained below.

    Part of the upgrade

    • Replacing the large tanks used during the three main stages of the treatment process: primary settlement, secondary treatment and final settlement
    • Upgrading or replacing mechanical and electrical equipment in this area
      • Not part of the upgrade

        • The inlet works (upgraded in 2012) where untreated wastewater first enters the site
        • The wastewater pre-treatment screening processes
        • The sewage sludge treatment processes
        • Maintenance and other work will continue to take place, before
        • and during the upgrade, in this area of the site

      How long it will take to build

      The upgrade is likely to take approximately three years to construct and, subject to planning permission, the main construction work is expected to start in 2015.

      The new wastewater treatment standards set by the Environment Agency will be met by March 2017 and we plan to finish building the upgrade and tidying up the site by late 2018.

      Who will pay for the upgrade and how much it will cost

      The cost of designing and building the Deephams Sewage Works Upgrade will be around £250m and will be paid for through the bills of our 15 million wastewater customers.

      As with all the costs of providing high quality tap water for our customers and removing and treating their sewage, the cost of the upgrade will be reflected in our customers’ bills. Similar upgrades to our other sewage works have also been funded in this way, with the costs of the work being spread across all of our customers’ bills, wherever they live in our region.

      Also in this section

      How we will build the upgrade Odour Being a good neighbour Assessing the environment Getting planning permission