In a complete turnaround Thames Water (may 2026) has announced that the TTP will not be built above the storm tanks in the Mogden site. Instead another in-site location will be chosen.
Thames Water are LIKELY - but not confirmed yet - to run a consultation on this change later this year. The TTP will be built above 2 of the storm tanks in Mogden.
The main tunnelling works for the treated sewage tunnel will still have to happen and still need a starting point. This will involve 24/7 works probably on the the western side of Mogden.
In 2025 RAPID highlighted that there is no “… detailed plan for [an] alternative option if the space at Mogden Wastewater Treatment Works is no longer available to use. The space is limited and in high demand and finding an alternative space may lead to changes in the TTP layout, design, and location within Mogden. This could lead to an impact on the scheme costs and programme.”.
So the potential of changing the location of the TTP has been on the cards for a long time! And it is incredible that Thames Water has not shown that construction of the TDRA infrastructure will not interfere with the operation of Mogden STW nor with the need to increase the capacity of Mogden over time.