Thames Water has awarded an AMP8 contract for a major upgrade at its Maple Lodge Sewage Treatment Works with a current estimated value between £140 million to £280 million (inc VAT).
Photo credit Mark Percy: Thames Water Maple Lodge STW
Scope of the wide-ranging project project includes the following packages of work:
- An additional inlet screen with civils alterations and screening handling upgrade
- An additional detritor and flow inlet channel, incorporating a new storm separation weir
- A new storm tank and river outfall, including flow transfer culvert and new storm return pumping station
- Upgrades to the existing six PSTs and conversion of three storm tanks into PSTs, fitted with chain and flight scraper Replacement Primary chemical dosing pumps to aid Phosphorus removal
- A new activated sludge plant Bank C, with new feed PS and blowers
- Eight new 28m diameter final settlement tanks, interconnecting pipework, distribution chambers and RAS system
- A new secondary chemical dosing system to aid Phosphorus removal
- Two new Tertiary Solids Removal treatment plants, one serving the effluent from Bank A and B, and one serving the effluent from the new Bank C
- An additional Drum thickener
- New incoming switchboard for the new DNO supply
- Modification and upgrade of HV/LV networks
- Modification and upgrade to the power management system and site-wide SCADA
- Modification and upgrade to the Process SCADA
- Additional standby powered generation
- Demolition and removal of redundant structures, plant and equipment
Kier Infrastructure has been awarded the contract – the standstill period will run until 26 February 2026 and the earliest date the contract will be signed is 31 March 2026.
Current estimated start and end contract dates are 1 April 2026 to 29 March 2030.