Trant Engineering complete £4.4m upgrade at South West water’s Yeoford STW
October 22, 2025
The multi-million-pound scheme to improve South West Water’s Yeoford Sewage Treatment Works (STW) is complete. The works, located in a rural agricultural area near Crediton in Devon, is bordered by farmland, including a 2000 strong herd of dairy cattle and an equestrian centre.
WINEP scheme
The scheme was part of the Water Industry National Environment Programme (WINEP), the regulatory framework developed by the Environment Agency (EA), Defra, Natural England (NE) and Ofwat, which outlines the environmental obligations for water companies.
There were two key regulatory dates, firstly increase storm water capacity by 94% by 31 March 2024, and secondly, double biological treatment capability by 30 September 2024.
In December 2023, South West Water awarded a £4.4m contract to Trant Engineering to carry out the required works, as well as improve the site by widening the access road to allow road tankers to reach the lower areas.
The Works
The increased storm water capacity was provided by a new glass coated steel tank together with feed pipework from the existing storm pumping system. The return flows back to the wet well are controlled by actuated flow control valves with internal tank benching and a flushing bell.
The increased biological treatment was achieved by a new process stream consisting of two moving bed bioreactors (MBBRs) with new blower kiosks followed by three lamella clarifiers for final settlement. Variable speed pump drives and controls including a new PLC ICA control panel were installed in a new kiosk.
Additionally, during the contract Trant were tasked with installing new MCERTS metering, and this was successfully completed by the 31 March 2025 deadline.
The secondary process stream
Site Challenges
“The completion deadlines were really tight”, says Kev Targett, Trant’s Contract Manager, “and we had to be aware of the welfare of the dairy cows, so we had to minimise noise and truck movements. No idling plant is a company policy, and that was strictly enforced.”
The single access road on the site, along with the 35-degree hill to the working area limited plant operations. All material deliveries and removed spoil had to be transported through the cattle sheds with each trip consisting of a ¼ mile round trip through the farm to the storage area to the north of the site. Ready mix concrete for the new construction areas had to be pumped from the site entrance.
The kiosk coming down the 35-degree hill
Over 4000 tonnes of material was removed by three 9-tonne dumpers on constant turnaround. All other material movements were by telehandler or farm tractor and trailer.
Project Success
Trant Engineering met all three deadlines and were awarded the Site Pride Gold Award by South West Water for excellence in health, safety and wellbeing.
The Trant team receiving the Gold ‘Site Pride Award’
“I am proud of the team and the work carried out” says Kev Targett, “We faced up to the tight deadlines and difficult site, and we delivered.”
Trant have a policy of using local personnel wherever possible, and only the Site Manager, General Foreman, Civils Supervisor and, for a short term, the Commissioning Engineer commuted from Trant’s office. The Project Manager lives locally, and all the site labour was employed either directly or through local agencies around Exeter.