Client: Southern Water
Services: Complex delivery
JV partners: MWH Treatment
Lingfield Wastewater Treatment Works (WwTW) in Surrey is approximately 2km north of Lingfield Park Racecourse. The catchment for the works serves the population of Lingfield and surrounding villages.
An upgrade project is currently taking place which, once complete, will improve the quality of treated water going back to the environment and make sure Southern Water can meet the new environmental standards set out by the Environment Agency in the Water Industry National Environment Programme (WINEP3). The project started on site in August 2023 and the main works are due to be complete in December 2024.
Project drivers
The Lingfield upgrade was required to fullfil the following drivers:
- WINEP - Phosphorus removal (regulatory date 22 December 2024): Lingfield WwTW is already required to achieve P removal, but a more stringent permit will be introduced at the site this AMP. New assets are required to meet the revised permit conditions.
- U_iMP5 Programme - increased flows (regulatory date 31 March 2025): A further project driver is to implement improvements at the site to facilitate an increase of the full flow to treatment (FFT) from 83 l/s to 127 l/s. This will involve the installation of new process assets to provide additional biological treatment capacity and accommodate projected population growth to the design horizon of 2035. The projected population equivalent (PE) at the design horizon is 13,390.
Project scope
The project encompasses the following:
- Upgrade the existing 30m3 ferric dosing facilities to incorporate a second dosing location
- New tertiary treatment plant (TTP) comprising a Bluewater Bio FilterClear package
- Convert the existing sand filter pumping station (PS) into TTP Feed PS (sized to accommodate new peak flow through works)
- Replace crude sewage pumps with larger capacity units and modify pipework and access to accommodate and enable certification of inlet flow meters at FFT
- New 12.5m diameter radial humus settlement tank with half bridge scraper
- New 31m diameter biological trickling filter with a working volume 1377m3
- Cross-site pipework to integrate the new filter into the existing treatment works.
- Upgrade the site power supply and telemetry system.
The challenges
One of the main challenges facing the site team at Lingfield was the considerable number of previously unidentified services in the area where construction was required.
There were approximately 140 services which needed to be found and avoided. The site team utilised Cable Avoidance Tools (CATs) and Signal Generators (Gennys) and Vac EX as well as multiple trial holes. There have been an estimated 45 permits to dig raised in order to safely establish the whereabouts of these buried services.
Another key challenge faced by the team at Lingfield was posed by the lack of space available on site. To overcome this challenge, the team designed a circular retaining wall for the new humus tank.
The site itself is also on a flood plain and due to the increased rainfall and weather conditions earlier in the year the site flooded and needed to be pumped out to allow works to continue.
Key benefits
-
As part of our commitment to positive change in construction, CMDP have registered with the Considerate Constructors Scheme and achieved a score of 45 out of 45 for the site’s most recent assessment visit earlier this year.
- To enhance the environment, bat boxes have been installed and upon completion of the works, these will aid local natural habitats. During works acoustic barriers have also been installed to limit impact.
-
Project engineer (Xenia Magdaleno-Tseng) is registered as a STEM ambassador and has judged a local school engineering competition. The STEM Ambassador Programme is an important part of CMDP’s work to inspire the next generation into the industry and capture interest.
Contact
Gerard Shore
Sector director
[email protected]