Earlswood STW
As part of a major site upgrade, Earlswood STW required a more dependable wash water system to meet rising flow demands. The existing system lacked capacity and struggled to maintain consistent pressure during peak periods. KGN Pillinger delivered a bespoke booster solution, designed, manufactured, and installed by a single team, ensuring reliable performance and improved pressure across the site.
Sector - Water utilities: Thames Water
Product / system type: AV Type booster
Location: Earlswood
Project year: 2025
Client / site name: Galliford Try – Earlswood STW
KGN contact: Chris Norman
Project Overview
Thames Water required a new wash water booster pumping station to replace the existing system, which lacked capacity and had become unreliable.
Earlswood STW receives wastewater flows from several surrounding areas, making it a key part of the local sewer network. To reduce untreated discharges, the site is planning to increase flow rate from 340l/s to 400l/s (Thames Water, 2026). The installation of a new wash water booster will help provide improved distribution of wash water throughout the site by increasing pressure and flow capacity.
As the site is located just 15 minutes from KGN’s Merstham offices, the team were keen to support the project and deliver a reliable solution locally.
The Challenge
As part of Thames Water’s wider initiative to upgrade existing facilities across the UK, Earlswood STW has been identified for a £22 million overhaul project (Nova Consultants Limited, 2026), with KGN Pillinger’s wash water booster for forming a key part of the upgrade.
Storm modelling indicates the site could receive flows of up to 2,309 l/s during storm events (Galiford Try , 2024). To ensure the treatment works are still effective, reliable wash water distribution is essential for routine cleaning and maintenance activities across the site.
The new booster system will therefore play an important role in improving wash water pressure and distribution during periods of high flow.
KGN Pillinger’s Approach
Site Survey
KGN's site survey engineer attended site to carry out a full survey. This included taking precision measurements of the concrete slabs, rising mains and duct locations to ensure our design team has every measurement required. The survey also confirmed adequate access for delivery vehicles.
Design
Once the site survey had been completed, the design department reviewed the survey with the project manager and developed the final design for the wash water booster.
A system comprising Lowara 46SV04 15kW Hydrovar pumps, a Lowara 200 litre pressure vessel, and a Gemini Controls Form 4 panel has been configured with specific parameters to deliver optimised variable speed flow and pressure control for Earlswood STW.
Manufacturing
Once the design had been authorised and confirmed by GT, the KGN team manufactured the high-quality stainless-steel base, headers and additionals.
With KGN’s state-of-the-art equipment on hand, the team were able to fabricate and perfect the Skid to an excellent standard.
Installation
Once delivery day had arrived, our engineers arrived on site ready to supervise the delivery of the Booster unit & the kiosk from our couriers.
Once the Booster and Kiosk had been delivered on site, our engineers began installing the unit to the mains, wiring in all the electrics and external crimping works using our modern crimping machine to manufacture pipeworks on-the-go!
There was a slight hiccup on-site with the generator not working, however thanks to the communication between the service team, service manager and the engineers on the ground, KGN were able to get a working generator to site to finish works.
Customer Service / Support
The project manager and coordinator maintained clear and consistent communication throughout the entire project, from initial stages through to completion. This included responding promptly to queries via email, discussing and resolving matters in Teams meetings, and providing accurate programmes to keep the customer informed of progress while the unit was at our facility.
The GT team also attended a witnessed Factory Acceptance Test, which was completed successfully and without issue.
Project Summary
KGN Pillinger delivered a new wash water booster system for Earlswood STW to improve reliability and increase pressure and flow capacity, supporting Thames Water’s wider site upgrade and higher treatment demands.
References
Galliford Try. (2024). M16 – Washwater Booster Pumping Station Particular Specification. Galliford Try.
Nova Consultants Limited. (2026). Transforming Water Treatment: Earlswood STW Upgrade. Retrieved from Linkedin: https://www.linkedin.com/posts/novo-consultants-limited_case-study-earlswood-sewage-upgrade-activity-7405199782861914114-3X7i/
Thames Water. (2026). Thames Water: Investment Plans for Storm Discharge Sites. Retrieved from Thames Water : https://www.thameswater.co.uk/about-us/performance/river-health/frequently-asked-questions/information-about-specific-sites#e