Testwood Water Supply Works (WSW) is Southern Water’s largest water treatment works in Hampshire and supplies water to over 250,000 customers. As part of a £50 million major upgrade to the Testwood WSW, Southern Water have committed to replacing equipment which has come to the end of its working life and to improve the treatment process to ensure a continuous fresh and clean water supply.  A review of the Polyelectrolyte and Coagulant Dosing Systems identified the requirement to replace the entire dosing systems without adversely affecting the operation or processes of the existing equipment, whilst also continuously maintaining the current production levels.

RSE was engaged by Southern Water’s Tier 1 contractor, Trant Engineering, to design and construct a modularised Chemical Dosing System. RSE’s innovative solution was to design a new modularised chemical dosing building to house the new Polyelectrolyte and Coagulant Dosing Systems, which enabled an offsite build with minimal disruption to the operation of the existing dosing systems and ensured continuous supply of wholesome water for Southern Water customers throughout the duration of the project.

RSE’s chemical dosing plant solution incorporated 6 No. Polyelectrolyte Dosing skids and 3 No. Ferric Dosing skids, each with duty/standby pumps designed and manufactured by RSE’s specialised Chemical Dosing division. Additionally, the plant required a Polyelectrolyte batching system, supplied by Richard Alan Engineering. The modularised plant further consisted of a Motor Control Centre (MCC), polyelectrolyte bulk storage room and building ventilation system.   

The new modular build solution allowed the entire chemical dosing building to be constructed offsite, before being transported to site in modular form for final assembly. One key benefit to Southern Water customers using this approach is that traffic in and around the site was greatly reduced, meaning a significant reduction for the projects carbon footprint. RSE’s delivery model provided a major programme efficiency, enabling the civil construction works to progress concurrently with the offsite electrical and mechanical (E&M) build programme. Further still, the offsite build solution allowed the dosing systems to be fully tested and commissioned off site, driving further programme efficiencies.

Michael Agolini

Michael Agolini

RSE Production Stream Lead

This project brought together RSE’s Chemical Dosing division and Modular Water Treatment Technologies experts to deliver an impressive offsite modular build and is an excellent demonstration of RSE’s vast array of design and manufacturing capabilities, across multiple business locations. Throughout the project, we worked closely with Trant Engineering to ensure the project was delivered on time and to the correct specification. This collaboration allowed both companies to succeed together whilst continually searching for methods of improving our design, build and delivery.

Olivia Kerr - Marketing Co-ordinator

Olivia Kerr

Marketing Co-ordinator

First Published

12th October 2022

Estimated Reading Time

3 minutes