Bridges was engaged to re-design a UV installation – the first Thames Water AMP6 project for the new eight2o Alliance. The scheme had been designed to be below ground due to the water coming from a ground spring that had been planned to work under gravity. We were given an opportunity in outline design stage to demonstrate an above ground solution. Our in-house design team quickly developed a 3D model of a 6m x 6m UV kiosk which was fed by a pumping station that intercepted the spring flows.

In order to service summer demands the project had to be in commission by June 2015. Bridges presented the UV system using a 3D model to Thames Water and eight2o at a Thames Water Opman (Hazop). The solution was accepted and we commenced the detailed design phase. Due to the time scales and the size of the project it was decided to develop an off-site solution that could be transported along narrow roads and through a built-up housing estate. The final solution consisted of the following off-site packages:

  • A dual reactor complete with support frame, containment, cabling, small bore pipework and flooring;

  • Internal kiosk walls pre-fitted with sample sink, small bore pipework, control panels, distribution boards, sockets and light switches;

  • Sample pumps starter stands pre-fitted with the starters; and

  • Sample pumps and UVT stand pre-fitted and wired with analytics, pipework, valves, pumps and isolators.

We were able to prebuild and test the solution within our workshops ready for final site connections and commissioning. In turn, by adopting this solution, eight2o’s team were able to demonstrate a £2.5M saving against their business plan. Our innovative thinking assisted in this by reducing site preliminary work due to a dramatically reduced programme and development of an above ground solution – thereby removing ground water issues in construction and civils costs.

The scheme had to meet a water `in supply` date of early June and due to these techniques we were able to build the UV system off-site in parallel with civil work on-site. This then left only a four-week window on site prior to commissioning start dates. This resulted in eight vital weeks being saved in the programme; along with eight weeks of working within a construction environment which also reduced health & safety risks on site. In addition, the project carbon savings for Bridges vehicle movements were also halved by using this method.

Another key benefit to our client was that their own staff were then able to move onto their next projects quickly thereby assisting in bringing the overall eight2o programme forward.