WET News

BRAY KELEHER IN NUMBERS • £22M: The cost of the project • 2020: The year that the project will be completed • 25,000: Tonnes of earthworks needed to prepare for the project • 350: Precast panels being used in construction • 68 ML/day: The new capacity of the plant wwtonline.co.uk | JANUARY 2019 WET NEWS 9 secured, work began in the sum- mer of 2018. One complication was that the earmarked land had previ- ously formed part of a local land- fill waste site, so contained con- taminants including asbestos had to be cleared before construction could start on the project. In total, 25,000 tonnes of earthworks were needed, with the material moved by a fleet of 40 heavy lorries. BAM Nuttall and nmcn (for- merly Nomenca) are the main contractors on the project, work- ing in a joint venture as part of South East Water's Lot A frame- work, which covers major works. The first construction phase con- sisted of piling, followed by build- ing the concrete bases of the tanks and units. Around 350 specially designed precast concrete panels – supplied by manufacturer Kijlstra and imported from the Netherlands – are being used for the upright sections of the construction, rep- resenting the fir st time this approach has been used on this scale by South East Water. The precast panels are being built off- site and then brought to the site just in time for installation. This dramatically reduces the construc- tion time required on site: for example, tanks that would require eight to nine weeks to build using in-situ concrete can be assembled in only eight or nine days. With space on site relatively con- strained, the approach means the work can be achieved in the most efficient manner with vehicle traf- fic, health and safety risks, and total worker hours on site all minimised. The design of the precast South East Water. "The model [showing the 3D design] has been shared between all of the supply chain," says Ste- venton. "It's been interesting to see the interface between the designers and the manufacturers. For example, when the panels are laid out they might want to put the rebars [reinforcing bars] in certain locations, which might not work with where the pipes go through, and in some cases we've had to move a pipe, in other cases move a rebar. It's been quite a detailed and challenging phase, and there's been some lively discussions." The project is introducing some improvements to treatment pro- cesses and equipment. New baf- fles will be installed in the pre- ozonation tank to make this more efficient. The settlement phase deploys a new, innovative technol- ogy, DWI-accredited TUBEdek Lamella Separation Tubular Set- tlers, made by 2H Water Technolo- gies. At the second ozonation stage (inter ozonation), ozone diffuser rods are being put in to replace diffuser domes, on the g r o u n d s t h a t t h e s e h av e a reduced surface area and are easier to clean during the site's annual maintenance shutdown. Finally, the site's sludge treat- m e n t w i l l b e s i g n i f i c a n t l y enhanced, with a new blending tank, two thickening tanks and one tank for thickened sludge, all of which improve the quality of sludge and its reliability for being recycled to land. Treated water from Bray Kele- her feeds the Surrey Hills service reservoir from where it goes into A diagram of the works, with the new sections highlighted in bright green "The Bray Keleher project is a flagship scheme within South East Water's current AMP investment programme and we are proud to be playing a leading role. The project has been meticulously planned and the collaborative approach to working is paying dividends, with work on site progressing well, and the project is on track for completion in spring 2020." Tony Stanbridge, operations manager, nmcn the mains. Since this reservoir is also fed by Egham Treatment Works, which is run by Affinity Water (with any plant shutdowns needing to be covered by the other), the two companies have maintained a constructive dia- logue about the project. The project is currently on time and on budget. The construction phase is expected to be complete in March next year, with the expanded plant being operational by November; this would be well in time to meet the March 2020 deadline that is required to fulfil the terms of the abstraction licence from the Environment Agency. panels required a high d e g re e o f co l l ab o r a t i o n between client, contractors and the supply chain, explains Brian Steventon, project manager at Ul mate Pump & Flow Control The only outsta on with integrated Ultrasonic & RADAR capability NOW WITH CERTIFICATION CAPEX savings from complete integra on - RTU, ultrasonic sensor and advanced pump controller OPEX savings from predic ve maintenance and efficient pumping The complete TOTEX solu on T: +44 (0) 1684 891371, E: info@pulsar-pm.com, W: www.pulsar-pm.com

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