Water & Wastewater Treatment Magazine
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Project focus Water networks Optimising the Wessex Grid Project focus W essex Water's integrated water supply grid is its largest ever and most complex project. The grid, which will be completed in 2018, includes the construction of 200km of new pipelines, 24 new or refurbished pumping stations, and 12 new storage tanks ranging in capacity from 2 to 8 million litres. The grid includes more than 50 individual projects designed to combat resilience issues within the water supply network, costing a total protect their ecology; and deal with seasonal or occasional deteriorating raw water quality, particularly increasing concentrations of nitrates at some groundwater sources. The Team Wessex Water's internal engineering and construction services business, Wessex Engineering and Construction Services (WECS) has managed the overall delivery programme, with both WECS and Atkins providing engineering design, planning and environmental services. Atkins were involved in scoping the route of the new trunk main and assisting WECS to receive buy-in to the preferred route. Innovation and the Optimiser One of the most innovative aspects of the scheme was the development of the 'Optimiser' which will manage and optimise the transfer of water along the trunk main. The Optimiser is a sophisticated closed loop central control system, which is designed to manage network operation efficiently and effectively. Atkins' role was Project Manager on behalf of WECS, to develop the conceptual design, prepare the initial business case for the Optimiser, and assistance with the implementation of the Optimiser to the network. Alongside the development of the Optimiser, Atkins also developed an overall control philosophy for the trunk main. This was based around 4 levels of Control: 1) Local Manual Control – the basic level of control with no automation and pumps/reservoir levels controlled manually. 2) Local Automatic Control – this is historically the normal method of control, with operating instructions issued to individual assets at each site. 3) Co-ordinated Control – two sub- systems are being integrated into the supply grid. Under this level, the local automatic controls receive commands/ set points over communication links from a centralised system. These can override locally held level set points and pump on/off commands. If the communication links fail, then the system should revert to automatic local control. 4) Optimiser Control - This will ultimately be the normal and preferred method of overall system control for the grid trunkmain. The Optimiser will control all strategic assets considering the whole strategic network and determine the of £228M over 8 years and two AMP cycles. It provides the first opportunity to transfer water between Wessex Water's northern and southern supply zone. On completion, it will meet future water supply demand for the next 25 years; improve the security of supply for customers by ensuring that customers are no longer supplied by a single source of water; help to meet reductions in abstraction licences required by the Environment Agency to improve flows in some rivers and A diagram of the Wessex Water supply grid project, with the new sections in red ● Flagship project enables water transfers to take place across Wessex area ● Optimiser so ware uses sophisticated closed loop control system ● System enables holistic view of supply network 72 hours ahead sTeve bIlTOn SENIOR ENGINEER INFRASTRUCTURE ATKINS drummOnd mOdley PROGRAMME MANAGER WESSEX WATER www.wwtonline.co.uk | WWT | MARCh 2017 | 21