Water & Wastewater Treatment

14 | AUGUST 2015 | WWT | www.wwtonline.co.uk Meanwhile, there have also been some archaeological surprises: the discovery of the skeletons of a Roman soldier, dating from 200AD, and a bronze age woman dated 500BC, being the most dramatic find. County archaelogists have been keeping a watching brief over the construction. The pipeline material varies between polyethylene, ductile iron and steel, and in diameters ranging from 200mm to 600mm. A corridor of 20-25m is required for the pipeline, with a typical trench being 1.2m wide and 1.5-2m deep. There are more than 120 crossings required in the total programme of work, including major trunk roads, rivers and railway lines. Great care is being taken with the appearance of the new assets. The new storage tanks are typically underground and grassed over, while pumping stations have been designed to be as unobtrusive as possible. For example, in response to feedback from residents, the newly completed station at Monkton Deverill, Wiltshire, has been built with a wooden cladding exterior to give it a rural feel, while it will be largely shielded from view by newly planted trees. As might be expected, a co- ordinated, collaborative approach has been necessary for the delivery of such a large project; a substantial core of expertise has been provided in-house by Wessex Engineering and Constructive Services (WECS). WECS established an external project workstream in 2010, dedicated to the delivery of the programme; the team set up a co-located office in the centre of the Wessex Water region at Yeovil, where staff of all disciplines could work alongside each other for part of a typical week. Atkins was engaged to carry out optioneering studies, outline designs and construction support services, while AECOM and Grontmij have been recently commissioned to complete outline and detailed design for water treatment plant refurbishment. The detailed design of more than 100km of new pipelines has been undertaken ● To ensure secure future supply for customers, Wessex Water need to link up the south of its area, where water is plentiful, with the north where it is less so ● It also wants to link up communities currently relying on a single source, such as a borehole, into an area-wide grid to mitigate possible water quality issues in future ● A reduction in abstraction licences from April 2018 at several water sources, including the River Avon, will heighten the need for water transfers • Drivers by WECS' own in-house pipeline design team. Key external contractor partners on the projects have included Trant Engineering Ltd, Lewis Civil Engineering and Clancy Docwra. One of the most innovative aspects of the project is the Optimiser control system which will manage and optimise the transfer of water along the new transfer main. Centrally controlled • Innovations ● New Optimiser control system will schedule water transfers along the trunk main at the best time to provide secure supplies at the lowest energy cost ● Blending of water containing nitrates with nitrate-free water will ensure nitrates remain at safe levels at key points in the network ● Most links within the scheme are designed to be bi-directional to maximise flexibility The new pumping station at Monkton Deverill has been designed to fit into its rural setting Project focus: pipes and pipelines

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