Water & Wastewater Treatment

14 | march 2015 | WWT | www.wwtonline.co.uk Project focus E ffective teamwork and a series of astute design changes made on site have helped Essex & Suffolk Water complete a major wastewater pipeline project ahead of schedule and under budget. The Chelmsford Effluent Pipeline transfers secondary treated effluent and storm water from Anglian Water's Chelmsford and Witham Sewage Treat- ment Works to an estuarial outfall on the River Chelmer near Beeleigh. Dat- ing from the 1920s and modified in the 1950s, its purpose is to carry effluent downstream of the river intake point that supplies raw water to Essex & Suffolk Water's Langford and Hanning- field impounding reservoirs. Despite the fact that Essex & Suffolk Water – which is part of the Northum- brian Water Group - is a water supply only company, it is responsible for the 11km pipeline for historical reasons, because it was constructed at the same time as the works at Langford to enable them to operate. Legislation dictates that E&SW must maintain a minimum flow capacity of effluent from Anglian's works, so when An- glian alerted E&SW to the fact that the pipeline was running close to capacity, E&SW started looking at plans to upgrade it. ● Essex & Suffolk Water pipeline carries effluent from Anglian works ● Creative use of abandoned pipe section spared disruption and saved money ● Direct procurement of concrete pipes meant further savings "Anglian Water wrote to us a few years ago saying that they believed our pipeline didn't have sufficient capacity to take all of their flow," said Paul Grimwood, project manager at Essex & Suffolk Water. "It was very close to capacity, and it wouldn't have lasted much longer without some work, espe- cially as Chelmsford has got a number of housing developments underway at the moment, with several thousand houses going up." James Brockett EDITOr, WaTEr & WaSTEWaTEr TrEaTmENT ● The existing effluent pipeline from chelmsford was nearing capacity, with housing developments in the chelmsford area set to increase flow ● Essex & Suffolk Water had a legal requirement to maintain the pipeline's capacity because of a historic arrangement with Anglian Water ● the 17m fall along the route enabled a gravity solution, with 8.1 km of concrete pipes • Drivers Pipes and pipelines Flexible thinking helps complete Chelmsford effluent pipeline Plans were drawn up for a new pipeline, with 1400mm diameter con- crete pipes to be laid between Cuton Lock in Chelmsford and Langford Water Treatment Works. It was decided that the last kilometre of the existing pipeline did not need to be added to, as it had sufficient capacity to last until at least 2030. Gravity solution With a 17m fall between the Chelms- Above: A digger shield was used for the two river crossings Above: Work underway in a compound chamber on the Chelmsford Effluent

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