Water & Wastewater Treatment Magazine
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20 | XXXXX 20XX | WWT | www.wwtonline.co.uk I n mid-January, Southern Water was alerted to a problem with a sewer pipe near Manston Airport in Kent. The airport had not been in use for almost five years, but a sinkhole had been spotted by Department for Transport (DfT) staff working there as part of the Government's preparations for a potential no-deal Brexit just over two months later. "Manston Airport was key for the Brexit planning – Operation Brock they called it," Chris Perkins, Southern Water's compliance man- ager for wastewater treatment, says. "If we leŒ with no deal on March 29 and things started to back up around the ports, they planned to funnel 6,000 lorries to Manston and carry out checks at the airport itself to relieve pressure on the motorway network." The sinkhole had occurred around the rising main that takes sewage from 90,000 people in Margate to the treatment works at Weatherlees Hill, and investiga- tions revealed that sulphuric acid had completely eroded the crown in one part of the 800mm, mortar-lined ductile iron pipeline. Working alongside delivery partners Cappagh Browne and BTU (Barhale Trant Utilities), Southern Water quickly decided that adopting a 'make do and mend' solu- tion would be pointless, instead resolving to replace an 800m section – some of which crossed the airport itself – with polyethylene. To facilitate Operation Brock, Southern Water agreed to complete the work taking place within the airport by 29 March, with a target to finish the whole project by the start of the bathing water season on 15 May. That schedule was challenging enough, but further factors complicated the matter significantly. "During World War II, Manston was one of the most heavily bombed airports – so much so that at one point the cabinet were looking at pulling out of it," Jon Yates, project manager at Southern Water, says. "That meant the risk of finding UXO [unexploded ordnance] was incredibly high. "There's also a high risk of finding pipe mines and fuel lines and all sorts of things that weren't necessarily German bombs but put in by the Allies to protect the airport. I believe when the rising main was first put into this airport, they found in the region of 80 pipe mines." Southern Water's £2.5 million project to replace an 800m stretch of sewer main in Kent was complicated by – among other issues – Brexit, World War II and ancient artefacts. WWT finds out how they managed to deliver against the odds By Robin Hackett Testing times 20 | JULY 2019 | WWT | www.wwtonline.co.uk The Works: Sewer networks