Water & Wastewater Treatment

www.wwtonline.co.uk | WWT | APRIL 2016 | 17 Project focus Sewer networks HDPE pipes break new ground with Lee Tunnel outfall Project focus L ondon's Victorian sewerage system was designed to overflow into the River Thames during extreme weather, when the sewers reached capacity. One hundred and fiy years on, the system has outgrown the demands of an increasingly populated 21st century city, and sewer discharges are now happening much more frequently – around once a week on average, according to Thames Water. To combat this and in order to future-proof one of the world's most populous cities, Thames Water has developed three major multi-billion ● Weholite technology used in multi-billion pound Thames Water engineering project ● Lee Tunnel benefits from the biggest plastic pipe outfall ever installed in the UK ● Partnership used combined expertise for land and marine applications burdened water management network up to the standard of the modern day, and beyond. In 2013 Asset International supplied over 5km of Weholite HDPE pipe for the Beckton Sewage Treatment Works upgrades. Weholite pipes were supplied in various sizes; ranging from 400mm to 3000mm in diameter. The pipes were used throughout the extensive project for inter-process pipe work, and all of the associated chamber fabrications. The Lee Tunnel is one of two tunnels which will collectively, with the under-construction Thames Tideway Tunnel, capture an average of 39 million tonnes of sewage a year from the 35 most polluting combined sewer overflows (CSOs). The £635M Lee Tunnel will manage discharges from Abbey Mills Pumping Station in Stratford - London's largest CSO - which accounts for 40% of the total discharge. At four miles long, the tunnel will run beneath the London Borough of Newham and will help prevent more than 16 million tonnes of sewage mixed with rainwater from overflowing into the River Lee each year. The new tunnel will capture the overflow and transfer it to Beckton Sewage Treatment Works, which as outlined above has undergone vast extension work in order to deal with the increased volumes it will be processing. The construction of the Lee Tunnel brought with it a unique set of demands, the main one being the boring of London's deepest ever tunnel, no small feat in a city that has one of the most complex subterranean networks in the world, creating something of a navigational and engineering headache. Construction work began in September 2010 and operations were completed in late 2015. In 2012, main contractors MVB (a joint venture between Morgan-Sindall, Vinci Construction Grands Projets and Bachy-Soletanche) approached Asset International Limited and Uponor Project Services to examine the complex design. The original idea included in-situ building a concrete box culvert in a dry trench by holding back the tidal waters of the Thames, which has a rise and fall of 7 metres. The Asset and Uponor PS partnership set about using their combined design expertise for land and marine applications to re- engineer the project by creating what is a landmark design, the biggest plastic outfall ever installed in the UK and one of the biggest in terms of diameter worldwide. pound engineering schemes to help prevent sewer overflows and improve water quality in the Thames. All five major sewage treatment works in London have undergone extensions and upgrades, the Lee Tunnel is in operation, and construction is underway on the Thames Tideway Tunnel. Asset International - which operates under license from Uponor Infra of Finland and is the world's largest manufacturer of Weholite HDPE products - is involved in several of the vast infrastructure projects to bring London's outmoded and over- Dr Vasilios samaras TechnIcAL DIRecToR AsseT InTeRnATIonAL The marine section of the outfall being manoeuvred into place

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