Thames Water has announced the first section of GRP lining has successfully been installed in the NOS at Stratford High Street, marking a pivotal moment in the upgrade of the Victorian sewer. This milestone comes as part of the company’s £70 million upgrade of the NOS to improve its resilience for generations to come.
The NOS is built above ground along an embankment, serving as a critical “underbridge” that helps to support key roads and railways that are placed over it. The underbridge at Stratford High Street is particularly vital as it supports a dual carriageway used by more than 40,000 vehicles each day. Over time the sewer soffit had weakened but with the installation of new durable GRP liners, the giant trunk sewer is reinforced to manage full traffic loads and is designed to last 120 years.
The company, worked with Principal Designer and Contractor McAllister to deliver an innovative solution with minimal disruption to the area. The bespoke GRP was manufactured off-site, with the different sections transported and carefully installed through an opening of the sewer adjacent to the road. Once this was completed, the GRP was then pushed into position under the carriageway. Precision was required with limited space around the units to manoeuvre.
Richard Smith, Senior Project Manager at Thames Water said:
“This was a collaborative effort between our teams – working together to improve resilience of our pipes so they can withstand the pressures of climate change and population growth, so we can deliver reliable services to our customers.
“Strengthening this sewer system, ensures that we can continue delivering life’s essential service while safeguarding our customers, communities, and the environment.”
Dan Watson, UK Managing Director at McAllister Group said:
“McAllister have been cleaning, inspecting and maintaining various sections of the Northern Outfall sewer for many years, whilst at the same time admiring the original workmanship and vision of Joseph Bazalgette. To now be given the opportunity to work with Thames Water and inject a further 120 years of life back into the sections beneath Stratford Hight Street, with modern trenchless technology is an honour”.
The Victorian pipes were originally constructed between 1860 – 1865 with each sewer measuring 2.7metres in diameter – large enough to drive a transit van through. Wastewater flows through the pipes at a rate of up to 20,000 litres per second.
The first two of eight sections have now been completed and when finished the total length of lined sewer will be 200m. This phased approach has allowed the rest of NOS to continue in operation to maximise sewer flows to Beckton Sewage Works for treatment.
