Water and Effluent Treatment Magazine
Issue link: https://read.utilityweek.co.uk/i/468709
The current phase of work is taking place in Ramsgate and has a value of £20M. Work will be completed this summer Going deeper underground • Southern Water, with the help of Clancy Docwra and Atkins, has been burrowing under- neath Ramsgate to ren- ovate the town's 'unique' Victorian sewer network. R amsgate's 'unique' sewers were built more than a century ago by miners who dug underground tunnels through the chalk, up to 10m deep in some places. These tun- nels remain in place and con- tinue to act as a conduit for the sewer network. The sewers have served the Kent seaside town well but are now in need of some attention in order for them to continue carrying flows safely from prop- erties in Ramsgate to Weather- lees treatment works. As a result, Southern Water is investing £20M to renovate 12km of Victorian sewers across Ramsgate. The project, which started in July last year, is part of a wider scheme to renovate sewers across Thanet, which represents an investment of more than £80M over ten years. The scheme in Ramsgate involves: • Lining 5.5km of existing tunnels • Rehabilitating more than 12km of sewers • Building more than 2km of new pipeline • Improving 98 manhole sha's • Building 15 new manholes Work on the project is being carried out by contractor Clancy Docwra, which is also construct- ing new manholes and enlarg- ing existing ones to make access easier and safer. Specialist technicians were trained to work in deep tunnels using breathing apparatus, have been working to seal and line sections of the tunnels, repair existing sewers and build new projects specs • Seal and repair existing sewers and manholes • Construct new overflow sewers to contain flows • Construct more than 2km of new pipeline • Line more than 12km of existing sewer • Improve 98 manhole shafts ONSITE SeWeR MAINTeNANCe pipelines. Its aim is to maintain the integrity of the sewers, reduce the risk of bursts, leaks and floods, and protect the envi- ronment and chalk aquifer that spans much of the area. The team comprising South- ern Water, designers Atkins and delivery partner Clancy Docwra developed new solutions to overcome a wide range of tech- nical, social and environmental challenges. 'Exciting scheme' Southern Water senior project manager Adnan Naeeni said: "From an engineering perspec- tive, this is a complex but excit- ing scheme. The Victorians cre- ated a unique sewer network in Ramsgate, by building tunnels to house the pipes, rather than trenches. This has given us some unusual challenges, not least how we access the sewers to start the work, which is where our specialists come in. They are working deep underground, refurbishing the sewers and building new ones where necessary. "The end result will be a more robust sewer network for Ramsgate, which will have many benefits. We've been working across Ramsgate in up to ten locations at any one time, so I know we've become a famil- iar sight." The current phase of work is taking place in Ramsgate and has a value of £20M. This phase started in July 2014 and is expected to finish in the sum- mer of 2015. The sewer network in Thanet is complex, in a region where techknow • Bespoke trenchless techniques were developed that had a small site footprint, reducing disruption and limiting the environmental impact • A stand-alone CIPP lining system was created for the chalk headings • The lining solution coupled with a UV light curing system for the chalk headings has provided minimal environmental impact • CIPP liners were designed and tested that negated the need for any grout infill neeD to know 1 The Ramsgate project is part of the wider £80M Thanet scheme to upgrade the 100-year old sewer network 2 Specialist technicians trained to work in deep tunnels using breathing apparatus 3 The Victorians created a unique sewer network in Ramsgate, by building tunnels to house the pipes, rather than trenches 4 The Victorians created a unique sewer network in Ramsgate, by building tunnels to house the pipes, rather than trenches the VerDIct • Southern Water says the use of headings for sewerage infrastructure is unique to the UK and has the potential to impact the aquifer if the sewers surcharge and flows are uncontrolled during storms. The new innovative solutions used on the project have been proved for use in delivering the future phases of the scheme over the next five-plus years. 8 WET NEWS MARCh 2015