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all UK water and wastewater service European and International water industry figures directory of water industry suppliers Listings grouped by category 2015 WHO'S WHO IN THE WATER INDUSTRY 2015 WW15 ofc-spine.indd 2 05/01/2015 10:34 Who's who in the water industry 2016 Pre-publication discount Order before 1st January and pay Only £62 water professionals to government licence Faversham House Ltd whoswho@fav-house.com Wood Street, East Grinstead, West Sussex, RH19 1UZ without delay includes 16/09/2015 18:08 T he brick sewer in York Place, Bristol, dates back to around 1870 has been preserved thanks to Wessex Water's decision to insert a 200m long lining. The work was completed in a matter of weeks – as opposed to the six months that would have been required to excavate the damaged sewer. What is more, the project offered a fascinating glimpse into the past. Sewer rehabilitation programme manager Julian Britton explains: "The challenges have definitely been the geology. The reason why Cli‰on is here, 70m above the city centre, is because of the incline of the quartzitic sandstone. This is around ten times the strength of structural concrete. "Our miners have met the same challenges as the original miners, and they have also been coming across some pick marks in the rock and even candles and candle wax that would have been used to light the way." Loose bricks at York Place were originally discovered by CCTV cameras, which showed the poor condition of the sewer. It is estimated the new lining will increase longevity of the sewer by about 200 years. Glimpsing the past • A slice of Victorian history has been preserved at the heart of Clifton in Bristol, and it is all down to a sewer renovation scheme. Richard Wortley explains. ONSITE RehABilitAtion the project was completed within weeks, rather than months The lining – the longest we have used in ten years – has been baked in place at a temperature of 90°C. Interventions The lining division of Onsite has been working with Wessex Water for more than 15 years, providing Cured in Place Pipeline (CIPP) solutions in support of its framework sewer renovation programme. The concept of CIPP developed by Wood, Chick and Chandler in the early 1970s is used extensively worldwide, yet some interventions have a resultant benefit which is exponentially higher than others. The sewer in question is 6m deep, a 690mm diameter circular sewer, routed along the crest of a steep hill with a single rank of three-story early Victorian houses positioned on one side. The sewer comprises a single ring of brickwork, in time deteriorated ash mortar. The structure was in an advanced state of failure, SRM grade 5, with one point of collapse some 18m downstream from the upstream manhole. The sewer is a total of 200m in length. Usually the local geology does not play a major part in the lining of a sewer, but on project specs • Renovate and preserve a Victorian sewer in Bristol • Construct a 6m deep shaft • establish two rotary boreholes this occasion it had two implications. Firstly, a new 6m deep, 1.5m diameter sha‰ was required, equidistant along the length to be lined and secondly, it was necessary to remove the collapsed brickwork to allow a full eversion from the new sha‰ though the defective section. The Wessex Water Critical Sewers Team, which manages the framework, undertook two rotary boreholes to prove the recorded solid geology as quarzitic sandstone at an angle of 30 degrees with interbedded mudstones. The team brought in consultant geologist Dr Brian Hawkins last autumn to establish the lithology, and in-situ and laboratory testing established that the rock was extremely strong at 450MPa uniaxial compressive strength, with a rock quality designation (RQD) which indicated few fractures, which could be exploited by pick excavation. One of the boreholes was positioned directly above the sewer line and taken down to within 400mm of the sewer soffit to establish if the original sewer had been constructed in heading, which proved to be the case. Consequently, any excavation down on the point of collapse would mean a high degree of vibration, when JUne 2016 Wet NeWs 11 passing through the sandstone bands, which could cause the brick sewer to unravel. Wessex Water undertook a potential hazard analysis and concluded for a number of reasons that the repair was best undertaken by following the existing heading with a new one, and building back a twin wall pipe, through which the CIPP liner could pass to the upstream manhole. Good choice Wessex Water has a long history following the principles of Sir Michael Latham in collaborative working, as encouraged by his 1994 report Constructing the Team. It brought in a specialist timber heading company, Matt Durbin Associates, who won a tender for the heading works. The tunnelling contractor opted for a traditional timber temporary support due to its versatility. This proved a good choice as the company soon encountered the extremely strong sandstone in the soffit of the heading, which was difficult to remove whilst adhering to trigger times on the hand tools, to ensure compliance with Hand Arm Vibration legislation. The heading was recognised by lead miner Mike Avent as some

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