Water and Effluent Treatment Magazine
Issue link: https://fhpublishing.uberflip.com/i/437549
12 WET NEWS JANUARY 2015 New high lift pumps feed treated water to the three service reservoirs inspected and patch repaired for the first time since commission- ing. All ten shutdowns ran to schedule, with many being com- pleted early, and the water works remained fully opera- tional at all times. Ironically, the very last con- nection to be tackled, linking treated water supplies into the delivery mains to Riverhill – the largest service reservoir – proved the most difficult and triggered a three-week contract extension. The existing, some- what fragile, 500mm diameter pipeline to Riverhill had burst and was repaired immediately before the contract started. Original mains This resulted in the new tie-in connection being moved an additional 80m to the north with an extended section of new pipe laid parallel and adjacent to the original mains. Even though the conven- tional 4m deep open-cut trench for this extended run was dug only in short sections to main- tain its stability, the excavation frequently flooded. Water ingress was eventu- ally traced not to the weak adja- cent pipe connecting to River- hill Reservoir but to a rogue uncharted salt-glazed early 1960s pipe that, it is thought, had been used as an overflow or run-off route for one of the nearby boreholes. The new pipelines were origi- nally all designed as ductile iron to be placed in open excavation. But where a 430m long section, running from the pumping sta- tion to connect with existing delivery mains to Solefields and Oakbank reservoirs, was routed largely beneath the site's only access road, Murphy came up with a less disruptive alternative. By laying this section using trenchless directional drilling, with more flexible 355mm diam- eter polyethylene SDR11 pipes being inserted from three drill- ing pits, the team gained unin- terrupted use of the access road It also eliminated possible access restrictions for local resi- dents who used the lane and it was very important they were not inconvenienced by the project. Open trenching Specialist contractor JMH Direc- tional Drilling completed the work in just three days – a sav- ing of at least four weeks over conventional open trenching methods. Control of the original treat- ment works had been largely manual, demanding permanent onsite staff. But a state-of-the-art fully automated motor control centre now only requires occasional onsite checking. Instead every operation is monitored by SEW engineers from the company's headquarters. With all the modifications complete, Cramptons Road Water Treatment Works is now one of South East Water's most technically advanced water treatment works and performs a crucial role in ensuring the quality and reliability of the supply of 565 million litres of potable water a day to a popula- tion of 2.1 million in surround- ing counties. n Stuart Griffiths is project manager at J Murphy & Sons ONSITE REFURBISHMENT Directional drilling was used to install pipes running beneath the site's access road, ensuring its uninterrupted use New high lift pumps feed treated water to the three service reservoirs