Utility Week

20 | 1ST - 7TH MARCH 2019 | UTILITY WEEK Operations & Assets Utility Week Awards winner case study E ver since it was opened in 1894 to treat sewage from Manchester's rap- idly growing population, Davyhulme Wastewater Treatment Works has been at the forefront of innovation in the water industry. In 1914, Edward Ardern and William T Lockett invented the ground-breaking acti- vated sludge process at the facility's on-site laboratory – a technique that was quickly adopted worldwide. What started out as "sewage farm in the countryside" is now flanked by roads, houses and shopping centres, and has grown to become one of the biggest waste- water treatment works in the UK, serving 1.3 million people across Greater Manchester. Anticipating a fresh population boom in the city over the coming decades and faced with tightening restrictions on levels of ammonia in outflows to the nearby Manches- ter Ship Canal, in 2015 United Utilities began a massive overhaul of the ageing facility. Working in partnership with Laing O'Rourke, the company designed and built an activated sludge plant (ASP) consisting of six primary settlement tanks, ten aeration lanes and ten final settlement tanks. It also installed inlet works and a sludge thickening plant, as well as refurbishing existing assets to improve their efficiency. Four-dimensional modelling was used to combine the civil, mechanical, electrical, instrumentation and supplier plans into a single reference point. Most of the excavations were reused to minimise outside movements. The new entrance was constructed first, to shiœ traf- fic away from the existing entrance and an adjacent housing estate, and tower cranes were installed on rails along the aeration lanes to reduce on-site congestion. Cutting costs To cut costs, speed up progress and enhance safety, the main concrete structures of the activated settlement plant were all precast off-site. Mechanical equipment such as pipe- work, steelwork, walkways and platforms was similarly prefabricated in modular form. United Utilities says this approach to con- struction saved 6,800 on-site working days. The £187 million project was delivered on budget and ahead of schedule by a team of 400 people, with some leœover cash allow- ing for further investments in landscap- ing and odour management to improve the views and smells for nearby residents. The new ASP began accepting flows in September 2017 – four months before the April 2018 deadline – while the sludge thick- ening plant was completed 12 months early in May 2017. To ensure the economic benefits of the investment flowed back to the surrounding community, £50 million was spent with local businesses, creating 26 new construction jobs and supporting 35 apprenticeships. United Utilities says the newly installed assets are now taking 60 per cent of the works' flow through the facility, bringing about "significant power and chemical con- sumption savings". The new sludge thickening plant has ena- bled the facility to produce greater volumes The sweet smell of success at Davyhulme United Utilities and Laing O'Rourke won Utility Week's coveted 2018 Capital Project Management Award for their work on the Davyhulme treatment plant. Utility Week finds out more about the project. "Over the past five years the Davyhulme modernisation project has been our flagship investment scheme at our biggest wastewater site in the UU region, and its delivery has been absolutely world class. "From the latest information management and visualisation technology to the way we've embraced a design for manufacturer and assembly approach and engaged with the local community, every aspect of this project has been a model for getting things right first time. "The whole project team should be incredibly proud of what we've achieved and winning this award is the icing on the cake." RICHARD RATCLIFF, ENGINEERING DELIVERY DIRECTOR, UNITED UTILITIES Winner's comments

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