Swinging Into Action – Poo Power Helps Yorkshire Water Drive Green Ambitions at Knostrop
Those who drive into Leeds on the M1 or A63 may have seen a rather large golf ball looking object appear on the Yorkshire Water Knostrop treatment plant near Leeds. The firm is not trying to create a mini Epcot Centre in Leeds, but are building a gas bag, with its construction meaning another landmark has been reached in the £72m Knostrop Energy and Recycling Facility project.
Methane produced from sludge treatment will be stored in the bag with up to 3,700 cubic metres of gas stored at any one time. All of this gas will then be turned into electricity to help power the plant. The facility will begin processing in August and once fully operational later this year, will contribute significantly to the recycling of 94% of Leeds’ sewage sludge by 2020.
The facility will be capable of processing up to 131 tonnes of dry sludge a day and will generate enough renewable energy, using heat and power engines, to provide 55% of Knostrop’s energy needs – enough to power 8,000 homes.
Yorkshire Water Project Manager, Lee Laherty, said: “This is the single biggest investment the company is making between 2015 and 2020. The installation is a huge deal because we can start creating more electricity for ourselves and do more to reduce carbon emissions and help the environment. It also supports Leeds council’s ambition for the Lower Aire Valley to become a hub for green energy and industry.”
The development is part of a growing trend for energy and recycling facilities, which increasingly use anaerobic digestion to generate biogas energy, from the large amounts of sludge they process. Work started on site in May 2016 and is part of Yorkshire Water’s blueprint commitment to investing in renewable energy to benefit the environment and keep customer’s bills low.
The development was approved by the Leeds City Council Planning Committee with global engineering and construction firms Black & Veatch and Clugston Construction Limited working on its construction. Clugston’s subcontract package included ground preparation and stabilisation, involving recycling of existing concrete structures and the installation of 300 CFA Piles. This was followed by the construction of the foundations for tanks, control buildings and installation of ductile iron pipework and cable ducting. Along with a new central process building, Clugston will also be responsible for the installation of 15,000sq.m of link roads and 10,000sq.m of hard standing.
One of Europe’s leading engineering, environmental and design consultancy agencies, Sweco were appointed by Black & Veatch to design, commission and guarantee the DEMON® (DE-amMONification) process at the site. Sweco have designed, commissioned and guaranteed the liquor treatment process at the facility. The DEMON® process will guarantee the removal of 85% of ammonia from liquors generated by the new sludge dewatering plant at the facility without any pH correction or carbon dosing. At maximum capacity the plant will remove 3,150kg of ammonia per day.
The new plant replaces an existing sludge and bio-solid incinerator constructed in 1993 and will enable more efficient sewage treatment, as well as the ability to produce on-site energy. In October 2014, Yorkshire Water constructed a 123 metre-high wind turbine at Knostrop at a cost of around £3.5 million. This is already a major source of power for the site and on average provides 10% of Knostrop’s energy needs.