New Wastewater Sludge Treatment Plant

Water experts and environmental engineers MWH (UK) are lead consultants on a new waste water sludge treatment plant being installed at the giant Bran Sands site, near Middlesbrough.
Work has just begun on the £28 million plant which is being constructed for Northumbrian Water (NWL). It uses the emerging new technology of thermal hydrolysis advanced digestion and is due to be fully operational in June 2009.
Dave Young, Programme Manager, based at MWH`s Newcastle upon Tyne office explains: “The raw sludge which is treated using the current plant is dried and pelletised using giant thermal driers. The new plant will use a completely different sludge treatment process, which provides NWL with many advantages.
“This means a significant reduction in gas and electricity currently used, with a consequent reduction in carbon emissions, and will also produce five mega watts of `green` electricity in the process.”
The Bran Sands plant is one of Northumbrian Water’s largest and treats the majority of sludge in the North East, England, produced as a result of the treatment of domestic sewage and industrial effluent from a population equivalent of 1.9 million people.
In the new process, the sludge water content will be reduced before being loaded into giant steam `pressure cookers` (at 165ºC), then cooled and fed into new digesters.
The methane given off by the digestion process will then be collected in 11-metre diameter biogas storage bags before being used to fuel gas engines (5MW) to create enough renewable electricity to power about half of the entire 52-acre treatment works site at Bran Sands.
The digested sludge cake remaining after the process will be an enhanced, treated product, with low odour, that will be used as a valuable agricultural fertiliser.