UK utility Thames Water has opened a £1.5 million sewage sludge dryer that will produce highly combustible flakes that can be burned like wood chip to generate power.
The company is producing the flakes from solid waste at Slough sewage works in Berkshire and will use them to generate renewable electricity.
Using the dried sewage as a fuel promises to bring Thames Water up to £300,000 a year in operational cost benefits and avoid over 500 tonnes a year of carbon emissions.
“This is the first time in Britain that a waste dryer has been used to create ready-to-burn fuel from sewage sludge, rather than simply being used as a waste-reducer,” explains Rupert Kruger, head of innovation at the utility.
The sewage sludge dryer can process five tonnes of sewage a day – roughly 20% of the solid matter left over from treatment at the Slough sewage works, heating it to 180°C and driving off any residual water.
The sewage flakes are then taken to Crossness sewage works in Bexley, east London, where there is a sludge-powered generator, capable of burning 160 tonnes a day.
“The new sludge dryer is the next chapter in our quest unlock the full energy potential of waste,” says Kruger.
Thames Water already generate £15 million worth of electricity a year by burning biomethane from sewage and feed renewable gas from its sewage works at Didcot in Oxfordshire into the gas supply network.
For further information:
UK Government gives go ahead for double boost to biomass (11-Aug)
Thames Water taps into solar power generation (3-Aug)
Sewage is potential energy source, say scientists (6-Jan)
29 September 2011