Sewage flakes flush with positive energy

Looks like coffee, but you wouldn’t want to drink it, sewage flakes are Thames Water’s latest bio-fuel venture

THEY look like instant coffee granules and sound like the worst breakfast cereal imaginable but Thames Water's latest creation, sewage flakes, could provide a positive energy boost for the whole of West Berkshire.

The highly-combustible new renewable fuel has been produced by drying sludge, the solids from sewage, in an eco-friendly machine at Slough sewage works in Berkshire.

The flakes, which burn like wood chip, then generate electricity.

Until now they have been produced simply to compact waste into order to get rid of it more conveniently.

The dryer promises to reduce the firm's carbon emissions by more than 500 tonnes a year – the equivalent of taking 180 cars off the road for good, as well as bringing up to £300,000 a year of operational cost benefits.

Five tonnes a day of sewage sludge are being put through the new dryer, which works by heating the sludge to around 180 degrees centigrade and driving off the water using enclosed heated rotating paddles.

The resulting sludge flakes are then transported to Crossness sewage works in Bexley, east London, where they are fed into a sludge-powered generator, which burns 160 tonnes a day of ‘sludge cake,' the de-watered solids from sewage, to generate renewable electricity.

Thames Water's head of innovation, Rupert Kruger, said: “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.

“This innovative approach demonstrates our clear intent to help move Britain towards becoming a low-carbon economy by unlocking every ounce of renewable energy potential from waste.”