WORK has begun on a Tyneside plant which will convert waste products into green electricity. Northumbrian Water is developing the advanced digestion plant at its Howdon sewage treatment works in North Tyneside.

It plans to process sludge remaining after sewage treatment to generate electricity to power the site in a major move towards environmental sustainability.

The firm already has a similar plant at its largest works at Bran Sands on Teesside.

This change of process at Northumbrian Water’s five-acre treatment works at Howdon is a £34m investment.

Work started on site at the end of January and the plant is due to be fully operational by summer next year.

It will use the emerging technology of thermal hydrolysis advanced digestion and keeps Northumbrian Water at the forefront of the water industry.

More than 500,000 tonnes of sludge – from the treatment of domestic sewage and industrial effluent from a population equivalent of one million people – will be reduced to about 60,000 tonnes and will generate four megawatts of green electricity.

Sludge will be loaded into pressurised reactors and heated at 165 degrees centigrade at 6Bar.

This stage of the process can be loosely compared to domestic pressure cookers, found in people’s kitchens.

The sludge is then de-pressurised and cooled before being fed into large concrete digesters for the bacterial process to start.