LONDON: When the world’s largest working advanced digestion plant opened last month, it showed the power-hungry process of treating waste in the $360 billion water industry can be self-sufficient in terms of energy use.

The Davyhulme facility that handles the sewage of 1.2 million people in Manchester today can export surplus power to the British grid. It uses waste formerly dumped in the Irish Sea, generating renewable power on a scale no utility has done to date using that method.

The sludge recycling centre runs on enough human waste to power 25,000 homes. It was built by Black & Veatch for United Utilities, Britain’s largest publicly traded Water Company. Awarded IChemE’s international prize as “the most innovative green-energy scheme on Earth,” it renders waste into what engineers call “black gold.”

Davyhulme’s plant, using thermal hydrolysis technology, turns a problem waste stream into clean energy. It cuts fossil-fuel consumption, greenhouse-gas emissions and produces a sludge made into free fertiliser for farmers. In a water industry always looking for energy savings, the THP plant “revolutionised our whole sludge-treatment operation,” Lee Donnellan, manager of the site, said in an interview.

These kinds of improvements are just what 2,500 experts will discuss and dissect at the World Water Week conference in Stockholm starting Aug. 31.

The new technology at Davyhulme “really has improved the amount of energy you get from the sludge,” Donnellan said. “It’s a bigger bang for the buck” as more gas is generated “than ever before.

That means really impressive power output from our CHP (combined heat and power) engines.” The Warringtonne-based company sees “sludge as a valuable resource,” said Richard Lancaster, regional sludge manager for United Utilities. “We call it ‘black gold.’”

By arrangement with Washington Post-Bloomberg News Service

Published in Dawn, August 31th, 2014