Sludge treatment at U.K. plant turns waste Into green energy

The Davyhulme facility in Manchester is the advanced sludge digestion plant that handles the sewage of 1.2 million people as well as export surplus power to the U.K. grid.

The sludge recycling center runs on human waste to power 25,000 homes.

The plant treats waste in the $360 billion water industry. It uses waste formerly dumped in the Irish Sea, generating renewable power.

It was built by Black & Veatch for United Utilities and was awarded IChemE’s international prize as the most innovative green-energy scheme on Earth, the facility condenses waste into “black gold.”

The Davyhulme has a capacity of 91,000 to 121,000 tons of dry solids a year.

Davyhulme plant uses thermal hydrolysis technology to turn the waste stream into clean energy. It cuts fossil- fuel consumption, greenhouse-gas emissions and produces a sludge made into free fertilizer for farmers.

In a water industry looking for energy savings, the THP plant is a revolutionized whole sludge-treatment operation, said, Lee Donnellan, manager of the site.

In addition, the THP facility can export sludge to agriculture as an enhanced treated product through a pipeline to United Utilities’ incineration facility at Widnes.

The 105 million-pound facelift to the facility by Black & Veatch, and a wastewater plant upgrade to treat larger volumes of sludge means a cleaner ship canal as more refined water will go to the canal.

Davyhulme’s sewage-treatment process known as activated sludge is now used worldwide to harness the power of micro-organisms.

The sludge is digested to generate biogas. Some goes for incineration while dry solids, left after wastewater cleaning waste water are exported to agriculture, which benefits grazing land for cows and sheep in the North West.

Once the harmful bacteria are destroyed, the sewage sludge becomes much more digestible with 50 – 60 percent more volume of biogas generated than by conventional techniques.

The biogas from digested sludge are held in two giant green “gas bags” visible to motorists from Barton Bridge. These are Europe’s largest inflatable gas holders.

The gas cleaned and used as fuel for five CHP engines and three steam boilers generates about 60 GWh a year. Suppliers include General Electric’s Jenbacher gas engines.

The new advanced digestion facility cutting operating costs to 45 percent, makes the power-consuming process of sewage treatment 96 percent energy-neutral, said, John Tattersall, global water technology director, Black & Veatch.

Meanwhile, United Utilities is capitalizing on its THP success with the world’s first sludge-powered data center, to be completed at Davyhulme next month.

This innovation will be discussed by 2,500 experts at the World Water Week conference in Stockholm started on 1st September.

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