DC Introduces the World’s Biggest Thermal Hydrolysis Waste-to-Energy System

Huuuuuuuuge New Thermal Hydrolysis System For DC Wastewater Is World’s Hugest

Cleantechnica, October 9, 2015. Image credit: Notre Dame

The world’s biggest thermal hydrolysis waste-to-energy system has just revved up its engines this week at the Blue Plains wastewater treatment plant on the banks of the Potomac River, making the District of Columbia — that would be the capital of the US — home to the only facility of its kind in all of North America. Oh, the irony! While certain members of Congress continue to deny that climate change is a thing, they will be making a direct contribution to some of the most advanced renewable energy technology on Earth every time they flush the toilet.

At a price tag of $470 million, the new thermal hydrolysis system has been 10 years in the making, and it adds a significant new layer of waste reclamation to the busy Blue Plains wastewater treatment plant. That’s no accident — Blue Plains is operated by the utility DC Water, which is well known for its in-house wastewater treatment R&D.

At peak flow, Blue Plains handles 1 billion gallons of wastewater daily from Washington, DC (yes, that includes the Capitol) as well as several neighboring jurisdictions, making it the biggest plant of its kind in the world. By way of comparison, New York City produces about 1.3 billion gallons daily on average, but that’s parceled out among 14 different treatment plants in all five boroughs.

Thermal hydrolysis deploys high heat and pressure to “pressure cook” the biosolids that are left over at the end of the wastewater treatment process. It’s a ramped up version of biogas capture, in which biosolids are put in closed tanks where wastewater-loving microorganisms digest them and produce renewable methane.

The difference is in the efficiency. With the addition of high heat and pressure, the cell walls of organic material in wastewater are weakened, making more energy accessible to the microbes. At Blue Plains, the captured methane is fed to three turbines the size of jet engines, which produce electricity to the tune of a net 10 megawatts.

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