World’s largest waste-to-energy system turns Washington D.C. poop into power
The District of Columbia Water and Sewer Authority just unveiled a new $470 million waste-to-energy system that converts solid sludge – otherwise known as human poop – into clean, renewable energy. D.C. Water is the first utility in North America to use a Norwegian thermal hydrolysis system in an urban treatment plant, and according to officials, the waste-to-energy system is the largest in the world.
Norwegian company Cambi AS built the thermal hydrolysis system for D.C. Water that uses “pressure cooker” or “steam explosion” technology. The process combines high heat and pressure to pressure cook the solids at the end of the wastewater treatment process, making the biosolids more biodegradable, improving digestion performance in the four concrete 80-foot high anaerobic digesters. The methane is captured and fed to three jet engine-sized turbines to produce clean, renewable power.
“This project embodies a shift from treating used water as waste to leveraging it as a resource,” D.C. Water CEO and General Manager George S. Hawkins said in a statement. “We are proud to be the first to bring this innovation to North America for the benefit of our ratepayers, the industry and the environment.”
Since starting up in September, the system has been producing a net 10 megawatts of electricity from the waste treatment process, enough to provide a third of the power for the 157-acre Blue Plains Advanced Wastewater Treatment Plant. The wastewater treatment plant is the largest of its kind in the world, with a capacity of 370 million gallons per day, and is the largest consumer of electricity in the nation’s capital. The waste-to-energy system is expected to save about $10 million annually on the power bill and will cut carbon emissions from the plant by one-third.