The 10MW power facility is expected to generate power to meet about one-third of energy needs of the Blue Plains plants.
DC Water board chair Matthew Brown said: "The Board of Directors approved this voluntary investment to create a better class of biosolids and generate 10MW of power to cut the electricity bill at the Blue Plains plant, which is the single largest consumer of electricity in the District."
Featuring a dewatering building, the facility comprises 32 sleek thermal hydrolysis vessels, four concrete 80ft-high anaerobic digesters with a capacity of 3.8 million gallons of solids each and three turbines equivalent to the size of jet engines.
District of Columbia Mayor Muriel Bowser said: "DC Waters Blue Plains facility is converting waste to clean water and a nutrient-rich soil byproduct, producing energy and helping to put the District on the path towards a zero waste future."
The CAMBI thermal hydrolysis technology at the facility uses high heat and pressure to "pressure cook" the sewage solids, which are the byproducts of the wastewater treatment process.
The sewage solids are treated as a sterile food source (carbon) for the microbes in the digesters, which then converts the carbon to methane.
The resulting menthe is then captured and fed to three large turbines in order to produce electricity while the generated steam will be captured and directed back into the process.
The solids at the end of the process are a cleaner Class A biosolids product, which can be used as a compost-like material for urban gardens and green infrastructure projects.
"Additionally, the cleaner biosolids can be applied locally, saving millions of dollars in hauling costs," Brown added.
DC Water CEO and general manager George Hawkins, said "This project embodies a shift from treating used water as waste to leveraging it as a resource.
"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."
DC Water also seeking ways to bring a compost-like product to market.
Image: The Cambi thermal hydrolysis reactors installed at the Blue Plains Wastewater Treatment Plant. Photo: courtesy of DC Water.com.
