Technology Used by DC Water Is the First of Its Kind in North America
DC Water, a water and wastewater services provider, has unveiled its $470 million waste-to-energy project that is now producing a net 10 megawatts (MW) of electricity from the wastewater treatment process at the Blue Plain’s plant. It is providing clean, renewable energy to power nearly one-third of the plant’s energy needs. The new facilities include a dewatering building, 32 thermal hydrolysis vessels, 4 concrete 80-foot high anaerobic digesters, and 3 turbines the size of jet engines.
After more than a decade of research, the project began in 2011 and was only able to be completed thanks to technology never before used in North America. Cambi thermal hydrolysis was utilized in the project, making the Blue Plains the largest thermal hydrolysis installation in the world.
Thermal hydrolysis uses high heat and pressure to manage the solids left at the end of the process, weakening the cell walls and making the energy accessible to the organisms during anaerobic digestion. The methane produced is captured and fed to three turbines in order to produce electricity, while steam is captured and directed back into the process.
At the end of the entire process, the solids are a clean Class A biosolids product that can be used as compost-like material in urban gardens and green infrastructure projects.
"This is yet another example of the district leading the nation in the adoption and implementation of sustainable practices," says District of Columbia Mayor Muriel Bowser. "DC Water's 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."
CEO and General Manager Hawkins says, "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."
Source: DC Water