In order to conserve energy and cleanly generate power, D.C. Water plans to get dirty this summer by embracing sewage.

The water utility’s plant proposal involves converting all waste from the surrounding Washington, D.C., Maryland and Virginia area into Class A biosolids and energy. The company hopes to use the green solution to reduce its energy bill and pass on savings to its customers.

The new technology, called thermal hydrolysis, was originally developed by Cambi, a Norway-based company focused on discovering ways to efficiently convert biodegradable substance into renewable energy.

“It had been used in several places in Europe, but never in North America,” D.C. Water Manager of Biosolids Operations Bill Brower said.

The D.C. Water plant will collect the sewage into large steel vats where it will undergo a preheating step, similar to a pressure cooker, sitting at high pressure and temperature. After 30 minutes, the pressure is lowered, causing cell walls to burst and allowing microorganisms to digest the material.

“It makes a Class A biosolids product and the main thing it does [is] it breaks down the cells and the solids before it goes into anaerobic digestion, which allows for higher loading of the digesters,” Brower said.

After this anaerobic digestion — when microorganisms break down biodegradable substances without the presence of oxygen — the vats are filled with Class A biosolids material void of pathogens, which were killed by the high temperature. This material can then be used as soil in green infrastructure, tree plantings and community gardens, among other things.

The real power source from thermal hydrolysis, however, stems from the natural release of methane gas from the digesters. D.C. Water plans to use the 13 megawatts of power from the methane gas in order to power 11,000 homes in the D.C., Maryland and Virginia area.

D.C. Water will also be able to reduce its electricity bill, which primarily comes from local electricity utility Pepco, by powering a third of its plant on its own with the energy from the sewage. It can then pass on those savings to nearly 2.2 million customers who will send their waste to the plant located in southeast D.C.

Brower hopes the reduced dependence on Pepco will eventually result in a self-sufficient process.

“We are [a] water utility so we are not used to running a power plant.” Brower said. “Pepco energy services are going to be running that part of the plant for us for the first 15 years at least.”

Georgetown student Jane Xie (SFS ’14), who works for the university’s Office of Sustainability, voiced her support for the proposal.

“This sounds like a viable solution to solve multiple regional problems — reducing biosolid waste, increasing water quality by reducing the wastewater runoff and sourcing a more sustainable energy source,” Xie said.

Caroline James (COL ’16), a member of GU Fossil Free and the GUSA secretary of sustainability, agreed.

“This initiative by D.C. Water is a great example of taking advantage of natural biological processes to help humans live more sustainably,” she said. “I’m excited to see how D.C.’s energy production improves over the next few years, and I hope other cities begin similar programs.”

Xie and James both expressed their enthusiasm for the solution, adding that they hope the plant sets a precedent for other cities.

“If it’s an economical solution, I would love to see D.C. start this trend and expand it into other cities,” Xie said.

Vice President of EcoAction Margaret Stebbins (COL ’15) lauded the initiative as a means to provide billions of people with energy.

“We have such a consumer culture where we just take and take and we don’t know how to deal with 9 billion people; all these people need energy and don’t have energy available in the future,” she said.

Charlotte Cherry (SFS ’16), board member of Georgetown Energy, also praised the initiative for its cost efficiency.

“Although waste-energy plants are a bit less glamorous than solar panels, people tend to complain about the aesthetics of many energy production techniques. It seems that this type of project will have benefits on many fronts, transferring waste to useable energy, saving energy costs and processing wastewater to a state where it can be used by farmers immediately. It’s a win-win and I am excited to hear about the impact going forward,” Cherry wrote in an email.

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