Treated Sewage Would Replace Groundwater
By Philip Rucker
Washington Post Staff Writer
Sunday, August 19, 2007
Government and industry officials are creating an innovative sewage system in Charles County that is believed to be the first in the nation that would use water flushed down the toilet to operate power plants.
Called a closed-loop system, the plan is to pump the county's sewage to treatment stations and then route the treated sewage, known as effluent, to area power plants. Instead of groundwater, the plants would use the effluent for their cooling towers and other operations.
The new system has not entered the permitting process, and the county government is still negotiating with power plant companies over details such as building the extensive pipe network and financing the project. But government and industry officials involved in the discussions described the plan as nearly finalized.
The system's design is receiving high marks from environmentalists and wastewater experts, who called it innovative and said its benefits would be twofold. The area's power plants would no longer draw groundwater, helping preserve a key natural resource in fast-growing Southern Maryland. In addition, the county would stop flushing its treated sewage into the Potomac River, an important step in cleaning the Chesapeake Bay.
"It's win-win all the way around," said Charles County Commissioners President Wayne Cooper (D-At Large).
John Reardon, the county's economic development director, said the plan would allow power plants -- long considered environmental scrooges -- to help limit area water pollution. "It takes it from a negative environmental impact to help green the planet," Reardon said. "It turns sewage from a liability into an asset."
The science behind the closed-loop system is not new, experts said. In such states as California and Florida, where groundwater is particularly scarce, some communities use treated effluent in lieu of water for landscaping at parks and golf courses.
But the closed-loop network being built in Charles -- connecting the county's sewage system to two power plants and a third that is planned for the area -- is new, officials said.
"A big system like this that covers several facilities in volume does not exist," Reardon said. "Nobody's done anything like this before."
"This is a process that is going to be very quickly imitated around the country," state Sen. Thomas M. Middleton (D-Charles) said.
According to drafts of the plans, the system would include two area power plants: a natural gas plant across the Prince George's County border in Brandywine, operated by Panda Energy, and a coal-burning plant along the Potomac in southern Charles, operated by Mirant Corp.
County officials said they hope a third facility, a natural gas plant planned in St. Charles by Silver Spring-based Competitive Power Ventures, will join the network.
Project director Sharon Segner said CPV has not entered an agreement with the county but is excited to learn more about the closed-loop system.
Mirant's facility will use treated effluent from the La Plata wastewater sewage treatment station to power its wet scrubbers, Mirant regional manager Misty Allen said. Using La Plata's sewage will help clean up the Port Tobacco River watershed, an environmentally sensitive area that has been polluted in part because of sewage discharges.
Charles is under pressure to preserve groundwater in the face of rapid residential growth, county planning director Melvin C. Beall Jr. said. One of the primary reasons for opposition to power plants in the area has been that they use large amounts of water. But by using treated effluent instead, power companies can weaken environmental opposition to their projects.
"If you can take a project and demonstrate that it will actually improve the environment, it's a real, real selling point," Middleton said.
Some scientists and water experts said the system is likely to have environmental benefits.
"It sounds like a very innovative idea," said Beth McGee, a water quality scientist at the Chesapeake Bay Foundation.
Linda Hanifin-Bonner, a spokeswoman for the National Onsite Wastewater Recycling Association, said the closed-loop system would be a "tremendous attribute."
"It's a smart way to manage the whole issue around wastewater and water resources management," Hanifin-Bonner said.
Charles officials briefed Maryland Department of the Environment officials on the closed-loop system this month. Although the Maryland department has not officially evaluated the proposal, officials signaled that they would support the project.
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