The five-year renewal of the Clean Water Act permit calls for the District of Columbia Water and Sewer Authority, known as DC Water, to upgrade Blue Plains to achieve a 45 percent reduction of nitrogen discharged from the plant.
The new permit sets limits for nitrogen, bacteria and trash controls in combined sewer overflows. DC Water is already achieving the phosphorus removal requirements at Blue Plains.
Blue Plains Advanced Wastewater Treatment Facility on the Potomac River (Photo courtesy DC WASA)
"These reductions are critical to protecting the health of the Chesapeake Bay as well as the Potomac River," said Shawn Garvin, EPA mid-Atlantic regional administrator. "By significantly reducing nitrogen pollution from the Blue Plains plant, we're taking a major step on the road to restoring the Bay for future generations."
Excess nitrogen harms fish and wildlife by reducing the amount of oxygen, clouding the water, and depleting underwater grasses and crucial natural habitats in the Potomac River and the Chesapeake Bay.
"DC Water was the first to meet the Chesapeake Bay Program goals to reduce nitrogen levels by 40 percent of the 1985 levels," DC Water General Manager George Hawkins said today. "And we have continued to meet those program goals every year since."
Under its existing permit, Hawkins says Blue Plains was operating under its limit of 8.5 million pounds of nitrogen per year. The new limit is 4.7 million pounds, which will require cutting-edge technology.
"We began planning more than 10 years ago to achieve these new nitrogen removal goals," Hawkins explained. "In fact, we will be breaking ground in a few months for a new, $950-million enhanced nitrogen removal facility."
The plant modifications must be completed by July 14, 2014 so that the pollution cuts in the new permit can be fully achieved in 2015.
Garvin is confident this deadline can be met. "DC Water through its early actions to enhance treatment levels at this facility is clearly a leader in the Bay restoration," he said.
The largest advanced wastewater treatment plant in the world, the Blue Plains facility is the single largest point source discharger of nitrogen in the Chesapeake Bay watershed.
Blue Plains treats wastewater for some 1.6 million people in the District of Columbia, Montgomery and Prince Georges counties in Maryland, and Fairfax and Loudoun counties in Virginia.
About $1 billion has been spent on upgrades to Blue Plains during the past decade, and an additional $950 million is budgeted for the new nitrogen removal facility.
Hawkins said, "Through the collaborative effort of the surrounding jurisdictions, we are making a difference in the health of our waterways."
Submersed aquatic vegetation in the Potomac River 2007 (Photo by Curtis Dalpra courtesy Interstate Commission on the Potomac River Basin)
That improvement in Potomac River water quality was documented in a study published Tuesday by scientists with the U.S. Geological Survey and England's National Oceanography Centre.
"Improvements to plant communities living at the bottom of the river have occurred nearly in lock step with decreases in nutrients and sediment in the water and incremental reductions in nitrogen effluent entering the river from the wastewater treatment plant for the Washington, DC area," said USGS scientist Dr. Nancy Rybicki.
Healthy beds of underwater plants increase oxygen and maintain clear water with low total suspended sediment in the river, the scientists have found.
"Upgrades to the wastewater treatment plant have benefited submerged aquatic vegetation habitats 50 miles downstream. These findings underscore the benefits of nutrient reduction efforts on a major tributary to the Chesapeake Bay," said Rybicki, who has been conducting research on the Potomac River since 1979.
"Our results suggest that widespread recovery of submerged vegetation abundance and diversity can be achievable if restoration efforts are enhanced across the bay," said Henry Ruhl of the National Oceanography Centre. "There are many other estuaries globally where nutrients have been identified as contributing to SAV habitat decline, so restoration is an issue for many governments."
Ed Merrifield, president of the nonprofit Potomac Riverkeeper, says the study showcases environmental gains but that pollutants still remain.
"It's nice to see," Merrifield said of the study. "But there are still plenty of issues. You can't even paddle a boat in some places on the river."
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