The Chesapeake Bay watershed is home to more than 17 million people, each of whom is reliant on water. But as populations grow and communities expand, we send pollutants into our rivers and streams, affecting every drop of water in the region. How, then, do so many of us still have access to clean water? The answer lies within wastewater treatment plants.
One plant, in particular, plays a pivotal role in the region’s water quality. Located in Washington, D.C., the Blue Plains Wastewater Treatment Plant has served the D.C. metropolitan area since 1983. The plant receives 40 percent of its flow from Maryland, 40 percent from the District and 20 percent from Virginia. With the capacity to treat 370 million gallons of sewage each day, it is the largest wastewater treatment plant in the world and the only one in the nation to serve multiple states.
Recently, the District of Columbia Water and Sewer Authority—also known as DC Water—made technological upgrades to Blue Plains. Evidence shows these upgrades have already accounted for reductions in nutrient pollution and a resurgence in the upper Potomac River’s bay grass beds. Indeed, putting new wastewater treatment technology in place is a critical step toward meeting the pollution limits established in the Chesapeake Bay Total Maximum Daily Load. As of 2012, 45 percent of the watershed's 467 wastewater treatment plants had limits in place that met water quality standards.
Because of spatial constraints, many of upgrades planned for Blue Plains will focus on intensifying the wastewater treatment process. According to Sudhir Muthy, innovation chief for DC Water, the more concentrated the purification process is, the more energy efficient the plant can be.
For decades, the philosophy behind wastewater treatment plants has been to imitate those clean water processes that you might see in natural systems. Lately, there has been a shift in thinking about how wastewater is treated. Murthy explains: “Now, more attention is given to using the energy created within the treatment process to run the plant. [For example,] carbon has a lot of energy and is created during the treatment process. We are trying to harness [carbon’s] energy to help the plant run in a more energy-efficient way. We are now asking: How do we optimize the use of energy within the wastewater treatment process?”
Blue Plains hopes to become energy neutral in 10 to 15 years, and upgrades to reduce pollution and save energy will continue for years to come. A new tunnel will allow both sewage and wastewater to flow from the District to the plant, where it will be treated to reduce the flow of polluted runoff into the Potomac River. And a new process will recycle “waste” heat to “steam explode” bacterial sludge, turning it into a biosolid that can be mixed with soil, used as fertilizer and generate extra revenue.
“All processes use energy,” Muthy said. “But if you can find ways to offset or recycle that energy use, then you can move towards being more efficient.”
The James River Association has measured a slight improvement in James River health, giving the waterway a “C” in its latest State of the James report.
Image courtesy tvnewsbadge/Flickr
The river’s score of 53 on a one-to-100 scale marks a two percent increase since the report was last issued in 2011, but continued problems with sediment pollution overshadow progress made elsewhere.
While sediment is a natural part of the environment, excess particles of sand, silt and clay can cloud the water, harming underwater grasses, fish and shellfish. According to the State of the James report, sediment pollution in the James has shown no improvement over the past two decades, indicating that stronger measures should be taken to restore streamside forests and other buffers that can filter runoff before it enters rivers and streams.
Virginia has made strides, however, in reducing nutrient pollution, as it works to meet limits set by the Chesapeake Bay Total Maximum Daily Load or “pollution diet.” The Commonwealth has invested in wastewater treatment, increased funding toward agricultural conservation and focused attention on controlling stormwater runoff.
Striped bass spawning success has improved in the Chesapeake Bay.
Image courtesy randychiu/Flickr
According to data from the Maryland Department of Natural Resources (DNR) and the Virginia Institute of Marine Science (VIMS), the number of juvenile striped bass in the watershed has rebounded from last year, when it was close to the lowest ever observed.
Known as the “juvenile striped bass index,” the number of young-of-the-year striped bass in the Bay is used to track the species’ reproductive success. To count the number of striped bass that hatched this spring, biologists take a series of seine net samples in noted spawning areas, from the Upper Bay to the James River.
Image courtesy VIMS
This year, the average number of juvenile striped bass caught in each Maryland sample was 5.8, which falls below the 11.7 average but above last year’s index of less than one. In Virginia waters, researchers caught more than 10 striped bass per seine sample, which is close to the historic average of 9. A VIMS media release called the results consistent with historically observed patterns in striped bass populations.
Striped bass, or rockfish, hold great value in the watershed: the fish is a top predator in the food web and a critical catch to commercial and recreational fisheries. Late-1980's fishing bans helped striped bass recover from harvest and pollution pressures, and it is now considered a recovered species.
Restoration partners across Maryland have set a national record: for the first time, an oyster hatchery has produced more than one billion spat in a single season.
Image courtesy U.S. Army Corps of Engineers Norfolk District/Flickr
The Horn Point Laboratory Oyster Hatchery is the largest hatchery on the East Coast and raises spat, or oyster larvae, for use in research, restoration, education and aquaculture. The lab produced 634 million spat last year, but a boost in spat production is a critical step in Maryland’s plan to expand oyster populations in the Chesapeake Bay.
Habitat loss, disease and historic over-harvesting have contributed to a dramatic decline in native oyster populations. But the bivalves play a critical role in the Bay’s environment and the region’s economy, filtering water, forming aquatic reef habitat and feeding countless watershed residents.
According to a media release from the Maryland Department of Natural Resources (DNR), 60 percent of the spat produced this season went into Harris Creek. The Choptank River tributary was declared an oyster sanctuary in 2010, and is the first target of the tributary-based oyster restoration strategy set forth by Chesapeake Bay Program partners. As of this month, half of the reef construction and seed planting in the creek is complete.
The rest of the season’s spat went toward local conservation efforts, a citizen oyster growing program and aquaculture businesses and training programs.