Upgrading wastewater treatment technologies has lowered pollution in the Potomac, Patuxent and Back rivers, leading researchers to celebrate the Clean Water Act and recommend continued investments in the sewage sector.
Introduced in 1972, the Clean Water Act’s National Pollutant Discharge Elimination System permit program regulates point sources of pollutants, or those that can be pinpointed to a specific location. Because wastewater treatment plants are a point source that can send nutrient-rich effluent into rivers and streams, this program has fueled advancements in wastewater treatment technologies. Biological nutrient removal, for instance, uses microorganisms to remove excess nutrients from wastewater, while the newer enhanced nutrient removal improves upon this process.
Researchers with the University of Maryland Center for Environmental Science (UMCES) have linked these wastewater treatment technologies to a cleaner environment. In a report released last month, five case studies show that wastewater treatment plant upgrades in Maryland, Virginia and the District of Columbia improved water quality in three Chesapeake Bay tributaries.
The link is clear: excess nutrients can fuel the growth of algae blooms, which block sunlight from reaching underwater grasses and create low-oxygen dead zones that suffocate marine life. Lowering the amount of nutrients that wastewater treatment plants send into rivers and streams can reduce algae blooms, bring back grass beds and improve water quality.
In New Insights: Science-based evidence of water quality improvements, challenges and opportunities in the Chesapeake, scientists show that new technologies at Baltimore’s Back River Wastewater Treatment Plant led to a drop in nitrogen concentrations in the Back River. Upgrades at plants in the upper Patuxent watershed led to a drop in nutrient concentrations and a resurgence in underwater grasses in the Patuxent River. And improvements at plants in northern Virginia and the District lowered nutrient pollution, shortened the duration of algae blooms and boosted underwater grass growth in the Potomac River.
Image courtesy Kevin Harber/Flickr
The Chesapeake Bay Program tracks wastewater permits as an indicator of Bay health. As of 2012, 45 percent of treatment plants in the watershed had limits in effect to meet water quality standards. But a growing watershed population is putting increasing pressure on urban and suburban sewage systems.
“Further investments in [wastewater treatment plants] are needed to reduce nutrient loading associated with an increasing number of people living in the Chesapeake Bay watershed,” New Insights notes.
Pollution-reducing practices can improve water quality in the Chesapeake Bay and have already improved the health of local rivers and streams, according to new research from the Chesapeake Bay Program partnership.
In a report released today, several case studies from across the watershed show that so-called “best management practices”—including upgrading wastewater treatment technologies, lowering vehicle and power plant emissions, and reducing runoff from farmland—have lowered nutrients and sediment in local waterways. In other words, the environmental practices supported under the Clean Water Act, the Clean Air Act and the Farm Bill are working.
Excess nutrients and sediment have long impaired local water quality: nitrogen and phosphorous can fuel the growth of algae blooms and lead to low-oxygen “dead zones” that suffocate marine life, while sediment can block sunlight from reaching underwater grasses and suffocate shellfish. Best management practices used in backyards, in cities and on farms can lower the flow of these pollutants into waterways.
Data collected and analyzed by the Bay Program, the University of Maryland Center for Environmental Science (UMCES) and the U.S. Geological Survey (USGS) have traced a number of local improvements in air, land and water to best management practices: a drop in power plant emissions across the mid-Atlantic has led to improvements in nine Appalachian watersheds, upgrades to the District of Columbia's Blue Plains Wastewater Treatment Plant have lowered the discharge of nutrients into the Potomac River and planting cover crops on Eastern Shore farms has lowered the amount of nutrients leaching into the earth and reduced nitrate concentrations in groundwater.
“In New Insights, we find the scientific evidence to support what we’ve said before: we are rebuilding nature’s resilience back into the Chesapeake Bay ecosystem, and the watershed can and will recover when our communities support clean local waters,” said Bay Program Director Nick DiPasquale in a media release.
But scientists have also noted that while we have improved water quality, our progress can be overwhelmed by intensified agriculture and unsustainable development, and our patience can be tested by the “lag-times” that delay the full benefits of restoration work.
“This report shows that long-term efforts to reduce pollution are working, but we need to remain patient and diligent in making sure we are putting the right practices in place at the right locations in Chesapeake Bay watershed,” said UMCES President Donald Boesch in a media release. “Science has and will continue to play a critical role informing us about what is working and what still needs to be done.”
UMCES Vice President for Science Applications Bill Dennison echoed Boesch’s support for patience and persistence, but added a third P to the list: perspiration. “We’ve got to do more to maintain the health of this magnificent Chesapeake Bay,” he said.
“We’ve learned that we can fix the Bay,” Dennison continued. “We can see this progress… and it’s not going to be hopeless. In fact, it’s quite hopeful. This report makes a good case for optimism about the Chesapeake Bay.”
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.”
Innovations in wastewater treatment are proving effective at removing nitrogen from our waste before it is returned to rivers and streams, according to a panel of experts convened by the Chesapeake Bay Program’s Scientific and Technical Advisory Committee (STAC).
In a report released last week, STAC concludes that exploring and adopting these new technologies could help the 467 wastewater treatment plants across the watershed better respond to development pressure and continue to reduce nutrient pollution and restore water quality in the Chesapeake Bay.
Three decades ago, wastewater treatment plants and combined sewer overflows were the second biggest source of nitrogen loads to the Bay. Excess nitrogen and phosphorous can fuel the growth of harmful algae blooms that block sunlight from reaching underwater grasses and rob water of the oxygen that aquatic species need to survive. But, since the mid-1980s, advancements in nutrient reduction technologies have allowed wastewater treatment plants to reduce their nutrient loads to our waterways: between 1985 and 2012, nitrogen loads to the Bay from wastewater discharges dropped 52 percent.
A number of these new technologies put hungry microbes to work, as algae or bacteria feed on the nitrogen and phosphorous in our waste. While research in this area is still evolving, it’s possible that these technologies could also work to transform the harmful pharmaceuticals that have increasingly appeared in our wastewater over the past few decades.
Read more about wastewater treatment technologies.
After eleven years, $40 million and more than 16,000 linear feet of pipe, West Virginia is set to bring a new wastewater treatment plant online and make huge cuts to the pollution it sends into the Chesapeake Bay.
Under construction in West Virginia’s Eastern Panhandle, the Moorefield Wastewater Treatment Plant will replace four existing plants with one new system, marking a significant milestone in the headwater state’s efforts to curb pollution and improve water quality. Expected to go into operation this fall, the plant will remove 90,000 pounds of nitrogen and 93,000 pounds of phosphorous from West Virginia wastewater each year.
Funded by a range of sources—including the West Virginia Economic Development Authority, the West Virginia Department of Environmental Protection and the U.S. Environmental Protection Agency (EPA)—the new plant is heralded as evidence that thoughtful planning and forward-thinking—especially where pollution regulations are concerned—can help a community move toward conservation and environmental change.
In the 1990s, the hundreds of wastewater treatment plants that are located across the watershed could be blamed for more than a quarter of the nutrient pollution entering the Bay, as the plants pumped water laden with nitrogen and phosphorous into local rivers and streams. Such an excess of nutrients can fuel the growth of algae blooms that block sunlight from reaching underwater grasses and, during decomposition, rob the water of the oxygen that aquatic species need to survive.
But in the last decade, technological upgrades to wastewater treatment plants have surged, and the pollution cuts that result mean these plants now contribute less than 20 percent of the nutrients still entering the Bay.
According to Rich Batiuk, Associate Director for Science with the EPA, the uptick in upgrades can be attributed to a number of factors.
“Wastewater treatment plants have always been regulated,” Batiuk said. “But [until the last decade], there wasn’t the science or the political will or the … water quality standards that could drive the higher levels of wastewater treatment that result in lower levels of nitrogen and phosphorous flowing into the watershed.”
As the science behind wastewater engineering has improved and the incentives for implementing upgrades have grown, more plants have begun to make changes. Some implement a “zero discharge” plan, using nutrient-rich effluent to feed agricultural crops rather than excess algae. Others—like the Moorefield plant—expose wastewater to nutrient-hungry microbes that feed on nitrogen and phosphorous; the resulting sludge, modified without the addition of chemicals, can be turned into compost rather than fodder for the local landfill.
Such modern upgrades to otherwise aging infrastructure have been celebrated as a boon for local communities and the wider watershed. While the Moorefield plant will, in the end, curb pollution into the Bay, it will first curb pollution in the South Branch of the Potomac River, into which it sends its effluent.
"The South Branch of the Potomac is a unique place,” Batiuk said. “People fish there, they swim there. This new plant helps more than the Chesapeake Bay.”
And Moorefield residents—including the Town of Moorefield Public Works Director Lucas Gagnon—plan to witness this local change firsthand.
“The residents in this area are aware of the Chesapeake Bay and its needed [nutrient] reductions,” Gagnon said. “But the biggest benefit for the local folks will be the reduction of nutrients in local waterways.”
“There are many people that fish and boat the South Branch,” Gagnon continued. “When this plant goes online, the water quality will be greatly enhanced, and they will have a much cleaner, better river to enjoy.”