Stormwater

Experience history and nature on rail-trails

by Virginia Thompson

A view from the Heritage Rail Trail County Park.

A view from the Heritage Rail Trail County Park.

My husband is a huge fan of biking on rail-trails created by the conversion of unused railroad rights-of-way.  Within the past year alone, he has ridden on many trails in the Philadelphia suburbs, as well as throughout the Mid-Atlantic states.  On a recent trip, we rode on two rail-trails in southcentral Pennsylvania.

The Heritage Rail Trail County Park in York County, recently ranked by the Rails-to-Trails Conservancy as the top rail-trail in the U.S. for American history, carried President Abraham Lincoln to Gettysburg for his famous address and also carried his funeral party to Springfield, Illinois, following his assassination.  The trail follows the South Branch of Codorus Creek, connecting the City of York and many small communities with beautifully restored train stations that now serve other purposes.  The trail, next to an active rail line, also continues across the Mason-Dixon line and connects with the Northern Central Rail Trail in Maryland.

The Safe Harbor Dam as seen from the Enola Low-Grade Trail

The Safe Harbor Dam as seen from the Enola Low-Grade Trail

Another trail we biked recently was in Lancaster County—the Enola Low-Grade Trail—which parallels the Susquehanna River as it approaches the Chesapeake Bay in Maryland.  One of the interesting facets of the trail is the juxtaposition of older and new forms of electric power.  On the cliffs above the trail are several large windmills, taking advantage of the height and open space to generate electricity.  Just below the windmills sits the Safe Harbor dam, reliably providing hydroelectric power since December 1931.  The fish congregating at the dam attract bald eagles, which can be seen flying above the dam. There’s nothing quite like experiencing history and nature by biking or hiking a rail-trail. At one stop on the trail, as I looked up at the windmills and down to the river and generating station, I felt small and insignificant in one respect, but also an important part of the natural balance.

Turning formerly used rail lines into biking and hiking trails is a great way to bring people closer to waterways in their regions. EPA’s Brownfields program has had a hand in converting unused rail lines, which often snake along picturesque rivers (our nation’s original highways), into prime recreational areas. The Harrison Township Mine Site in Allegheny County, Pennsylvania was assessed through a Brownfields grant, and is now part of the Rachel Carson trail, attracting area visitors as well as hiking and running events. Allegheny County is even acquiring additional land so that the Harrison Hills Park Mine Site will ultimately connect three trails – the Rachel Carson Trail, the Butler-Freeport Trail, and the Baker Trail.

Leave a comment below to let us know about rail-trails in your area.

 

About the author: Virginia Thompson works at EPA Region 3 and accompanies her husband on his rail-trail adventures as often as possible.

 

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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The Bottom Line: Why Permeable Pavements are Good for the Environment and Your Pocket

by Jeanna Henry

A Philadelphia Water Department parking lot includes interlocking concrete permeable pavers and other types of permeable pavements

A Philadelphia Water Department parking lot includes interlocking concrete permeable pavers and other types of permeable pavements

Are you looking for ways to reduce your environmental footprint, improve water quality, and save money?  If so, permeable pavements are a great way to green your community – and put some “green” back in your pockets.

We’ve blogged recently about the environmental benefits of permeable pavements, a green infrastructure alternative that can be used for stormwater management in urban areas.  Did you know this technology also provides a host of economic benefits?

Permeable pavements are one way take advantage of financial incentives from many state and local governments for reducing stormwater fees, and they can potentially help developers and property owners qualify for credits under the U.S. Green Building Council’s Leadership in Energy & Environmental Design (LEED) certification program.

Local economies also benefit from the use of permeable pavements because they create “green” jobs. In addition, permeable pavements serve as both a paved surface and a stormwater management system, so they can reduce the need for conventional stormwater management practices such as piping, retention ponds and swales, resulting in overall cost savings.

Permeable paving is being used across the mid-Atlantic, in places like Philadelphia, PA, Washington, DC, and Baltimore, MD. But my favorite illustration of cost savings is out of the University of New Hampshire (UNH), which happens to also be one of five recent Science to Achieve Results (STAR) grant recipients researching green infrastructure in Philadelphia.

This UNH case study compares the costs of conventional and low impact development (LID) stormwater management designs.  The LID design included the installation of two porous asphalt parking lots covering a total of 4.5 acres.  Although the paving costs for the porous asphalt drainage systems were estimated to cost an additional $884,000, the LID option provided significant cost savings for earthwork ($71,000) and stormwater management ($1,743,000). Total project cost savings were around $930,000, a 26% decrease in the overall cost for stormwater management.

The LID option doesn’t just save money, monitoring results from the case study show that porous asphalt systems are successfully treating stormwater to remove sediment and nutrients to protect local waterways, and meeting durability and permeability expectations for peak flow.

Interested in more on permeable pavements, like porous asphalt and pervious concrete? The National Ready Mix Concrete Association, the National Asphalt Pavement Association, and the Interlocking Concrete Pavement Institute have information on certified craftsmen, installers and technicians in your area as well as information on how to become certified in these green infrastructure techniques.

 

About the author: Jeanna Henry joined EPA in 2000 as an Environmental Scientist. She currently works in the Water Protection Division focusing on stormwater management through the use of Green Infrastructure. Jeanna loves nothing more than spending time outdoors with family and friends hiking, kayaking or spending a day at the beach.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Making a Difference through Green Streets Funding

 EPA, the Chesapeake Bay Trust and MD DNR announced $727,500 in grants to 15 organizations via the Green Streets, Green Towns, Green Jobs Grant Initiative

EPA, the Chesapeake Bay Trust and MD DNR announced $727,500 in grants to 15 organizations via the Green Streets, Green Towns, Green Jobs Grant Initiative

by Tom Damm

Transforming lives is something Sarah’s Hope in Baltimore does every day as an emergency homeless shelter for families.

But this week, the focus at the safe haven was on a different type of transformation: replacing the asphalt and concrete on the property with an environmentally friendly community green space and outdoor playground area.

Earlier this week, EPA Regional Administrator Shawn M. Garvin was at Sarah’s Hope to join partners in announcing funding for a key phase of the project.

A $75,000 grant from the Green Streets, Green Jobs, Green Towns (G3) program will be used to tear up the hard surfaces in front of the property that during storms send rain water rushing into the street and drains, leading to flooding and pollution problems.   The surfaces will be replaced with lawn, shade trees, native plants, and other green features that will let the rain soak in and provide a welcome lift to this troubled neighborhood.

The atmosphere at the event was upbeat as the project partners, Parks & People Foundation, the City of Baltimore and St. Vincent de Paul, described their plans for the facility.

The G3 grant will tie into a larger Baltimore City project to create public open space, a playground area and a community garden at the site, which is now almost fully covered with impervious surface.  The work will improve the property for shelter residents and the community at large, and transform the appearance of the Sandtown-Winchester neighborhood.

Many of the other grantees were also on hand at the event to talk about how the G3 funds will help expand urban tree canopies, create bioretention cells to capture stormwater, and install other types of green infrastructure in neighborhoods in Maryland, Pennsylvania, and Virginia.

By keeping rain water from coming into contact with pollution in the first place, green infrastructure improves the health of our waters, while effectively reducing flooding, and helping our communities adapt to the very real challenges of climate change.

The G3 program – sponsored by EPA, and the Chesapeake Bay Trust, with assistance from the Maryland Department of Natural Resources – is in its fifth year. In this latest round of grants, 15 recipients will share in more than $727,000 in funding –  bringing the total aggregate investment in G3 grants to more than $11 million when matching funds are included over the five-years that the program has been in existence.

 

About the Author: Tom Damm has been with EPA since 2002 and now serves as communications coordinator for the region’s Water Protection Division.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Water Wednesday: “Mommy, Where Does It Go When I Flush?”

By Chrislyn Johnson

Last spring, when I was potty training my 3-year-old, he asked me where it goes after we flush the toilet. I thought about this before I answered him, because I have often overwhelmed the poor child with my answers. He once asked me “What is water?” and I told him it was two hydrogen atoms and one oxygen atom.

For most people, it is enough to be told that when you flush the toilet, it goes to the sewage treatment plant. Since I worked in wastewater regulation for a little while, I know it goes far beyond that, and I have trouble answering this seemingly simple question with a simple answer.

Once it goes down the drain, the water travels through a sometimes aging, sometimes modern, infrastructure of pipes to a wastewater treatment plant. Treatment options vary, from open lagoons to all-inclusive mechanical plants, all with the same goal: to treat sewage so it can be released into the environment. Many modern facilities do this with an “activated sludge” process that uses bacteria to naturally break down the waste.

As it enters the plant, the solids are separated out by a grit screen and settling basins. Heavier solids like plastics, eggshells, and intact items are settled out and removed; then taken to the landfill. The next step is the primary clarifier, where the sewage moves slowly along so heavier particles and sludge can settle out. At the same time, grease and oils dumped down the drain float to the top and are skimmed off the surface.

After the clarifier, the water is moved to the main part of the treatment: the aeration basin. Bacteria feast on the nutrients to break down the sewage and remove chemicals in the wastewater as it bubbles and roils with oxygen. Depending on the plant, an additional tank is sometimes added to help remove nitrogen. Since the treated water goes back into rivers and streams, this additional step is helpful in removing nitrogen before it can cause problems. Nitrogen can cause algal blooms that not only can be toxic, but also consume a lot of oxygen during decomposition, which kills the fish.

Following the aeration and nitrogen removal processes, the water then flows into a secondary clarifier. Water trickles out from weirs at the top of the large, circular tanks of the clarifier. The water is disinfected, either by chemical means (such as chlorination, similar to bleach), or through newer alternatives like ultraviolet (UV) lights. Once disinfected, the treated water is released into a nearby river or stream.

Whereas the water treatment is nearly finished in the secondary clarifier, the sludge often has a few more steps to completion. The bacteria slowly settle to the bottom of the clarifier into what is called the sludge blanket. Some of the sludge blanket from the clarifier is recycled and added back into the incoming wastewater to begin the treatment reaction in the aeration basin. Depending on the type of plant, the remainder of the sludge travels to the digesters for either aerobic or anaerobic digestion (where the bacteria eat each other).

Aerobic digestion uses oxygen to further break down the sludge. It is nearly odorless, but also costly since the process has to be manually oxygenated. The other common alternative is anaerobic digestion, which is not so odorless since it produces methane. However, the methane can be captured and used to generate electricity to operate the plant. The waste heat from the generators even can be used to keep the anaerobic digesters at the correct operating temperature. After leaving the digesters, water is removed from the sludge, which can then be disposed of or used as a soil conditioner. With clean water going back to the stream or river, and sludge going back to the earth, the cycle is complete.

I thought about this intricate series of steps that mimics the breakdown processes wastes would undergo in nature, given sufficient time and space. I thought about how fortunate we are to live in a country where water quality is a high priority, and we can make a daily difference to protect our local waterways (see graphic below).

I also thought about my son’s level of understanding, as he impatiently asked me again, “Where it go?” With all of this in mind, I looked down at my innocent little boy and told him, “It goes to the sewage treatment plant, honey.”

Click image to see larger version.

Click image to see larger version.

About the Author: Chrislyn Johnson is a Life Scientist with EPA Region 7’s Water, Wetlands, and Pesticides Division. She holds degrees in biology and photography from the University of Central Missouri and loves all things nature. She also enjoys access to flush toilets.

Sources:
Scientific American
U.S. Census Bureau
World Health Organization

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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The Promise of Permeable Pavement

by Jeanna Henry

Permeable pavement products can be used together with other green infrastructure.

When it rains, or as snow and ice melt, I frequently notice streams of water running off of my lawn, onto the street, into the storm sewer, and ultimately to a local waterway. I’ve also noticed an increase in flooded roadways and neighborhoods in my area even after a moderate to heavy rain. Unfortunately, stormwater is not just a localized issue, it is a problem across the country. As the saying goes: when it rains, it pours.

Flooding results in economic costs, human health impacts, and environmental damage in its wake. A major factor in more frequent flooding events is the increasing cover of impervious surfaces, such as roadways, parking lots and rooftops. Since these hard surfaces do not allow stormwater to naturally seep into the ground, most rainfall turns into runoff. With continuing development and growth, what options are available to minimize the effects of impervious surfaces? A more sustainable solution is to replace or substitute conventional pavements with permeable pavements – a green infrastructure tool.

Porous asphalt allows water to drain through it.

Porous asphalt allows water to drain through it.

Permeable pavements include pervious concrete, porous asphalt, and permeable interlocking pavers that mimic nature by capturing, infiltrating, treating, and/or storing rainwater where it falls. EPA considers these materials a Best Management Practice (BMP) for the management of stormwater runoff. Permeable pavements also provide multiple benefits beyond stormwater management and reducing localized flooding: they also have the ability to improve water quality; reduce the “heat island” effect in urban areas; reduce roadway hazards like ponding water and icing; create green jobs; and can increase the livability and resiliency of communities and increase property values when used with other green infrastructure. In fact, these benefits are already being realized throughout EPA’s Mid-Atlantic Region.

Permeable pavements along with green infrastructure are effective ways to address flooding as well as supporting green, sustainable growth. So the next time it rains, think about where permeable pavements and other types of green infrastructure could fit into your community.

 

About the author: Jeanna Henry joined EPA in 2000 as an Environmental Scientist. She currently works in the Water Protection Division focusing on stormwater management through the use of Green Infrastructure. Jeanna loves nothing more than spending time outdoors with family and friends hiking, kayaking, or spending a day at the beach.

 

 

 

 

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Storm Water Management Model Gets Climate Update

By Marguerite Huber

Image of a flooded local park

EPA researchers are helping address runoff problems.

EPA researchers are developing strategies and resources to help city planners, managers, and others address stormwater runoff problems, including those related to impervious surfaces and combined sewer overflows. One powerful tool available is the Stormwater Management Model, also known by its acronym, “SWMM.”

EPA’s Storm Water Management Model is a publically-available rainfall-runoff simulation model that provides a suite of information about urban water patterns. It is used for planning, analysis, and design related to stormwater runoff, combined sewers, sanitary sewers, and other drainage systems in urban areas, and is the basis for the National Stormwater Calculator.

SWMM has the ability to estimate the pollution loads associated with stormwater runoff. Various versions of the model have been in existence since 1971, and it has been used in thousands of hydrology and drainage system design projects around the world.

The tool is designed to be customizable, helping particular urban areas meet local watershed challenges. For example, municipalities and communities can use it to design and size drainage system components for flood control, to design control strategies for minimizing combined sewer overflows, and to control site runoff using low impact development practices.

The Storm Water Management Model Climate Adjustment Tool (SWMM-CAT) is a new addition to SWMM. It is a simple to use software utility that allows future climate change projections to be incorporated into SWMM.

Screen shot of EPA's SWMM-CAT tool showing a map with stormwater data

Storm Water Management Model

SWMM-CAT provides a set of location-specific adjustments that derived from global climate change models run as part of the World Climate Research Programme (WCRP) Coupled Model Intercomparison Project Phase 3 (CMIP3) archive. These are the same climate change simulations that helped inform the United Nations Intergovernmental Panel on Climate Change in preparing its Fourth Assessment report.

Both SWMM and the Stormwater Calculator are a part of the President’s Climate Action Plan.

“Climate change threatens our health, our economy, and our environment,” said Gina McCarthy, EPA Administrator. “As part of the President’s Climate Action Plan, this tool will help us better prepare for climate impacts by helping build safer, sustainable, and more resilient water infrastructure.”

The continued development of predictive modeling tools such as SWMM will provide urban planners and other stakeholders with the resources they need to incorporate both traditional stormwater and wastewater system technologies with the emerging, innovative techniques of green infrastructure. The collective impact will be more sustainable urban areas and healthier waterways across the nation.

SWMM-CAT can be downloaded here.

If you are interested in learning more about SWMM-CAT, join our webinar on 2/25/15 at 12:00 PM ET!

About the Author: Marguerite Huber is a Student Contractor with EPA’s Science Communications Team.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action.

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Oyster Bay Goes Green with New Rain Garden

The newly installed rain garden at Oyster Bay’s Western Waterfront will capture, treat, and infiltrate polluted stormwater runoff before entering nearby Oyster Bay, and eventually Long Island Sound. Photo credit: Amy Mandelbaum, New York Sea Grant/ Long Island Sound Study.

The newly installed rain garden at Oyster Bay’s Western Waterfront will capture, treat, and infiltrate polluted stormwater runoff before entering nearby Oyster Bay, and eventually Long Island Sound. Photo credit: Amy Mandelbaum, New York Sea Grant/ Long Island Sound Study.

By Amy Mandelbaum and Mark A. Tedesco

Did you ever stop to think where water goes after it leaves your downspout? If you’re like most people, once stormwater is out of sight, it’s out of mind. Most likely, the stormwater rushes down your driveway, onto the street, and to the nearest storm drain. If you don’t live in the Big, I mean, Green Apple, then that drain goes directly to your local waterway, whether it be a lake, creek, river, bay, estuary, or even the ocean. So, what’s the big deal?

Well, that stormwater isn’t so clean by the time it makes it to your local waterway, as it picks up litter, nutrients, and plenty of other things along the way. This polluted stormwater runoff goes directly into the water without having a chance to be cleaned.

So, what can we do about it? That’s where green infrastructure comes into play. Green infrastructure is essentially mimicking what nature did before we started building gray infrastructure, such as gutters, roads, pipes, etc. Out of the many green infrastructure practices, one of the best for filtering polluted stormwater runoff is a rain garden: a shallow, vegetated basin that captures, treats, and infiltrates polluted stormwater runoff within a day. It is designed to treat the first inch of rain, which is the most polluted, and the plants, soil, and mulch filter the polluted stormwater runoff before it enters your local waterway.

The Town of Oyster Bay realized the need to redirect the polluted stormwater runoff from the roadway along the waterfront before going into nearby Oyster Bay, a Long Island Sound Stewardship Area, and eventually Long Island Sound. The Town sought and received a Long Island Sound Futures Fund grant to install a rain garden, all while educating the local community. The rain garden was installed in October, with assistance from other local organizations and volunteers. As part of the project, a corresponding rain garden training program is also offered for homeowners, municipal officials, and landscape professionals. This rain garden now serves as a demonstration to the local community and its visitors of a green infrastructure practice that can be easily incorporated into the landscape.

So, the next time it rains, I hope you take a closer look at your downspout.

If your town would like assistance mitigating the effects of stormwater runoff, contact your local Nonpoint Education for Municipal Officials (NEMO) office in New York or Connecticut.

About the Authors: Amy Mandelbaum is the New York Outreach Coordinator for the Long Island Sound Study. She works for New York Sea Grant in Stony Brook, NY. She received her Ed.M. in science education in 2012 and a B.S. in environmental science in 2007 from Rutgers University.

Mark Tedesco is director of the United States Environmental Protection Agency’s Long Island Sound Office. Mr. Tedesco is responsible for supporting implementation of a Comprehensive Conservation and Management Plan for Long Island Sound, approved in 1994 by the Governors of New York and Connecticut and the EPA Administrator, in cooperation with federal, state, and local government, private organizations, and the public. Mr. Tedesco received his M.S. in marine environmental science in 1986 and a B.S in biology in 1982 from Stony Brook University.

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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Partners in Preventing Pollution

by Ms. Kyle J. Zieba

 

MS4 Training Exercise

MS4 Training Exercise

 

It was truly rewarding watching professionals from Prince William and Fairfax counties in Virginia help lead our recent training exercises in how to ensure towns follow the rules when it comes to preventing municipal stormwater pollution.

Our EPA team worked with these counties to strengthen their stormwater programs following compliance inspections in 2011. And now here they were at the front of the class showing others how to do the job right.

Stormwater runoff is a leading cause of pollution in our rivers and streams. Over the last few years, EPA has worked with many municipalities and counties in the region to improve their Municipal Separate Storm Sewer System (MS4) compliance. As a result, many local governments have stepped up to better their operations.

Today, Prince William and Fairfax counties are proactively managing their MS4 compliance obligations, and sharing their experiences.

The counties recently hosted, and joined EPA, in leading the training sessions for state inspectors from throughout the mid-Atlantic region on how to check for stormwater violations. They explained some of their model procedures and led the trainees through mock inspections, a demonstration in detecting illicit discharges, and other activities.

One of EPA’s priorities, launching a new era of local partnerships, is on full display in our MS4 compliance work with Fairfax and Prince William counties. By working together, we’re demonstrating a new paradigm for how compliance assurance activities to protect human health and the environment can lead to long-term collaboration and shared accountability.

 

About the author: Ms. Zieba is an National Pollutant Discharge Elimination System (NPDES) Enforcement Officer in the Water Protection Division in EPA’s Mid-Atlantic Regional Office.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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A Decade of Partnership for the Nation’s River

: A view of the Potomac River at Great Falls. Photo credit: C&O Canal NHP via Flickr.

A view of the Potomac River at Great Falls. Photo credit: C&O Canal NHP via Flickr.

by Vicky Binetti

This year, members of the Potomac River Drinking Water Source Protection Partnership are marking the tenth anniversary of their 2004 partnership resolution. I recall the excitement as water utilities from the middle Potomac, and federal, interstate and state government representatives signed a giant version of the partnership’s framework document at Little Seneca Reservoir in Maryland, pledging to work together to protect the quality of the Nation’s River, the source of drinking water for more than 5 million people.

On that September day, our aspirations were high: to develop a unified voice for the protection of drinking water sources, provide a forum to enhance understanding of important water quality issues, and build a team to coordinate action on priority concerns. Over the past 10 years, partnership members have joined forces to conduct unique sampling studies for pathogens and emerging contaminants. We’ve conducted workshops on runoff of salt-laden stormwater from winter storms; on the potential risks posed by newly recognized contaminants, and ways to reduce their presence in water supplies; and on the potential for nutrient pollution from agricultural and urban sources to contribute to harmful algal blooms. We’ve developed coordinated early warning systems and emergency response strategies; conducted exercises to simulate real disasters; and shared lessons learned and contingencies planned in dealing with floods, droughts and power failures. We’ve examined the success and value of land conservation efforts in the basin, and probed the simple elegance of how forested lands protect downstream water quality.

After a decade in partnership, our experience tells us that even as our understanding has increased, challenges remain. As our population has grown, and land and water use have become more intense, the need for safeguarding sources of our water supply remains a priority. Whatever challenges lie ahead, this partnership will build upon a foundation of strong science and collaboration.

So, in this same year that we’re celebrating the 40th anniversary of the Safe Drinking Water Act, let’s also raise a toast – with tap water, of course – to 10 years of protecting the Potomac River.

 

About the author: Vicky Binetti is Associate Director of EPA Region 3’s Water Protection Division, with responsibilities including public drinking water system compliance, source water protection and underground injection control in the mid-Atlantic states. At home in southern New Jersey, Vicky is a member of the Environmental Commission and Open Space Advisory Committee.

 

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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An Internship that Wasn’t a Waste

By Sarah Martynowski

During the summer, EPA hosts several events to provide interns with enriching experiences in the D.C. metropolitan area. Last summer, we visited the Blue Plains Advanced Wastewater Treatment Plant, located along the Potomac River. Designed to treat an average daily flow of 370 million gallons of wastewater per day, Blue Plains is the largest treatment plant of its kind in the world. It’s known globally for its state-of-the-art technology and innovative research.

We began the tour at the point where 1,800 miles of pipes bring both raw sewage and stormwater into the plant from D.C., Maryland, and Virginia. The first step screens and removes grit. Then the wastewater moves through primary and secondary treatment. Primary treatment is a physical process that removes floating materials, while secondary treatment is a biological process that removes organic matter. And while most treatment plants stop after primary and secondary treatment, the advanced system at Blue Plains continues the process to remove nitrogen and phosphorous that can hurt local waterways. The treated water then passes through filters and is disinfected before flowing into the Potomac River.

Blue Plains is currently constructing an anaerobic digestion facility and a thermal hydrolysis process to further treat the solids that are removed in the treatment process. The digesters will produce enough biogas to generate 10 megawatts of electricity: enough to provide one-third of the plant’s own power requirements. The thermal hydrolysis process will create “Class A” biosolids that can be safely applied to land as a fertilizer.

DC Water is also working to improve treatment of its “combined sewer system,” meaning that storm water and wastewater come together when it rains. A massive tunneling project called “the Clean Rivers Project” will capture excess flows. Currently, many of these combined sewers become overloaded during storms and raw sewage overflows into local rivers. When the tunnel system is complete in 2025, most of these excess flows will be captured and conveyed to Blue Plains for treatment. As a result, DC Water expects to reduce overflows by 96 percent.

Our tour was an excellent opportunity to learn about wastewater treatment plants, beyond just the information found in my environmental textbooks. I may never operate a wastewater treatment plant, but I think it’s important to understand how they work and their vital role in keeping our waters clean and healthy.

About the author: Sarah Martynowski is a senior at the University of Cincinnati majoring in environmental studies and political science. She was an intern for EPA’s Office of Water during the summer of 2014.

 

Editor's Note: The opinions expressed here are those of the author. They do not reflect EPA policy, endorsement, or action, and EPA does not verify the accuracy or science of the contents of the blog.

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