Safe and Sustainable Water Research

Using Green to Combat Saline: Testing Salt-Tolerant Algae as a Desalination Method

By Christina Burchette

In 2014, the Lawrence Berkeley National Lab Institute for Globally Transformative Technologies released a report called “The 50 most critical scientific & technological breakthroughs required for sustainable global development.” Of all the technologies the report highlighted, the number one priority on the list was a new method for desalinating water. That’s because water security is closely linked with energy and food security issues—world water demand is rising, and more than 70% is used for agriculture.

Algae water sample, desalinated sample, desalinated and filtered water sample

From left: Desalinated and filtered water sample, desalinated water sample, algae water sample

There is a large volume of brackish water (salt water and fresh water mixed together) in many arid areas of the world, but current desalination methods are expensive and use a lot of energy, which means that most people who need them can’t use them. Finding a low-cost and renewable desalination method could help alleviate some of the effects of water scarcity, which is becoming an increasingly apparent problem as we continue to feel the impacts of climate change around the world.

So how do we find a sustainable, low-cost, and energy efficient way to remove salinity from water, making it suitable for drinking and agriculture? By harnessing the power of the ultimate technology: Mother Nature. Recently, some of our scientists investigated the use of salt tolerant algae—also known as halophytic algae—as a natural and sustainable method to decrease salinity in brackish water and seawater. Some species of salt-tolerant algae can absorb up to 50 times more salt than the concentration of salt in the water they inhabit, making them a perfect (and natural!) way to desalinate water for potable use. In addition, the growing algae can be used to mitigate carbon dioxide from point source emissions. Once the algae has been used for desalination, it can then be harvested and used as a raw material for biofuel production to reduce the use of fossil fuels.

The photobioreactor looks like a large glass tube

The photobioreactor

To gather insight about which algae species would perform the best during experiments, researchers visited an algae bank at the University of Texas at Austin. After screening more than 12 different types of algae species and noting special conditions like pH, micronutrient requirements, and light cycle sensitivity, researchers picked four types of halophytic algae that had the best salt uptake rates.

They then grew and tested the algae for its salt-removal capabilities in a photobioreactor, which is a vessel that housed the algae and provided it with the light it needed to mature. Researchers manipulated the algae’s breeding and feeding conditions to optimize growth rate, survival rate, and absorbency and discovered that they could remove up to 30% salinity in brackish water samples in one treatment stage.

While complete desalination can’t be achieved with algae alone, this method can serve as a pretreatment to other desalination technologies—reducing the energy footprint and financial costs of desalination while making the process more sustainable. EPA researchers are currently comparing the sustainability advantages of biodesalination technology with conventional approaches. This research highlights not only what our researchers are doing to provide potential solutions to global water issues, but also the amazing things that can be achieved with natural resources and a little bit of science.

Various algae species in smaller bioreactors

Various algae species in smaller bioreactors

About the Author: Christina Burchette is an Oak Ridge Associated Universities contractor and writer for the science communication team in EPA’s Office of Research and Development.

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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The Northeast Cyanobacteria Monitoring Program: One Program, Three Opportunities for You To Get Involved!

By Sara Ernst

If you ever have noticed a waterbody wigreen water on the edge of a laketh a layer of green scum coating its surface or a slick green film resembling a paint spill, you likely have witnessed a cyanobacteria bloom. Cyanobacteria, sometimes referred to as blue-green algae, are tiny organisms found naturally in aquatic ecosystems and numerous other environments. Typically, these organisms are harmless and go unnoticed; however, under certain conditions, cyanobacteria can form a dense mat or bloom on the surface of the water that may produce harmful toxins. These blooms and associated toxins pose a significant threat to humans, animals, and the ecosystem. They can cause illnesses, skin irritations, or worse and can threaten drinking water supplies and recreational opportunities. As cyanobacteria bloom incidence continues to increase, EPA strives to create and improve methods for bloom prediction, monitoring, and management.

The Northeast Cyanobacteria Monitoring Program, covering the states of Rhode Island, Connecticut, Massachusetts, Vermont, New Hampshire, and Maine, will help generate region-wide data on bloom frequencies, cyanobacteria concentrations, and spatial distribution through three coordinated projects: bloomWatch, cyanoScope, and Cyanomonitoring. Each project relies on the general public, citizen scientists, and trained water professionals to locate potential blooms and report applicable information, so we can improve cyanobacteria monitoring and learn more about harmful blooms in the Northeast.

The amount of time, equipment, and training needed to participate varies for each project. The simplest reporting tool to use is bloomWatch, a smartphone app that enables participants to help track cyanobacteria blooms by taking and submitting photos. All you need to do is download the app and you’re in business! bloomWatch teaches you what to look for, provides on-screen instructions on how to take good photos of blooms, and prompts you to answer some questions about the sighting. After submitting the photos and sighting details through the app, you can also send a bloom report to your state’s environmental agency.

The cyanoScope project helps scientists and water resource managers learn more about where and when blooms occur and what types of cyanobacteria are present across the region. With the appropriate gear and training, cyanoScope participants collect water samples of possible blooms, view the samples under a microscope, take photos of cyanobacteria, and upload the photos and sighting details to the cyanoScope project on The cyanoScope community then helps to identify the cyanobacteria present.

The Cyanomonitoring project builds on bloomWatch and cyanoScope; it is the most involved project, and therefore contributes the most detailed information. In this project, professionals and trained citizen scientists use specific gear to monitor cyanobacteria concentrations in lakes and ponds to help determine where, when, and why cyanobacteria are blooming in those areas. Participants also assist in tracking regional trends resulting from climate and land use changes and assess waterbody and human health vulnerability to toxic cyanobacteria.

By participating in any of the three projects, you can contribute valuable data that will help scientists learn more about cyanobacteria blooms and how best to monitor them in the future. Interested in getting involved? Visit for more information on the Northeast Cyanobacteria Monitoring Program and each of the coordinated projects!


About the Author: Sara Ernst is an Oak Ridge Associated Universities contractor who works as the Science Communications Specialist in the Atlantic Ecology Division of EPA’s Office of Research and Development.

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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When Green Goes Bad

Flyer banner for "When Green Goes Bad" webinar

By Lahne Mattas-Curry

When you think about the environment, what color comes to mind? Green, right? Because in everything we know in the environment “Green is Good.”

And while that is very often true, in the case of lakes and ponds that suddenly go green, it is most likely the result of an algae bloom, which, increasingly, contain many harmful cyanobacteria.  Also known as “blue-green algae,” some species of these tiny, photosynthetic aquatic organisms produce toxins. The impacts of these harmful algal blooms are widespread and often not good. Not good at all.

From acute adverse human health impacts such as respiratory and gastrointestinal problems (yuck) to known deaths of animals (keep the family dog out of green water, please!!), blooms like these are becoming a more frequent occurrence and are having greater impacts.

To better understand how algal blooms impact human health, identify the toxicity of cyanobacteria, predict the probability of bloom occurrences, and share this information broadly, our researchers have been working on a research project focused this topic since 2012.

The researchers involved in the project will be sharing what they have learned during a webinar on Wednesday, June 25 from 12:00 to 1:00pm as part of EPA’s Water Research Webinar Series.

We hope you will join them to hear an overview of the breadth of their algae bloom research, and learn details about ecological modeling they conducted on cyanobacterial blooms in U.S. lakes. They will explain how they embraced the concept of “Open Science”—the movement to make scientific research and data accessible to the public.

And if that’s not enough, they will also be available for a twitter chat on June 26 from 2:00pm to 3:00pm. You can submit questions now by using #greenwater or you can wait until the day of the chat. Please follow us @EPAresearch.

To register for the webinar, please send an email to with your name, title, organization and contact information.

Meet our Scientists

Jeff Hollister, Ph.D.
EPA research ecologist Jeff Hollister received his Ph.D. in Environmental Science from the University of Rhode Island. His past experience is in applications of geospatial technologies to environmental research and broad-scale environmental monitoring, modeling, and assessment. His current research focuses on how nutrients drive the risk of cyanobacterial blooms in lakes and ponds.

Betty Kreakie, Ph.D.
EPA research ecologist Betty Kreakie earned her Ph.D. in integrative biology from the University of Texas. Her work focuses on the development of spatially-explicit landscape level models that predict how biological populations and communities will respond to human-caused influences, such as nutrient and contaminant pollution, climate change, and habitat conversion.

Bryan Milstead, Ph.D.
EPA post-doctoral research ecologist Bryan Milstead received his Ph.D. from Northern Illinois University for work on small mammal population dynamics in Chile. Before coming to EPA, he worked for the U.S. National Park Service and for the Charles Darwin Foundation for the Galapagos Islands. His current work focuses on understanding how nutrient over-enrichment affects the aesthetic quality and risk of cyanobacteria blooms in lakes.

About the Author: Lahne Mattas-Curry communicates the many cool things happening in water science for EPA and hates #greenwater. She urges everyone to think twice about what fertilizers they use on their lawn and encourages pet owners to “pick up the poop” to reduce nutrient pollution.

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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Around the Water Cooler: What’s In Your Water?

By Lahne Mattas-Curry  

What's in your water?

Recently a friend who knows I work on water issues asked me, “What’s in our water?” Good question, right? The answer is a little more complex than just H2O. The truth is that things we flush, throw away, or pour down the sink all have an impact on “what’s in our water.” 

Toxins, contaminants, sediments, and other pollutants all are things that can affect our water quality. 

But the good news is that EPA researchers are developing a variety of tools that can help water utilities better manage our water and make sure that it not only complies with the Safe Drinking Water Act, but goes beyond to protect public health and make sure we have tasty water to drink. 

One of those tools, a one-stop-shop type of tool, called the Drinking Water Treatability Database, helps users looking for information on water contaminants and water treatment techniques. This information can then inform on-the-job decisions about contamination control and treatment. Researchers, environmental groups, and academics can also use the database to enhance understanding and direct future research of drinking water contaminants and their treatment processes. To learn more about the database, click here

Another model under development helps prioritize chemicals for testing. EPA researchers and their partners are developing user-friendly online tools called Dashboards. These interactive web-based tools will provide accessible, user-friendly chemical exposure data, hazard data, decision rules, and predictive models. This information will then help decision makers prioritize chemicals that warrant further testing and will eventually help predict a chemical’s potential to cause harm to human health and the environment. 

The Ubertool, for example, combines different data sources and ecological models to help decision makers estimate the effects of chemicals on aquatic plants and animals. 

Next time you go to your sink and pour a big glass of delicious water, know that EPA researchers are working hard to make sure that it stays cool, refreshing and safe. They are constantly assessing threats to our water and making sure we stay ahead of the game. 

Lahne Mattas-Curry works with EPA’s Safe and Sustainable Water Resources research team and a frequent “Around the Water Cooler” contributor.

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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Around the Water Cooler: Dive Right Into Our Latest Newsletter!

By Aaron Ferster

Chances are if you hear someone yell out “come on in—the water’s great!” you can be pretty sure they mean that the temperature of the water is delightful. Not too hot, not too cold. But 40 years ago, before the establishment of the EPA and the passage of the Clean Water Act, you might have had cause to wonder if what they were referring to was the quality of the water: that it is free of pollution or other potentially harmful contaminants.

As Dr. Suzanne van Drunick, National Program Director for EPA’s Safe and Sustainable Water Resources Research Program writes in the latest issue of our Science Matters newsletter:

“Forty years ago, the dire state of the nation’s water resources was a national concern. The assaults were direct and numerous: untreated sewage, industrial and toxic discharges, contaminated runoff, and widespread destruction of wetlands.

For many, the symbol of that decay came in June of 1969, when something perhaps as simple as a wayward spark from a passing train ignited a mass of oil-soaked debris floating on the surface of the contaminated Cuyahoga River—sending thick, billowing black clouds of smoke into the air. A river on fire.” 

As Dr. van Drunick points out, in the 40 years since, much of the nation’s waters have become significantly cleaner and safer. How did the clean up begin? It all started with science.

The EPA science and engineering designed to keep the environmental and human health success story of the Clean Water Act moving forward is the focus of the newsletter. The stories illustrate how EPA’s Safe and Sustainable Water Resources Research program is providing the innovative science and engineering solutions needed to meet 21st Century challenges, such as the need for more “green infrastructure” to reduce the burden on aging sewer systems, protecting recreational water, combating invasive species from ballast water, and much, much more.

I invite you to “dive right in” and enjoy the latest issue of EPA’s Science Matters  to learn more. 

About the Author: Aaron Ferster is an EPA science writer.

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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Around the Water Cooler: Keeping Stormwater In Place

By Lahne Mattas-Curry

Raining in the city

No where to run: stormwater has no place to go but the sewer.

In the first post of my series on EPA water research, I gave a little history lesson and introduced green infrastructure. This week, we’re going to focus on the cost of combined sewer systems—to our health, our environment and even our economy.

There are hundreds of cities across the country that have combined sewer systems. For example, in New York City, more than 27 billion gallons of raw sewage and polluted stormwater discharge out of 460 combined sewer overflows into the New York Harbor alone each year. Think about all the impermeable surfaces in the city: sidewalks, streets, roofs, patios. It’s a concrete jungle.

To manage stormwater—and set up scenarios to see the impact of development—EPA scientists are developing the Stormwater Calculator that estimates the annual amount of stormwater runoff from a specific site and provides city planners, developers, and property owners a way to calculate the result of specific actions on our waterways. The online tool will be available later this fall.

As stormwater flows over the surface of your property, driveways, parking lots, roofs, etc, it picks up lots of sediments, such as animal droppings, tire residue, motor oil, brake dust, deicing compounds (in the winter), fertilizers, pesticides, trash, heavy metals and other pollutants and carries them to the nearest storm drain.

Obviously, there are things that cities can do to help reduce stormwater run off, and the steep price tag that goes with the cost of separating the combined sewer systems.

For example, in Omaha, the city is testing green infrastructure throughout the city to help reduce the $1.7 billion sewer system separation project. EPA scientists are testing and monitoring soils in Omaha, and other cities such as Cleveland and Cincinnati, to measure how successful green infrastructure is at keeping the combined sewer overflows to a minimum.

City of Omaha

Cities like Omaha are looking for ways to use green infrastructure to reduce stormwater costs.

There are steps you can take too.

According to the University of Nebraska, for every 1,000 square feet of impermeable surface on your property, every 1 inch of rainfall generates approximately 626 gallons of water. If you add two 55 gallon rain barrels to your property, you now have water to irrigate your gardens. Add a rain garden, and you probably take care of much of the excess. Now, rain is absorbed back into our aquifers instead of rushing into the nearest storm drain, keeping waterways clean and ecosystems functioning.

Many states and counties subsidize the installation of green infrastructure on property, so check with your county and state government. It’s worth it to make sure we have clean water for generations to come.

About the Author: Known around the office as “AguaGirl,” Lahne Mattas-Curry works with EPA’s Safe and Sustainable Water Resources team and  communicates water research to anyone who will listen or read her blog posts.

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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