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As climate change flames a megadrought in the U.S. Southwest, the country is hitting some worrisome records. The water level of Lake Mead, which provides water for millions of people, is hovering near its lowest ever. And in some places, the shrinking Colorado River, which irrigates about 5 million acres of farmland and quenches the thirst of over 40 million people, is just desert and dust.

Meanwhile, as of 2018, about 80% of the country’s wastewater—including water used in agriculture, power plants, and mines—gets dumped back into the world, untreated and unusable, a wasted opportunity. And although today’s go-to purification technologies, which use a process called reverse osmosis, are still the most cost-effective and energy-efficient way to treat seawater and briny groundwater, conventional reverse osmosis cannot handle super-salty waters—those containing double the salt content of the ocean. As U.S. water supplies shrink (and get saltier), the country can no longer afford to dump even the saltiest sources back into the world.

Now, in a new study published in Desalination, members of the National Alliance for Water Innovation (NAWI) research consortium analyzed an emerging form of reverse osmosis, called low-salt-rejection reverse osmosis. These novel systems could treat even highly salty water. But the design is so new it is still theoretical.

So, to learn how these technologies might compete with other water treatment options, the NAWI research team developed a mathematical model that could, with help from a supercomputer, quickly evaluate the cost, clean water output, and energy consumption of more than 130,000 potential system designs. Their results show that, in many cases, low-salt-rejection reverse osmosis could be the most cost-effective choice, potentially reducing the overall cost of producing clean water by up to 63%.

“The ultimate goal of this research is to conduct a thorough techno-economic evaluation of a new technology that hasn’t been tested in the real world yet but has the potential to enable high-water-recovery desalination,” said Adam Atia, a senior engineer at the National Energy Technology Laboratory and the paper’s lead author.

Although a few studies have evaluated the potential cost and efficiency of low-salt-rejection reverse osmosis systems, this study offers a more comprehensive analysis of their design, operation, and performance. To better understand the potential promise of these theoretical systems, the team used a supercomputer to hone in on the most optimal, cost-effective designs. They then explored how those designs might function in hundreds of thousands of scenarios (as opposed to just a handful).

Because low-salt-rejection reverse osmosis systems allow more salt to pass through each membrane, they require less force—and therefore less energy—to push the water through. But, if more salt can squeeze through, the resulting water is, not surprisingly, still too salty to drink. To produce potable water, this still-too-salty water gets recycled back into the previous membrane stages. Once the salt content is low enough, standard reverse osmosis can take care of the rest, generating high-quality drinking water.

All that recycling adds to the system’s complexity. So, the team needed to find out: How many membrane stages are optimal? How many recycling loops are needed? And how much cost and energy do those loops add? To answer these questions, researchers could calculate, individually, how much clean water each design could produce from waters with different concentrations of salt.

“That would potentially take a really, really, really long time for them to solve,” said Ethan Young, a researcher at the National Renewable Energy Laboratory (NREL) and an author on the study. “We were able to do it in a few minutes with high-performance computing.”

And, in those few minutes, they examined not one but hundreds of thousands of potential scenarios.

“The novelty of our study is the computational force power we brought to bear on this analysis,” added Bernard (Ben) Knueven, a fellow NREL researcher and author.

Without a supercomputer, all those calculations would take about 88 days instead of one hour or even a few minutes, Young said. Of course, the supercomputer also needed Knueven and Young’s mathematical magic to solve these complex design problems both quickly and accurately.

With all that speedy math, the team discovered that low-salt-rejection reverse osmosis could outperform its competitors in both cost and energy use—at least for water containing less than 125 grams of salt per liter. But the team’s model could also help other research teams identify, build, and test the most promising system designs.

“The hope is, by doing these computational analyses, we can give the experimentalists information to say, ‘Oh, here’s an interesting thing to study,’ or, ‘No, this is probably completely ruled out,’” Knueven said.

The model could be expanded, too, to help experimentalists hone in on the best designs for reverse osmosis systems, generally. Their study is the first to both use and add to NAWI’s Water treatment Technoeconomic Assessment Platform (WaterTAP). A publicly available software tool, WaterTAP gives users the power to model and simulate various water treatment technologies and evaluate their cost, energy, and environmental trade-offs.

“I think it’s so cool. We’re building a tool that can help us and other researchers assess the potential of new and exciting technologies,” Knueven said of WaterTAP, which was built through a collaboration between NREL, Lawrence Berkeley National Laboratory, the National Energy Technology Laboratory, Oak Ridge National Laboratory, and the Regents of the University of California.

Next, the researchers hope to partner with experimental teams to build and evaluate how low-salt-rejection reverse osmosis systems function in the real world. Mineral buildup, for example, could slow the system down and should be accounted for in future evaluations.

Even so, Atia said, this emerging form of reverse osmosis could be a valuable tool to maximize water recovery from high-salinity sources. “And our model can play a key role in supporting the technology’s deployment,” he said.

“To me,” Knueven said, “it’s a demonstration of what we can do with a little bit of computation and a little bit of optimization.”

Learn more about NAWI and its members’ efforts to secure an affordable, energy-efficient, and resilient water supply for the United States.

The National Alliance for Water Innovation is a public-private partnership that brings together a world-class team of industry and academic partners to examine the critical technical barriers and research needed to radically lower the cost and energy of desalination. The alliance is led by the U.S. Department of Energy’s Lawrence Berkeley National Laboratory in collaboration with the National Energy Technology Laboratory, the National Renewable Energy Laboratory, and Oak Ridge National Laboratory and is funded by the U.S. Department of Energy’s Industrial Efficiency and Decarbonization Office.

Republished with permission from the University of Illinois Urbana Champaign.

The nitrate runoff problem, a source of carcinogens and a cause of suffocating algal blooms in U.S. waterways, may not be all gloom and doom. A new study led by the University of Illinois Urbana-Champaign demonstrates an approach for the integrated capture and conversion of nitrate-contaminated waters into valuable ammonia within a single electrochemical cell.

The study, directed by chemical and biomolecular engineering professor Xiao Su, demonstrates a device capable of an eightfold concentration of nitrate, a 24-times enhancement of ammonium production rate and a greater than tenfold enhancement in energy efficiency compared with previous nitrate-to-ammonia electrocatalysis methods.

“By combining separation with reaction, we overcame previously existing limitations of producing ammonia directly from groundwater, where the concentrations of nitrate are very low, and thus make the conversion step inefficient,” Su said.

The findings are published in the journal Nature Communications.

“The goal of this study was to use as little energy as possible to remove nitrate from agricultural runoff before it hits our waterways, and transform it back to a fertilizer or sell it as a chemical feedstock,” Su said. “Our technology can thus have an impact on waste treatment, sustainable chemical production and advance decarbonization. We are hoping to bring greater circularity into the nitrogen cycle.”

The team developed a unique, bifunctional electrode that can separate and up-concentrate nitrate from a water stream, while converting to ammonia in a single unit using purely electrochemical control. “The bifunctional electrode combines a redox-polymer adsorbent, which captures the nitrate, with cobalt-based catalysts that drive the electrocatalytic conversion to ammonium,” Su said.

The system was tested in the lab using agricultural runoff collected from drain tiles around the U. of I. research farmlands to evaluate the potential of the technology for real-world conditions, the researchers said.

“This is a very efficient capture and conversion platform with a low footprint,” Su said. “We don’t need separate electrochemical cells for the water treatment and ammonium production or adding extra chemicals or solvents. Instead, we envision a module installed directly onto farmland and run using the power generated from the electrocatalytic process and a small solar panel.”

The team said its next goal is to develop even more selective materials used in the device to achieve higher nitrate removal and accelerate the conversion to ammonia – while engineering larger scale systems for practical deployment in the field.

Kwiyong Kim is the first author of the study, with contributions from Jaeyoung Hong and Jing Lian Ng, from the Su group. The work was carried out in collaboration with Tuan Anh Pham, from the Lawrence Livermore National Laboratory, and Alexandra Zagalskaya and Vitaly Alexandrov, from the University of Nebraska.

Su also is affiliated with the Beckman Institute for Advanced Science and Technology and also is a professor of civil and environmental engineering at Illinois.

The National Alliance for Water Innovation, funded by the U.S. Department of Energy and the Institute for Sustainability, Energy, and Environment at Illinois supported this study.

Editor’s notes:

To reach Xiao Su, call 217-300-0134; email x2su@illinois.edu.

The paper “Coupling nitrate capture with ammonia production through bifunctional redox-electrodes” is available online.

DOI: 10.1038/s41467-023-36318-1

In April 2022, a team of engineers hiked into California’s Sierra Nevada mountains to hunt for snow. Instead, they found mostly bare, dry dirt and only a few of the snow patches that provide one-third of California’s water supply.

In the coming decades, water scarcity and insecurity are likely to intensify across much of the United States. In California, the Sierra Nevadas are expected to lose a staggering 65% of their snowpack over the next century, said Hariswaran (Hari) Sitaraman, a researcher at the National Renewable Energy Laboratory. That loss, plus political, economic, and other challenges, is making it essential for drought-prone states, like California, to tap alternative water sources such as brackish (or salty) waters and agricultural runoff.

And yet, the most common way to treat and reuse nontraditional water supplies is through a process called reverse osmosis, which can be both expensive and energy intensive.

Now, Sitaraman and Ilenia Battiato, two members of the National Alliance for Water Innovation (NAWI) research consortium, have used supercomputers to study reverse osmosis systems as a whole—a first for both the type and scale of reverse osmosis research. With their new technique, the duo also discovered a new system design that could make these technologies about 40% more energy efficient—and therefore more cost-effective—while producing the same amount and quality of clean drinking water.

“Until now, people have been looking at a tiny piece of the entire reverse osmosis module and drawing conclusions from that,” Sitaraman said. “But we looked at the entire thing.”

The results are published in a new paper in Separation and Purification Technology.

Along with Battiato, an assistant professor of energy science and engineering at Stanford University, Sitaraman created a fluid dynamics solver—a numerical tool that can analyze how fluids, like salty water, flow into a reverse osmosis system, pass through several membrane filters, and come out clean on the other side.

With their solver, Sitaraman and Battiato studied reverse osmosis systems with high precision, enabling them to uncover any snags or inefficiencies. For example, to filter brackish waters, reverse osmosis systems use high pressure to push the water through several membranes, which, like sophisticated coffee filters, block salts and other minerals from passing through. That process cleans the water, but it also creates thin layers of salty buildup on the membranes. And that buildup can affect how well the water flows, potentially reducing the system’s efficiency.

“That thin layer needs to be measured correctly to understand how much pure water you get out of salt water,” Sitaraman said. “If you don’t capture that right, you cannot understand how much it costs to run a reverse osmosis plant.”

A more efficient reverse osmosis system is more cost-effective, too.

Yet, most reverse osmosis plant owners do not have a high-performance computer to replicate Sitaraman and Battiato’s high-fidelity simulations—which so accurately mimic real-life reverse osmosis technologies—to uncover snags in their own systems. So, Sitaraman performed the complex work of creating a simpler model equation that can predict a system’s mass transfer, estimating how much pure water can be filtered out of brackish water. With his model, engineers can now discover how to improve the efficiency (and cost) of their own systems.

“If the economics improve,” Sitaraman said, “then of course reverse osmosis systems will be more widely used. And if they’re more energy efficient, they will contribute less to greenhouse gas emissions and climate change.”

That is a huge win, but Sitaraman and Battiato’s tools can benefit far more than reverse osmosis plant owners. Other researchers can build on their work to study the efficiency and cost of all kinds of reverse osmosis filtration technologies beyond those used to treat unconventional water sources. The food industry uses these filters to create highly concentrated fruit juices, more flavorful cheeses, and much more. Aquariums need them to remove harmful chemicals from their waters. And reverse osmosis systems can even extract valuable minerals and other substances that could be used to make cheap fertilizer or fuel.

One huge advantage of high-fidelity simulations, Battiato said, is the ability to study a vast range of reverse osmosis system configurations without investing the time and money required to build and experiment with real-life systems.

“We want the system to correctly capture the physics,” Battiato said, “but we are theoretically not constrained by manufacturing.”

With simulations, the team can quickly explore far more potential designs and home in on the best. That is how Battiato and Sitaraman identified their potentially more effective arrangement of spacers (which are bits within the reverse osmosis system that create turbulence and keep channels open to help water flow through). Their new spacer arrangement not only improves the system’s energy efficiency by 40%, but it also produces the same amount of equally pure water.

Although the duo’s simulations accurately replicate real-life systems, they are still theoretical. Sitaraman hopes another research team will build their design and evaluate how closely the real system matches their models. In the meantime, their higher-resolution (or more precise and comprehensive) simulations could help researchers avoid making inaccurate assumptions about how reverse osmosis systems work and, in so doing, learn how to improve the technologies.

Today, most engineers use trial and error to discover how to improve their reverse osmosis systems. But that process is slow, and water shortages are coming fast. With Battiato and Sitaraman’s simulations, engineers could speed up the development of more efficient and cost-effective technologies, so the country can access unconventional water sources when communities—like drought-stricken western towns—desperately need them.

“Water is a scarce resource,” Battiato said. “I don’t think we can afford to do coarse optimization anymore. We need to save every drop of water that we can.”

Learn more about the National Alliance of Water Innovation and their efforts to secure an affordable, energy-efficient, and resilient water supply for the United States.

The National Alliance of Water Innovation is a public–private partnership that brings together a world-class team of industry and academic partners to examine the critical technical barriers and research needed to radically lower the cost and energy of desalination. The alliance is led by the U.S. Department of Energy’s Lawrence Berkeley National Laboratory in collaboration with the National Energy Technology Laboratory, the National Renewable Energy Laboratory, and Oak Ridge National Laboratory and is funded by the U.S. Department of Energy’s Industrial Efficiency and Decarbonization Office.

After a summer of COVID restrictions, travel and (hopefully) a bit of vacation, many of us are heading back into the office or classroom.  While we might not spend a great deal of time thinking about the implications for our water use at work, NAWI friends at Phoenix Process Equipment Co. and Aquacell Water Recycling Ltd. certainly do.  Over the past month, they have graciously hosted NAWI members on tours of the Salesforce Tower in San Francisco and Meta corporate campus in Menlo Park, CA (yes, that Meta) where they designed and installed onsite “blackwater” reuse facilities. They shared some important lessons in operating small-scale water treatment systems.

First the stats.  Both facilities were designed to accommodate large office populations and treat between 40 to 90 thousand gallons per day of rainwater, toilet, and sink wastewater to a quality safe for additional toilet flushing and/or irrigation (of salinity sensitive redwoods!). Both facilities used roughly the same process train consisting of belt filter (with solids discharged to sewer), aerobic membrane bioreactor system (MBR), RO, ultraviolet (UV), and remineralization. While the Salesforce system was idle at the time of our visit, Meta’s system was just getting restarted after a long COVID hiatus, and will be resuming water delivery in the coming weeks. 

Next the insights:  

1. COVID threw onsite systems a major curveball. Meta’s campus was fully populated before the 2.5 year-long COVID shutdown; the new “normal” office population (about one-third of pre-pandemic numbers) is sufficient to sustain the MBR, but is far below the original design capacity. We had some great discussions about resilient designs, including what it would take for systems to operate at a mere 10% of their design capacity for an extended period of time.  
2. Tanks, tanks, tanks! Water treatment and reuse systems require a LOT of water storage. This is often overlooked in academic studies. Not only are tanks expensive ($2-$10 per stored gallon) but they also have a significant footprint — not cheap when it means displacing coveted parking spots and valuable Silicon Valley real estate. Ideally, below-grade storage tanks are integrated into the original building design. Researchers probably need to do a better job of factoring storage into the total cost projections for on-site systems. 
3. Insensitivity (indifference?) to electricity consumption. During both of our tours, we had a hard time even finding the electrical meter and system designers often have no information about the actual system energy use once its installed and operating.
4. Odor and color control is essential. Office building tenants do NOT want to smell even a whiff of typical wastewater treatment plant “fragrance”, and tenants don’t want to flush their toilets with yellow water. A lot of our process designs for onsite blackwater reuse are dictated by odor and color rather than by safety concerns. We wondered aloud where NAWI technologies could make an impact in these two important aesthetic areas. 
5. Permitting blackwater recycling systems remains a regulatory challenge. While greywater recycling has become significantly easier to permit over the past decade, blackwater systems are really first-of-a-kind demonstration sites in most regions. They are often held to the same standards for daily monitoring, sample collection, and thus demand frequent sensor monitoring and calibration. Technology and regulations are going to have to evolve together for building-scale reuse to really take hold.
6. These systems are far too complex to be managed by a typical property manager or site engineer. Both sites we visited had real-time remote monitoring. The (operational) Meta facility had a dedicated Level 2 operator onsite, as well as a contract with a local laboratory for daily sampling collection/analysis. Additional facilities operation support and maintenance was a phone call away. 

Katie Weitzel and her team were awarded for their research poster titled Treatment and Reuse of Agricultural Drainage Water: Challenges and Opportunities. Weitzel, a Ph.D. student at the University of Cincinnati, attended the 2022 Association of Environmental Engineering and Science Professors (AEESP) Research and Education Conference to represent her work. 

“There were a lot of people interested in this work and I had a lot of interaction with people during the poster session,” said Weitzel. “It was nice to see so many people interested in this and starting discussions about treatment of non-traditional water sources.”

Weitzel and her team’s research focuses on water innovation surrounding agricultural drainage, and their poster presented information from the agricultural baseline work they’ve been investigating as part of the NAWI research consortium. The poster content complemented the conference theme, “Environmental Engineering at the Confluence,” which covered the full breadth of environmental engineering. The conference explored emerging developments in the field and focused four areas of convergence: convergence of education and research, convergence of research in air, water, and soil, convergence of research and action, and convergence of research, practice, and entrepreneurship.

 I was recently introduced to Prof. R. S. Silver’s 1979 history of desalination, slyly titled For want of a nail (Desalination Volume 31, Issues 1–3, October 1979, Pages 39-44). Silver summarizes his career in desalination research, noting that it is often the small things in desalination that end up mattering the most. 

This cautionary tale weighed on my mind when I recently toured the Advanced Water Treatment Plant (AWTP) located in Cambria, California. Prior to the development of the plant, Cambria had relied on groundwater from a nearby creek. The Central Californian local community knew it was time for a water-supply related change after years of low rainfall and over-reliance on a single water supply.  

Cambria’s AWTP⁠—a secondary water supply based on reuse of treated wastewater⁠—was thus built in 2015 during the height of California’s most recent multi-year drought. 

The picturesque town’s treated wastewater is first diverted to a percolation basin where it seeps into the subsurface. It then interacts with freshwater percolating from the mountains to the East and seawater seeping inland from the West. The mixed groundwater is then pumped out of the basin, filtered, and desalinated with a 2-stage Reverse Osmosis (RO) system. This RO system recovers 92% of the fresh water, which is then reintroduced into the town’s groundwater well-field further upslope. The MF-RO-UV-H2O2 unit processes of the packaged desalination facility are elegantly housed in a set of cargo containers, cleverly laid out so that the entire system resembles a set of large tan Legos.

Unfortunately, R. S. Silver’s admonition became particularly apparent once the system was up and running. The small amount of brine generated from the facility was disposed of by pumping it into an evaporation basin nearby. The evaporation basin itself was rigorously engineered to prevent leaks but… the cool foggy weather common for the central coast resulted in very low evaporation rates. And, when a winter storm caused runoff to overtop the basin, the entire water project was put on indefinite hold.

The entire “kingdom” of brackish desalination has been waiting for a brine disposal nail.

On a related note, NAWI has begun to review Concept Papers submitted in response to our recent call for proposals for piloting novel small-scale desalination systems (read the Pilot Program FAQ for more information). I am very hopeful that the desalination community will come forward with breakthrough approaches to further treating and reducing (or even eliminating?) the liquid brine waste stream that has bedeviled brackish desalination for so long.

NAWI’s theory of action is based on the belief that technical innovation is most impactful when it is performed in context. Materials are contextualized within a process; processes are contextualized within treatment trains; treatment trains are contextualized within water systems. While pandemic shut-downs have had minimal effect on our materials and process development projects, we have sorely missed the opportunity to visit water system operators. Pre-pandemic visits to Carlsbad West Basin Water District in LA and the Kay Bailey Hutchison Desalination Plant in El Paso, Texas allowed us to learn about non-traditional source water treatment trains designs, operational challenges, and economic benefits for water users.  

So it was tremendously exciting when federal travel restrictions were eased in March and we were finally able to resume NAWI field trips. Our first three visits were to Trevi Systems, a NAWI project performer working on concentrate management in Petaluma, CA; Red Rocks community college, the site of a USBR pilot facility for reusing cooling water blowdown; and Dr. Tzahi Cath’s Direct Potable Reuse (DPR) trailer, then located in Colorado Springs. Visits to each site provided an opportunity to see NAWI technologies (or related unit processes) in action, hear directly from operators about the challenges and opportunities for low TRL research to make a difference in the cost and energy intensity of their treatment trains, and brainstorm creative new ideas for future collaboration.  

The NAWI technical program looks forward to facilitating and hosting many similar site-visits in the months to come. If you are an Alliance Member operating a small scale facility that would like to host NAWI performers, please reach out to Zach Stoll, our Research Program Manager, who will gladly work with you and our project performers to facilitate future visits. Similarly, if you are a NAWI performer interested in attending a site with the NAWI team, please stay tuned for future emails about opportunities to join.

Aurora Kuras is a graduate student in Environmental Engineering at the Colorado School of Mines, a NAWI Consortium Member. She defended her thesis on Functional Data Analysis for Detecting Faults in Water and Wastewater Treatment on Wednesday, March 30th. This research is important because early and effective fault detection in water and wastewater treatment plants is important to maintain water quality and prevent process disruptions. Her work applies a method in functional data analysis (FDA) for fault detection to drift faults observed in a sequencing batch membrane bioreactor and closed-circuit reverse osmosis system. Her research is advised by Profs. Tzahi Cath and Amanda Hering.

Colorado Springs Utilities, Colorado School of Mines (Mines), and Carollo Engineers partnered in 2020 to create a mobile direct potable reuse (DPR) demonstration system (7,000 gpd) that purifies municipal wastewater for potable use. On March 8, the project team won the 2022 WateReuse Award for Excellence in Education and Outreach. Award recipients include Colorado Springs Utilities (Kirk Olds, Donene Dillow, Birgit Landin, Shaun Thompson, Jennifer Kemp, Lisa Halcomb), Colorado School of Mines (Tzahi Cath, Mike Veres, James Rosenblum, Tani Cath, Mason Manross, Chris Bellona), and Carollo Engineers (Jason Assouline, Andrew Salveson, Tasie Kade, John Rehring). Read the article.

Water scarcity and insecurity is a pervasive problem around the world. Climate change, population growth, and changes in how communities use freshwater all contribute to shrinking resources worldwide. In the next few years, water managers in 40 U.S. states expect to face increased freshwater shortages. Water is not only necessary for individuals to hydrate, clean, and cook, it is also essential to produce food and energy.

Solving a Looming Problem

From seas to sewers to salty groundwater, it may seem like water is everywhere you look. But the amount of freshwater available on Earth is limited—and demand is rising. Equalizing freshwater demand with supply requires more efficient use of existing water resources. And that requires new, innovative ways to repurpose or reuse water that is often unused or discarded.

For example, immense underground reservoirs of brackish water lie beneath some of the world’s most drought-stricken regions. This water is too saline to be used in its current state, and desalination is still too costly and inefficient. But how can unconventional water sources become a cost-effective and sustainable way to boost draining supplies?

The National Alliance for Water Innovation (NAWI) is developing technologies that bring a wider range of unconventional water sources within reach while ensuring efficient-as-possible usage. Formed in 2017 as a partnership between Lawrence Berkeley National Laboratory, the National Renewable Energy Laboratory, Oak Ridge National Laboratory, the National Energy Technology Laboratory and roughly 30 stakeholders across the academic, industry, and non-profit spheres, NAWI was incorporated as a Department of Energy innovation hub in 2020. It currently exists as a five-year, $110 million research program that brings together experts from over 300 organizations, including national laboratories, universities, companies, water utilities, and state agencies.

“Today’s water system is not sustainable for a number of reasons,” said Yarom Polsky, NAWI’s Process Innovation and Intensification topic area leader and a group leader for the Sensors and Embedded Systems group at Oak Ridge National Laboratory. “We’re at a point where we’re beginning to have to treat sources of water that are much more complicated that require more advanced water treatment technologies.”

NAWI’s Present Roadmap

NAWI is working to design energy-efficient and cost-effective desalination technologies, which extract salts and other impurities from both salt water and wastewater to produce clean water with the same (or higher) quality as current water treatment methods. They aim to achieve this for 90% of nontraditional water resources within the next 10 years.

How, exactly? To recycle wastewater while reducing energy use and water treatment costs, NAWI has a plan—or five, to be exact. Following a 2020 roadmapping initiative, the NAWI Alliance published five technology roadmaps (and one master roadmap) tailored to five sectors: power, resource extraction (which includes mining for minerals and oil), industrial, municipal, and agricultural (PRIMA). Many desalination technologies are still relatively expensive. But NAWI’s roadmaps can guide technology developers and adopters to overcome technological and economic barriers as well as social and cultural hurdles.

“We aim to identify the key barriers to lowering the cost and energy of water treatment and then attack those barriers through a coordinated campaign of applied research,” said Peter Fiske, the executive director of NAWI and a researcher at the Lawrence Berkeley National Laboratory.

NAWI’s master roadmap synthesizes the highest-priority research needs for state-of-the-art, emerging, and existing desalination and advanced water technologies. In 2021 and 2022, NAWI added to their growing list of guides and tools, publishing eight foundational, sector-specific, baseline studies that provide a comprehensive assessment of challenges and opportunities associated with different source waters, which could help accelerate the creation of a circular water economy. Several of these studies relied on a new analytical tool developed by NAWI researchers. Called the Water Technoeconomic Assessment Platform (TAP), this tool evaluates water treatment costs, energy needs, environmental impacts, and resiliency trade-offs in a consistent manner across sectors.

Did you miss NAWI’s recent sector-specific studies? Here’s a refresher of what desalination technologies can offer individual sectors, such as:

• Power: NAWI researchers explored the economic and technical feasibility of extracting salt from seawater for use in power plants, for example, as well as reusing water that cools machinery in power plant facilities to keep them running safely.
• Resource Extraction: NAWI researchers assessed how novel water treatment technologies and strategies can help mining operations reclaim water used to clean quarried material. They also studied how the oil and gas industries could transition to new water treatment technologies to reclaim and reuse the wastewater generated from cooling the rigs used to extract oil from the ground.
• Industrial: Including food and beverage companies, data centers, and industrial campuses, industry makes up the fourth largest category of U.S. water use. In this study, researchers at NAWI explored the potential for industrial wastewater to serve as an alternative water resource for these same companies, irrigation of farms or city parks, or drinking water.
• Municipal: Two NAWI studies examined the cost and energy needed for alternative municipal water treatment methods and the challenges and opportunities of desalinating brackish water from groundwater, for use in irrigation or as drinking water, for example.
• Agricultural: A significant amount of freshwater is used to grow fruits and vegetables and raise livestock in the United States. In fact, irrigation for farms may account for 42% of total freshwater use in the United States, according to this 2021 NAWI study, which examined the institutional and economic barriers preventing states from reusing agricultural drainage.

Preparing For the Future

In early 2022, NAWI also issued a request for information on innovative, small-scale desalination and water-reuse technologies and systems. This effort could lead to a request for proposals to build and operate small-scale systems to treat unconventional water sources and achieve pipe parity (meaning similar- or higher-quality water than conventional water treatment methods.)

“We do not have a water shortage on this planet,” said Benny Freeman, a NAWI Research Consortium and Alliance member and chemical engineering professor at the University of Texas at Austin. “The problem is that it’s contaminated with salt and other constituents. I think, in the future, we’re going to have a society and an environment where we have enormous amounts of water … because of desalination technologies.”

Countries and communities require sustainable sources of water for economic growth, sociopolitical stability, and quality of life. However, water scarcity and insecurity are pervasive problems around much of the world. As such, it is important to urgently develop technologies for advanced water reuse that are cost efficient and effective – that may even change the way we use and reuse water.

Nature uses water over and over again, in an endless long cycle of evaporation and precipitation, powered by the sun. Humans, in contrast, tend to use water only once – drawing fresh water from a local source, using it for various purposes, and then discarding the wastewater back into the environment after minimal treatment, often exhausting their limited water resources.

For decades, scientists have been working on new technologies to enable treatment and direct potable reuse of water, but the applications have been largely limited to “out-of-this-world” environments such as water supply systems on the International Space Station.

Colorado Springs Utilities, Colorado School of Mines (Mines), and Carollo Engineers partnered in 2020 to create a “down-to-Earth” version of this technology: a mobile direct potable reuse (DPR) demonstration system (7,000 gpd) that purifies municipal wastewater for potable use. The system is now being tested and demonstrated at the Colorado Springs Utilities’ JD Phillips water reclamation plant, but is due to travel to several other locations in Colorado later this year.

The DPR demonstration lab is the vision of Dr. Tzahi Cath, a Professor of Civil and Environmental Engineering at Mines. “If we can take the water, and instead of just wasting it we could recover it and reuse it again for potable purposes, it will save money and energy, and it will save many problems during drought years” says Cath, “[…] communities must have a wider portfolio of sources of water to make sure that we have drinkable water under any circumstances.”

While there have been previous examples of  DPR technology, including units packaged in mobile systems, most of these have relied on reverse osmosis, which leaves behind a waste stream of concentrated contaminants that must be managed and disposed of, also limiting the percent water recovery of the system. In contrast, the Mines mobile DPR lab utilizes advanced treatment technologies such as ozonation, biologically active filtration, ceramic microfiltration, ultraviolet disinfection with advanced oxidation, and granular activated carbon to efficiently destroy pathogens and trap and remove contaminants of emerging concern, purifying close to 100% of the water. The mobile system also has a range of advanced sensors and automated fault detection technologies to ensure that all processes are operating properly and synchronously, and that the water meets drinking water regulations at all times.

The DPR system was recently put to the test, and it passed with flying colors — close to a million gallons of water were successfully treated over the first 6 months of operation. The water met all Colorado’s drinking water quality limits, and a few batches of water from the mobile lab were used to produce beer by several local breweries and soft drinks that were served in public outreach events. Specifically, all emerging contaminants of concern and disinfection by products such as PFAS, 1,4-dioxane, TCEP, TCPP, and NDMA were reduced to much below the regulatory or advisory levels, and microorganisms such as coliforms were completely eliminated from the product water. 

Seeing (and Tasting) is Believing

Mines embarked on this technology demonstration project, anticipating that some residents would be nervous about the concept of drinking recycled water. The system is designed to allow visitors to observe the water treatment process directly, and taste the high-quality water produced. 

Tourists can visit the PureWater Colorado Mobile Demonstration in Colorado Springs and watch the entire water treatment process in action. Funded by a Colorado Water Conservation Board Grant, with additional support from the National Science Foundation (NSF), and other industry partners, the interactive exhibit shows a scaled model of the carbon-based DPR process. 

The mobile DPR demonstrates that advanced water reuse technologies are not as far off as we think, and that you don’t have to be an astronaut to use one. DPR and other advanced water reuse technologies could help communities facing water insecurity and shortages by diversifying water supply and hedging against water risk. DPR could also  help to provide clean water quickly and cost-efficiently to people displaced by natural disasters and drought. 

On March 8, the project team won the 2022 WateReuse Award for Excellence in Education and Outreach. Award recipients include Colorado Springs Utilities (Kirk Olds, Donene Dillow, Birgit Landin, Shaun Thompson, Jennifer Kemp, Lisa Halcomb), Colorado School of Mines (Tzahi Cath, Mike Veres, James Rosenblum, Tani Cath, Mason Manross, Chris Bellona), and Carollo Engineers (Jason Assouline, Andrew Salveson, Tasie Kade, John Rehring).

DPR, Desalination, and More

Mines is part of the National Alliance for Water Innovation (NAWI), the U.S. Department of Energy’s 5-year research program to lower the cost and energy of desalination and water reuse technologies. NAWI is working to revolutionize the US water supply by enabling the affordable treatment and reuse of non-traditional sources such as wastewater. The operating data generated by the mobile lab will help researchers to develop new control sensors and algorithms to allow such systems to autonomously operate safely, reliably, and inexpensively. The mobile DPR lab is one more step in the shift toward a circular water economy.

Trevi Systems, Inc., a NAWI Alliance organization, recently licensed a pair of new switchable solvent water extraction technologies that were developed by a team of researchers at Idaho National Laboratory (INL). The research team is led by NAWI Alliance member and INL researcher, Aaron Wilson.

“Trevi Systems is excited to be partnering with NAWI and INL on this promising technology,” said John Webley, Founding Chairman and CEO of Trevi Systems. “With INL providing the theoretical framework underpinning the desalination mechanism and NAWI the funding and strong project management oversight, Trevi is uniquely positioned to rapidly advance the technology to commercial deployment.”

The newly licensed technologies use a closed loop condensable gas solvent process to enable low-energy desalination and contaminant precipitation from aqueous feed streams. Researchers expect that these technologies will be able to produce fresh water from brines (and other high salinity sources, including sea water) using substantially less energy. NAWI plans to help further develop the technologies as part of the “Solvent-Driven Zero Liquid Discharge for Production of Synthetic Gypsum” task.

Read the in-depth journal article to learn more about the fundamentals of the aqueous separation technologies.

In a rapidly evolving landscape of water treatment and resource management, innovative tools are paving the way for cutting-edge research and sustainable practices. The world of desalination, water reuse, and water treatment technology has witnessed a transformative leap, and three exceptional tools stand at the forefront of this progress. Meet “River Runner,” a creation by data scientist Sam Learner, offering a remarkable journey alongside a drop of water, connecting you to its destination on a global scale. Delve into the “Aquifer Risk Map,” recently unveiled by the California State Water Resources Control Board, revealing the vulnerability of water systems to contaminants. Finally, explore the “Regulations and End-Use Specifications Explorer (REUSExplorer),” a pivotal resource from the EPA’s Water Reuse Action Plan, unveiling state regulations, treatment requirements, and more. These tools not only empower water treatment researchers but also open doors to a world of context, compliance, and opportunity for NAWI’s research program. Welcome to the future of water innovation.

1. Explore: River Runner. Data scientist Sam Learner created this marvelous tool so that anyone can follow the pathway of a drop of water anywhere in the world. This interactive tool, based on topographic and hydrological data from the United States Geological Service, enables you to follow the path of water all the way to the ocean or into a landlocked basin. As desalination enthusiasts, we are always concerned about where solutes contained in water will end up; this tool also demonstrates what parts of the U.S. are accumulating salts.
2. Explore: Aquifer Risk Map. The California State Water Resources Control Board (SWRCB) just released the Aquifer Risk Map through its Safe and Affordable Funding for Equity and Resilience (SAFER) Program. This interactive tool shows which small water systems and private wells are at risk of producing water with contaminants above the maximum contamination limit (MCL). The map enables you to explore specific localities and also to select specific contaminants such as nitrate, arsenic, and/or uranium. For NAWI teams that are considering starting pilot projects in California, this interactive map may help you identify which communities and areas may be interested in hosting your pilot. 
3. Explore: Regulations and End-Use Specifications Explorer (REUSExplorer). As part of its Water Reuse Action Plan (WRAP), the EPA just released a database of all state regulations governing water reuse. This website allows you to select a specific state, a source of water, and/or a reuse application of interest using the available drop-down menus. The results do not include laws and policies under development. It is valuable for water treatment researchers to understand what contaminant levels and treatment requirements exist in different states. The database also includes a summary of the technical basis for the regulatory framework, as well as specific information related to which waters are permitted for reuse.

Each of these tools can help the water treatment research community better understand the context, regulatory requirements, and opportunities for NAWI’s research program.

Eden Tech recently licensed two aqueous separation technologies developed by researchers at Idaho National Laboratory (INL), one of which is supported by NAWI. NAWI Alliance member and INL researcher, Aaron Wilson, is leading the vital NAWI project, which pioneers the use of dimethyl ether (DME) as a solvent to concentrate brines for zero-liquid discharge (ZLD).

The second technology, which was supported by DOE’s Critical Materials Institute, also leverages a condensable gas solvent to drive low-cost dewatering and selective precipitation of target products from aqueous feed streams. Eden plans to deploy both technologies in solution mining applications related to the Circular Water project in Saudi Arabia, and is marketing the technology under the CircularH2O brand.

Let’s talk about an aspect of desalination that is truly spooky: magnetic effects on scaling and water softening.

Claims that fixed or variable magnetic fields can reduce mineral scaling and improve water softening have been around since the 1890’s. Today you can find a dizzying variety of devices on Amazon that claim to be able to reduce mineral scaling in pipes and soften water (“Remove dissolved Ca and Mg! Without chemicals!”). The scientific literature, however, is not nearly so positive. Some reputable researchers have reported measurable effects while others report no such effects, using seemingly similar experimental approaches. Spooky!

Into this dark and haunted field of water treatment, our intrepid colleague Prof. Pei Xu of New Mexico State University and her team will try to get to the bottom of this mystery. Like the brave characters in the long-running animated children’s show Scooby-Doo, Where Are You?, Pei and her team (which includes Huiyao Wang, Fanjun Shu, Yanxing Wang, and Lambis Papelis at NMSU and Lawrence Anovitz at Oak Ridge National Lab) intend to bravely enter the haunted house of past studies of magnetic water treatment and shine a bright light to better understand what may be the source of the mystery. That bright flashlight? Small-angle X-ray and neutron scattering to resolve the atomic-level structure of nano-clusters of scaling ions in solution.

“Like the blind people feeling parts of the elephant, many researchers have touched an aspect of this phenomenon”, Pei told me recently. “We intend to develop a complete picture of the phenomenon including examining the effects of field strength, gradient strength, and the impact of dissolved organics.”

Pei and her team will also attempt to unify the range of past observations and the various theories that have been proposed to explain the strange effects observed. “For example,” notes Pei, “surface tension is observed to increase under strong magnetic fields, but surface tension is also observed to go in the opposite direction under weaker fields.” Spooky!

I asked Pei if she grew up watching the TV show Scooby-Doo, Where Are You? “Unfortunately, I did not,” Pei replied. I explained that there were 5 teen characters and a Great Dane named Scooby Doo who drove around in a van called the Mystery Machine solving crimes and debunking stories of ghosts and paranormal activities (and uncovering the nefarious adults who were perpetrating each hoax). “That’s very interesting”, Pei patiently replied.

We look forward to learning what NAWI’s version of “the Mystery Gang” uncovers as they investigate this strange phenomenon. Don’t change that dial!

Mr. Jishan Wu of the University of California Los Angeles received a fellowship from the American Membrane Technology Association (AMTA) and the Bureau of Reclamation. His research will help to solve water supply and quality issues through the widespread application of membrane technology.

Researchers lack the tools for quantitatively evaluating the impact of their research on technology costs, especially when those technologies comprise multiple components or when the component costs are highly uncertain. A new publication from NAWI researchers proposes a suite of tools to aid in evaluating technology platforms, setting system- and component-level research targets and identifying high-impact innovation trajectories. These tools are applicable to any technology composed of multiple components whose performance or cost will benefit from innovation, but they are especially valuable for membrane systems in which the high interdependence in components amplifies or dampens the effects of innovation in nonintuitive ways. Read the paper published in PNAS here.

I think it’s time for us to settle a longstanding issue that has been mildly irritating to me and perhaps to many of you as well: the use of the terms Desalination and Desalinization interchangeably.

I was recently interviewed on the Chip Franklin Show and the host (Chip) referred to the process of extracting fresh water from ocean water as “desalinization.” Not wanting to reveal my inherent pedanticism in public, I let it pass. But with NAWI becoming a nationally recognized authority on desalination, I thought we could “use our power for good” and set the record straight on the Desalination versus Desalinization issue.

I think we can all agree that “Desalination” refers to the process of extracting fresh water from an originally salty water source. Not only does the DOE refer to us as the Desalination Hub, but many journals in our space also use the term “desalination” to describe the process of extracting pure water from salt water. “Desalinization,” in contrast, is not simply a synonym for “desalination” but has a subtle but important distinction. The prefix “De-“ in front of the word “salinization” implies that the critical process is not extracting water from a salty source but rather extracting the salt from a material.

Consider the root word “salinization.” Salinization is very specifically defined as the process of accumulating salt in soil (which renders the soil less productive for agriculture). De-salinization would be the reverse of that process: the removal of salt from soil, or, at the very least: arresting the process that is leading to the salinization of the soil.

 Where does this leave us in our research program? NAWI is focused on producing fresh water from non-traditional water sources: desalination. However some of our research projects (such as Aaron Wilson (INL), MIT and Trevi Systems’ project using Dimethylether as a draw solution to produce synthetic gypsum) are focused on precipitating and physically removing the salts themselves from the fluid. In this definitional schema, we would call that “desalinization of the brine.”

 I suppose the test would be: what are you hoping to end up making? If it’s a puddle of water: you are desalinating. If it’s a pile of salt: you are desalinizing.

 What do you think? Are the terms desalination and desalinization one and the same? Do you have an alternate definitional schema in mind? Let’s hear it: Email us your thoughts here.

DOE’s Office of Science is now accepting applications for Office of Science Graduate Student Research (SCGSR) Awards. SCGSR graduate awardees receive supplemental funds to conduct part of their thesis research at a DOE National Lab/facility for a period of 3 to 12 consecutive months, with the goal of preparing them for STEM careers that help advance the DOE Office of Science mission.

This is a GREAT opportunity for graduate students at NAWI Alliance universities to explore doing some of their PhD research at a national lab. Past participants have found the experience to be intellectually and professionally outstanding, and this is one of the best ways to build their professional networks.

Possible NAWI-related topical areas include:

Data Science

Basic Science for Advanced Manufacturing

Data and Computer Science for Materials and Chemical Sciences

Fundamental Electrochemistry for Chemical and Materials Sciences

 Eligibility – for full eligibility requirements, go here:

•            Must be minimum age of 18 years, and US Citizen or Permanent Resident at the time of application

•            Must be enrolled full-time in a Qualified Graduate Program with the Ph.D. as the degree objective, at an accredited college or university in the United States or its territories

•            Graduate Research aligned with DOE Office of Science Research Programs

•            Establishment of a Collaborating DOE Laboratory Scientist

 The applicant and their primary graduate thesis advisor are responsible for identifying a collaborating research scientist at a DOE laboratory and jointly developing the research proposal as part of the SCGSR application process.

The National Alliance for Water Innovation (NAWI) announced today that ExxonMobil has officially joined the Alliance as a member. In 2019 NAWI was selected to lead a U.S. Department of Energy (DOE) Energy-Water Desalination Hub to support United States water security. As a founding member of the NAWI Research Consortium, ExxonMobil is part of a world-class team of industry and academic partners formed to examine the critical technical barriers and research needed to radically lower the cost and energy of desalination.

“We’re pleased to support the efforts of the National Alliance for Water Innovation,” said Monte Dobson, ExxonMobil Unconventional Technology Development Manager. “We will leverage our capabilities to jointly develop a roadmap of different technologies to find beneficial ways to use treated produced water.”

The NAWI Research Consortium is headquartered at Berkeley Lab and includes Oak Ridge National Laboratory, the National Renewable Energy Laboratory, the National Energy Technology Laboratory, 19 founding university partners, and 10 founding industry partners including Exxon Mobil. NAWI’s goal is to advance a portfolio of novel technologies that will secure a circular water economy in which 90% of nontraditional water sources – such as seawater, brackish water, and produced waters – can be cost-competitive with existing water sources within 10 years.

“ExxonMobil’s objectives align well with the research space of NAWI. We are excited to have them as part of our team as we embark on our research efforts,” said Dr. Peter Fiske, NAWI Executive Director.

In the NAWI Alliance, the four national laboratories and founding industry and academic partners are joined by a member community of hundreds of public and private sector organizations – all focused on the future of water treatment and stability of water supplies for U.S. industries and communities.

Each member hopes to influence technology development by participating in steering and technical working groups to help develop research roadmaps and review research projects.

Find a link to the official Press Release here.