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California Ground Water Shortage 033016 GettyImages-468519400.0.0California Ground Water Shortage 033016 GettyImages-468519400.0.0water 061715 california-getty

Some of the world’s most important farming regions rely on freshwater from large underground aquifers that have filled up slowly over thousands of years. Think of the Central Valley aquifer system in California. Or the Indus basin in Pakistan and India. This groundwater is particularly valuable when rain is scarce or during droughts.

But that groundwater may not last forever. Data from NASA’s Grace satellites suggests that 13 of the world’s 37 biggest aquifers are being seriously depleted by irrigation and other uses much faster than they can be recharged by rain or runoff. And, disturbingly, we don’t even know how much water is left in these basins. That’s according to a 2015 paper in Water Resources Research.

The map below gives an overview. There were 21 major groundwater basins — in red, orange, and yellow — that lost water faster than they could be recharged between 2003 and 2013. The 16 major aquifers in blue, by contrast, gained water during that period. Click to enlarge:

World WAter Short Map 033016 uci_news_image_download

(UC Irvine/NASA)

The researchers found that 13 basins around the world — fully one-third of the total — appeared to be in serious trouble.

Eight aquifer systems could be categorized as “overstressed”: that is, there’s hardly any natural recharge to offset the water being consumed. In the direst state was the Arabian aquifer system beneath Saudi Arabia and Yemen, which provides water for 60 million people and is being depleted by irrigation for agriculture. Also in bad shape were the Indus Basin that straddles India and Pakistan and the Murzuq-Djado Basin in Africa.

Another five aquifer systems were categorized as “extremely” or “highly” stressed — they’re being replenished by some rainwater, but not nearly enough to offset withdrawals. That list includes the aquifers underneath California’s Central Valley. During California’s recent brutal, five-year drought, many farmers compensated for the lack of surface water by pumping groundwater at increasing rates. (There are few regulations around this, though California’s legislature recently passed laws that will gradually regulate groundwater withdrawals.)

The result? The basins beneath the Central Valley are being depleted, and the ground is actually sinking, which in turn means these aquifers will be able to store less water in the future. Farmers are losing a crucial buffer against both this drought, if it persists, and future droughts.

The big question: How soon until these aquifers run dry?

Here’s the other troubling bit: It’s unclear exactly when some of these stressed aquifers might be completely depleted — no one knows for sure how much water they actually contain.

In a companion paper in Water Resources Research, the researchers took stock of how little we know about these basins. In the highly stressed Northwest Sahara Aquifer System, for instance, estimates of when the system will be fully drained run anywhere from 10 years to 21,000 years. In order to get better measurements, researchers would have to drill down through many rock layers to measure how much water is there — a difficult task, but not impossible.

“We don’t actually know how much is stored in each of these aquifers. Estimates of remaining storage might vary from decades to millennia,” said Alexandra Richey, a graduate student at UC Irvine and lead author on both papers, in a press release. “In a water-scarce society, we can no longer tolerate this level of uncertainty, especially since groundwater is disappearing so rapidly.”

The researchers note that we should figure this out if we want to manage these aquifers properly — and make sure they last for many years to come. Hundreds of millions of people now rely on aquifers that are rapidly being depleted. And once they’re gone, they can’t easily be refilled.

Further reading

— Saudi Arabia squandered its groundwater and agriculture collapsed. The rest of the world should take note.

MIT Desal Shock 111315 bt1511_MIT-fracking-pondAs the availability of clean, potable water becomes an increasingly urgent issue in many parts of the world, researchers are searching for new ways to treat salty, brackish or contaminated water to make it usable. Now a team at MIT has come up with an innovative approach that, unlike most traditional desalination systems, does not separate ions or water molecules with filters, which can become clogged, or boiling, which consumes great amounts of energy.

Instead, the system uses an electrically driven shockwave within a stream of flowing water, which pushes salty water to one side of the flow and fresh water to the other, allowing easy separation of the two streams. The new approach is described in the journal Environmental Science and Technology Letters, in a paper by professor of chemical engineering and mathematics Martin Bazant, graduate student Sven Schlumpberger, undergraduate Nancy Lu, and former postdoc Matthew Suss.

This approach is “a fundamentally new and different separation system,” Bazant says. And unlike most other approaches to desalination or water purification, he adds, this one performs a “membrane-less separation” of ions and particles.

Membranes in traditional desalination systems, such as those that use reverse osmosis or electrodialysis, are “selective barriers,” Bazant explains: They allow molecules of water to pass through, but block the larger sodium and chlorine atoms of salt. Compared to conventional electrodialysis, “This process looks similar, but it’s fundamentally different,” he says.

In the new process, called shock electrodialysis, water flows through a porous material —in this case, made of tiny glass particles, called a frit — with membranes or electrodes sandwiching the porous material on each side. When an electric current flows through the system, the salty water divides into regions where the salt concentration is either depleted or enriched. When that current is increased to a certain point, it generates a shockwave between these two zones, sharply dividing the streams and allowing the fresh and salty regions to be separated by a simple physical barrier at the center of the flow.

“It generates a very strong gradient,” Bazant says.

Even though the system can use membranes on each side of the porous material, Bazant explains, the water flows across those membranes, not through them. That means they are not as vulnerable to fouling — a buildup of filtered material — or to degradation due to water pressure, as happens with conventional membrane-based desalination, including conventional electrodialysis. “The salt doesn’t have to push through something,” Bazant says. The charged salt particles, or ions, “just move to one side,” he says.

The underlying phenomenon of generating a shockwave of salt concentration was discovered a few years ago by the group of Juan Santiago at Stanford University. But that finding, which involved experiments with a tiny microfluidic device and no flowing water, was not used to remove salt from the water, says Bazant, who is currently on sabbatical at Stanford.

The new system, by contrast, is a continuous process, using water flowing through cheap porous media, that should be relatively easy to scale up for desalination or water purification. “The breakthrough here is the engineering [of a practical system],” Bazant says.

One possible application would be in cleaning the vast amounts of wastewater generated by hydraulic fracturing, or fracking. This contaminated water tends to be salty, sometimes with trace amounts of toxic ions, so finding a practical and inexpensive way of cleaning it would be highly desirable. This system not only removes salt, but also a wide variety of other contaminants — and because of the electrical current passing through, it may also sterilize the stream. “The electric fields are pretty high, so we may be able to kill the bacteria,” Schlumpberger says.

The research produced both a laboratory demonstration of the process in action and a theoretical analysis that explains why the process works, Bazant says. The next step is to design a scaled-up system that could go through practical testing.

Initially at least, this process would not be competitive with methods such as reverse osmosis for large-scale seawater desalination. But it could find other uses in the cleanup of contaminated water, Schlumpberger says.

Unlike some other approaches to desalination, he adds, this one requires little infrastructure, so it might be useful for portable systems for use in remote locations, or for emergencies where water supplies are disrupted by storms or earthquakes.

Maarten Biesheuvel, a principal scientist at the Netherlands Water Technology Institute who was not involved in this research, says the work “is of very high significance to the field of water desalination. It opens up a whole range of new possibilities for water desalination, both for seawater and brackish water resources, such as groundwater.”

Biesheuvel adds that this team “shows a radically new design where within one and the same channel ions are separated between different regions. … I expect that this discovery will become a big ‘hit’ in the academic field. … It will be interesting to see whether the upscaling of this technology, from a single cell to a stack of thousands of cells, can be achieved without undue problems.”

The research was supported by the MIT Energy Initiative, Weatherford International, the USA-Israel Binational Science Foundation, and the SUTD-MIT Graduate Fellows Program.

Source: Massachusetts Institute of Technology

Gaps in fracking-happeningx250Though applied since the 1940s, hydraulic fracturing boomed in the 1990s, according to The Geological Society of America. New technology allowed the practice to be applied to horizontal wells for extracting shale gas. Unprecedented growth followed. According to a 2014 report by FracTracker Alliance, over 1.1 million active oil and gas wells exist in the U.S.

“The rapid pace of shale gas development in the U.S. has naturally led to several gaps in knowledge about environmental impacts,” said Douglas Arent, executive director of the Joint Institute for Strategic Energy Analysis at the U.S. Dept. of Energy’s National Renewable Energy Laboratory.

Arent and colleagues recently published a paper in MRS Energy & Sustainability overviewing the developments of unconventional gas in the U.S., particularly focusing on trends in water and greenhouse gas emissions.

“If unconventional natural gas is produced and distributed responsibly, and incorporated into resilient energy systems with increasing levels of renewables, then gas can likely play a significant role in realizing a more sustainable energy future,” said Arent.

Gaps in fracking-happeningx250

Image: EPA

Water

With many U.S. states experiencing droughts—the west coast especially—water resources are stressed. Fresh water is a valuable resource. Even if one removes hydraulic fracturing from the equation, other domestic, agricultural and industrial water needs abound.

A recent Stanford Univ. study found that regardless how deep a well was, amounts of water used to frack were indistinguishable. The average volume used to frack, according to the study, was 2.4 million gallons.

“Groundwater depletion—a situation in which water is withdrawn from aquifers faster than it can be replenished—is occurring in many areas where there are shale plays,” Arent et al. write. “Depletion not only reduces the quantity of available water, it can also result in an overall deterioration of water quality.”

Water quality degradation can occur in a myriad of ways, from leaking wells and poor wastewater treatment practices, to spills and toxic element accumulation in soil. Clarity regarding the sources and mechanisms of contamination are needed, followed by an examination of effective practices to eliminate risks, according to the researchers.

“Currently, best management practices to mitigate (water) quantity and quality related risks have not been established by industry and stakeholder groups,” the researchers write. Further, no uniformity exists across the country. Individual states are responsible for regulations regarding well construction, and mitigating potential risks to water quality. Often separate state regulations don’t mesh due to each state’s geological makeup.

An “analysis will be critical to establishing those (best management practices) and government regulations, where needed, which will ensure that shale gas can be responsibly and sustainably produced,” write the researchers.

Greenhouse gas emissions
Natural gas production, compared to coal production, results in half the carbon emissions per unit of energy. The researchers contend natural gas can offer greenhouse gas mitigation benefits relative to coal, if methane emissions are small.

In 2014, the Environmental Protection Agency reported methane gas emissions from fractured natural gas wells decreased by 73% since 2011.

“Significant work is needed to measure and verify methane emissions across the full production, transportation and distribution value chain,” the researchers write. “If natural gas is to help mitigate climate change, it will do so primarily by displacing coal. However, in the long term, natural gas itself…will not significantly alter long-range climate projections.”

While natural gas, according to the researchers, will play an important role in the U.S.’s energy future, renewable energies or carbon capture and storage will be needed to meet carbon mitigation goals.

“More transparent and accessible data related to water use and emissions from shale gas development and use…are essential to providing a more complete understanding of all the pathways to a decarbonized energy future,” said Arent.

kuwait-desalination_0Funding sponsored through the Kuwait-MIT Center for Natural Resources and the Environment.

A team of MIT researchers, together with a team from Kuwait University, has been awarded a $5.5 million dollar grant for a collaborative research project titled, “Next Generation Brine Desalination and Management for Efficiency, Reliability, and Sustainability”.

The project is being funded through the Signature Research Program of the Kuwait-MIT Center for Natural Resources and the Environment (CNRE) by the Kuwait Foundation for the Advancement of Sciences (KFAS) with a performance period of three years.

The project is designed to address several coupled challenges and to investigate desalination systems from the microfluidic scale up to the system level scale:

  • innovations in electrical desalination technologies combined with high-fidelity modeling, multi-staging and system-wide optimization with detailed techno-economic analysis;
  • innovation in materials and surface coating for increased reliability of operation; and
  • mitigation of negative environmental impacts of brine discharge through innovative coastal discharge configurations, combined with reduction in discharge salinity due to blending of brine with treated waste water effluent, as part of integrated energy recovery schemes.

These core research areas will be investigated in parallel while accounting for coupling between them, adding to the uniqueness of this project.

Jongyoon Han, principal investigator of the project and a professor of both the Department of Electrical Engineering and Computer Science and the Department of Biological Engineering, says, “The issue of proper and efficient brine treatment, both in terms of economic and environmental aspects, is truly an ‘MIT-hard’ challenge, so all of us in the team are motivated by it. Not only will this project have potential impact to Kuwait and other Gulf states, the ideas and concepts developed in this project may have implications to other challenging environmental remediation such as the treatment of produced water from oil and gas industries.”

Bader Al-Anzi, professor at the Department of Environmental Technology Management at Kuwait University and the leading co-principal investigator at Kuwait University was instrumental in the formation of the team and the scope of this collaborative research project during his yearlong appointment at MIT as a visiting scientist.

“Like other GCC countries in the region, Kuwait replenishes its water resources through desalination process, for potable water, and treated wastewater for non-human consumption purposes/applications,” Al-Anzi says. “However, the foregoing processes discharge brine and treated wastewater, respectively, into the Gulf that may pose a serious threat to the marine life if left untreated. The current project addresses such challenges by increasing both energetic and environmental sustainability of Kuwaiti water management by developing / validating novel ideas and interfacing them optimally with existing plant workflow.”

“The ideas in this project build on the unique and synergistic expertise of the MIT and Kuwait University team in desalination and environmental related technologies and sciences,” says Murad Abu-Khalaf, the executive director of CNRE. “The team has the expertise needed to create new innovations in desalination systems from the microfluidic levels up to the system wide level. The project addresses a critical challenge to the sustainable growth of Kuwait, which gets more than 90 percent of its freshwater from desalination, and the Gulf states at large. We are excited by the prospects this collaboration between MIT and Kuwait University brings in addressing challenges of such a global scope. This is the second project to be initiated through CNRE’s Signature Research Program that, collaboratively with researchers in Kuwait, investigates technical challenges that have both regional and global impact.”

The other co-PIs from MIT are Karen Gleason, professor of chemical engineering, John Lienhard, professor of mechanical engineering, Jacob White, professor of electrical engineering and computer science, and Eric Adams, senior research engineer at the Department of Civil and Environmental Engineering.

Directed by Mujid Kazimi alongside associate director Jacopo Buongiorno — both professors in the Department of Nuclear Science and Engineering at MIT — and executive director Murad Abu-Khalaf, CNRE was established at MIT in 2005 to foster collaborations in research and education in areas of energy, water and the environment between MIT and research institutions in Kuwait. The center is funded by the Kuwait Foundation for the Advancement of Sciences.

MIT-natasha-wright-01MIT’s Natasha Wright

MIT: PhD student Natasha Wright makes water safe to drink for rural, off-grid Indian villages. 

When graduate student Natasha Wright began her PhD program in mechanical engineering, she had no idea how to remove salt from groundwater to make it more palatable, nor had she ever been to India, where this is an ongoing need.

Now, three years and six trips to India later, this is the sole focus of her work.

Wright joined the lab of Amos Winter, an assistant professor of mechanical engineering, in 2012. The lab was just getting established, and the aim of Wright’s project was vague at first: Work on water treatment in India, with a possible focus on filtering biological contaminants from groundwater to make it safe to drink.

There are already a number of filters on the market that can do this, and during her second trip to India, Wright interviewed a number of villagers, finding that many of them weren’t using these filters. She became skeptical of how useful it would be to develop yet another device like this.

Although the available filters made water safe to drink, they did nothing to mitigate its saltiness — so the villagers’ drinking water tasted bad and eroded pots and pans, providing little motivation to use these filters. In reviewing the list of questions she had prepared for her interviews with locals, Wright noticed that there were no questions about the water’s salty taste.

“No one had ever asked them about that. And although this might sound obvious, people really don’t like the taste of salt,” Wright says. “So once I started asking, it’s all anyone would talk about.’”

“The biggest surprise of the project so far has been this salt issue, which was the thing that changed the entire purpose of the research,” she adds.

Almost 60 percent of India has groundwater that’s noticeably salty, so later, after returning to MIT, Wright  began designing an electrodialysis desalination system, which uses a difference in electric potential to pull salt out of water.

This type of desalination system has been around since the 1950s, but is typically only used municipally, to justify its costs. Wright’s project aims to build a system that’s scaled for a village of 5,000 people and still cost-effective.

While other companies are already installing desalination systems across India, their designs are intended to be grid-powered. When operating off the grid, these systems are not cost-effective, essentially blocking disconnected, rural villages from using them.

Wright’s solution offers an alternative to grid power: She’s designed a village-scale desalination system that runs on solar power. Since her system is powered by the sun, operational and maintenance costs are fairly minimal: The system requires an occasional cartridge filter change, and that’s it.

The system is also equipped to treat the biological contaminants that Wright initially thought she’d be treating, using ultraviolet light. The end result is safe drinking water that also tastes good.

Earlier this year, Wright’s team won a grant from the United States Agency for International Development (USAID), enabling the researchers to test this system at full scale for the first time in New Mexico two months ago. A second stage of the grant will help bring a pilot to India this summer. Local farmers will use the system and provide feedback at a conference organized by Jain Irrigation, Inc., a company based in Jalgaon, India. Wright’s team is now looking to find out how easy it is for users.

The USAID competition was actually intended for systems built for individual farms, but Wright calculated that the amount of water used by a single farm is similar to the amount of water that a small village needs for its daily drinking water — 6 to 12 cubic meters. 

Although Wright’s work is currently focused on rural villages in India, she sees many uses for the technology in the United States as well. In isolated areas, such as the ranches in New Mexico where she tested her system at full scale, poor access to water pipelines often leads to a heavy reliance on well water. But some ranchers find that even their livestock won’t tolerate the saltiness of this water.

“It’s useful to install a small-scale desalination system where people are so spread out that it’s more costly to pump in water from a municipal plant,” she says. “That’s true in India and that’s also true in the U.S.”

LARGE_NEWTisometric NEWT Center will use nanotechnology to transform economics of water treatment A Rice University-led consortium of industry, university and government partners has been chosen to establish one of the National Science Foundation’s (NSF) prestigious Engineering Research Centers in Houston to develop compact, mobile, off-grid water-treatment systems that can provide clean water to millions of people who lack it and make U.S. energy production more sustainable and cost-effective.

Nanotechnology Enabled Water Treatment Systems, or NEWT, is Houston’s first NSF Engineering Research Center (ERC) and only the third in Texas in nearly 30 years. It is funded by a five-year, $18.5 million NSF grant that can be renewed for a potential term of 10 years. NEWT brings together experts from Rice, Arizona State University, Yale University and the University of Texas at El Paso (UTEP) to work with more than 30 partners: including Shell, Baker Hughes, UNESCO, U.S. Army Corps of Engineers and NASA.

ERCs are interdisciplinary, multi-institutional centers that join academia, industry and government in partnership to produce both transformational technology and innovative-minded engineering graduates who are primed to lead the global economy. ERCs often become self-sustaining and typically leverage more than $40 million in federal and industry research funding during their first decade.

“The importance of clean water to global health and economic development simply cannot be overstated,” said NEWT Director Pedro Alvarez, the grant’s principal investigator. “We envision using technology and advanced materials to provide clean water to millions of people who lack it and to enable energy production in the United States to be more cost-effective and more sustainable in regard to its water footprint.”

NEWT Center will use nanotechnology to transform water treatment: Video

 

Houston-area Congressman John Culberson, R-Texas, chair of the House Subcommittee on Commerce, Justice and Science, said, “Technology is a key enabler for the energy industry, and NEWT is ideally located at Rice, in the heart of the world’s energy capital, where it can partner with industry to ensure that the United States remains a leading energy producer.”

Alvarez, Rice’s George R. Brown Professor of Civil and Environmental Engineering and professor of chemistry, materials science and nanoengineering, said treated water is often unavailable in rural areas and low-resource communities that cannot afford large treatment plants or the miles of underground pipes to deliver water. Moreover, large-scale treatment and distribution uses a great deal of energy. “About 25 percent of the energy bill for a typical city is associated with the cost of moving water,” he said.

NEWT Deputy Director Paul Westerhoff said the new modular water-treatment systems, which will be small enough to fit in the back of a tractor-trailer, will use nanoengineered catalysts, membranes and light-activated materials to change the economics of water treatment.0629_NEWT-truck-lg-310x239

“NEWT’s vision goes well beyond today’s technology,” said Westerhoff, vice provost of academic research at ASU and co-principal investigator on the NSF grant. “We’ve set a path for transformative new technology that will move water treatment from a predominantly chemical treatment process to more efficient catalytic and physical processes that exploit solar energy and generate less waste.”

Co-principal investigator and NEWT Associate Director for Research Qilin Li, the leader of NEWT’s advanced treatment test beds at Rice, said the system’s technology will be useful in places where water and power infrastructure does not exist.

“The NEWT drinking water system will be able to produce drinking water from any source, including pond water, seawater and floodwater, using solar energy and even under cloudy conditions,” said Li, associate professor of civil and environmental engineering, chemical and biomolecular engineering, and of materials science and nanoengineering at Rice. “The modular treatment units will be easy to configure and reconfigure to meet desired water-quality levels. The system will include components that target suspended solids, microbes, dissolved contaminants and salts, and it will have the ability to treat a variety of industrial wastewater according to the industry’s need for discharge or reuse.”0629_NEWT-mod-lg-310x239

NEWT will focus on applications for humanitarian emergency response, rural water systems and wastewater treatment and reuse at remote sites, including both onshore and offshore drilling platforms for oil and gas exploration.

0629_NEWT-log-lg-310x310Yale’s Menachem “Meny” Elimelech, co-principal investigator and lead researcher for membrane processes, said NEWT’s innovative enabling technologies are founded on rigorous basic research into nanomaterials, membrane dynamics, photonics, scaling, paramagnetism and more.

“Our modular water-treatment systems will use a combination of component technologies,” said Elimelech, Yale’s Roberto C. Goizueta Professor of Environmental and Chemical Engineering. “For example, we expect to use high-permeability membranes that resist fouling; engineered nanomaterials that can be used for membrane surface self-cleaning and biofilm control; capacitive deionization to eliminate scaly mineral deposits; and reusable magnetic nanoparticles that can soak up pollutants like a sponge.”

UTEP’s Jorge Gardea-Torresdey, co-principal investigator and co-leader of NEWT’s safety and sustainability effort, said the rapid development of engineered nanomaterials has brought NEWT’s transformative vision within reach.

“Treating water using fewer chemicals and less energy is crucial in this day and age,” said Gardea-Torresdey, UTEP’s Dudley Professor of Chemistry and Environmental Science and Engineering. “The exceptional properties of engineered nanomaterials will enable us to do this safely and effectively.”

Alvarez said another significant research thrust in nanophotonics will be headed by Rice co-principal investigator Naomi Halas, the inventor of “solar steam” technology, and co-led by ASU’s Mary Laura Lind.

“More than half of the cost associated with desalination of water comes from energy,” said Halas, Rice’s Stanley C. Moore Professor of Electrical and Computer Engineering and professor of chemistry, bioengineering, physics and astronomy, and materials science and nanoengineering. “We are working to develop several supporting technologies for NEWT, including nanophotonics-enabled direct solar membrane distillation for low-energy desalination.”

Mike Wong Lake%20ZurichRice’s Michael Wong, Yale’s Jaehong Kim and UTEP’s Dino Villagran will collaborate in efforts to develop novel multifunctional materials such as superior sorbents and catalysts, and Yale’s Julie Zimmerman will co-lead cross-cutting efforts in safety and sustainability. Rice’s Roland Smith will lead a comprehensive diversity program that aims to attract more women and underrepresented minority students and faculty, and Rice’s Brad Burke will head up innovation and commercialization efforts with private partners. Rice’s Rebecca Richards-Kortum will lead an innovative educational program that incorporates some of the “experiential learning” techniques she developed for the award-winning undergraduate research programs at Rice 360º: Institute for Global Health Technologies, and Rice’s Carolyn Nichol will lead the K-12 education efforts.

Alvarez said NEWT’s goal is to attract industry funding and become self-sufficient within 10 years. Toward that end, he said NEWT was careful to select industrial partners from every part of the water market, including equipment makers and vendors, system operators, industrial service firms and others.

NEWT is one of three new ERCs announced by the NSF today in Washington. They join 16 existing centers that are still receiving federal support, including Texas’ only other active ERC, the University of Texas at Austin’s NASCENT, as well as the other active center in which Rice is a partner, Princeton University’s MIRTHE.

0629_NEWT-Alvarez29-lg-310x465Alvarez credited Culberson and the Texas Railroad Commission for helping facilitate partnerships that were crucial for NEWT. He said the consortium’s bid to land the NSF grant was also made possible by seed funding from Rice’s Energy and Environment Initiative, a sweeping institutional initiative to engage Rice faculty from all disciplines in creating sustainable, transformative energy technologies.

“Rice’s Energy and Environment Initiative was instrumental in developing a competitive proposal, in facilitating a team-building effort and in facilitating contacts with industry to get the necessary buy-in for our vision,” Alvarez said.

Nanotechnology Enabled Water Treatment Program

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MIT-GradiantCorp 071715-2

Gradiant’s 12,000-barrel-per-day, carrier gas extraction plant (shown here), uses a humidification and dehumidification (HDH) technique that heats produced water into vapor, and condenses it back into water, without contaminants. This yields freshwater and saturated brine, commonly used in drilling and completion processes.

Courtesy of Gradiant Corp.

Rob Matheson | MIT News Office

But MIT spinout Gradiant Corporation is working toward making fracking a water-neutral process, by making water reuse more economical. Founded by Anurag Bajpayee SM ’08, PhD ’12, and Prakash Govindan PhD ’12, Gradiant has developed cost-effective systems to treat briny oilfield water for reuse, saving millions of gallons of water — and millions of dollars — annually.

Launched in 2012 with help from MIT’s industry-connected ecosystem, Gradiant has erected two 12,000-barrel-per-day plants in the Permian Basin of Texas, partnering with two drilling clients who treat about 10,000 barrels daily there. “That’s 10,000 barrels a day they’re not disposing of, and 10,000 they’re not buying from the city or taking off the public water supply,” says Bajpayee, now Gradiant’s CEO.

Gradiant's selective chemical extraction plant (shown here, near the pools of water) uses chemical reactions to remove specific contaminants from produced water to make clean brine. MIT spinout makes treating, recycling highly contaminated oilfield water more economical

The plants each use separate technologies that treat varying infeed water, which can be adjusted to customer specifications. Carrier gas extraction (CGE), a humidification and dehumidification (HDH) technique developed by the Gradiant co-founders at MIT, heats produced water into vapor, and condenses it back into water, without contaminants. This yields freshwater and saturated brine, commonly used in drilling and completion processes.

Selective chemical extraction (SCE) is a cost-effective version of standard chemical-precipitation techniques — where chemical reactions remove specific contaminants to produce clean brine. Both systems employ custom control algorithms that minimize operator intervention and chemical consumption, while continuously adjusting the process to account for varying feed water quality.

Thanks to several design innovations, these systems can treat water with higher levels of contamination using less energy and at lower costs than competing treatment methods, according to Gradiant.

Reverse osmosis, for example, treats water with a maximum contamination level of around 7 percent, while legacy thermal desalination reaches about 20 to 22 percent. But Gradiant’s technology uses even less energy to treat water beyond 25 percent, broadening the range of water that can be treated, Bajpayee says. “Our technology is unique in its capability of going through true saturation limits … to the point where you can actually start seeing crystals in the water,” he says.

Commercializing HDH

HDH is a decades-old concept: Water is vaporized and condensed on a cold metallic surface to remove salts. But commercial-scale systems have always been too energy-intensive, because water must be boiled while condensing surfaces must be kept very cold.

But Gradiant’s system — designed by Govindan and colleagues in the lab of Gradiant co-founder John H. Lienhard, the Abdul Latif Jameel World Water and Food Security Professor at MIT — scaled well by using a readily available carrier gas (dry air) that vaporizes water below boiling temperatures, and incorporating a column with microbubbles that optimizes condensing surfaces.

In the Gradiant system’s humidifier chamber, briny water drops through packing material and mixes with dry air to produce a hot and humid vapor stripped of contaminants — such as salts — that forms at the top of the chamber. “We creatively mimic nature’s rain cycle — we create the cloud and then we condense that water back out to create rain,” Bajpayee says.

This “raining” happens in a bubble column, which has several levels of perforated trays, each containing a shallow pool of freshwater. As vapor rises through the bubble column, it passes through the plates’ holes, causing an extremely rapid mixing process that cools and condenses the water within the pools. As levels rise, the water overflows and is captured in a tray as fresh, nearly distilled water.

The temperature difference between the warm and cool water is much less than in a conventional dehumidifying system, using less energy, and the surface area provided by the microbubbles in the trays offers a more efficient heat-transfer ratio than a flat, metallic condenser surface. Not using expensive materials, such as titanium, in the heat exchanger also reduces the capital costs.

Heated water is also reused to preheat incoming feed water. Instead of fully heating the incoming water to the desired temperature, Bajpayee says, “you only have to make up the little bit that you couldn’t recover,” which saves energy.

Working alongside industry

Gradiant’s rapid ascension, Bajpayee says, is thanks in large part to MIT’s entrepreneurial ecosystem, which connects researchers to mentors, industry, and investors. “Every day you learn something new, or meet a new contact, that adds to what you knew the previous day, and it all builds upon itself,” he says. “Before you know it, you’re in a completely different place then where you started.”

Indeed, Bajpayee and Govindan met in the late 2000s while working on separate water-treatment technologies in MIT’s Rohsenow Kendall Heat Transfer Laboratory. The oil and gas industry were then heavily investing in fracking, leading to outcries about wastewater.

The solution was in Govindan’s PhD thesis, in which he fleshed out a CGE system with dry air and a bubble column. Based on this work, Govindan, MIT engineers, and collaborators at King Fahd University of Petroleum and Minerals built a 12-foot-high prototype, which produced about 700 liters of clean water per day. (The system’s design was described in papers published in the International Journal of Heat and Mass Transfer, Applied Energy, and the AIChE Journal.)

Soon, Bajpayee teamed with Govindan on the system, and they began reaching out to different industries — oil and gas, leather, and power plants — for feedback. “Because we wanted to see the societal and commercial impact of our work, we started seeing what was happening in the industry, and then started … asking them how to solve their problems,” Bajpayee says.

Through the MIT Deshpande Center for Technological Innovation, the team also began connecting with investors. This constant contact with industry, Bajpayee says, gradually helped refine the system for commercial use. “We did not develop something and try to market it to our customers,” he says. “It was developed along with the customers, so by the time we were ready to start the company, there were already people lined up who wanted to use it.”

That’s why in two years the startup has managed to build two plants, and commercialize two product lines. It also has three additional water-treatment technologies — one based on Bajpayee’s PhD thesis — under development that could be commercialized in the next two years.

Although Gradiant’s first market is the oil industry, it plans to introduce its technologies to different industries across the globe — wherever there’s incentive to recycle highly contaminated water, according to the company.

Moving forward, says Govindan, Gradiant’s chief technology officer, the company will stay focused on making water treatment and recycling more energy efficient for the oilfield and other industries — an enduring philosophy from his alma mater. “At the core of everything is research and development,” he says. “That holds from the MIT days.”


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