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Salt-Free Electrodialysis Metathesis Hits 99% Recovery

Silicon Scoop · Episode 579 · November 12, 2026

Salt-free electrodialysis metathesis reached 99% recovery with RO in pilots. Learn what it means for high recovery desalination and brine management.

With Craig Major and Jon Irwin

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Salt-Free Electrodialysis Metathesis Hits 99% Recovery

Estimated reading time: 10 minutes

Key Takeaways

  • Higher recovery: Tayia Oddonetto's 2025 UTEP dissertation reports up to 97% hydraulic recovery and 99% total system recovery when SF-EDM follows reverse osmosis. The 2024 coverage reported 90%.
  • Real brine, real sites: Testing used synthetic brine, real RO brine from El Paso's Kay Bailey Hutchison Desalination Plant, and a weeklong pilot at the Yuma Desalting Plant in Arizona.
  • Cost and energy: The 2024 study put SF-EDM cost at 80% of conventional electrodialysis. A 2024 technical presentation says it needs about half the energy.
  • Resource recovery: The process split calcium and sulfate into separate concentrate streams, which could open paths to selling minerals.
  • Still unproven at scale: The sources found no independent commercial deployment, no utility-scale operating-cost record, and no verified revenue from recovered minerals.

Table of contents

Salt free electrodialysis metathesis (SF-EDM) just posted a bigger number than the one that made headlines in 2024. Oddonetto's 2025 doctoral dissertation at the University of Texas at El Paso (UTEP) reports up to 97% hydraulic recovery and 99% total system recovery when SF-EDM is combined with upstream reverse osmosis (RO). The original article reported 90%.

Here is the basic problem. RO is the industry standard for desalination, but it turns only up to 85% of salty water into fresh water. The other 15% is brine, a heavy salt solution that is costly to dispose of. SF-EDM treats that brine so more of it becomes usable water.

For water-technology founders and utility operators, the results point to a commercial opportunity in concentrate treatment and mineral recovery. But pilot validation, scaling control, energy performance, permitting and customer-specific economics remain the key barriers before deployment.

How Salt-Free Electrodialysis Metathesis Treats Brine Desalination Technology's Hardest Leftover

Electrodialysis (EDM) uses electric current to pull charged particles, called ions, through special membranes. Salt breaks into ions in water, so the current can move them out of the water stream. Salt-free electrodialysis metathesis does this without adding sodium chloride (table salt) to the process.

That detail matters because conventional methods add extra salt to help the process work. That means the system has to move that extra salt too. A 2024 technical presentation says SF-EDM needs about half the energy of conventional EDM because it does not transport additional sodium chloride.

The original 2024 study, led by Oddonetto and published in Desalination, reported three results:

  • 93% salinity reduction without adding sodium chloride
  • 90% total recovery when SF-EDM followed RO
  • A cost estimated at 80% of conventional methods

Oddonetto, a doctoral student in environmental science and engineering at UTEP, said a professor's comment in class set her on this path. The professor said finding value in brine would matter a great deal for the planet. She decided to be the one to find the answer.

Her work earned first place and funding at the National Science Foundation (NSF) Engineering Research Centers Perfect Pitch Competition.

Source: UTEP newsfeed, Desalination article, 2024 MSSC program

From 90% to 99%: What High Recovery Desalination Looks Like in the 2025 Data

The 2025 dissertation goes well beyond the award-stage results. It reports 97% hydraulic recovery. Hydraulic recovery is the share of the incoming water that comes out as usable water.

It also reports 99% total system recovery when SF-EDM is integrated with upstream RO. Total system recovery counts the whole chain, from the first RO stage through the SF-EDM stage.

The two numbers are not a contradiction. The 90% figure from 2024 and the 99% figure from 2025 come from different experimental stages and configurations. The later number comes from dissertation-scale pilot work.

A related 2025 paper adds detail. It appeared in Desalination as volume 616, article 119342, titled "Salt-free electrodialysis metathesis for brackish water desalination brine management." It evaluates three setups:

  • Batch operation
  • Semi-continuous operation
  • Pretreatment configurations

Its focus is on how the system is run, not only how much salt it removes in a lab. The paper looks at hydraulic recovery, energy consumption, ion separation and scaling control. Scaling is mineral crust that builds up on membranes and can shut a system down.

Source: UTEP ScholarWorks dissertation, NMSU water publications

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Three Kinds of Brine: Testing From Lab Water to the Yuma Desalting Plant

Lab tests are easy to control. Real plants are not. The dissertation tested SF-EDM on three kinds of water, which makes the results more credible than modeled feedwater alone.

  1. Synthetic brine from the Brackish Groundwater National Desalination Research Facility
  2. Real RO brine from El Paso's Kay Bailey Hutchison Desalination Plant
  3. A weeklong pilot demonstration at the Yuma Desalting Plant in Arizona

Real brine is messier than a lab mix. It carries a changing blend of minerals and other compounds, and those can foul membranes. Success on real RO concentrate is a stronger signal than success on a recipe.

The Multi-State Salinity Coalition's 2026 profile fills in more. It says Oddonetto demonstrated SF-EDM at pilot scale through the Bureau of Reclamation's More Water Less Concentrate competition. She also batch-tested the process at the Kay Bailey Hutchison plant.

Next, she is scheduled to deploy a pilot at the Alamogordo facility. That pilot will treat brackish well water of varying salinities, with support from the National Alliance for Water Innovation (NAWI).

Source: UTEP ScholarWorks dissertation, Multi-State Salinity Coalition awards

Calcium and Sulfate Streams: A Different Route Toward Zero Liquid Discharge Water

"Zero liquid discharge" means a plant sends no liquid waste out the door. Everything is either reused or turned into solids. The 99% result does not meet that bar, but it pushes in that direction by shrinking the brine volume left over.

The dissertation also reports a second result. SF-EDM successfully partitioned calcium and sulfate into separate concentrate streams. That creates potential downstream resource-recovery pathways.

NAWI describes the logic this way. The process runs in continuous flow. It uses the thermodynamics of highly soluble concentrates to separate divalent cations and anions into two concentrate streams. Divalent ions carry a double electric charge, and calcium and sulfate are examples.

Oddonetto also reported that the process produced higher concentrations of important metals and minerals. These are used in food, health and technology.

Keeping those streams apart is useful for two reasons:

  • Separate streams are easier to handle and may be easier to sell.
  • Separating the scale-forming ions may help control scaling.

The sources describe a potential pathway. They do not report verified revenue from recovered minerals.

Source: UTEP ScholarWorks dissertation, NAWI research, UTEP newsfeed

Who Backs the Project: NAWI, Reclamation and Utility Partners

SF-EDM has institutional support behind it. NAWI lists it as Project 3.18, titled "Salt-Free Electrodialysis Metathesis for High Recovery Concentrate Management." W. Shane Walker leads the project, working with Texas Tech University, UTEP and New Mexico State University.

A related DOE/NAWI research record identifies a $282,607 award for salt-free EDM research. It was funded from August 2022 through September 2026, so that funding window has just closed. A separate curriculum-vitae record lists $44,000 in NAWI support to Texas Tech University.

The Bureau of Reclamation's Brackish Groundwater National Desalination Research Facility in Alamogordo, New Mexico, is central to the testing. It is the only major U.S. research facility dedicated solely to desalination of brackish and impaired groundwater. Its mission explicitly includes concentrate management, beneficial uses of concentrate and byproduct production.

Reclamation's research program operates under the federal Desalination Act framework described in the facility history.

Oddonetto's live tests also involve New Mexico State University, El Paso Water and the Kay Bailey Hutchison facility. Her advisor, Ivonne Santiago of UTEP, said the research will help public utilities save money and let people cut their utility bills in a meaningful way.

Source: NAWI, Bureau of Reclamation, UTEP newsfeed

Why 99% Recovery Is Not Yet Commercial Proof

The expert direction is broadly positive. UTEP, NAWI, Reclamation and the project's academic researchers describe SF-EDM as a promising high-recovery approach. They say it can:

  • Reduce concentrate volume
  • Avoid sodium-chloride substitution
  • Separate calcium and sulfate
  • Support resource recovery

The newer pilot work strengthens the case because it uses real RO brine and field facilities. But the same sources say several issues must be resolved:

  • Pretreatment: what the brine needs before it reaches the membranes
  • System configuration: batch, semi-continuous or continuous operation
  • Scaling risk: mineral buildup that can foul membranes
  • Energy use: the 2024 half-the-energy claim needs confirmation at scale
  • Water-quality blending: how treated streams mix with other supplies
  • Full-scale technoeconomics: the real cost of building and running a plant

The gaps are plain. The sources did not find an independent commercial deployment. They did not find a utility-scale operating-cost record. They did not find verified revenue from recovered minerals.

Read the 99% as a strong pilot result and not as a finished product. The numbers show what is possible under tested conditions. They do not yet show what a plant operator will pay per cubic meter over ten years.

Source: UTEP ScholarWorks dissertation, NAWI, Bureau of Reclamation

What This Means for Startups and Small Businesses

The opportunity here is real, but it favors patient, focused teams. Here is what to do with it.

  • Pick a niche in concentrate management. Brine is a growing problem for any inland brackish-water plant. Startups can offer pretreatment, monitoring, scaling control or software that supports pilots, without building the membrane stack.
  • Treat mineral recovery as a hypothesis. Separate calcium and sulfate streams are promising. Until someone shows buyers and verified revenue, build business plans that work without that income.
  • Ask for customer-specific numbers. Brine chemistry differs from site to site. Any pitch to a utility needs a pilot on that utility's own concentrate, with energy and cost data.
  • Plan for permitting early. Discharge rules and water-quality blending requirements can slow deployment. Raise them in the first meeting.
  • Use public test beds. Reclamation's Alamogordo facility exists to test desalination concentrate management. Its annual Water Innovations and Networking Workshop is listed for October 14-15, 2026, which gives researchers, utilities, investors and industry partners a near-term place to review pilots and commercialization prospects.
  • Watch the follow-on work. With the listed DOE/NAWI funding window ending in September 2026, new awards or partnerships would be a useful signal.

For operators, the practical step is to log your concentrate volumes, disposal costs and chemistry now. That gives you a baseline for judging any future recovery pitch.

Source: Bureau of Reclamation, Multi-State Salinity Coalition awards, NAWI

Frequently Asked Questions

Q: What is salt free electrodialysis metathesis?

A: It is a brine treatment process that uses electric current and ion exchange membranes to separate ions from water. "Salt-free" means it does not add sodium chloride, which conventional methods use and then must move. It is known as SF-EDM.

Q: How does salt free electrodialysis metathesis differ from reverse osmosis?

A: RO pushes water through membranes under pressure and recovers up to about 85% as fresh water. SF-EDM uses electric current to treat the leftover brine. In the research, the two are used in sequence.

Q: What recovery rate has SF-EDM achieved?

A: The 2024 study reported 90% combined recovery with RO. Oddonetto's 2025 dissertation reports up to 97% hydraulic recovery and 99% total system recovery. The numbers come from different experimental stages and configurations.

Q: Is SF-EDM a form of high recovery desalination?

A: Yes. High recovery desalination aims to turn more of the incoming water into usable water and leave less brine. SF-EDM is designed to do this as a second step after RO.

Q: What is brine desalination technology?

A: It is equipment and methods for treating the concentrated salty leftover from desalination. Options include reducing its volume, separating minerals from it, or disposing of it safely. SF-EDM falls in the first two groups.

Q: Does SF-EDM achieve zero liquid discharge water treatment?

A: The sources do not claim that. A 99% total recovery cuts the leftover brine volume sharply, but zero liquid discharge means no liquid waste leaves the site. Full-scale performance has not been shown.

Q: How much cheaper is SF-EDM than conventional electrodialysis?

A: The 2024 study estimated SF-EDM cost at 80% of conventional methods. A 2024 technical presentation says it needs about half the energy because it does not move extra sodium chloride. Utility-scale operating costs have not been documented in the sources.

Q: Where has SF-EDM been tested on real brine?

A: The dissertation covers real RO brine from El Paso's Kay Bailey Hutchison Desalination Plant and a weeklong pilot at the Yuma Desalting Plant in Arizona. It also used synthetic brine from the Brackish Groundwater National Desalination Research Facility. A pilot is scheduled at the Alamogordo facility.

Q: What minerals can SF-EDM recover from brine?

A: The dissertation reports that calcium and sulfate were partitioned into separate concentrate streams. Oddonetto also reported higher concentrations of metals and minerals used in food, health and technology. Verified revenue from selling them has not been found.

Q: Is SF-EDM ready for commercial use?

A: Not yet, based on the sources. The pilot results are encouraging, but pretreatment, scaling control, energy use, water-quality blending and full-scale economics still need to be resolved. No independent commercial deployment was located.

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Episode transcript

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Craig: 99%. that's how much water a texas research team recovered in pilot work on brine, the salty leftover water from desalination. it's up from 90% in 2024, but a pilot result isn't a product. here's what's real and what isn't yet. reverse osmosis or ro is the industry standard for desalination. it turns up to 85% of water fresh, of salt water into fresh water. the other 15% is concentrated brine. tayah odenado, a doctoral student at the university of texas el paso, is working on the second step. it's called salt free electrodialysis math... mathethesis... metathesis.

Jon: metathesis.

Craig: i'll call it s f e d m from now on.

Jon: well, how

Craig: were you gonna pronounce it, john? metathesis. metathesis. thank you. that's exactly right. it uses electric current and special membranes to pull salt particles out of the water, and it does without adding the table salt to the process. so what do you think about this, john?

Jon: i think this is cool, but let's... let... like, let's talk about the... like, let's do a deep dive into, like, reverse osmosis for those that don't know. so, reverse... so normally, osmosis causes water to naturally move through a membrane toward the side containing more dissolved salt. and so what reverse osmosis does is the opposite. so powerful pumps create pressure high enough to force water through a semipermeable membrane, while most salts remain behind. and so the result is permeate equals lower salinity product water and concentrate equals high salinity brine. and so the problem is that as water leaves the feed system, everything that does not pass through the membrane becomes progressively more concentrated. so, eventually, ions such as calcium, sulfate, carbonate, silica, and other soluble compounds reach concentrations where they begin to precipitate. and so this creates scale on the membrane surfaces. and so scale blocks flow. it increases pressure requirements. it reduces efficiency, and it can damage equipment. and so, the metathesis is, essentially, it refers to exchanging ionic part... partners. right? so a normal dissolved salt might contain calcium plus sulfate, sodium plus chloride, magnesium plus sulfate, and so on and so forth. so the clever part of electrodialysis, metathesis, is that... well, it's a... that's a mouthful. electrodialysis metathesis is that it can rearrange where those ions end up. and so traditional edm can use multiple ion selective membranes and a sodium chloride substitution solution to create separate concentrated streams. so, this... the process that they came up with eliminates the added salt stream. so you get a salt free electrodialysis metathesis. and so the peer reviewed studied, it was successful where preferentially transported singly ion... charged ions while restricting multivalent ions. so this allowed the device to manipulate where ions such as calcium and sulfate accumulate, which was... gets you closer to that 99%. there is a lot of chemistry in this that went a little bit over my head. but for the most part, in... so, the reason why calcium and sulfate matter so much, instead of letting two troublesome chemicals meet and form rock on your membrane, this technology essentially sends them into different rooms so i can make it as simply as possible. i don't know if you have a better way to to to, to describe this. but i think this is really cool, because it solves a huge problem with reverse osmosis.

Craig: yeah. if we can actually get to that 99%, it's a strong pilot result, but it's not commercial proof. they tested in three different types of brine, which is good, and they got different results. they did separate the, calcium and sulfate test. so that's into a separate stream now. so that could open up past the recovering materials from waste differently, which is great. but anytime we can get that whole hydraulic process down to where we can get 99% or whatever back, i'm all for it when we can clean our water through all of this process. so i'm excited about this. we haven't... we've... we could find no independent commercial deployment, no utility scale operating cost record, or what have you. pretreatment, scaling risk, energy use, water quality, blending, and full scale economics are still open. so the number shows what's possible under test conditions. they don't show what a plant will pay to run. what's the biggest hurdle between this pilot and a real plant? well, let us know what you think. is it, a full scale cost, scaling of the membranes, or permitting of, water quality rules? so we'll have to see because our... currently, we'd have to change our water quality rules to reuse these kinds of things. so i'm excited about this.

Jon: i've got i've got a perfect way to describe this

Craig: so that

Jon: people can understand. so think of reverse osmosis as squeezing most of the water out of a sponge. this technology comes along afterwards and squeezes so much more out of what we currently call waste. if that makes sense. that's my best analogy i can come up with.

Craig: yeah. and i think that's a great analogy. so follow odenado, and her story because, obviously, promising results from her and what they're doing then there. 90 to 99% is real progress on real brine at real field sites. so... but it's a pilot result. so until someone shows plant scale cost, 99% is a promising start, but not proof. but we'll be watching this. let us know what you think about this technology, in the comments below. we'd love to hear from you.

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