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Houston researchers harness dialysis for new wastewater treatment process

Rice University's Menachem Elimelech and Yuanmiaoliang “Selina” Chen published a study in Nature Water on mimicking dialysis from the medical field to treat wastewater. Photo by Gustavo Raskosky/Rice University

By employing medical field technology dialysis, researchers at Rice University and the Guangdong University of Technology in China uncovered a new way to treat high-salinity organic wastewater.

In the medical field, dialysis uses a machine called a dialyzer to filter waste and excess fluid from the blood. In a study published in Nature Water, Rice’s team found that mimicking dialysis can separate salts from organic substances with minimal dilution of the wastewater, addressing some of the limitations of previous methods.

The researchers say this has the potential to lower costs, recover valuable resources across a range of industrial sectors and reduce environmental impacts.

“Traditional methods often demand a lot of energy and require repeated dilutions,” Yuanmiaoliang “Selina” Chen, a co-first author and postdoctoral associate in Elimelech’s lab at Rice, said in a news release. “Dialysis eliminates many of these pain points, reducing water consumption and operational overheads.”

Various industries generate high-salinity organic wastewater, including petrochemical, pharmaceutical and textile manufacturing. The wastewater’s high salt and organic content can present challenges for existing treatment processes. Biological and advanced oxidation treatments become less effective with higher salinity levels. Thermal methods are considered “energy intensive” and susceptible to corrosion.

Ultimately, the researchers found that dialysis effectively removed salt from water without requiring large amounts of fresh water. This process allows salts to move into the dialysate stream while keeping most organic compounds in the original solution. Because dialysis relies on diffusion instead of pressure, salts and organics cross the membrane at different speeds, making the separation method more efficient.

“Dialysis was astonishingly effective in separating the salts from the organics in our trials,” Menachem Elimelech, a corresponding author on the study and professor of civil and environmental engineering and chemical and biomolecular engineering at Rice, said in a news release. “It’s an exciting discovery with the potential to redefine how we handle some of our most intractable wastewater challenges.”

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A View From HETI

Houston biotech company Gold H2's proprietary biotechnology has generated hydrogen from depleted oil reservoirs in a California field trial. Photo courtesy Gold H2.

Houston climatech company Gold H2 completed its first field trial that demonstrates subsurface bio-stimulated hydrogen production, which leverages microbiology and existing infrastructure to produce clean hydrogen.

Gold H2 is a spinoff of another Houston biotech company, Cemvita.

“When we compare our tech to the rest of the stack, I think we blow the competition out of the water," Prabhdeep Singh Sekhon, CEO of Gold H2 Sekhon previously told Energy Capital.

The project represented the first-of-its-kind application of Gold H2’s proprietary biotechnology, which generates hydrogen from depleted oil reservoirs, eliminating the need for new drilling, electrolysis or energy-intensive surface facilities. The Woodlands-based ChampionX LLC served as the oilfield services provider, and the trial was conducted in an oilfield in California’s San Joaquin Basin.

According to the company, Gold H2’s technology could yield up to 250 billion kilograms of low-carbon hydrogen, which is estimated to provide enough clean power to Los Angeles for over 50 years and avoid roughly 1 billion metric tons of CO2 equivalent.

“This field trial is tangible proof. We’ve taken a climate liability and turned it into a scalable, low-cost hydrogen solution,” Sekhon said in a news release. “It’s a new blueprint for decarbonization, built for speed, affordability, and global impact.”

Highlights of the trial include:

  • First-ever demonstration of biologically stimulated hydrogen generation at commercial field scale with unprecedented results of 40 percent H2 in the gas stream.
  • Demonstrated how end-of-life oilfield liabilities can be repurposed into hydrogen-producing assets.
  • The trial achieved 400,000 ppm of hydrogen in produced gases, which, according to the company,y is an “unprecedented concentration for a huff-and-puff style operation and a strong indicator of just how robust the process can perform under real-world conditions.”
  • The field trial marked readiness for commercial deployment with targeted hydrogen production costs below $0.50/kg.

“This breakthrough isn’t just a step forward, it’s a leap toward climate impact at scale,” Jillian Evanko, CEO and president at Chart Industries Inc., Gold H2 investor and advisor, added in the release. “By turning depleted oil fields into clean hydrogen generators, Gold H2 has provided a roadmap to produce low-cost, low-carbon energy using the very infrastructure that powered the last century. This changes the game for how the world can decarbonize heavy industry, power grids, and economies, faster and more affordably than we ever thought possible.”

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