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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

Vema Hydrogen is conducting a pilot for its Engineered Mineral Hydrogen technology. Photo courtesy Vema Hydrogen.

Houston climatech company Vema Hydrogen recently completed drilling its first two pilot wells in Quebec for its Engineered Mineral Hydrogen (EMH) pilot. The company says the project is the first EMH pilot of its kind.

Vema’s EMH technology produces low-cost, high-purity hydrogen from subsurface rock formations. It has the capacity to support e-fuel and clean mobility industries and the shipping and air transport markets. The pilot project is the first field deployment of the company’s technology.

“This pilot will provide the critical data needed to validate Engineered Mineral Hydrogen at commercial scale and demonstrate that Quebec can lead the world in this emerging clean energy category,” Pierre Levin, CEO of Vema Hydrogen, said in a news release.

Levin added that the sample collected thus far in the pilot is “exactly what we expected, and is very promising for hydrogen yields.”

Through the pilot, Vema will collect core samples and begin subsurface analysis to evaluate fluid movement and monitor hydrogen production from the wells. The data collected from the pilot will shape Vema's plans for commercialization and provide documentation for proof of concept in the field, according to the news release.

“Vema Hydrogen perfectly embodies the spirit of the grey to green movement: transforming mining liabilities into drivers of innovation and ecological transition,” Ludovic Beauregard, circular economy commissioner at the Thetford Region Economic Development Corporation, added in the release.

“This project demonstrates that it is possible to reconcile the revitalization of mining regions, clean energy and sustainable economic development for these areas.”

In addition to its pilot in Canada, Vema also recently signed a 10-year hydrogen purchase and sale agreement with San Francisco-based Verne Power to supply clean hydrogen for data centers across California. The company was selected as a Qualified Supplier by The First Public Hydrogen Authority, which will allow it to supply clean hydrogen at scale to California’s municipalities, transit agencies and businesses through the FPH2 network.

Vema aims to produce Engineered Mineral Hydrogen for less than $1 per kilogram. The company, founded in 2024, is working toward a gigawatt-scale hydrogen supply in North America.

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