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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

ExxonMobil has gotten the green light for a major carbon capture project in the Beaumont-Port Arthur area. Photo via htxenergytransition.org

Spring-based ExxonMobil has won approval from the Texas Railroad Commission for a $5 billion carbon capture and storage project in East Texas.

Dominic Genetti, senior vice president of CCS at ExxonMobil, told The Financial Times, which broke the news, that the Railroad Commission’s action is a “major milestone” that lets the company keep expanding along the Gulf Coast. In a 2-1 vote, commissioners authorized a carbon sequestration permit for the project.

“The Railroad Commission clearly recognizes the important role carbon capture and storage can play in meeting growing global demand for lower-carbon products while supporting new jobs and economic growth,” Genetti said.

The U.S. Environmental Protection Agency (EPA) approved ExxonMobil’s Rose CCS project last year.

The project will enable the company to inject about 53 metric tons of industrial customers’ carbon emissions into three underground wells it drilled in the Beaumont-Port Arthur area. Over a 13-year period, ExxonMobil plans to inject about 4 million metric tons per year into the Fleming and Upper Frio rock formations, according to Carbon Herald.

ExxonMobil says it owns the world’s first and largest CCS system, comprising 1,300 miles of CO2 pipeline and secure storage sites. Seventy percent of the pipelines are along the Gulf Coast.

The company ramped up its CCS business in 2023 with the $4.9 billion purchase of Denbury, which owned about 1,000 miles of CO2 pipelines.

“Our expertise, combined with Denbury’s talent and CO2 pipeline network, expands our low-carbon leadership and best positions us to meet the decarbonization needs of industrial customers while also reducing emissions in our own operations,” ExxonMobil Chairman and CEO Darren Woods said when the deal closed.

In January, Genetti wrote in a post on ExxonMobil’s website that the company is committed to CCS “for the long haul.”

“CCS is not new technology, but it’s flown relatively under the radar compared with the attention that production of hydrocarbons commands,” he wrote. “Now, as the world becomes more aware of the need to reduce emissions, CCS finally has a brighter spotlight and a broader runway to scale up.”

The company also announced this week that it has begun CCS operations at a direct reduced iron facility in Convent, Louisiana. The project will capture, transport and store up to 800,000 metric tons of CO2 per year, according to the company.

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