Jan 20, 2020

Clarkson University Researchers & U.S. Air Force Use Plasma to Remove PFAS

Researchers at Clarkson University and U.S. Air Force are using plasma reactors to remove PFAS from groundwater.

pfas contamination

A group of researchers at Clarkson University in New York is developing a way to destroy per- and polyfluoroalkyl substances (PFAS) in water. 

In collaboration with the U.S. Air Force, the team is using machines called plasma reactors to sever the chemicals' carbon-fluorine bonds, according to Business Insider

An important distinction to make is that the technology applies only to PFAS in groundwater. The researchers are in the process of working on a separate project to remove PFAS from soil, however. This technology could also be more cost-efficient, according to Business Insider.

Researchers built a 20 foot long mobile trailer, which holds two plasma reactors. For two weeks in September, PFAS contaminated groundwater was pumped from the Wright-Patterson Air Force Base in Ohio into the reactors, reported Business Insider.

Argon gas at the bottom of the reactors carries the PFAS molecules to the surface, then high-voltage electrodes are used to generate plasma. The plasma zaps the water's surface, where it spreads, hitting PFAS molecules and splitting them, according to Business Insider. Once the carbon and fluorine molecules have been separated, the PFAS compound is destroyed. 

The Clarkson team's plasma reactor reduces PFAS concentrations in water well below the EPA's 70 parts per trillion (ppt) limit.

According to Selma Mededovic, the principal researcher overseeing the project, treating a single gallon of water this way only takes one minute. This is slower than one of the standard methods for removing PFAS, adding carbon to contaminated water, but the spent carbon needed to be incinerated afterward.

That incineration process costs about $3 to $4 per gallon of contaminated water. The plasma method is at least 40% cheaper, according to Mededovic, although the estimate does not include the cost of the reactors.

The first commercial prototype is expected to be operational by the end of 2020 year, reported Business Insider. Mededovic’s team eventually hopes to treat approximately 200 gallons per minute.  

"We are working on scaling up our process to be competitive to carbon," said Mededovic.

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