State and university collaboration to address innovative PFAS treatment options
The recent announcement of a new federal rule aimed at reducing PFAS (per- and polyfluoroalkyl substances) in drinking water gives water utilities a few years for implementation. In Arizona, the state Department of Environmental Quality (ADEQ) will be responsible for ensuring the new regulatory standards are met.
While meeting this latest standard may sound straightforward, questions remain about the best treatment options for removing PFAS from drinking water.
That’s where Treavor Boyer comes in. Boyer, a Professor of Environmental Engineering in ASU’s School of Sustainable Engineering and the Built Environment whose research focuses on water quality and treatment, is working with ADEQ to provide technical advice on PFAS treatment options.
“PFAS is really the top contaminant we are facing in the environment right now,” says Boyer. “I tell students who are getting ready to graduate that if they go into water or wastewater, they're going to be working on PFAS for a long time because the more we look for it, the more we find it in both groundwater and surface water.”
PFAS is a different type of chemical compared to most regulated drinking water pollutants because it has unique chemical properties and is a health concern at very low concentrations. This has made it difficult to find PFAS in the environment, and makes removing it from water more challenging.
There are currently two primary methods used to remove PFAS from drinking water: activated carbon adsorption and ion exchange resin. While activated carbon is more commonly used, ion exchange resin may be more useful in some circumstances, especially as more detailed research and guidance develops.
“You might think that carbon treatment seems more straightforward than resin and that’s true,” says Boyer, who is also supported by the Global Center for Water Technology, which is a pillar of the Arizona Water Innovation Initiative. “However, what research shows is that it's possible resins can remove more types of PFAS chemicals – of which there are thousands – more effectively. As with anything, different water treatment technology have their pros and cons.”
One of the main challenges with PFAS treatment is that no matter the water source, when PFAS are removed, they end up concentrated on the carbon or resin surface that then needs to be disposed of or treated as well.
“You can use ion exchange resin to effectively remove PFAS from water,” says Boyer, “but the big questions and uncertainties surround the fact that the resin is then typically regenerated. This is different from activated carbon, which is taken off site and reactivated or disposed of.”
Regeneration involves exposing the PFAS-laden resin to a chemical solution that removes the PFAS and allows for reuse of the resin, which creates a relatively smaller volume waste stream to manage.
“Water utility personnel are used to regenerating ion exchange resin after it is used for removal of nitrate or calcium hardness,” says Boyer, “but PFAS regeneration is more complex and may involve a different set of chemicals than they might usually have on hand.”
To address the questions that ADEQ has about regenerating the resin, Boyer says that researchers in his lab will start with a review of very recent literature “because PFAS is a topic that evolves on a weekly timescale.” They’ll then move on to an experimental plan, and then experimental work, focused on regeneration specific to water conditions in Arizona.
In the end, they will provide ADEQ with guidance on ion resin exchange regeneration for PFAS removal that includes a cost analysis and other considerations for utilities.
“With something as complex as PFAS, regulators know that there's not going to be one way,” says Boyer. “Carbon will probably work great and do what it needs to do in many circumstances. But down the road, there may be situations where regenerative ion exchange could be the best fit for a utility. I give ADEQ a lot of credit for working ahead so that when there are these multiple ways forward, they have enough internal resources to make decisions and provide guidance.”
Boyer’s collaborators at ADEQ agree.
“Through our state-wide testing program, ADEQ saw that even isolated rural water systems are not spared from PFAS contamination,” says Jasmina Markovski, senior engineer with ADEQ. “Every public drinking water system, regardless of size, is unique and deserves a custom PFAS solution. While tempting, ‘plug-and-play’ solutions directly off the shelf are usually not the most effective treatment choice because they do not consider a system’s specifics.”
“That’s where this collaboration between ASU and ADEQ is valuable. We are testing innovative, Arizona-specific PFAS treatment approaches and providing science-based testing protocols to assess performance potential for different systems with different goals,” continues Markovski. “We are lucky to have a local university that is a national leader when it comes to PFAS research to support ADEQ in bridging science with application.”
Over time, PFAS is only one set of what are called “emerging contaminants” that will need to be addressed. For example, phosphorus, which Boyer notes can be considered a resource or a contaminant depending on the context, is an area he and other researchers are addressing as part of a large research program supported by the National Science Foundation. The desire to reuse phosphorus present in wastewater is complicated by the potential for PFAS contamination as well.
“There is a lot of innovative research happening when it comes to water contaminants,” says Boyer, “but putting the research into practice really requires partnerships with regulators and utilities, so we are glad to be working with ADEQ from the start to provide support for this complex process.”
Related reading:
Explaining the new federal regulation for PFAS in drinking water | AWII Blog
Removing 'forever' chemicals from drinking water | ASU News
PFAS Resources | Arizona Department of Environmental Quality