Per- and polyfluoroalkyl substances (PFAS) are widely used synthetic chemicals that do not break down naturally and are found in water, soil, and air globally. These persistent organic pollutants are of significant concern because of their widespread environmental distribution, bioaccumulative potential, and links to health risks such as various cancers, hormone disruption, weakened immunity, and reproductive problems. Water is a sink for these highly mobile, persistent chemicals, leading to the contamination of drinking water. A 2022 analysis of drinking water from 41 cities in 15 countries detected PFAS in every sample.
Common PFAS management falls short
Most commercially available PFAS testing is compound-specific, detecting fewer than 100 compounds and focusing on regulated ones. However, there are more than 12,000 PFAS compounds and regulations of them differ by location and are subject to change. Testing has been playing catchup with the continuously growing list of known PFAS compounds. Calls for a class-based approach to PFAS management have led to new testing such as the U.S. Environmental Protection Agency’s recently published draft method for adsorbable organic fluorine (AOF). However, AOF is less sensitive, does not provide compound-specific information, and is biased toward longer-chain PFAS compounds.
Current PFAS management is also problematic. The most common practices for PFAS removal in wastewater are reverse osmosis, foam fractionation, ion resins, and granulated activated carbon. Effective capture and removal of short- and ultrashort-chain PFAS is especially challenging in water with high concentrations of other organic compounds and ions. Filters are often sent to landfills or incinerated, which breaks PFAS into smaller compounds that are transferred to another environmental matrix. For example, industrial-scale incineration generates small-chain PFAS that are spread widely by ash and smoke and accumulate in soils. The U.S. Department of Defense recently banned the incineration of PFAS materials, and there are efforts worldwide to do the same.
Technology offers safer solutions
Scientific technology may have led to the PFAS contamination problem, but it’s also leading to solutions. Technologies developed at the University of Minnesota and being offered by Claros Technologies detect and destroy PFAS in wastewater, leaving only detoxified water and naturally occurring elements. The first step in remediation is comprehensive testing that utilizes compound-specific methods and those that address PFAS as a class, such as AOF and total organic fluorine (TOF). The second step is the capture of short- and long-chain PFAS and other pollutants. An innovative sorbent is more efficient than granulated activated carbon in capturing PFAS, allowing for a faster empty bed contact time and a higher loading capacity. It also has a much smaller footprint that can be easily retrofitted into existing capture systems, making wide-scale adoption feasible.
The final steps are concentrating and permanently destroying PFAS. Reducing millions of gallons of wastewater into a few gallons of PFAS concentrate makes destruction more manageable. Defluorination is accomplished through a photochemical process that breaks the powerful C-F bond at room temperature and atmospheric pressure.
The future of PFAS remediation
PFAS were developed to solve problems, not create them. Designed to be strong and durable, those very qualities have become a liability. It’s important to mind that lesson when it comes to PFAS remediation. Every new solution brought to market should be thoroughly vetted to ensure it doesn’t create new problems downstream.
Written by Zijie “Beryl” Xia, Lead Scientist at Claros Technologies
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