PFAS Treatment Technologies for Drinking Water 

According to the EPA, roughly 10% of drinking water systems across the country are discovering elevated levels of PFAS in their drinking water. In a recent webinar, I collaborated with Bryan Pate, CEO of LW Utilities, to discuss some of the latest advancements in PFAS treatment technologies for drinking water. I’ll provide highlights in this post, but I invite you to watch the webinar on-demand for more details. 

Watch: Navigating PFAS in Drinking Water: Treatability Insights and Analytical Overview 

EPA Best Available Treatment Options 

First, to help water systems address high levels of PFAS in their drinking water, the U.S. EPA published a list of Best Available Treatment (BAT) options. This list includes: 

• Granular Activated Carbon (GAC) filtration: PFAS adhere to the carbon as water passes through the filter. 

• Anion exchange resins: Exchanges ions between the resin and water, specifically targeting PFAS molecules for removal. 

• High-pressure membrane technologies: E.g., nanofiltration or reverse osmosis, which use high pressure to force water through semipermeable membranes, capturing PFAS molecules and other contaminants. 

 The EPA considers these “best” because they are widely used and multiple studies have shown them to be practical and effective in reducing PFAS levels in drinking water. However, the EPA’s BAT options share one common feature: They all work by removing PFAS from the water, the first two methods by absorption and the last by filtration.  

The EPA does not dictate which removal method a water system may use as long as that system is in compliance with the PFAS Maximum Contamination Levels (MCLs) outlined in the Safe Drinking Water Act.  There are emerging technologies that utilize novel sorbents for PFAS removal similar to carbon or anion exchange. Some methods focus on concentrating the PFAS into a manageable waste stream that can be disposed of or coupled with destruction technologies.  

Destruction technologies focus on breaking the carbon-fluorine bond within a PFAS compound, essentially turning organic fluorine into inorganic fluoride. Pace® works with a wide array of these companies and can aid in measurement techniques for both organic fluorine and inorganic fluoride. These destruction technologies have the added advantage of eliminating the challenge of disposing of spent media such as carbon or resin as well as treating PFAS latent waste streams. Below we will explore a few of these technologies. 

PFAS Treatment Technologies: Emerging Options 

In the webinar, Brian listed sixteen alternate technologies they’ve piloted or implemented. Of these, he called out four technologies he felt were particularly promising: 

Ozone foam fractionation – Foam fractionation is a technique widely used in wastewater treatment to remove surfactants, including PFAS. Ozone foam fractionation is seen as a promising option for drinking water, especially when combined with the next option: electrochemical oxidation.  

Electrochemical oxidation – Electrochemical oxidation uses electric current to generate hydroxyl radicals, which can then be broken down. Bryan’s organization has used ozone foam fractionation to concentrate the waste stream. They then use electrochemical oxidation to break the carbon-fluorine bonds.  

AquaPRS® – This system uses a suspended absorbent to absorb the PFAS compounds. Then a separator system extracts the clean water. This sorbent is a much finer material than traditional carbon or ion exchange resins, so the operational cost and the waste generation are significantly less. Bryan and his team have seen very good results from pilot studies using this method for single-stage groundwater systems and two-stage surface water systems, even when the surface water is challenging.  

Nanobubble Oxidation Technology (NBOT) – This approach combines several proven technologies: nanobubbles, ozone, and UV light. First, the nanobubbles are infused with ozone and injected into the flow stream. The flow stream is then run through UV light at a specific wavelength to weaken the carbon-fluorine bonds. Normally, UV destroys ozone, but in this case, the ozone is protected inside the nanobubbles and the hydroxyl radicals generated by the ozone destroy the carbon-fluorine bond in the PFAS. This approach is still being researched, but early results suggest it may prove to be very economical and effective, especially for high-volume systems. 

How to Choose the Best Approach
 

What works best for one water system may not work for another. In the webinar, Bryan showcased a project where a water system had two treatment facilities just a few miles from each other. However, one was a groundwater system and the other used surface water. In the end, they implemented different technologies because the most effective, affordable approach differed. Pilot testing was crucial to ensure project success because the source water conditions varied.  

The Pace® PFAS Treatability Studies Center of Excellence supports water systems and water treatment professionals as they seek to determine the most effective and economical removal technology for their system. To learn more, visit our website. I also invite you to reach out to me to discuss your PFAS treatment project.