Search and Destroy: The Future of PFAS Remediation

Search and Destroy: The Future of PFAS Remediation
CDM Smith has been inves­ti­gat­ing PFAS destruction for nearly a decade. Discover the oppor­tu­ni­ties and risks associated with this approach.

With one of the strongest chemical bonds, per- and poly­flu­o­roalkyl substances (PFAS) upend conven­tional approaches and call for creative solutions. In our Februrary 2019 PFAS Newsletter we introduced two treatment tech­nolo­gies—granular activated carbon (GAC) and anion exchange resin (AIX). These methods use a sorbent (GAC or AIX) to separate PFAS from a drinking water or groundwater source. Though successful pilot and full-scale appli­ca­tions have elevated the profile of these separation tech­nolo­gies, they have not entirely solved the PFAS problem.  

Recir­cu­lat­ing PFAS in the environment from one media to another without destruction draws significant concern globally. Currently, there is no clear guidance on managing PFAS-laden wastes. As such, spent GAC or AIX are often disposed in local landfills or are incinerated at temperature below 1000°C, which removes PFAS from spent sorbent but does not destroy them. In addition, there are concerns about accidental PFAS releases during shipping and handling PFAS-laden wastes off site. To effectively neutralize PFAS as a threat to human health, researchers are increas­ingly testing the power of destruction tech­nolo­gies. 

When Destruction Works
Destruction technology, in the context of PFAS, is defined as a technology that can completely deflu­o­ri­nate PFAAs (such as PFOS and PFOA) to innocuous end products. PFAS destruction tech­nolo­gies typically require large amounts of energy and have higher price tags. Therefore, it’s important to selectively employ them on highly-concen­trated, low-volume targets, including: 

  • AFFF concen­trates 

  • Groundwater within PFAS source areas

  • Remediation waste streams (such as wastewater generated from regen­er­a­tion of GAC or regenerable ion exchange resin, foam frac­tion­a­tion, soil washing, rejected reverse osmosis concen­trates, chemical or electro-coagulation)

  • Landfill leachate
Often, the destruction technology is coupled with another form of treatment to generate a high-strength, low-volume concen­trated waste stream. 
Destruction technology...can completely defluorinate PFAAs (such as PFOS and PFOA) to innocuous end products.
Tread Carefully
There are numerous PFAS destruction tech­nolo­gies under development, conve­niently summarized in this ITRC PFAS Fact Sheet. Promising ex-situ destruction tech­nolo­gies include elec­tro­chem­i­cal, plasma and reductive options. These approaches have success­fully degraded an array of high-concen­tra­tion PFAS at the laboratory scale. However, none are suffi­ciently mature yet to assess PFAS treatment costs and overall effec­tive­ness with confidence at the field scale. 

Because of the emerging market for destructive PFAS tech­nolo­gies, they are often promoted hastily without demon­strat­ing complete deflu­o­ri­na­tion and without confidence the technology can meet stringent effluent discharge require­ments. Carefully consider the applic­a­bil­ity of these tech­nolo­gies for a specific site and/or application before investment in full-scale treatment systems.

The Road Ahead
The development and commer­cial­iza­tion of PFAS destruction tech­nolo­gies will not be easy. Several ex-situ destructive tech­nolo­gies have moved from flask to field, which include sonolysis, elec­tro­chem­i­cal oxidation and ultraviolet oxidative/reductive destruction. Careful consid­er­a­tion and under­stand­ing of PFAS trans­for­ma­tion and deflu­o­ri­na­tion must be incor­po­rated into the technology evaluation for a particular site/application with thoughtful design of bench and pilot scale systems to demonstrate technology and incorporate economic feasibility in the selection process. 

Consid­er­a­tion of balanced technology benefits and limitations that should be discussed with technology providers include: 
  • High energy demand and feasibility of high energy/cost at the scale required for the system

  • Health and safety concerns

  • Feasibility of operating large-scale systems, if required

  • Incomplete PFAS destruction resulting in accu­mu­la­tion of fluorinated inter­me­di­ates that are generated but not measurable

  • Feasibility of achieving stringent (i.e. very low) treatment require­ments

  • Effec­tive­ness in destroying all PFAS chemicals, including short chain PFAS    

  • Generation of non-PFAS toxic byproducts

At CDM Smith, our approach to assessing PFAS destructive tech­nolo­gies includes treata­bil­ity testing at the bench, pilot and full-scale using three lines of evidence, which results in more accurate veri­fi­ca­tion of PFAS destruction. And our collab­o­ra­tions with univer­si­ties and research foundations allow us to explore the latest analytical methods for under­stand­ing the destructive mechanisms, including Total Oxidizable Precursor Assay, nontarget PFAS analysis, and total extractable organic fluorine analysis.

Jen Hooper Jen Hooper
Every site is comprised of different contaminants. We’re in a unique position to make sure a combination of technologies will fit exact site specifications.

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