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Mitigating PFAS Cross Contamination During AFFF Replacement Projects

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Tetra Tech’s David Fulton shares potential advances in firefighting systems per- and polyfluoroalkyl substances (PFAS) decontamination strategies using Tetra Tech’s PFAScrub® cleaning agent coupled with sound program development and performance verification.

Recognizing the impact from legacy PFAS

Many firefighting foam users will be transitioning away from aqueous film forming foam (AFFF) containing PFAS, due to environmental, human health, and regulatory risks. A successful transition program recognizes that simply draining the old foam and replacing it with a new foam can result in cross contamination with residual or legacy PFAS, leading to future environmental liabilities.

PFAS adheres to surfaces by forming multiple layers on interior piping and equipment, which means the interior of fire suppression systems can be coated with a significant mass of PFAS that will eventually rebound into the replacement foam. This cross-contamination effect will potentially negate the benefit of transitioning to a PFAS-free foam and could result in decades of environmental cleanup if released into the environment. Traditional approaches of flushing the system with water have only had limited effectiveness and generate large volumes of rinsate that require management and disposal.

Decontaminating retained equipment before transitioning to a new foam is the best way to prevent legacy PFAS cross contamination.

Although current best practices include water flushing of the AFFF systems prior to chemical switchover, Tetra Tech’s PFAScrub and application methodology is being tested at industry sites to demonstrate its ability to remove residual PFAS. The cleaning formulation drives the dissolution and desorption of PFAS into a solution and the repetition of flushing and residence time cycles could address the most difficult PFAS adhesion characteristic associated with pipe-wall layering. Other potential benefits include:

  • PFAScrub can be reused until PFAS saturation levels warrant a change-out to a fresh solution
  • Recirculating PFAScrub in a closed looped manner is more economical and effective compared to the excessive waste volumes generated through conventional water-flushing methodologies
  • Using PFAScrub can avoid costly replacement of system components that cannot easily be accessed or would severely impact facility operations if a total replacement program were implemented

Right team, right approach yields positive outcome

Over the past 50 years, Tetra Tech has built a legacy of Leading with Science® by providing innovative, technical solutions for our clients. With our global footprint and experience with foam transition work across four continents, we can manage all aspects of a foam transition project, partnering with your existing team to enhance your forward-moving transition program. Together with our global teaming partners, we bring a highly qualified and experienced team to support your AFFF transition program with the following services:

  • Program development and consulting
  • Equipment replacement
  • Fire suppression system decontamination and verification
  • AFFF waste management
  • New equipment installation and foam replacement

Tetra Tech is equipped to provide solutions that minimize unnecessary replacement of system components, minimize expensive waste disposal, and reduce future environmental liabilities. Please contact us to support your AFFF transition projects.

About the author

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David Fulton

David Fulton is an environmental program director specializing in solutions related to PFAS remediation and firefighting foam transition projects. 

With more than 30 years of experience in environmental remediation and engineering consulting, David specializes in providing interdisciplinary solutions for global clients seeking innovative and cost-effective environmental management solutions. He focuses on portfolio and program management techniques that integrate technology, strategy, and global resources to deliver customer value through efficient operations and quality standards. 

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