While granulated activated carbon (GAC), ion exchange resin (IX), and, to a lesser extent, Fluoro-Sorb® have been widely implemented for the removal of per- and polyfluoroalkyl substances (PFAS) in impacted streams, their performance is significantly hindered by the presence of interfering compounds, in particular organic matter. These constituents reduce PFAS adsorption capacity and kinetics, accelerate media fouling, and shorten the operational life of both selective and non-selective PFAS adsorbents, resulting in a substantial increase in the life-cycle costs of treatment implementations. Therefore, cost-effective pretreatment strategies capable of mitigating key interferences are urgently needed to maintain the efficacy and economic viability of downstream sorbent systems. The overall objective of this project is to demonstrate and validate pretreatment technologies including ozone (O₃)-based pretreatments to improve the performance and longevity of GAC, IX, and Fluoro-Sorb® for PFAS remediation. Specific project objectives are as follows:

• Demonstrate and validate that investigated pretreatment technologies improve PFAS removal performance and hydraulic performance in downstream adsorbents across variable influent conditions.
• Quantify the reduction in operational cost and media replacement frequency resulting from pretreatment implementation.
• Assess the unintended consequences associated with large-scale application of selective adsorbents (e.g., leaching of nitrogen-based functional groups) as well as pretreatment technologies to inform long-term risk and regulatory acceptance.
• Develop site-specific design guidance and disseminate results.

Leveraging a state-of-the-art mobile demonstration system and based on the promising preliminary results of prolonged adsorption effectiveness, this project will demonstrate and validate O₃-based pretreatment technologies to enhance the performance and operational longevity of GAC, IX, and Fluoro-Sorb® for the removal of PFAS and co-occurring chemicals at a minimum of two impacted locations. Conventional low-dose O₃ will be applied to oxidize reactive fractions of organic matter and other constituents that contribute to fouling and interfere with PFAS adsorption. This approach can be coupled with a subsequent biologically active filtration step to enable biological degradation of residual organics and remove potential oxidation byproducts. The pretreatment trains are designed to mitigate fouling, improve media longevity, and maintain hydraulic performance under relevant site conditions. The project will also assess unintended consequences associated with the use of selective adsorbents (e.g., leaching of nitrogen-containing functional groups with disinfection byproduct– formation potential) and with O₃ pretreatment (e.g., formation of oxidation byproducts). The demonstration will generate treatment performance and cost data to support full-scale implementation and life-cycle cost analysis, leveraging prior and ongoing ESTCP-funded efforts (ER22-7482 and ER18-5053), to deliver a field-ready, scalable solution. Furthermore, the mobile treatment system enables rapid deployment with minimal infrastructure changes, allowing testing under diverse water matrices. This flexibility enhances the relevance and transferability of results to full-scale implementation across different treatment scenarios. 

This project is designed to generate critical field-scale data to enable systematic evaluation of the operational, performance, and cost advantages of incorporating O₃-based pretreatment into existing PFAS treatment trains using GAC, IX, and Fluoro-Sorb®. Currently, an unbiased and comprehensive pilot-scale assessment of such integrated systems targeting PFAS treatment is lacking, and improving adsorbent longevity is critically important. The project leverages a fully constructed and performance-verified mobile demonstration system, ensuring cost-effective execution of comparative assessments across treatment scenarios. In addition to identifying whether pretreatment improves permeability, PFAS and co-occurring chemicals removal, and media replacement frequency, the project will produce high-resolution treatability and cost data to support treatment selection, life-cycle analysis, and full-scale implementation. Insights from this project will support lower-cost, high-impact remediation approaches, ultimately increasing operational efficiency for installations. (Anticipated Project Completion - 2028)