Case Studies

Pilot Demonstration of PFASigator® for Mobile PFAS Destruction in Groundwater Concentrate

 

Authors: Dr. Tess Sobolewski

In September 2025, Enspired Solutions conducted a pilot demonstration of using PFASigator® treatment at a Department of Defense (DoD) site on the U.S. East Coast. The project successfully destroyed PFAS in groundwater foamate generated through in-situ foam fractionation of PFAS-impacted groundwater. Treated effluent consistently met EPA Maximum Contaminant Levels (MCLs), enabling compliant on-site discharge and eliminating the need for costly off-site disposal.

 

Study Highlights
  • Efficient PFAS destruction: achieved >99.9% destruction of ∑EPA MCL PFAS and >99% destruction of ∑Total PFAS, in which PFOS reduced from 6,000,000 ppt to 740 ppt and PFOA reduced from 1,100,000 ppt to 500 ppt.
  • Regulatory compliance: After polishing step, treated effluent was able to meet EPA MCLs, enabling compliant on-site discharge.
  • Real-time verification: Automated fluoride monitoring in PFASigator provided consistent batch-to-batch validation and a strong fluorine/fluoride mass balance.
  • Operational reliability: PFASigator operated from a manned manual operation for safety verification to continuous 24/7 schedule. In short period, the mobile treatment unit treated ~600 gallons of groundwater foamate with consistent, reproducible results.
  • Treatment Capacity: Using a new chemical recipe boosted one single PFASigator throughput from 200 to 1,000 gallons per day.
Pilot Project Objectives

The demonstration pursued four primary goals:

  • Feasibility & Applicability: evaluate the practicality, safety, and reliability of deploying PFASigator for on‑site destruction of PFAS concentrated waste stream.
  • Technical Performance: Quantify destruction for individual PFAS and key sums (∑EPA MCL PFAS and ΣTotal PFAS) across practical energy usage range.
  • Cost & Energy: Calculate costs (±25%) and document energy inputs, acknowledging energy efficiency as a primary driver for concentrate treatment.
  • Discharge Strategy & Compliance: Evaluate discharge considerations and confirm no undesirable byproducts under field conditions.

Together, these objectives support the broader goal of advancing PFASigator as an integrated, onsite PFAS treatment and destruction technology suitable for site, especially DoD, remediation needs.

  

 

Pilot Project Design

The pilot project was conducted using groundwater concentrate that contained total PFAS levels exceeding 14 ppm, with PFOS and PFOA as the dominant species. Groundwater concentrate was processed in 50 gallon batches. Each batch of foamate was conveyed to the PFASigator, where liquid reagents were added to enable photoactivated reductive defluorination (PRD), Enspired Solutions’ patented chemistry to break down PFAS molecules under atmospheric temperature and pressure. The prepared concentrate was circulated through the PFASigator’s ultraviolet (UV) light reactor, which catalyzed the PRD reaction and initiated PFAS destruction.  The PFASigator continuously monitored fluoride ion, the final product of PFAS destruction, in real time, providing automated confirmation of treatment progress and completion and allowing the extent of defluorination to be tracked throughout the process. Once PFAS destruction was achieved, the treated effluent was polished using 8-inch Cyclopure’s Dexsorb® adsorbent media vessel to remove any residual PFAS and guarantee compliance with discharge limits. The PFASigator and other treatment accessories were placed in a standard Cargo trailer (Figure 1), serving as a mobile treatment unit at the site (Figure 2).

Pilot Project Results and Conclusions

  1. Efficiently destroyed PFAS on site

The foamate exhibited an average Σ40 PFAS ≈ 18 mg/L (18,000,000 ng/L) with a baseline profile dominated by PFOS (~45%), 6:2 FTS (~27%), PFHxS (~15%), and PFOA (~8%) as a typical of AFFF impacted groundwater concentrates.

Figure 3 provides the PFAS fingerprint graph along the treatment duration while using the regular PRD recipe, in which PFAS concentrations of the sample treated by certain UV doses are shown.  Priority PFAS compounds were reduced rapidly by 215 - 600 kWh/m³. ∑EPA MCL PFAS was destructed 99% at an energy input of 400 kWh/m³. By 800 - 1,600 kWh/m³, priority PFAS compounds approached 99.9% reductions, e.g., PFOA was destructed from 1,500,000 to 430 ng/L (99.97%), PFOS was destructed from 8,600,000 to 2,400 ng/L (99.97%), PFHxS  was destructed from 2,900,000 to 5,900 ng/L (99.8%) and 6:2 FTS was destructed from 5,100,000 to 46,000 ng/L (99.1%).

The destruction efficiency shows typical tailing behavior of first‑order kinetics at low PFAS concentration range. Between 600 and 1,600 kWh/m³, ∑40 PFAS drops from 201,650 to 72,234 ng/L, only a 0.6% improvement (99% to 99.6%) despite more than doubling the energy input. This is why treatment batches were run at 600 - 800 kWh/m³ to maximize PFAS destruction with polishing media for discharge compliance while maintaining energy efficiency.

  1. Destruction and polishing achieved discharge limit enabling compliant on-site discharge

All EPA MCL PFAS were non-detect in the 1,600 kWh/m³ final effluent. PFASigator treatment steps were also confirmed not to impact priority metals, which remained non-detect throughout the process, or total organic carbon (TOC), which stayed generally stable.

  1. Real-time fluoride monitoring confirms PFAS destruction

 

As PFAS destruction occurs and carbon-fluorine bonds are broken in PRD, fluorine is released into solution as inorganic fluoride ions. The PFASigator is equipped with a real-time fluoride ion-selective electrode (ISE) probe to continuously monitor fluoride generation. From start to end of the PFAS destruction batch, fluoride ion recovery was ~125.8% of the total organic fluorine quantified in baseline PFAS profile. The excellent fluorine mass balance achieved using PRD indicates 1) the utility of using fluoride ion as a proxy for extent of PFAS destruction and 2) the PRD reaction defluorinates PFAS with little loss of PFAS to other pathways such as physical adsorption, conversion into toxic byproducts, etc. Also, this real‑time monitoring enabled uninterrupted observation of destruction kinetics during autonomous 24/7 operation. fluoride generation monitored by PFASigator (Figure 4) showed strong repeatability across sampled batches, confirming stable system performance and reliable PFAS destruction.

  1. Mobile treatment unit operational reliability

The mobile PFASigator system demonstrated strong operational reliability during the pilot, integrating all necessary components - treatment unit, transfer tote, secondary containment, and tools - into a single mobile trailer. Its fully automated batch loading, discharge, and reagent dosing, combined with realtime fluoride monitoring to verify PFAS mineralization, enabled continuous 24/7 operation without the use of pressure or heat. The unit supported remote monitoring and control and required minimal onsite attention, operating unattended for roughly 53% of its 100+ hours runtime while maintaining 100% availability during the project.

  1. Treatment Capacity Boost

In 2025, Enspired Solutions developed a new PRD formulation that significantly accelerated PFAS destruction kinetics. Table 1 shows the PFAS concentration decrease as a function of UV dose on the same groundwater foamate treated by this alternative PRD recipe.

Results showed a similar baseline PFAS profile but far more rapid destruction. Following a short UV dose of 50 kWh/m3, PFOA decreased by 99.3% (1,500,000 ng/L to 11,000 ng/L), PFOS decreased by 98.9% (7,600,000 ng/L to 81,000 ng/L), and PFHxS decreased by 97.6% (2,700,000 ng/L to 64,000 ng/L). In total, ∑40 PFAS decreased by 96% (17,610,000 ng/L to 703,300 ng/L) and ∑ EPA MCL PFAS decreased by 99% (11,800,000 ng/L to 164,800 ng/L). For reference, this magnitude of destruction was not achieved until a UV dose of 400 kWh/m3 during the field study using the standard PRD recipe. This alternative recipe boosted one single PFASigator treatment capacity from 200 to 1,000 gallons per day.

  1. Cost Assessment

The cost of dedicated PFASigator destruction reflects both CAPEX and OPEX, largely driven by the UV dose needed to achieve the target destruction level. Field data collected from the pilot demonstration were used to estimate total treatment cost of using PFASigator, which was approximately $1.20 per gallon PFAS concentrate. These costs apply to a dedicated destruction scenario; mobile PFASigator deployments include additional fixed expenses such as mobilization, demobilization, labor, travel, site setup, support, cleanup, and teardown, which increase the overall per‑gallon cost for field services.

Acknowledgements

We thank the ESTCP committee for its guidance and support, the Naval Air Station team for site coordination and access, the Noblis team for project management, Eurofins Environmental Testing for analytical support, and Cyclopure for providing the Dexsorb polishing unit. We also express sincere appreciation to our own Enspired Solutions team, whose expertise, field and laboratory efforts, and dedication were essential to the successful execution of this project.