Posters

Posters are sorted by presenters last name.

Evaluation and Visualization of PFAS Fate and Transport

Candace Beauvais, P.G., Hydrogeologist, Tetra Tech

Abstract:

A prominent application of PFAS compounds is as a key ingredient in Aqueous Film Forming Foams (AFFF), which are used to combat fuel-related fires. PFAS compounds can partition between air and water interfaces, enhancing their effectiveness as fire suppressants and complicating their environmental interactions. AFFF has been extensively utilized at fire training facilities, civilian and military airports, and chemical manufacturing sites resulting in impacts to all environmental media. The behavior and movement of PFAS are highly complex, necessitating thorough and detailed site investigations to develop a conceptual site model that accurately describes contaminant migration. This poster illustrates techniques employed during multiple site investigations to evaluate PFAS movement, predict step out sampling locations, visualize PFAS extent in the subsurface, and modeling of PFAS fate and transport. 

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Versatility of Deployment: PFAS Environmental Remediation and Water Treatment with Surface-Modified Clay Adsorbents 

Rebecca Dickman, Technical Services Manager, CETCO

Abstract:

FLUORO-SORB® Adsorbent, a surface-modified clay (SMC), has been shown to have a strong affinity and capacity for the adsorption of per- and polyfluoroalkyl substance (PFAS) in a wide variety of environmental remediation and water treatment applications. Through displacement of sodium from bentonite clays, modification with cationic organic functional groups creates an adsorbent characterized by positively charged galleries (inter-platelet layers) which do not swell because of hydration. As a result, the SMC has a high adsorptive capacity for a variety of PFAS via electrostatic, hydrophobic, and fluorophilic mechanisms.  FLUORO-SORB® Adsorbent has been investigated in laboratory and field settings for PFAS removal in drinking water, ground water, stormwater/ surface water, and landfill leachate. Additionally, it is effective for soil stabilization and sediment capping at PFAS contaminated sites to prevent leaching into groundwater. FLUORO-SORB® Adsorbent can achieve non-detect concentrations in drinking water and is effective at maintaining concentrations below U.S. Environmental Protection Agency drinking water maximum concentration levels (MCLs) with up to 5-times the bed life of granular activated carbon (GAC). FLUORO-SORB® Adsorbent is resistant to competitive effects of organic matrix co-contaminants (dissolved organic carbon, salts) on PFAS adsorption and has been characterized as having rapid adsorption kinetics. FLUORO-SORB® Adsorbent can also be used as a component in a Reactive Core Mat® composite geotextile mat, where it is placed between geotextiles creating a PFAS-resistant layer that is permeable to water. Several case studies will be showcased in this presentation, which show the highly effective nature of novel SMC adsorbent, FLUORO-SORB® Adsorbent, for the treatment of PFAS in a wide range of complex environmental remediation applications including, landfill leachate, wastewater, groundwater, stormwater, sediment capping, and soil stabilization.  

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Treatment of PFAS Using Non-thermal Plasma and Bubbling. 

Susanna Kurian, Environmental Engineer, The University of Sydney

Abstract:

Pfas Forum 5  Treatment of PFAS using non-thermal plasma and bubbling.  Susanna Kurian1, David Alam1, David Fletcher1, Xinying Liu1, Johan le Nepvou de Carfort2, Ulrich Krühne3, John Kavanagh1  1.  School of Chemical and Biomolecular Engineering, University of Sydney, Darlington, 2006, Australia.  2. PROSYS Technical University of Denmark Chemical and Biochemical Engineering, Kongens Lyngby 2800, Denmark.  3.  Centre for Process Engineering and Technology, Department of Chemical and Biochemical Engineering, Technical University of Denmark, Søltofts plads, 2800 Kgs. Lyngby, Denmark  Several competing technologies exist for the separation and/or destruction of Per and poly-fluoroalkyl substances (PFAS). In this work, we use a 1.5 L scale-down plasma bubble column system to compare the effects of dissolved metals (Fe, Mg, Ca and Zn) and gas types (Argon, Air and Nitrogen) on the destruction of PFOS and PFOA. The gas bubbling increased the PFAS transport rate and provided a larger surface area to float PFAS to the surface of the reactor for plasma treatment. The average bubble diameter in all tests was 1.4 mm, and the gas flow rate was 0.5 LPM.  The plasma bubble column behavior is readily modelled as a first-order process, allowing the rate constants of different PFAS species and other conditions to be compared. It was found that the Mg, Ca, and Zn all gave similar enhancements to the breakdown rate, whilst Fe was less beneficial unless the pH was acidic. The use of Argon gave the highest breakdown rates, while Air and Nitrogen gave slower breakdown rates, but the effect was more pronounced for PFOA than PFOS indicating a difference in the interaction between radicals and the PFAS species. The 50 ppb PFOA and PFOS rate constants with Argon bubbling and calcium addition were 0.089 min-1 and 0.3019 min-1, whereas the same conditions with 500 ppb PFOA and PFOS were 0.0567 min-1, 0.0587 min-1 respectively. Rate constants were determined from the first 40 minutes, showing a straight regression line in the plot of the logarithm of concentration vs time. PFOA and PFOS showed high removal and degradation rates (99% in 30 mins) with breakdown products of fluoride ions and short-chain-PFAS.  The model we previously developed for the 25L system was readily applied to the 1.5 L scale-down system. Samples taken from the liquid surface contained higher PFAS concentrations than samples from the bulk of the reactor volume. The sampling position and the gas used for the bubbling emerged as key factors for the sampling. This significantly influences the composition and overall breakdown rate of the compounds in the treatment reactor.  We acknowledge the funding from the Australian Research Council’s Special Research Initiative on PFAS (SR180200046).  

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PFAS Degradation During Hazardous Waste Incineration: A Pilot-Scale Study with Comprehensive Analytical Approach

Flore Martin, Environmental Engineer and Project Coordinator, Veolia North America

Abstract:

The environmental persistence of per- and polyfluoroalkyl substances (PFAS) raises concerns about their remediation. This study assesses PFAS degradation during thermal treatment of Aqueous Film-Forming Foam samples, and other PFAS-laden wastes, under controlled operating conditions, simulating hazardous waste incineration processes at pilot scale.  A custom-designed reactor replicates thermal treatment conditions (temperature, residence time, and O2% in fumes) of combustion (850-1100°C) and post-combustion chamber (1100-1200°C)  phases typical of hazardous waste industrial incinerators.  An innovative analytical strategy, consisting of 3 complementary protocols, was deployed to monitor these compounds during thermal treatment.  PFAS-contaminated wastes were characterized using liquid chromatography coupled with tandem-mass spectrometry (LC-MS/MS) to quantify targeted PFAS. Destruction and Removal Efficiency (DRE) was determined by analyzing the same targeted PFAS in flue gases using the OTM-45 method. Analysis of the solid residues was performed to assess the Destruction Efficiency (DE).  A fluorine balance was established through total fluorine (TF) analysis by Combustion Ion Chromatography  (C-IC) on solids and hydrogen fluoride (HF) measurement in flue gases by sampling and direct Ion Chromatography analysis (IC).  Additional analyses were conducted to identify the presence of Products of Incomplete Combustion (PICs) in the flue gases. A Non-Targeted Analysis (NTA) method was developed using liquid chromatography coupled with high-resolution mass spectrometry (LC-HRMS) and performed on OTM-45 analytical fractions to identify semi-volatile PICs. In addition, the OTM-50 method was implemented for volatile species determination.  This study provides crucial data on the effectiveness of thermal treatments for PFAS-containing waste and contributes to developing more efficient management strategies for these persistent pollutants.

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Cost-Effective Remediation Technology for PFAS in Soil Utilizing a Proprietary Rapid Leaching and Dewatering Technology

Bryan Massa, LSP, Principal & Regional Manager, HRP Associates, Inc.

Abstract:

HRP Associates, Inc. (HRP) and Next Earth Environmental, Inc. (NEE) have developed a soil remediation approach that utilizes a proprietary and patent pending (application number 63/608,515) technology used to remediate PFAS in soil. The remediation technology mobilizes contaminants from a solid state (soil) to a liquid state resulting in clean soil. The technology is easily scalable and can be designed to manage any weekly throughput (i.e., <100 cubic yards or >1,000 cubic yards).  The technology uses a unique and patented filtration system that allows soil to be fully saturated with water and then rapidly dewatered in a watertight containment cell constructed from geomembrane and geosynthetic clay liners. The leachate is collected in a secondary watertight cell that is similarly constructed and then pumped through a wastewater treatment system to remove PFAS for future destruction or disposal.  This PFAS remediation process is referred to as Rapid Leaching and Dewatering Technology (RLDT). Once the soil is saturated, the highly soluble PFAS contaminates within the soil matrix are partitioned into a liquid phase. Once in a liquid phase, the PFAS analytes can be easily removed and consolidated through a wastewater treatment process.  The soil is then resaturated with the treated water within the containment cell as necessary until the desired PFAS removal limits have been obtained (i.e., EPA Regional Screening Levels). Once the appropriate number of rinses have been completed to meet the applicable PFAS standards, the soil is left to dry for 24 hours. After 24-hours, the soil will reach an appropriate moisture content (i.e., non-saturated and can be removed for reuse or disposal.)  Two separate benchtop studies of the remediation technology have documented average total PFAS (sum of all reported analytes using EPA Method 1633) removal ranging from 89 to 93 percent. The technology removed 94 to 100 percent of the five PFAS analytes regulated by the EPA. Additional rise cycles can be incorporated into the technology to achieve additional PFAS removal to meet the target site concentrations.  The benchtop studies used three and four rinse cycles to determine the effectiveness.  The benchtop study successfully demonstrates the capability of our patent-pending technology to transfer (partition) PFAS from soil to a liquid state. Once liquefied, the contaminants are destroyed using sorption with high temperature destruction and regeneration, sonication, or other innovative destructive methods.  

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Comparative Evaluation of HydraSleeve Passive Samplers and Low-Flow Purge Methods in PFAS Groundwater Sampling

Dr. Jenny Zenobio, Ph.D., Environmental Engineer, Jacobs

Abstract:

This study systematically evaluated the performance of HydraSleeve passive samplers relative to the conventional low-flow purge method for the sampling of per- and polyfluoroalkyl substances (PFAS) in groundwater. The low-flow purge technique, though widely used, is associated with substantial investigation-derived waste (IDW) generation, requires skilled operators, and involves complex operational procedures, with the potential to generate up to 3 gallons of IDW per well. In contrast, HydraSleeves offer a more cost-effective and labor-efficient alternative, significantly reducing IDW production and operational complexity.  Field sampling was conducted across monitoring wells characterized by varying hydrostratigraphic conditions to evaluate the consistency and reliability of PFAS concentration measurements obtained using both methods. Additionally, adsorption studies were undertaken to assess the interaction of PFAS compounds with HydraSleeve materials. Initial experiments using deionized water revealed selective adsorption patterns, with longer-chain PFAS compounds exhibiting higher adsorption rates, highlighting the influence of molecular structure on adsorption dynamics. Subsequent tests with site-specific groundwater demonstrated lower adsorption rates across all PFAS compounds, suggesting that the presence of competing constituents in groundwater may mitigate PFAS adsorption onto HydraSleeve surfaces.  Statistical analysis, including linear regression, indicated strong correlations between PFAS concentration measurements obtained via HydraSleeve and low-flow methods, suggesting that variability in one method could reliably predict the other. However, further analysis using Bland-Altman plots revealed that while HydraSleeve measurements were comparable to those of the low-flow method at lower concentrations, increased variability, and potential biases were observed at higher concentrations.  In summary, the findings suggest that HydraSleeves offer substantial potential for PFAS analysis, particularly at lower concentrations.

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Cracking the PFAS Code: Fingerprinting for Source Differentiation

Dr. Jenny Zenobio, Ph.D., Environmental Engineer, Jacobs

Abstract:

Per- and polyfluoroalkyl substances (PFAS) are complex and persistent chemicals originating from diverse sources, including industrial processes, consumer products, and firefighting foams. Their widespread use and chemical stability pose significant challenges for tracing and managing PFAS in environmental systems. A primary difficulty in PFAS investigations lies in distinguishing overlapping sources, such as industrial discharges, atmospheric deposition, and legacy contamination from firefighting foams. These sources generate complex mixtures of PFAS compounds, including parent compounds, precursors, and transformation products, complicating efforts to link contamination to specific origins. Moreover, PFAS transport through groundwater, surface water, and soil can alter their profiles through processes such as sorption, desorption, and chemical or microbial transformation. These dynamics necessitate innovative fingerprinting tools to resolve source contributions and understand transport pathways.  This study advanced PFAS fingerprinting by integrating compound ratios, isomer patterns, local and regional background contributions, and advanced data-driven tools to enhance source differentiation, support site investigations, and inform remediation strategies. Targeted quantification of PFAS compounds focused on compound ratios (e.g., PFOS to PFOA) and isomer patterns (linear vs. branched) to identify source-specific profiles. A comprehensive database of PFAS fingerprints was developed, capturing variations across industrial processes, product formulations, and environmental matrices. Field samples from soil and groundwater were analyzed to validate the approach and trace PFAS evolution along transport pathways. The methodology incorporated baseline PFAS background data to refine source attribution and reduce misclassification of anthropogenic contributions. Statistical clustering and AI-driven source attribution tools were applied to associate PFAS profiles with sources and account for transformations during environmental transport.  The results demonstrated clear differentiation between PFAS sources, identifying unique chemical signatures and transformation pathways. The integration of compound-specific metrics, machine learning, and statistical clustering improved source attribution efficiency and reliability. This approach highlights the potential of advanced fingerprinting to resolve overlapping sources, trace PFAS transport, and support informed environmental management.

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