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Defluorination of PFAS-impacted Matrices and Detection Methodologies


OUSD (R&E) CRITICAL TECHNOLOGY AREA(S): Advanced Materials;Sustainment OBJECTIVE: This topic seeks to: (1) demonstrate the integration of new treatment technologies for Per- and Polyfluoroalkyl substances (PFAS) impacted matrices to enable complete on-site disposal/management of PFAS-containing wastewater and solid wastes; (2) demonstrate and validate a rapid field portable solution for PFAS detection in wastewater and solid waste; and (3) develop a standardized analytical approach to properly quantify microplastics in drinking water, wastewater, and solid matrices. DESCRIPTION: The Department of the Navy (DON) installations vary significantly in their missions, industrial operations, and functions but common to all of them is the generation of wastewater streams. Ensuring proper treatment of these wastewater streams is critical to comply with the installations’ permits and secure the availability of potable and non-potable water supplies to sustain missions. Currently, treatment of wastewater streams impacted by contaminants of emerging concern (CEC), such as Per- and Polyfluoroalkyl Substances (PFAS) and potential microplastics, present DON installations with an ongoing challenge. With present interest in replacing aqueous film forming foam (AFFF) with fluorine-free foam (F3) alternatives, there is a need to dispose of AFFF stockpiles and to treat wastewater streams derived from cleaning fixed (hangars) and mobile (firetrucks) fire suppression systems to less than 70 parts per trillion (ppt.) before discharging into sewers [Refs 1-4]. Often these wastewater streams are treated via conventional methods that involve granular activated carbon (GAC) and ion-exchange (IX) resin—thus producing PFAS-impacted waste that requires off-site disposal. In addition, wastewater treatment plants (WWTP) owned by DON installations may produce PFAS-impacted sewage-sludge and biosolids as a result of processing PFAS-impacted wastewaters from households using products containing PFAS (e.g., cleaning/degreasing agents; water-resistant, stain resistant, and fire-resistant fabrics; non-sticky cookware; personal-care products, etc.). Treated sewage-sludge or biosolids are often applied to crops and fields to supply plant organic nutrients without the use of synthetic fertilizer. If biosolids are PFAS-impacted, they have the potential to become a direct source of PFAS release into the soil and groundwater. In a similar manner, microplastics may end up in soil and groundwater due to the application of treated sewage-sludge or biosolids derived from the processing of domestic wastewater streams containing personal care products (e.g., toiletries and cosmetics) and washing of synthetic textiles [Refs 5-6]. As such, there is a need for PFAS destruction technologies for wastewater and solid waste (e.g., PFAS-impacted wastewater, PFAS-laden GAC, PFAS-laden IX-resin, and PFAS-impacted biosolids) [Refs 6-11]. Prototype technologies must demonstrate the ability to mineralize total PFAS to benign products without producing toxic waste and/or by-products. Particular emphasis must be placed in the mineralization of the six PFAS compounds—perfluorooctanoic acid (PFOA), perfluorooctane sulfonic acid (PFOS), perfluorononanoic acid (PFNA), hexafluoropropylene oxide dimer acid (HFPO-DA, commonly known as GenX Chemicals), perfluorohexane sulfonic acid (PFHxS), and perfluorobutane sulfonic acid (PFBS)—for which the U.S. Environmental Protection Agency (USEPA) is set to establish maximum contaminant levels (MCLs) under the National Primary Drinking Water Regulation (NPDWR). Conversely, it is also critical to have a rapid field portable solution for PFAS detection in wastewater, solid waste and treated PFAS-impacted sources (i.e., wastewater and solid waste). The rapid field portable solution for PFAS detection must be capable of reading PFAS concentration levels for PFOA and PFOS as low as 4 ppt. whereas PFNA, GenX chemicals, PFHxS, and PFBS must attained a combined Hazard Index of 1 (unit less) as proposed by the USEPA [Ref 12]. The latter implies that individual concentrations for these 4 PFAS compounds may be as low as single digit ppt. to double-digit ppt. In the case of microplastics, for which there is no USEPA health advisory and/or proposed federal regulations but are set to become the next major environmental concern in drinking water, wastewater, and solid waste, there is a need to first develop a standardized analytical approach to properly quantify microplastics in drinking water, wastewater, and solid matrices. Once the standardized analytical approach is reliable and consistent across testing, a strategy must be developed to quantify sources of microplastics entering WWTPs and their effectiveness in removing microplastics. If WWTPs are not capable of addressing the removal of microplastics, an explanation must be provided and potential prototype treatment solutions must be identified. PHASE I: Determine the feasibility of utilizing an emerging PFAS destruction technology to process PFAS-impacted matrices (i.e., wastewater and solid waste) of relevance to DON stakeholders. Some PFAS-impacted matrices of interest include (i) spent granulated activated carbon (GAC), (ii) spent powdered activated carbon (PAC), (iii) spent ion exchange resins (IXR), and/or (iv) complex PFAS-impacted wastewaters (e.g., fire truck rinse out byproducts). Ensure that matrices must be treated using lab-scale systems. Evaluate treatment success through measuring PFAS destruction levels, assessing the fate of fluorine after treatment, and assessing the fate of co-contaminants and matrix constituents (e.g., the filter material) during treatment. For the rapid field portable solution for PFAS detection, the solution must be practical and not cumbersome as it will be conducted by personnel with and without engineering or scientific backgrounds. In addition, the rapid field portable solution must provide reliable PFAS concentration readings in the presence of other contaminants that may be present in real-life samples provided by DON stakeholders. PFAS detection and concentration levels by the field portable solution must be double-checked by PFAS analytical methods such as USAEPA Methods 533, 537.1, and/or 1633. Information on the capabilities of the solution as well as its shortcomings must be explained. This will provide information as to what areas still need development and how realistic it is to bring a solution into Phase II. In the case of the standardized analytical approach to properly quantify microplastics in drinking water, wastewater and solid matrices, define, develop, and identify analytical tools that are both microplastic selective (i.e., specific only for some types of microplastics) and inclusive (i.e., able to detect all types of microplastics with adequate recoveries). Ensure that the microplastics comprise a variety of sizes, colors, and chemical compositions to include fibers, fragments, pellets, flakes, sheets, or foams. Discuss the advantages and disadvantages based on analytical tools in a summary of results and provide the best approach for a path forward to improve analysis of microplastics in the aforementioned matrices. At the end of Phase I, include in the final deliverables information substantiated by results and a Phase II plan that includes a concept for the Phase II field test and demonstration. PHASE II: Demonstrate the PFAS destruction technology at a DON installation by treating one of the PFAS-impacted matrices identified in Phase I. Based on the results of Phase I, use the demonstration to validate the PFAS destruction performance at a realistic field site, processing a real waste stream. Use demonstration results to assess the feasibility of integrating the proposed technology into longer-term waste management projects. Demonstrate and validate the rapid field portable solution for PFAS detection at a DON installation that has different sources of PFAS-impacted matrices. Use the equipment in real-time in the field test and demonstration and have it validated with support from DON personnel. Field testing readings must be supported by PFAS analytical testing as indicated in Phase I. Assess ease of use and portability of solution by personnel in the field. Develop and test a step-by-step protocol of the microplastics standardized analytical approach to standardize collection, extraction, quantification, and identification of microplastics in drinking water, wastewater, and solid matrices to improve reliability, consistency and comparability across testing. PHASE III DUAL USE APPLICATIONS: Integrate the Phase II-demonstrated technology with full-scale waste disposal and compliance-related PFAS management efforts and coordinate with the Air Force Civil Engineer Center (AFCEC) and the U.S. Army Corps of Engineers (USACE) to transition the technology to tackle broader (not just DON) Department of Defense (DoD)-wide challenges around PFAS-impacted sites. Address non-DoD Governmental and commercial needs including remediation of PFAS-impacted airport and fire training facilities, industrial wastewater treatment, and waste disposal. Work with USEPA regulators to qualify Phase II rapid field portable PFAS detection and microplastics standardized analytical approach in order to mainstream them. Use rapid field portable PFAS detection and microplastics standardized analysis to quantify sources entering WWTPs and their effectiveness in removing them. If WWTPs are not capable of addressing the removal of PFAS and/or microplastics, provide an explanation and identify potential prototype treatment solutions. REFERENCES: 1. ASD (Sustainment) Policy Memo: “Per- and Polyfluoroalkyl Substances Sampling of Department of Defense Drinking Water Systems.” 2 Mar, 2020. 1. ASD (Sustainment) Policy Memo: “Monitoring of PFAS Sampling for Installations with Non-Department of Defense Drinking Water Systems.” 23 Jul, 2020. 2. ASD (Energy, Installations, and Environment) Policy Memo: “Response and Reporting of Aqueous Film Forming Foam Usage, and Accidental Releases/Spills on Military Installations and National Guard Facilities.” 7 Apr, 2022. 3. ASD (Sustainment) Policy Memo: “Temporary Prohibition on Incineration of Materials Containing Per- and Polyfluoroalkyl Substances (PFAS).” 26 Apr, 2022. 4. USEPA Microplastic Research: 5. “Statewide Microplastics Strategy, Understanding and Addressing Impacts to Protect Coastal and Ocean Health.” California Ocean Protection Council, February 2022. 6. Hao, S., Choi, Y.J., Wu, B., Higgins, C.P., Deeb, R. and Strathmann, T.J. “Hydrothermal alkaline treatment for destruction of per-and polyfluoroalkyl substances in aqueous film-forming foam.” Environmental Science & Technology, 55(5), 2021, pp.3283-3295. 7. Wu, B., Hao, S., Choi, Y., Higgins, C.P., Deeb, R. and Strathmann, T.J. “Rapid destruction and defluorination of perfluorooctanesulfonate by alkaline hydrothermal reaction.” Environmental Science & Technology Letters, 6(10), 2019, pp.630-636. 8. Pinkard, B.R. “Aqueous Film-Forming Foam Treatment under Alkaline Hydrothermal Conditions.” Journal of Environmental Engineering, 2022, 148(2), p.05021007. 9. Pinkard, B.R., Shetty, S., Stritzinger, D., Bellona, C. and Novosselov, I.V. “Destruction of perfluorooctanesulfonate (PFOS) in a batch supercritical water oxidation reactor.” Chemosphere, 279, 2021, p.130834. 10. Krause, M.J., Thoma, E., Sahle-Damesessie, E., Crone, B., Whitehill, A., Shields, E. and Gullett, B. "Supercritical Water Oxidation as an Innovative Technology for PFAS Destruction." Journal of Environmental Engineering, 148(2), 2022, p.05021006. 11. “Proposed PFAS: National Primary Drinking Water Regulation (Public Webinar Brief) March 29, 2023.” US Environmental Protection Agency, Office of Water, Washington, DC. KEYWORDS: Per- and polyfluoroalkyl substance; PFAS; PFAS destruction; Perfluorooctane sulfonic acid; PFOS; Perfluorooctanoic acid; PFOA; Aqueous film-forming foam; AFFF; Environmental Compliance; Environmental Restoration; AFFF-impacted media; Granular Activated Carbon; GAC; Ion Exchange Resin; Solid-derived Wastes; Rapid Field PFAS Detection; Portable PFAS Detection; PFAS Detection in Real-Time; Microplastics; Microfibers
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