Evaluation of PFAS treatment technology: Alkaline ozonation

Some of the same unique physical and chemical properties that make per‐ and polyfluoroalkyl substances (PFAS) desirable for a wide range of commercial applications render them recalcitrant to many liquid treatment technologies. As developments in PFAS‐related toxicological studies increasingly suggest potential adverse human health effects, our industry has made great progress in the past several years on concentrating PFAS into small volume waste streams via adsorption and separation mechanisms. Coupled with residual PFAS‐containing commercial products that are being phased out, management of these concentrated waste streams presents an urgent need for the development and validation of destructive treatment technologies. Here, we field‐validate supercritical water oxidation to treat a concentrated waste stream of 12 perfluoroalkyl acids (PFAAs) with liquid and gaseous analysis, adhering to the recent Other Test Method 45 for stack emission sampling from the United States Environmental Protection Agency (USEPA) and USEPA Method 537.1, with quality control and quality assurance protocols from the Department of Defense/Department of Energy Quality Systems Manual 5.3. Results generated suggest greater than 99.999% destruction and removal efficiency of these 12 PFAAs after two ∼120‐min continuous flow trials, with an overall defluorination percentage of approximately 62.6%.

Section: Resultsmentioning

confidence: 99%

Validation of supercritical water oxidation to destroy perfluoroalkyl acids

McDonough

Kirby

Bellona

et al. 2022

“…Due to the pervasive nature of PFAS in the environment, accepted sampling procedures were followed with respect to field/laboratory equipment, clothing, personal protective equipment, and sample bottles to mitigate the introduction of background contaminants into the groundwater sample. The sampling protocols and best practices were based on the guidance provided by the ITRC (2020) PFAS team and previous procedures (Thomas et al, 2020).…”

Section: Methodsmentioning

confidence: 99%

Early breakthrough of short‐chain perfluoroalkyl substances in adsorptive media treatment

Crawford

Thomas²,

Taylor³

et al. 2022

Self Cite

Activated carbon (AC) adsorption continues to be the default technology to remove low levels of per-and polyfluoroalkyl substances (PFAS) from water, despite varying reports of the relatively early breakthrough of short-chain PFAS and high operating costs. Ion-exchange processes using regenerable and single-use media have been emerging as practical alternatives which may provide improved treatment and system performance. However, long-term performance with respect to the more difficult to remove short-chain PFAS such as perfluorobutanoic acid and perfluorobutanesulfonic acid is less often reported. Treatability testing on PFAS-impacted groundwater using batch-equilibration reactors and column flushing apparatus experiments was implemented to compare removal efficiency, breakthrough, and longevity of various media, specifically for shorter chain PFAS. Adsorbents tested included surface-modified natural media, synthetic resin, and AC. Results indicated that both surface modified natural media and AC achieved >99 percent removal of all detected PFAS after approximately 10,300-bed volumes (16 weeks) of column flushing, and outperformed the selected resin under site-specific conditions.In addition, unconventional breakthrough patterns (i.e., the breakthrough of longer chain PFAS before shorter chain PFAS) were observed for some PFAS including perfluoropentanoic acid, perfluorohexanesulfonic acid, and perfluorooctanesulfonic acid. The results of this study suggested that, while the generally accepted breakthrough patterns for PFAS can be reasonably anticipated, column flushing studies were preferred over batch sorption tests to reveal site-specific or mediaspecific breakthrough patterns that can impact overall performance. | INTRODUCTIONActivated carbon (AC) adsorption continues to be the default adsorption technology to remove low levels of poly-and perfluoroalkyl substances (PFAS) from water, despite varying reports of the relatively early breakthrough of short-chain PFAS and variable operating costs (Belkouteb et al., 2020;Speth et al., 2019). The adequacy of adsorption technologies to date has been judged primarily on the removal of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) since these molecules were among the earliest to be detected in drinking water supplies and are being regulated at state levels and/or to municipal objectives. Technology performance with respect to the more difficult to remove short-chain PFAS (i.e., early breakthrough), such as perfluorobutanoic acid (PFBA) and perfluorobutanesulfonic acid (PFBS), has been gaining recognition (Westreich et al., 2018). It is anticipated that the regulated list of PFAS will continue to expand, and the

“…Another study also mentioned in the EPA's drinking water TDB on the effectiveness of ozonation used alkaline conditions for the removal of PFAS. This study by Thomas et al (2020) tested the effects of alkalinity and ozonation on the removal of PFAS from PFAS-contaminated groundwater. The results showed this treatment to be effective in reducing the concentration of different PFAS including PFOA, PFNA, the 6:2 fluorotelomer sulfonate (6:2 FtS), and up to 97% reduction of PFOS.…”

Section: Ozone Including the Use Of Hydrogen Peroxidementioning

confidence: 99%

EPA's detection methods, the drinking water treatability database, and innovative technologies for PFAS remediation

Kuzniewski¹

2022

Per-and polyfluoroalkyl substances (PFAS) are a large group of highly fluorinated, aliphatic chemicals detected throughout the environment, including in human serum.Several regulatory milestones have been achieved in the United States for these environmentally toxic chemicals linked to health problems in humans, the latest one being the US Environmental Protection Agency's (EPA's) PFAS Strategic Roadmap necessitating detection and remediation of PFAS. This article, in addition to briefly discussing these regulatory milestones, evaluates the EPA's detection methods for PFAS including EPA Methods 533, 537.1, and 8327 and other methods currently under development such as the total organic fluorine (TOF) and total organic precursor (TOP) methods. The article also mentions the methods used by other federal agencies for PFAS quantitation. The EPA's drinking water treatability database (TDB) is also described along with the advantages and challenges of the effective treatment methods for PFAS. Most of these treatment methods in the EPA's drinking water TDB face the challenge of disposing wastes containing PFAS, an issue not faced by innovative technologies, and some of these innovative technologies are also discussed. This article will help to understand the current status on the detection and remediation technologies for PFAS treatment in soil and water. It is imperative to have these technologies ready to assist with the remediation objectives in the PFAS Strategic Roadmap.