The sources, fate, transport, and remediation of perfluorinated and polyfluorinated alkyl substances (PFAS) are of considerable interest today. This broad group of compounds is proving to be present in groundwater at a wide range of sites, often comingled with other contaminants such as chlorinated solvents and petroleum hydrocarbons. One characteristic uniting these compounds is carbon to fluorine (C-F) bonds, which are among the strongest bonds in organic chemistry. This makes PFAS compounds useful for a wide range of applications, but also makes them very difficult to remediate.
The susceptibility of PFAS compounds to in-situ chemical remediation, by either oxidative or reductive approaches, is an area of active research. Some groups of PFAS compounds are readily susceptible to chemical oxidation utilizing methods that generate hydroxyl and/or sulfate radicals. However, oxidative treatment is commonly incomplete and more recalcitrant PFAS compounds, such as perfluorooctanoic acid (PFOA), are reported as reaction products that are not further degraded (e.g., Houtz and Sedlak, 2012; McKenzie et al., 2015; Santos et al., 2016). However, other researchers report degradation of PFAS compounds including PFOA under oxidizing conditions (e.g., Liu et al., 2012; Park et al., 2016), via reactions that sequentially eliminate CF2 groups and produce shorter-chained intermediate and final products. This pattern suggests that nucleophilic attack by reactive species other than hydroxyl or sulfate radicals is responsible. Mitchell et al. (2014) report PFOA is mineralized in catalyzed hydrogen peroxide reactions that primarily produce superoxide radicals and hydroperoxide, rather than hydroxyl or sulfate radicals. Superoxide and hydroperoxide are reactive oxygen species that can be formed in some oxidative treatment systems; they are strong nucleophiles and can attack a wide range of compounds that are not susceptible to oxidative degradation by hydroxyl or sulfate radicals.
Geo-Cleanse has developed and patented (U.S. Patent 8,556,537) an in-situ chemical remediation approach that effectively generates superoxide radicals. This method was initially developed to target compounds such as chloromethanes (e.g., carbon tetrachloride) and certain fluorinated compounds (e.g., Freon 113) that are not reactive towards hydroxyl radicals but are readily destroyed by superoxide. We have now completed research to extend application of our method to PFAS compounds. Our method utilizes reaction of hydrogen peroxide with manganese dioxide under neutral to slightly basic conditions to effectively produce superoxide radicals. Laboratory tests confirm that this approach effectively destroys PFOA, without measurable formation of shorter-chained PFAS compounds (Figure 1); indeed, some shorter-chained PFAS compounds (such as PFHpA) that are present at trace concentrations in reagent blanks are also destroyed (Figure 1).
Additional research is needed to further optimize our approach and improve PFAS degradation. We have had considerable success with this approach at DNAPL sites impacted with a wide range of comingled compounds, and thus our approach may also be applicable at typical fire training or other sites in which PFAS compounds are comingled with a range of other contaminants, without concern that incomplete degradation will transform PFAS compounds into more mobile or toxic intermediates.
For a PDF copy of this article and the references cited, please click here.
Please contact Will Moody for questions regarding this article.
Geo-Cleanse International, Inc.
Phone: (732) 970-6696
On May 19, 2016 – The Environmental Business Council (EBC) of the Commerce and Industry Association of New Jersey (CIANJ) honored and presented distinguished service awards to several recipients for their involvement with its inception. Since 1995, the council’s mission has been “to recognize the important economic role the environmental industry plays within the state, to demonstrate that environmental issues are also business issues, and to teach the business and regulatory communities that environmental responsibility and economic growth are fundamentally related.” Geo-Cleanse International, Inc.’s Vice President, Robert Glaser, was one of the recipients of the award (above picture of all recipients).
Robert Glaser is a Vice President at Geo-Cleanse International, Inc. and has been working with the company for the past 20 years. He has experience in both the legal and business fields, working in many areas of the industry, including in-house counsel and private practice. Mr. Glaser has a Bachelor’s of Science degree, an M.B.A., and a J.D. from Syracuse University. He is admitted to practice law in New Jersey, New York, and Arizona.
To read the article, as published in Commerce magazine,
click here or visit http://www.cianj.org/.
CIANJ hosted the 20th Anniversary Celebration of the Environmental Business Council at the Renaissance Woodbridge Hotel in Iselin, NJ.
On January 7, 2016, Dr. Dan Bryant of Geo-Cleanse International, Inc. provided a technical presentation during an internet-based online training seminar for the Interstate Technology & Regulatory Council (ITRC). The ITRC in conjunction with the U.S. EPA’s Technology Innovation and Field Services Division develops and provides a variety of training courses annually to state and federal officials, consultants, the private sector and other members of the environmental industry. This state-led coalition consists of regulators, industry experts, academia, citizen stakeholders and federal partners. The training courses are free to attend, and provide technical and regulatory information relating to environmental technologies and innovative approaches within the industry.
Topics & Presenters:
Introduction & Remedial Objectives – Alex MacDonald, CA Regional Water Quality Control Board
Conceptual Site Model (CSM) – Wilson Clayton, Trihydro Corporation
Remedial Technologies – Dr. Dan Bryant, Geo-Cleanse International, Inc.
Monitoring – Aaron Cohen, Florida DEP –
Remedy Evaluation – Tamzen Macbeth, CDM Smith
The topic of this training course was “Integrated DNAPL Site Strategy (IDSS).” Over 200 people registered for this seminar, which lasted over two hours. Dr. Bryant, a member of the ITRC team, provided a technical presentation on remediation technologies and assessing performance, coupling technologies, transitioning to other technologies, and relevant case studies. The other presentations included introduction to IDSS, remedial objectives, monitoring, conceptual site model, and remedy evaluation.
For a copy of this webinar, please click here.
For information or questions regarding this course, please contact Dan Bryant or Stephanie Turkot.
December 2013 Newsletter
Geo-Cleanse International, Inc.’s (Geo-Cleanse) Vice President, Dr. Dan Bryant, recently received U.S. Patent No. 8,556,537 for Manganese-Mediated Redox Processes for Environmental Contaminant Remediation. This is Dr. Bryant’s third remediation technology U.S. patent, the first being granted for In-Situ Chemical Oxidation-Reduction of Precipitation of Heavy Metals in Soil and Groundwater in 2003 and the second being granted for Additives for Bioremediation Oils and Methods for Using in 2008.
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Remediation of a chlorinated solvent DNAPL plume in groundwater presented several challenges due to: 1) the nature of the contaminant in the source area was heavier than water, 2) its occurrence in low permeability saprolite and fractured crystalline bedrock, and 3) an extremely shortened remediation time frame selected by the owner. After completing a Remedial Investigation/Risk Assessment/ Feasibility Study (RI/RA/FS), Rogers & Callcott Environmental was tasked with identifying an aggressive remedial approach to meet these challenges. Working with Geo-Cleanse International, a novel remedy was developed…
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Soil and groundwater contaminated by chlorinated solvents (PCE, TCE and DC) posed a potential delay to the construction of the Orlando Events Center, the future home of the Orlando Magic basketball team. Geo-Cleanse was contracted by the City of Orlando to provide turnkey in-situ chemical oxidation (ISCO) remediation at the site…
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April 2014 Newsletter
Contaminated site cleanup has commonly been accomplished by deployment of just one remediation technology. This one technology was expected to be effective and applicable over the entire life of the remediation. As our collective experience and knowledge base has expanded, this paradigm has shifted and coupling of multiple technologies in time or space has become the norm.
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