Practice Area Leader
Nathan Hagelin is the Practice Area Leader for Environmental Remediation at Wood working out of Portland, Maine. He leads research and development efforts for PFAS remediation technologies. He is a Certified Geologist and Licensed Environmental Professional working for 27 years on the remediation of contaminated industrial properties and military installations. He has prior experience as a Hydrologist with the U.S. Geological Survey Water Resource Division.
PRACTITIONER WORKSHOP #3: Lessons Learned from PFAS Site Investigations
PFAS Strategic Management Flyover: Lessons Learned from >100 DOD Sites
Since 2012, US DoD has initiated numerous measures to address releases of PFAS resulting from its use of AFFF. These response actions include the issuance of policy memorandums and guidance; revamping its fire training facilities, revising training protocols, and initiating the replacement of C8-based AFFF; execution of PA/SIâ€™s to confirm releases; conducting and sponsoring research in analytical techniques, risk assessment, and treatment technologies; and implementing mitigation measures to eliminate drinking water exposures. These activities have been supported by consultants, contractors, technology vendors, and laboratories with significant advancement in many technical areas. Much has been reported in the literature, presented at conferences, and highlighted in webinars about extraordinary sampling and analytical procedures and treatment technology challenges. However, very little comparison has been made across a portfolio of sites and less attention has been placed on strategic management lessons learned. Amec Foster Wheeler has supported PFAS response actions at over 100 DOO sites since 2013. A large multi-base data set is revealing trends in PFAS occurrence in soil, sediment, pore-water, surface water, groundwater and biota. Our experience has informed strategic management decisions that RMs will face. This presentation examines the strategic management of PFAS liabilities.
Our PFAS Work Group is a multi-disciplined team of technical experts who provide a centralized and coordinated forum that tracks regulatory activity, establishes QA/QC requirements and SOPs, trains staff, sets uniform data analysis and reporting guidelines, conducts research, participates in benchmarking forums and the development of PFAS guidance, and is responsible for the program-wide dissemination of the state of the practice. The Work Group collaborates with our larger community of over 300 professionals working on PFAS projects and maintains the collective experience of the PFAS program in a central platform. The collective experience of our program teams is fed back to the Work Group where we look for trends in the data and commonality in the program that inform our technical approach and decision making. The ultimate goal of the Work Group is to provide a centralized platform for our client decision makers to access critical, relevant and timely information.
Our ongoing analysis reveals several technical strategic management considerations that are unique to PFAS and require a different approach compared to traditional classes of contaminants for site investigations, exposure mitigation, risk communication, and liability containment. The scope and timing of PFAS investigations, interim response actions, and remediation require a well-developed strategic management program. Capturing and considering these management strategies enables RMs to avoid mistakes, mitigate unacceptable risk rapidly, and cost-effectively manage PFAS liabilities.
Sustainable Removal of Poly- and Per-Flouroalkyl Substances (PFAS) from Groundwater Using Regenerable Ion Exchange Media and On-Site Destruction of PFAS by Plasma Treatment
PFAS have emerged as high-priority and high-profile contaminants. PFAS contamination is widespread, and many communities need large scale and point of use treatment systems to treat drinking water supplies for PFAS. There is an emerging need for remediation technologies that will contain and treat PFAS at the source. However, many PFAS are highly water soluble, have low volatility, and are difficult to treat. Ion-exchange resin has shown significant promise for treating a broad suite of PFAS. Synthetic media can be regenerated on site and reused. Regenerant solutions can be distilled on site yielding a concentrated PFAS residue. PFAS in residue can be mineralized completely using a plasma reactor, resulting in a closed loop treatment system with minimal offsite waste. This presentation shares the results of treatment trials demonstrating the proven effectiveness of ion-exchange for PFAS removal, media regeneration, and PFAS destruction.
Bench-scale column testing of five commercially available IX media, 2 regenerable and 3 non-regenerable, was conducted using groundwater from an FTA contaminated with PFAS from AFFF. All five IX media were effective at removing PFAS; non-regenerable media out-performed regenerable. One of the regenerable media was successfully regenerated and retained for pilot testing at the FTA site. Identical systems were designed for both synthetic media and GAC at pilot scale to treat groundwater with total PFAS concentrations of approximately 100 Âµg/L. The IX resin, named SORBIX A3F, was regenerated and reused on site multiple times with negligible performance degradation. The regenerant residue was treated with the plasma reactor, resulting in complete destruction of PFAS.
Bench and pilot scale testing of IX resin for PFAS removal from groundwater shows promise, particularly considering the on-site regenerability and opportunity for on-site destruction in the plasma reactor. Our findings to date include: IX resin has removal capacity that exceeds GAC for many PFAS; regeneration results in complete recovery of PFAS and restored adsorption capacity; distillation of regenerate solution results in a concentrated PFAS residue; plasma destruction results in complete mineralization of PFAS residue. Full-scale IX systems for groundwater treatment have been designed for commissioning in 2017 and show an advantageous lifecycle cost and sustainability profile. The optimal IX solution depends on PFAS profile, PFAS concentration, and co-contaminants.
Ion exchange media, by virtue of their ability to both adsorb PFAS and exchange ions, offer a dual mechanism for PFAS removal that is superior to GAC with up to 8x removal for some PFAS. Regenerable IX offers a cost benefit over single use GAC, although single use, non-regenerable IX may be more efficient even without regeneration. A closed loop system with no off-site disposal of PFAS is achievable with on-site plasma destruction.