Plasma Based Treatment Processes for PFAS Investigation Derived Waste

Dr. Thomas Holsen | Clarkson University

ER18-1624

Objective

This project has two objectives: 1) for aqueous investigation derived waste (IDW) investigate the use of an integrated sorption/plasma reactor (hybrid reactor) to remove per- and polyfluoroalkyl substances (PFASs) onto ion exchange resin (IX) and then desorb and destroy the removed PFASs using a previously developed and validated plasma technique. This process will regenerate the sorbent material in place and allow it to be used repeatedly and 2) for soil cuttings investigate soil washing followed by treatment of the soil washing solution in the previously developed plasma reactor to destroy the desorbed PFASs. The research leverages several on-going projects.

If successful, the combination of systems will permit unrestricted disposal and/or discharge of IDW onsite. Information from this study and ongoing PFAS research efforts will serve as a foundation for the development of fully developed field-scale systems for the treatment of PFAS-impacted IDW. These systems would be mobile and easily deployable, minimizing the spatial footprint and mobilization time and effort and allow cost effective treatment compared to current disposal methods.

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Technical Approach

This work will leverage several existing projects to specifically target both aqueous and soil IDW at the bench-scale. IDW will be obtained through the existing contacts and sent to Clarkson University at the start of the project. Since removal of PFASs from the aqueous IDW using direct plasma treatment will be evaluated as part of an ongoing Air Force Civil Engineer Center (AFCEC) project, this project will evaluate a new hybrid sorption plasma reactor that may be particularly effective at removing and then destroying PFAS in low concentration IDW solutions. The reactor will employ a sorbent (IX resin) to remove PFASs from solution. After adequate amounts of PFASs are sorbed, the feed stream will be turned off and a desorption solution added to the reactor to initiate PFASs desorption. Plasma will then be used to treat the desorbed PFASs. As destruction continues, additional PFASs will be desorbed and destruction will continue. The regenerated sorbent will then be re-exposed to PFASs to determine how many cycles it can be used for.

Removal of PFASs from soil IDW using soil washing will also be evaluated. A variety of solutions including water alone, water plus MeOH and water plus methanol (MeOH) and salt will be evaluated. If necessary the addition of non-PFAS surfactants will also be investigated. Destruction of desorbed PFASs in these soil washing solutions using the enhanced contact electrical discharge plasma reactor will not be evaluated as part of this project as that work is included in currently funded projects.

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Benefits

Cost-effective and efficient technologies for treatment of IDW from PFAS investigations of Department of Defense (DoD) sites will improve Remedial Project Managers (RPMs) ability to manage these sites. On-site options that treat the waste and destroy the PFASs will result in significant cost reductions compared to off-site disposal and incineration. (Anticipated Completion - June 2019)

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Points of Contact

Principal Investigator

Dr. Thomas Holsen

Clarkson University

Phone: 315-268-3851

Program Manager

Environmental Restoration

SERDP and ESTCP

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