Regenerable Resin Sorbent Technologies with Regenerant Solution Recycling for Sustainable Treatment of Per- and Polyfluoroalkyl Substances (PFASs)

Timothy Strathmann | Colorado School of Mines



The overall goal of this project is to develop a regenerable resin sorbent technology that is effective for treating the full diversity of per- and polyfluoroalkyl substances (PFASs) present in groundwater contaminated by aqueous film-forming foam (AFFF). Specifically, researchers hypothesize that a combination of commercially available regenerable resin sorbents (ion exchange + non-ionic resins) can be applied to remove the full range of PFASs (including emerging classes of PFASs recently identified through the application of high resolution mass spectrometry methods) and co-contaminants in AFFF-impacted groundwater, and that the sorbents can be regenerated using an innovative approach where destruction of the PFASs can be accomplished efficiently within the waste regenerant concentrates. The preliminary data show successful removal of all PFASs identified in an AFFF (by LC-QToF-MS screening of ~1500 PFAS structures) following sequential treatment with an anion exchange resin plus a non-ionic resin, indicating that the project framework holds exceptional promise for mitigating current and future liabilities associated with AFFF-impacted groundwater sources at DoD facilities. 

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Technical Approach

Experiments and modeling will be combined to test the hypotheses outlined above and meet the project objective of delivering a cost-effective and sustainable remedial technology capable of addressing the full range of PFASs present in AFFF-impacted groundwater. The project team will apply a unique process systems engineering framework that integrates life cycle cost analysis (LCCA) and life cycle assessment (LCA) modeling throughout the work to guide experimental design decisions and quantify the impacts of experimental results on the overall treatment train costs and life cycle environmental impacts. Experimental work will be aimed at (i) identifying critical resin characteristics that control both adsorption of different classes of PFASs and regenerability, (ii) identifying combinations and sequences of regenerable resins capable of successfully removing the full range of PFASs identified in AFFF, (iii) assessing the influence of co-contaminants and co-contaminant pretreatment steps on resin adsorption of PFASs, (iv) identifying mixtures of salt brines and alcohol co-solvents needed to desorb PFASs and regenerate resins, (v) assessing potential for co-solvent recovery from waste regenerant concentrates and reuse, and (vi) evaluating the effectiveness of electrochemical and photochemical treatment processes for destroying PFASs in the waste regenerant solutions. Application of the process systems engineering approach will also enable systems-level quantification of the economic and life cycle environmental impact tradeoffs associated with individual process design decisions like the selection of resins, the resin regeneration protocol, and the strategy for managing and/or recycling the regenerant waste concentrate stream. 

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Successful completion of this research will provide the DoD with a cost-effective and environmentally sustainable treatment technology that can be applied to improve management of AFFF impacted sites. The process systems engineering models that will be established with integrated LCCA and LCA will also provide for site-specific design modifications tailored to the composition of PFASs, co-contaminants, and natural groundwater constituents at the site. This will serve the DoD by providing a viable path for mitigating significant liabilities and accelerating site closure plans. (Anticipated Project Completion - 2021)

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Points of Contact

Principal Investigator

Timothy Strathmann

Colorado School of Mines

Phone: 303-384-2226

Program Manager

Environmental Restoration