Field Mesocosm Testing of in situ PFAS Treatment Trains at the Naval Information Warfare Center Pacific

Abstract

The overall project will demonstrate an efficient method to evaluate promising in situ adsorptive amendment materials. This method will be demonstrated using several amendments: granulated activated carbon (GAC), colloidal active carbon (e.g. PlumeStop®), an ion-exchange resin (e.g. A600E, A300, etc.), biochar, and Osorb®. The list of tested sorbents may change based on new promising sorbents being detected, or as directed due to end user or NESDI Technology Development Work Group (TDWG) interest. To be selected for use in this project, the sorbent should be sufficiently mature and cost-effective that its use as an in situ amendment is reasonable (as determined during a thorough literature review of relevant sorbents [Task 1]). After completing the literature review and selecting candidate sorbents, benchtop evaluations will be conducted. This will include a series of laboratory studies to quantify adsorptive capacities for both long (e.g. PFOS, PFOA, PFHxS) and short chained (e.g. PFBA, PFHxA, PFBS) PFAS, including a faster screening method as well as a rapid small scale column test (RSSCT) evaluation. In addition, breakthough potential and bioavailability will be assessed of the compounds. These laboratory studies will indicate what amendments would be most effective for different PFAS constituents and water quality conditions, which vary from site to site. Sequential exposure to the amendments is likely necessary to achieve cleanup goals of the wide variety of PFAS constituents that occur at contaminated sites. Therefore, the second main objective is to develop a field-testing apparatus to test the efficacy of adsorptive amendments, in parallel or in sequence, at specific field sites. This field-testing apparatus will be designed to be used at a given site before in-situ remediation is undertaken. Initial mesocosm testing using this apparatus, as well as the results from the lab evaluation, will first indicate which individual or sequence of amendments would be most effective, so that this treatment can be delivered at a site. This apparatus will be demonstrated with currently-available amendments, and will also provide a framework to test future, promising amendments in this rapidly evolving field.