Date of Award

8-2025

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Environmental Engineering and Earth Science

Committee Chair/Advisor

Kevin Finneran

Committee Member

Sudeep Popat

Committee Member

Nicole Martinez

Abstract

Perfluoroalkyl substances (PFAS) and chlorinated ethenes are frequently co-detected at contaminated sites, yet little is know about how PFAS influence the performance of in-situ reductive dechlorination processes, particularly in systems amended with activated carbon.

The objective of this research was to study the impact of PFAS on in-situ reductive dechlorination of chlorinated ethenes using activated carbon. This research aims to characterize the sorption behavior of PCE and TCE (and its daughter products) and PFAS (PFOS and PFOA) onto activated carbon, and to assess how this sorption influences PCE and TCE removal from contaminated media in the presence of activated carbon.

This study utilized activated carbon suspensions and experimental batch studies in contaminated aquifer and SDC-9 culture to determine the interaction between chlorinated ethenes, PFAS, and activated carbon, with the goal of advancing the understanding and application of in-situ activated carbon for remediation of co-mingled plumes.

Reductive dechlorination was most effective in aquifer treatments using 1.0 mg/g colloidal activated carbon (CAC) with emulsified vegetable oil (EVO) and in SDC-9 treatments using granular activated carbon (GAC) pre-sorbed with PFAS and amended with a mixture of lactate, acetate, and formate. Results indicate that excess surfactants and smaller activated carbon particles (PAC or CAC) may inhibit complete dechlorination, particularly in the presence of PFAS. The use of mixed electron donors outperformed lactate alone, and larger activated carbon particle sizes (GAC) were more conductive to full dechlorination.

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