Date of Award

Fall 8-15-2025

Level of Access Assigned by Author

Open-Access Thesis

Degree Name

Master of Science (MS)

Department

Civil Engineering

First Committee Advisor

Onur Apul

Second Committee Member

Jean D. MacRae

Third Committee Member

Arjun Venkatesan

Abstract

A nationwide surge of granular activated carbon (GAC) use is expected in the municipal water treatment facilities in the United States, because of the recent national primary drinking water regulation of per- and polyfluoroalkyl substances (PFAS). Once used, PFAS-laden GAC requires careful management to avoid potential re-contamination. For this, understanding the release mechanisms of PFAS from spent GAC in landfill-relevant conditions is timely and critical. This study presents a mechanistic evaluation of PFAS release from spent GAC through standardized leaching procedures. Specifically, the effects of physicochemical properties of four commercial GACs in terms of perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) release using the toxicity characteristic leaching procedure (TCLP 1311), the Australian standard leaching procedure (ASLP 2019), and the multiple extraction procedure (MEP 1320) are presented. Our findings indicate that the oxygen content of GAC significantly increases PFAS leaching, making it the most influential factor among those evaluated. Additionally, higher pH levels, common in aged and stabilized landfills, further enhance leaching rates. Also, PFOA, leaches more readily than PFOS, across all tested conditions. These results highlight the need for a thorough understanding of the physicochemical properties of GAC and the environmental conditions affecting PFAS release to inform strategies for managing spent GAC and mitigating the risk of recontamination.

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