Topic Area: 4c. Activated Carbon-Based PFAS Treatment Technologies

Formatted Title:

Treatability Evaluation of Pretreatment and PFAS Removal via Rapid Small-Scale Column Testing (RSSCT) in Surface Water

Background/Objectives:

A bench-scale treatability study program was executed using surface water collected from an Air Force Base (AFB) installation to evaluate adsorption-based treatment of per- and polyfluoroalkyl substances (PFAS), as well as pretreatment strategies to optimize sorbent performance. The objective of this study included the evaluation of sorbent media tailored for PFAS treatment based on adsorption capacities under equilibrium conditions and their relative performance (specific throughput) under flow-through conditions to meet Regional Screening Levels (RSLs) and EPA Maximum Contaminant Levels (MCLs) for PFAS. The study also had the objective to evaluate the quality of the surface water and the necessary pretreatment strategies to reduce total suspended solids (TSS) and iron and manganese, among other constituents, to optimize sorbent media performance.

Approach/Activities:

Bench-scale treatability activities consisted of a sequential approach starting with a baseline characterization of the surface water to determine the pretreatment steps needed. Pretreatment strategies were considered to meet the water quality criteria suggested by the PFAS sorbent vendors which provided threshold limits for oil and grease (non-detection), chlorine (non-detection), TSS (1 mg/L) and iron and manganese (0.1 mg/L each). Chlorine and oil and grease were below detection level in the surface samples collected. TSS removal was evaluated via centrifugation and filtration, whereas removal of iron and manganese was evaluated via oxidation (aeration, permanganate, and hypochlorite approaches) and catalytic media treatment (quartz sand, Greensand+, and pyrolusite media). PFAS treatment by granular activated carbon, two single-use ion exchange resins, a surface-modified organoclay, and a cyclodextrin polymer, was evaluated via batch isotherms (to determine adsorption capacity) and RSSCTs (to determine breakthrough curves).

Daniel Stockard

Affiliation

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(Group 1, Poster Board #17) Treatability Evaluation of Pretreatment and PFAS Removal via Rapid Small-Scale Column Testing (RSSCT) in Surface Water