Granular Activated Carbon for PFAS Removal in Municipal Wastewater: A Rapid Small-Scale Column Test Study

Abstract

This study evaluated the effectiveness and economic viability of granular activated carbon (GAC) as a final treatment step for PFAS removal in municipal wastewater treatment. Rapid small-scale column tests (RSSCTs) were performed on postdisinfected wastewater effluents collected from two full-scale facilities spiked with ∼200 ng/L of PFOA, PFOS, PFHxA, and PFHxS to investigate their breakthrough for two types of GAC and a commercial biochar. Results demonstrated that the biochar was ineffective for these PFAS. PFHxA was the least well-adsorbed, with the other three PFAS breaking through after longer service times in the range of 1 order of magnitude. A cost estimate was evaluated for a municipal wastewater treatment facility implementing a postdisinfection GAC treatment system for 50% removal of PFOA and PFOS with an initial concentration of 200 ng/L. The 30-year amortized capital and O&M costs were estimated to be between $900 and $1400 USD per million gallons of water treated. For perspective, this represents a 60% increase to the estimated current costs for the City of Toronto to handle its wastewater. Thus, treatment strategies focusing on the control of upstream PFAS emission or PFAS removal from concentrated streams within the plant may be a more feasible method for PFAS control.