ACH-based Water Treatment Residuals for Mitigation of Perfluoroalkyl Acids Leaching from Biosolids

Full title: Potential for ACH-based Water Treatment Residuals for Mitigation of Perfluoroalkyl Acids Leaching from Biosolids

Presented on April 27, 2022, by Elijah Openiyi - Purdue University - 2022 Emerging Contaminants in the Environment Conference (ECEC22)

Aluminum chlorohydrate (ACH) is used by treatment plants to improve finished water quality. The Al-based residuals after water treatment (WTRs) have been found to be a good sorptive medium for phosphates. We hypothesized WTRs may have a high potential to sorb perfluoroalkyl acids (PFAAs). We evaluated the affinity of ACH-based WTRs (less than 2 mm) to sorb seven PFAAs (PFBS, PFHxS, PFOS, PFHxA, PFHpA, PFOA and PFNA) from porewater generated from two biosolids. PFAA sorption (24-h) and desorption (48-h) were conducted using 0.005 to 0.5g ACH-WTRs equilibrated with 9-mL of porewater amended with PFAAs to increase initial concentrations. Adsorption increased with increasing ACH-WTR concentrations and increasing PFAA chain length. Desorption decreased with increasing ACH-WTR concentrations and generally increasing PFAA chain length. Although trends were similar for both porewaters, one porewater resulted in higher percent sorption and lower percent desorption for most PFAAs. Electrolyte composition and DOM concentrations are being measured and may offer insight into the differences observed between the porewaters. The results support that applying ACH-WTR to biosolid-amended fields may be a good mitigation approach for reducing PFAS leaching.

Download slides: http://hdl.handle.net/2142/114136