Treatment of PFAS-containing landfill leachate using an enhanced contact plasma reactor

A bench-scale plasma reactor was used to degrade poly- and perfluoroalkyl substances (PFAS) in landfill leachate samples obtained from three different locations. In the leachate samples before treatment, five long-chain, six short-chain perfluoroalkyl acids (PFAAs) and eight PFAA precursors were detected in a wide concentration range (similar to 10(2) to 10(5) ng/L; total oxidizable precursors (TOP) similar to 10(6) ng/L). The concentration of perfluorooctane sulfonate (PFOS) plus perfluorooctanoic acid (PFOA) ranged between 2000 and 3000 ng/L. Plasma-based water treatment of 500 mL samples resulted in faster removal rates for longer-chain than shorter chain length PFAAs. Both PFOS and PFOA were removed to below United States Environmental Protection Agency's (USEPA's) health advisory concentration level (HAL) concentrations (<70 ng/L) in 10-75 min; 90% PFOA and PFOS removal was achieved in 10 min. Long-chain and short-chain PFAAs were removed by >99.9% and 10-99.9%, respectively. The removal rate constant (k(PFOA+PFOS)) for combined PFOA and PFOS ranged between 0.20 and 0.34 min(-1). Overall, 60 +/- 2% of the TOP concentration and 34 +/- 2% of the TOC were removed. No effect of non-PFAS co-contaminants (e.g., total initial organic carbon concentration similar to 2000 mg/L) on the degradation efficiency was observed. Short-chain PFAA removal efficacy was enhanced by adding a cationic surfactant (cetrimonium bromide). Overall, the results indicate that plasma-based technology may be a viable technology for the treatment of PFAS-contaminated landfill leachates.

Automated summary

Using a bench-scale plasma reactor, PFAS in landfill leachate samples were effectively degraded, with PFOS and PFOA removed below USEPA's health advisory concentration levels in a short time. Long-chain PFAAs were removed by over 99.9% and short-chain PFAAs by 10-99.9%, demonstrating high removal efficiency.