Comparative study of per- and polyfluoroalkyl substances (PFAS) removal from landfill leachate

Landfill leachate is one of the major point sources of per- and polyfluoroalkyl substances (PFAS) pollution. In this study, powdered activated carbon (PAC), granular activated carbon (GAC), anion exchange resin (AIX), nanofiltration (NF), ozonation, and foam fractionation were tested for treatment of the same leachate. These methods were compared in terms of PFAS removal efficiencies and treatment cost. More than 75% removal of long-chain PFAS (6-9 CF2) could be achieved with all the studied methods, though with high resource consumption. It was demonstrated that PFAS breakthrough was up to 27 times faster when the leachate was treated with GAC and AIX compared to groundwater treatment. Nanofiltration was the only method which could be practically applied for removal of PFAS with the shortest fluorinated carbon chain (3-4 CF2). Foam fractionation and AIX offered the most economical treatment, with an estimated cost of < 1 €/m3 for PFOS and PFOA reduction to ≥90%. The cost of treatment was shown to increase exponentially if the goal of > 60% ΣPFAS11 removal was applied. It was also discussed that composite parameters that include expected toxicity of different PFAS, such as ΣPFOAeq, should be used to obtain a cost-efficient reduction of PFAS-induced water toxicity. Per- and polyfluoroalkyl substances (PFAS) are a group of highly persistent and potentially chronically toxic substances, which are widespread in the environment. Landfill leachate is one of the main point sources of PFAS pollution; it also has one of the highest concentrations compared to other water streams. The research on PFAS removal from leachate is, however, highly limited. This study not only compares various methods for leachate treatment in terms of removal efficiencies but also provides a cost estimation that is crucial for selecting the most cost-efficient treatment method.