In this study, we investigated the potential of biochar filters as a replacement or complement for sand filters for removal of per- and polyfluoroalkyl substances from wastewater in onsite sewage facilities. In a 22-weeks experiment, concentrations, removal and adsorption of nine perfluoroalkyl carboxylates (PFCAs; C3- 11) and three perfluoroalkane sulfonates (PFSAs; C4, 6, 8) and one perfluorooctanesulfonamide (FOSA; C8) were investigated in four treatments: biochar with active, biochar with inactive biofilm, biochar without biofilm and sand with active biofilm. We found that biochar with no biofilm achieved higher removal efficiency (90-99%) and the adsorption capacity (73 -168 ng g-1 ) for C7-C11 PFCAs, C6, C8 PFSAs and FOSA, than the other biochar and sand treatments. For all biochar treatments, shorter-chain PFASs were more resistant to removal than longer-chain PFASs.
For more results and findings, click on this link to access the full article