Portal de Periódicos da CAPES

Aerobic Biotransformation and Fate of N -Ethyl Perfluorooctane Sulfonamidoethanol ( N -EtFOSE) in Activated Sludge

2008; American Chemical Society; Volume: 42; Issue: 8 Linguagem: Inglês

10.1021/es702866c

1520-5851

Kurt R. Rhoads, Elisabeth M.‐L. Janssen, Richard G. Luthy, Craig S. Criddle,

Carbon Dioxide Capture Technologies

Processes affecting the fate of perfluorinated organics are of increasing concern due to the global dispersal, persistence, and bioaccumulation of these contaminants. The volatile compound N-ethyl perfluorooctane sulfonamidoethanol (N-EtFOSE) and its phosphate esters have been used in protective surface coatings. In this report, we describe the fate of N-EtFOSE in aerobic batch assays. These assays were performed using undiluted activated sludge in serum bottles that were sealed to prevent the escape of N-EtFOSE and volatile transformation products. Separate assays were performed with N-EtFOSE and reported transformation products. N-EtFOSE degraded to N-ethyl perfluorooctane sulfonamido acetic acid (N-EtFOSAA) with an observed first-order rate of 0.99 ± 0.08 day−1 and a pseudosecond order rate of 0.26 ± 0.02 L/mg VSS day−1. N-EtFOSAA underwent further transformation at a slower rate (0.093 ± 0.012 day−1) to N-ethylperfluorooctane sulfonamide (N-EtFOSA). N-EtFOSA then transformed to perfluorooctane sulfonamide (FOSA). FOSA transformed to perfluorooctane sulfinate (PFOSI), and PFOSI transformed to perfluorooctane sulfonate (PFOS). Perfluorooctanoic acid (PFOA) was not detected as a transformation product of any compound. Using the measured rate of N-EtFOSE biotransformation and literature values for phase partitioning and mass transfer in aeration basins, we modeled the fate of N-EtFOSE in a typical activated sludge aeration basin open to the atmosphere. The model predicts that 76% of the N-EtFOSE is stripped into the atmosphere, 5% sorbs to waste solids, 13% undergoes transformation to N-EtFOSAA, and 6% is discharged in the wastewater effluent.