Influence of Dissolved Oxygen on the Degradation and Transformation of NEtFOSE within a Secondary Wastewater Treatment Bioreactor System

—Alexis Eaton (Mentor: Paula Mouser)
Alexis Eaton

With funding from a Summer Undergraduate Research Fellowship (SURF), I studied how dissolved oxygen levels influence the degradation and transformation of N-ethyl perfluorooctanesulfonamidoethanol (NEtFOSE) during wastewater treatment. NEtFOSE is a toxic compound used to make protective paper coatings. It has a tendency to degrade and transform into even more harmful perfluoroalkyl and polyfluoroalkyl substances such as perfluorooctanesulfonate, also referred to as PFOS, under certain environmental conditions. The goal was to build a semi-permeable membrane bioreactor that could be placed in the secondary treatment basin of Exeter, New Hampshire’s wastewater treatment plant and used to safely evaluate this toxic compound’s degradation and transformation. By collecting wastewater samples spiked with NEtFOSE from both aerobic and anaerobic zones of this secondary treatment basin, I was able to observe the biotransformation pathways of the compound in each environment and make meaningful comparisons. Preliminary findings showed a distinct difference in the way NEtFOSE breaks down in anaerobic vs aerobic conditions. Ultimately, studying the influence of dissolved oxygen on the compound’s transformative nature allowed me to gain a better understanding of how the compound degrades and what terminal metabolites are generated in aerobic versus anaerobic environments, allowing scientists to better target these metabolites for destruction and eventually take PFOS out of the water supply. 

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