Foam Fractionation Meets Activated Sludge

Abstract

The main research question of this project was:
"How effective is the integration of a foam fractionation system in an activated sludge water treatment plant, on the removal of Per- and Polyfluoroalkyl Substances?"
To determine how foam and activated sludge can have an influence on PFAS removal, a controlled environment was created by building a bench-scale reactor that tries to mimics the full scale activated sludge WWTP of landfill Zeeasterweg. By doing this the effect on the biological performance was tried to be determined. Furthermore, a representative sample of the landfill leachate from the landfill, was used as the influent for the bench scale reactor. This leachate predominant PFAS compounds were: MeFBSAA (13.5 μg/L) and PFBS (8.8 μg/L) accounting for 70 % of total PFAS levels. To answer the main research question, two mass balances for a selected group of target PFAS compounds were develop for two experiments. The fist experiment was focusing on the PFAS removal efficiency without any foam production at all. To achieve this, antifoam was dosed on top of the nitrification zone so that no foam could be produced. The second experiment was called the "Foam Fractionation". In this experiment anfoam fractionation system was added to the nitrification zone of the bench scale reactor. This was done to determine the effect of collecting and removing the foam that was being produced inside the reactor.