Abstract: The present work analyses a pilot scale hybrid nanofiltration/electrooxidation process for the removal of persistent perfluorohexanoic acid (PFHxA) from industrial process waters. A mathematical model was developed enabling the simulation and scale-up of the independent nanofiltration (NF) and electrooxidation (ELOX) units. Commercial spiral wound membrane modules and recirculation strategies were implemented in the NF simulation. One single NF unit and a cascade of NF stages were compared. A battery of serial-parallel electrochemical cells was designed for the ELOX system. The simulations showed that the electrochemical treatment is, when one and two NF stages are used, the most energy demanding process. Adding more NF stages increased noticeably the contribution of NF to the global energy consumption. The NF reconcentration strategy was able to reduce significantly the ELOX energy consumption (up to 86 %) and the overall energy demand. The hybrid NF/ELOX process is foreseen as a beneficial strategy to reduce the energy consumption of large-scale electrochemical processes aimed at the treatment of waters polluted by persistent organic compounds.

Authorship

Download reference