Combined membrane bioreactor and electrochemical oxidation using Ti/PbO2 anode for the removal of carbamazepine

• MBR showed high capacity to remove the COD and NH4+–N.
• The combination of MBR with EO resulted in complete CBZ removal.
• MBR is an efficient method for the decrease of wastewater detoxification.
• Beneficial synergic action was obtained with the integration of MBR/EO processes.

This study aims to demonstrate that a combined system of membrane bioreactor (MBR) with electro-oxidation (EO) can be a promising technology to treat compounds such as carbamazepine (CBZ). The MBR showed high capacity to remove the chemical oxygen demand (COD) and low capacity for the degradation (20% of removal), after 120 d of operation; which presumably indicates that CBZ was not toxic for microorganisms, despite its poor degradation. On the other hand, the EO system was capable to completely degrade CBZ (99.99% of removal). In addition, the MBR achieved 83% of conversion efficiency of NH4+ to NO3− or NO2−; and only 20.5% of PO4− removal. A toxicity test using Dapnia magna and Vibrio fischeri was carried out. Results indicated that MBR is an efficient method to decrease wastewater toxicity but during electrooxidation treatment higher toxicity was obtained, probably due to the generation of more toxic compounds than the initial pollutants.

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