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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 NH 4 + to NO 3 − or NO 2 − ; and only 20.5% of PO 4 − 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. [ABSTRACT FROM AUTHOR]

Scale-up of a lead dioxide (PbO2) anode system is significant to the practical application of electrochemical oxidation (EO) in biorefractory wastewater treatment. In this study, response surface methodology (RSM) was employed to investigate the effects of different operating conditions on phenol removal by electro-oxidation with a Ti/PbO2 anode. A central composite design (CCD) was used to optimize the electro-oxidation process and to evaluate the individual and interactions effects of current intensity, electrolysis time, and recirculation flow rate on phenol removal. Synthetic wastewater (or distillate water) with phenol concentration of 10 mg/L-1 was used in this study. Optimal conditions for phenol removal were established at 1.12 A current intensity, 40 min electrolysis time, and 188 mL . min-1 recirculation flow rate, in which a removal of 78.97 ± 1.72% was achieved. The decay kinetics of phenol removal was fitted a first-order reaction. [ABSTRACT FROM AUTHOR]