Removal of azo dye in an up-flow membrane-less bioelectrochemical system integrated with bio-contact oxidation reactor

] An up-flow membrane-less bioelectrochemical system integrated with bio-contact oxidation (BES-BCO) was developed for degradation and/ or mineralization of the Acid Orange 7 (AO7) in wastewater. The performance of BES-BCO was evaluated based on decolorization removal efficiency, chemical oxygen demand (COD) removal efficiency and the concentration of decolorized byproducts in effluent. The study found that the BES-BCO system can degrade AO7 and COD effectively. Further, the toxic decolorized byproducts of azo dye, which are not generally degrade in the traditional BES system, can be further mineralized by the BES-BCO system. In addition, the COD removal efficiency increased with the increase of aeration at BCO. However, higher DO concentration at anode can hinder the electrons transfer between anode and exoelectrogen, resulting in a significant decrease of decolorization removal efficiency. This study provided a novel compact technology for advanced treatment of azo dyes wastewater for engineering applications, and concluded that the integrated BES-BCO system is effective for advanced treatment of azo dye-containing wastewater. (C) 2017 Published by Elsevier B.V.