Enhancement of azo dye decolourization in a MFC-MEC coupled system. 
Microbial fuel cells (MFCs) have shown the potential for azo dye decolourization.  In this study, a MFC-MEC (microbial electrolysis cell) coupled system was established in order to enhance azo dye decolourization, and the influence of several key factors on reactor performance was evaluated.  Moreover, a theoretical analysis was conducted to find the essential preconditions for successfully develop this MFC-MEC coupled system.  The results indicate that the decolourization rate in the coupled system had a 36.52-75.28% improvement compared to the single MFC.  Anodic acetate concentration of both the MFC and the MEC showed a positive effect on azo dye decolourization, while the cathodic pH of both MEC and MFC in the range of 7.0-10.3 had an insignificant impact on reactor performance in the coupled system.  The theoretical analysis reveals that the MFC should have higher short-circuit electricity generation than the MEC before connecting together for a successful coupled system.