BACKGROUNDGreywater and blackwater treatment is necessary to make sanitation and water reuse possible, and microbial fuel cells (MFCs) have emerged as a promising technology for achieving this objective. Ion exchange membranes play a key role in double chamber microbial fuel cell performance, but there are differences of opinion as to which membrane type is better. RESULTSThis project was set up to study the effect of three ion exchange membranes (Nafion (R) 117, Ultrex CMI-7000 and Ultrex AMI-7001) in MFCs using greywater as catholyte in stacks of three microbial fuel cells each. The results demonstrate that the stacks with cationic membranes (Nafion (R) 117 and Ultrex CMI-7000) generated higher power (201.5021.62 and 178.74 +/- 56.89mWm(,)(-3) respectively) than those with the anionic membrane stack Ultrex AMI-7001 (71.57 +/- 3.46mWm(-3)). For the greywater catholyte, a 31% of chemical oxygen demand removal was achieved and proved to be an option as a catholyte in microbial fuel cells for countries that carry out wastewater separation. CONCLUSIONSThe results obtained in this study demonstrated that an anion exchange membrane is not a better option for double chamber MFCs. (c) 2019 Society of Chemical Industry