On the staking of miniaturized air-breathing microbial fuel cells

This work focuses on the scale-up of the MFCs by miniaturization and multiplication strategy. Performances of five stacks containing 1, 2, 5, 8 and 16 MFCs were compared. Each stack was evaluated under individual, parallel and series electrical connection as well as for cascade or individual hydraulic connection. Cascade feeding mode with a tank per stack favours the COD removal when the number of MFCs in the stack increases. However, despite operating without COD limitations, the energy production was disadvantaged. By changing the feeding system of a tank per stack into an individual tank per MFC, the performance of the whole stack enhances considerably. Stacking in series can increase the voltage 6 times while stacking in parallel can increase the current output about 4 times. For example, 8 MFCs can achieve 2.03 V connected in series and 6.98 mA connected in parallel. In addition, the power can be increased up to about 10 times leading to a power range high enough for real life applications.