Residence time distribution in microbial fuel cell and its influence on COD removal with electricity generation

The liquid flow characteristics in a microbial fuel cell (MFC) were determined using a residence time distribution (RTD) test, and its effects on the performance of the MFC were investigated in terms of electricity generation and chemical oxygen demand (COD) removal. A membrane-less MFC was used with two different anode structures; normal graphite felt disk (“Normal” MFC) and perforated graphite felt disk (“Perforated” MFC). The RTD results showed that there exists nonideal flows such as channeling and tailing in the “Normal” MFC and the flow characteristics were much better in the “Perforated” MFC with the improved electricity generation. COD removal rate was similar between the MFCs. These results show that the flow characterization is an important area of study for the optimization of an MFC.