Impact of wastewater volume on cathode environment of the multi-anode shared cathode and standard single anode/cathode microbial fuel cells

To examine the impact of wastewater volume on the ionic strength of an electron acceptor, the performance of a 1000 mL multi (4)-anode shared single cathode MFC (MFC 1) was investigated and its performance was compared to two 250 mL standard single anode/cathode MFCs, the first (MFC 2) with the same cathode surface area as MFC 1: 84cm(2) and the second (MFC 3) with 42cm(2). The performance of the MFCs was evaluated under high and low external resistances to elucidate the differences in MFCs' performance. MFC 2 (4.36 mW/cm(2) at 0.0102 mA/cm(2)) produced 2.8-times and 1.02-times higher in power density than that of MFC 1 and MFC 3, respectively. The multi (4)-anode shared cathode MFC (MFC 1) produced the lowest internal resistance (100 Omega), which was more than 3-times lower than MFC 2 and MFC 3. At the lower external resistance of 100 Omega, a more distinct difference between the multi-anode shared cathode MFC and the single anode/cathode MFCs was revealed in continuous current and power generation (1.2 mA and 153.76 mW), which were 1.7-times and 2.7-times than that of MFC 2 and MFC 3, respectively. MFC 1 also attained a 1.1-times higher COD removal efficiency and treated 1000 mL of wastewater without any significant difference in anolyte/catholyte conductivity and pH, compared to MFC 2 and MFC 3 which only treated 250 mL of wastewater over the same time. To deplete the cationic conductivity of the shared single cathode in MFC 1, an estimated 7.945 mL of wastewater is required. [GRAPHICS] .