Continuous electricity production from leachate in a novel upflow air-cathode membrane-free microbial fuel cell

In this study, a novel microbial fuel cell, i.e. upflow air-cathode membrane-free microbial fuel cell (UAMMFC) was reported and its performance in electricity generation from original leachate was examined. The experimental results demonstrated that the UAMMFC could continuously generate electricity from leachate (0.3V; R_EX=150 Ω) for an operational period of time (50 h). The maximum volumetric power reached 12.8 W/m³ at current density of 41 A/m³ (93 Ω). NH₄⁺-N elimination from the leachate was shown to be a consequence of electrochemistry-independent oxidation occurred in the MFC. Increasing organic loading rate from 0.65 to 5.2 kgCOD/m³ d resulted in a decrease of overall Coulombic efficiency (CE) from 14.4% to 1.2%. The low CE obtained here should be attributed to severe oxygen diffusion from the open-to-air cathode.