Bioelectricity production by mediatorless microbial fuel cell under acidophilic condition using wastewater as substrate: Influence of substrate loading rate

摘要

Microbial fuel cell (MFC) employing low-cost materials (non-coated plain graphite electrodes) without any toxic mediators (aerated cathode and mediatorless anode) was evaluated under acidophilic (anode pH of 5.5) conditions using anaerobic mixed consortia to enumerate the influence of substrate loading rate on bioelectricity generation from anaerobic wastewater treatment at ambient temperature (28 plus or minus 2 degree C). Experimental data showed the feasibility of power generation from waste-water treatment. However, the overall voltage generation, power yield and substrate degradation was found to depend on the substrate/organic loading rate (OLR). Maximum potential difference of 423 mV (1.66 mA) was recorded at stable operating conditions. Apart from power generation, the fuel cell also demonstrated substrate removal (62.5%). Applied OLR documented marked influence on both power yield and substrate degradation rate. Maximum power yield (274 mW/g COD sub(R); 50 Omega ), was observed at operation OLR of 0.574 kg COD/m super(3)-day. Voltage and current started decreasing due to substrate exhaustion (COD reduction) in the anode chamber. It is evident from the experimental data that the anodic chamber of MFC mimicked anaerobic suspended growth reactor normally used for wastewater treatment with respect to COD removal. The study documented the advantage of both wastewater treatment and electricity production in a single system.