Studies On Simulated Organic Wastewater Disposal By Mediator-less Microbial Fuel Cell And Its Influencing Factors

Microbial fuel cell (MFC) is a device directly converting microbial metabolic power into electricity with the microbial catalysts, which has the advantages of abundant fuel resource, mild reaction condition and high efficiency. Although it is still in experimental stage, the study of factors affecting the performance of MFC in wastewater treatment provides a significant guidance for practical application.MFC is typically designed as a two-chamber system with the bacteria in the anode chamber separated from the cathode chamber by a polymeric proton exchange. Electricity is produced from simulated organic wastewater containing sodium lactate or glucose by anaerobic microorganisms obtained from anaerobic activated sludge and it is called as electricity production integrated with COD reduction. Current density and Coulombic yields in a mediator-less MFC are examined as a function of initial pH, substrate concentration and types of substrates.The results show that the Monod equation can be used to describe the relationship between cumulative Coulombic and initial COD. A orthogonal test is implemented to investigate the corporate effect of initial pH, substrate COD concentration on cumulative Coulombic in glucose-MFC. Polynomial regression and response surface plots demonstrate that the optimal initial pH and COD are 7.0～8.0 and 6～10 g/L, respectively. This study investigates the process of electricity production integrated with COD reduction by use of two comparative substrates glucose and sodium lactate. The COD reduction of glucose is much higher than that of sodium lactate (25%～40%), reaching 30%～70% at running time 12 hours. The results demonstrate glucose is better than sodium lactate in view of higher Coulombic cumulation and COD reduction. MFC can easily accomplish the dual goals of waste reduction and electricity production and possesses a promising future in engineering practice.