Experimental Research On Sludge Digestion And Electricity Generation Of Microbial Fuel Cell

The sludge disposal issue of municipal wastewater treatment plant has always been a problem. It is very difficult to dispose so lot of sludge just by landfill and dumping. Although burning can minimize sludge volume and cause great waste of resources, but its cost is too high. There is inefficiency, difficult to manage and not high energy recovery of the conventional anaerobic digestion technology. How to deal with the excess sludge of municipal wastewater treatment plant efficiently, minimize sludge volume and recover sludge biomass efficiently become a hotspot and difficult of research.Using stainless steel wire as anode to build an air-cathode single chamber microbial fuel cell (MFC) without a proton exchange membrane, and using glucose as the sole substrate with an initial chemical oxygen demand (CODCr) concentration of 576mg/L and the external resistance of 1000? under room temperature, electricity of was generated continuously by the MFC and the highest voltage reached up to 256.16mV, the open circuit voltage was measured at 475.64mV and the internal resistance was about 5827?. The MFC achieved a maximum power density of 85.1mW/m2 and coulombic efficiency of 38.2% with the external resistance of 500? under the experimental condition. It is more practical because that the Character of the MFC is better than the double-chambers MFC.Taking the MFC for the excess sludge treatment comparative experiments, the CODCr removal rate of the MFC reached up to 60% higher than the anaerobic treatment efficiency of about 5% ~ 10%. At the same time, sludge volume and sludge quantity decreased 52.3% and 62.3% respectively, higher than the anaerobic digestion of 19.5% and 28.5%. The voltage of the external resistance of 1000? reached up to 172mV meanwhile the MFC achieved the maximum power density of 30.8mW/m2.At the same time, the result shows that the SCOD/TCOD of excess sludge arose from 2.8% to 15.4% with fluctuations by studying the organic matter removal in excess sludge. Through comparative experiments we find that it is more stable and effective on COD removal of excess sludge by MFC than the anaerobic device. The results show that MFC remaining in the digested sludge while producing electricity are derived from microbial degradation of the substrate. And it is indicated that the MFC technology can not only reduce the excess sludge in organic matter and the sludge volume but also obtain power so that it has a certain potential in excess sludge treatment and disposal.