The Electrical Properties And Changes On The Substrates Of Microbial Fuel Cells Using Excess Sludge As Fuel And Ehanced By Additional Enzyme

Microbial fuel cell that convert the chemical energy in the fuel into electrical energy is highly active and cleaning technology in recent years. Compared to the traditional hydrogen fuel cell and solid oxide fuel cell, the microbial fuel cell not only has extensive fuel, but also can attain double effects of producing electricity and degradation of pollutants. Some researches proved that the maximum output power density produced by MFC with mixture was lower than by MFC with pure, but the MFC with mixture possesses the value of practical application. At present, a few of researchers apply MFC to the treatment of pollutants such as sewage, sludge, landfill leachate and so on. Through the microbial fuel cells, there are lots of cleaning electricity to be produced and those pollutants could be reduced.Surplus sludge is the production of using active sludge to deal with sewage, and has much organic content, such as proton, carbohydrate, and fat. So surplus sludge is a potential fuel.However, the MFC which directly use surplus sludge as substrate produces extremely low the maximum output power density and the reduction of excess sludge. The reason is that slow hydrolysis rate of huge organic substance limits the degradation of organics by microorganism,and even has great impact on the efficiency of producing electricty and reduction of excess sludge.How improve hydrolysis and the SCOD is the key to enhance the power produced by microbial fuel cell and the reduction of surplus sludge. Enhanced hydrolysis by additional enzyme can not only improve sludge digestibility, but also reduce disposal costs, and its products are harmless to environment.Combining the sludge hydrolysis with surplus suldge MFC,the effects of commercial enzyme preparation containing alpha amylase and neutral protease on the features of electricity production and hydrolysis of excess sludge were investigated. The results indicated that additional enzyme greatly enhanced the maximum output power characteristics and the reduction of surplus sludge. The maximum output power destinies, coulomb efficiency, efficiency of reducing TCOD, efficiency of reducing TSS and efficiency of reducing VSS could respectively reach up to507W·m-2(700mW·m-2),3.98%(5.11%),88.31%(94.09%),83.18%(98.02%) and89.03%(98.80%) for protease(a-amylase) at the dosage of10mg·g-1. Moreover, a-amylase had higher efficiency than protease in the promotion of electricity generation. During the system operation, the activity of enzyme, protein and glucose all first quickly increased and then slowly decreased.