| In China ,there are about 50%～70% organic matters in sewage sludge which contants a lot of carbohydrate ,belonging to the low-fat type, meanwhile, the sludge has abundant nutrition elements, such as N,P,K etc and all kinds of trace elements like Ca, Mg, Cu, Zn, Fe etc which can meet the need of microorganism in the sludge. With the development of the modern city and the industry, the output of sludge increases sharply, we are now confronted with the problem of unwieldiness and high investment during the process of sludge treatment. We can cut down the cost of disposal of sludge and may produce some economic interest on condition that the organic matters in the sludge could be made use of. These days, people are actively searching every kind of new technology and method to solve the matter caused by sludge resourcization. For example ,we can try to use sludge to produce hydrogen. With the energy source become more and more scarce, the speed of the development of microbial fuel cells(MFC) technology become more and more fast .MFC is a new kind of bioreactor which is a device transforming the chemical energy stored in the organic into electricity energy using microorganism as catalyst, and this technology is developping based on the electrochemistry technology. Therefore, under this circumstance the paper bring forward this new technology using microbial fuel cells to change the organic matter in sewage sludge into electricity power. We hope that it can pose a new thinking for the development of sewage sludge resourcization and change sewage sludge into useful resource so as to meet the needs of achieving good economic and social benefits.In this paper we use sludge as fuel ,single chamber MFC without membrane as reactor and the origin microorganism exist in the sludge itself to start the MFC device by 20 days without any other chemicals. And then, after the successful start ,we study the character of electricity production and the rule of cyclical changes of matters in the solid and liquid phase of the system during the process of electricity production by this MFC using sludge as fuel. After the experiment we make the conclusion that this MFC can output 495mV(external resistance is 1000Ω), 44mW·m-2 at its best. And the internal resistance is about 300? when the system is in stationary phase. During one cycle of operation, the rate of removing of SS and VSS of the sludge are 27.3% and 28.7%, respectively, and the range of variation of pH is 6.5～8, the original concentration of COD is 617 mg·L-1, and it is increasing as the time goes by until it comes to about 1150 mg·L-1,after that, it falls gradually, the original concentration of sugar is 47mg·L-1, and then it gradually increases to 60mg·L-1 before it slowly falls down at last.With the aim of taking one step ahead to increase the output voltage and power density , some researches on the influencing factor and internal resistance are made of in this paper. The results shows that, there are many characters could affect the MFC system, such as temperature, electrode material, running time, the area of the anode, and the ability of electricity production of MFC can be increased with the raise of the temperature, chosing the material of electrode with good biocompatibility can remarkably increased the output power, the ability of electricity production of MFC would gradually falls down as the time goes on, increasing the area of anode the output power can't be always improved, the internal resistance firstly reduces and then increase as the time goes on, the resistance becomes very large when the distance between the anode and the cathode increased. But there is no notable rule of variety of the internal resistance of MFC with the change of salinity in this experimentation because of the stability and complexity of the sludge. |
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