| In 21th century, how to solve the shortage of energy and resources is one of the challenges the world faced. Environmental biotechnology focused on the development of efficient ways of biological response of recovery as chemical products and electric energy from wastewater or solid waste. Microbial fuel cell (MFC) is a new method of producing electric power from substrate by the use of bacteria ,which is the most direct means to obtain energy from the wastewater and waste.MFC technology has great value for further development. On the basis of Sediment MFC (SMFC) construction, studied its power generation from MFC's structure, characteristics of cathode solution and anode microbial respectively, explored the feasibility of dealing with cyan bacteria by SMFC at the same time. The major content of research and results are as follows:(1) Building a SMFC using granular sludge from the UASB reactor as anode inoculation, phosphate buffer solution as cathode was feasible, the Methanogens in granular sludge could compete with Electricigens, so added 3% volume concentration of chloroform that play the role as inhibitor of Methanogens and the output of power improved, the power density of constructed SMFC raised from 3.0 mW/m2 to 14.1 mW/m2 during 45 days, added cyan bacteria in anode sludge as fuel and the output increased, indicated that this SMFC system had potential to using cyan bacteria producing electricity.(2)The anode electrode area of SMFC impacted on its power density greater than cathode, the electrode diameter both as 80mm had the top power density as 3.0 mW/m2. The best electrode distance of SMFC was 70mm. The best ratio of volume of sludge in anode and cathode water was 1: 1. Polished electrode with sandpapers could increased its surface area, the device had the highest power generation when anode and cathode both polished. The ratio of height to diameter of device also influenced power production, when the ratio is relatively small, the device producted higher power density. By optimizing the cell structure ,the electric power density of SMFC increased by 50%.(3)The characteristic of cathode solution influenced electricity production greatly, the level of dissolved oxygen in cathode could not meet the requirement of electricity production under natural state, the power would be improved through aeration and adding other strong oxidize electron acceptor in system. The impact of cathode ionic strength and pH value on the electricity production was in line with the Nernst equation of electrochemical kinetics. Overall, the higher level of electricity production, the lower internal resistance of SMFC system, the internal resistance was reflected from the electron produced through the load resistance and all. The power density of SMFC could reach to 373.0 mW/m2 while using potassium permanganate as cathode electron acceptor and its internal resistance had the lowest value as 112?.(4) The effect of running between glucose and sodium acetate had no significant difference due to the constraint ion of mass transfer rate at anode. Glucose at the anode region was first to be oxidized to organic acids, and finally oxidized into carbon dioxide. Electricigens were sensitive to temperature, the activity of Electricigens and electricity production capacity of the system both influenced if temperature was too low or too high. Added a small amount of electron transfer intermediates in anode sludge and the system's electricity production increased, indicated the existence of both direct and indirect electricity production approach at the same time. The microbial community that from the surface layer of the anode biofilm found to be changed through the SEM photographs, the ratio of Bacillus sp was higher in sludge had better electricity production.
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