Abstract:A single-chamber, membrane-less and floating-cathode microbial fuel cell (MFC) was established. The effects of operating characteristics on the microbial fuel cell using sludge (SMFC) were studied. Compared to the SMFC without churning, the maximum output power density of SMFC with churning was increased from 45.94mW/m2 to 124.03mW/m2(1300r/min) and 136.5mW/m2(2600 r/min), respectively. This may be attributed to the improvement of the material transmission in SMFC. The influence of temperature on the electrogenesis characteristic of SMFC was generally distinct. However, the power output did not change significantly in the certain temperature ranges (such as 20~25℃; 30~40℃; 45~50℃). Electrogenic bacteria had appropriate temperature ranges, and different electrogenic bacteria grew at different temperatures. Compared to the original sludge, the power density of SMFC using sludge undergone microwave treatment or using the supernatant fluid of microwave pretreated sludge was increased rapidly. This was because the microbial competition in the sludge had an important role in SMFC electric efficiency. The increasing of cathodic area could reduce SMFC cathodic potential and internal resistance, which resulted in the increasing of the power density.