Feasibility Study On Simultaneous Wastewater Biotreatment And Electricity Generation By Microbial Fuel Cell

In this study, the air-cathode microbial fuel cell was inoculated with wastewater and anaerobia activated sludge, stable voltage of 0.24V was obtained after 110h during the starting period. Using acetate and glucose as substrates, the maximum power density of 145.56mW/m~2 and 192.04 mW/m~2 were observed respectively; the COD removal efficiency and the electron recovery efficiency were 99%,9.56% and 87%,10.47% respectively. The lower electron recovery efficiency is mainly due to substrate consumption by facultative microorganisms present in the system that use the oxygen as electron acceptor diffused into from cathode.We compared electricity generation from two ACMFCs with different design. In this study, ACMFC2 generated a maximum power density of 9800mW/m3, higher than ACMFC1 of 3070mW/m~3. The different design was leading to different internal resistance for ACMFC2(106.19Ω) and ACMFC1(281.28Ω); lower anode potential for ACMFC2 (-442mV) than that of ACMFC1(-323mV), these are all possible responsible for higher power generation. ACMFC2 can sustain generating electricity for nearly 220h (electron recovery efficiency of 30.1%), which was comparable with ACMFC1 of lea than 50h (electron recovery efficiency of 30.1%) under batch operation.In other to suggest a method that could be used to link electricity production by MFC to anaerobic organic wastewater treatment, some typical hydrolysis or fermentation products produced in anaerobic process were used to generated electricity, electricity generation were achieved with the maximum power density of 11476mW/m~3, 11400mW/m~3 and 10368 mW/m3 for sucrose, lactose and glucose as substrate respectively, higher than that obtained from acetate of 9248 mW/m~3, ethanol of 9800 mW/m3 and propionate of 7200 mW/m~3. Meanwhile, internal resistance of about 110Ωfor glucose, sucrose, lactose, acetate and ethanol was obtained, suggesting that substrate was not a factor that influenced the internal resistance. However, propionate was observed different from the other substrates in internal resistance (321Ω) and in anode potential development.