Microbial Fuel Cell-Energy Production While Wastewater Treatment

As a new technology of wastewater treatment, microbial fuel cell (MFC) can produce electricity while wastewater degradation. With dual-chamber microbial fuel cell(DMFC) and upflow single-chamber microbial fuel cell(USMFC) used in this article, the influencing factors of the cell's performance and the efficiency of wastewater treatment was studied, and the application of USMFC used in brewery wastewater treatment also be researched.DMFC was constructed with graphite plate as cathode and nickel foam as anode. The influencing factors to the performance of the cell were studied when potassium ferricyanide and hydrogen peroxide used as the cathode electronic receptors. The results of the study showed: in a certain range, the higher concentration was, the better performance MFC had (this means more output power and open circuit voltage, as well as less internal resistance). While pH decreased, the output power increased, internal resistant decreased. When pH was 7, potassium ferricyanide concentration was 10000mg/L, the cell's open circuit voltage was 721 mV. maximum output power was 4061 mW/m~3 and internal resistance was 151Ω. and at the condition of pH was 2, hydrogen peroxide concentration was 1000mg/L, the cell's open circuit voltage was 942 mV, with maximum output power 6778 mW/m~3 and internal resistance 192Ω.USMFC was constructed with air electrode as cathode and granular activated carbon as anode. The effect of KC1 concentration, glucose and hydraulic retention time(HRT) on the performance(open circuit,output power and internal resistance) and the efficiency of wastewater treatment of the cell was studied in continuous running status. Research demonstrated: the performance of cell was improved with the increasing of electrolyte and glucose concentration. The relationship between glucose concentration and output power can be described by Monod equation form, and the semi-saturation constant is 110mg/L, the maximum output power was 21585mW/m~3. HRT in a certain range can be extended to improve the performance of the cell and the efficiency of wastewater treatment. At the condition of glucose concentration 850mg/L, HRT 8h. the maximum output voltage and output power of USMFC was 0.915V and 44.3W/m~3, and COD removal rate was 45%. The basic study of the degradation of wastewater showed that the degradation of organic compound in wastewater was accordance with the pseudo-first order reaction kinetics.The research on USMFC applied to brewery wastewater treatment experiment showed that: the smaller the load resistance was, the higher coulomb efficiency and COD removal were, the relationship between brewery wastewater concentration and battery maximum output power can be described by Monod equation form, the semi-saturation constant was 286mg/L, the maximum output power was 15473mW/m~3. The higher brewery wastewater concentration was, the higher output power and open circuit voltage were. The open circuit voltage and maximum output power of USMFC was 0.642V and 13542mW/m~3, and internal resistance was 65Ωwhen load resistance was 500Ω, brewery wastewater concentration was 1953.2mg/L, HRT was 3h.The research showed that microbial fuel cell can produce electricity while disposal of wastewater, and it can be optimiced of wastewater treatment and performance through operating conditions adjustment, this makes it a broad application prospects in the field of wastewater treatment.