Electricity Generation And Wastewater Treatment In Single Microbial Fuel Cells

Microbial fuel cell(MFC) is a new technology of biological treatment, which converts chemical energy in organic components to electricity. However, there are still many problems to be solved about electricity generation and wastwater treatment of the MFC. This research subject is aiming at the disposal of synthetic wastwater and landfill leachate. Here, the electrochemical performance and treatment effect of single chamber MFCs are showed as follows:A single chamber MFC,which cathodic catalyst was platinum carbon, was used to remove nitrogen and phosphorus from synthetic wastewater. The result showed that the concentration of NH4 Cl had obvious effect on the electrochemical performance of the MFC.When the NH4 Cl was 4 mmol/L, the output voltage was 371 mV, and the power density was301.6 mW/m2. The internal resistance was 200 Ω. The best operation time of the MFC was 72 h. The removal rate of COD, TN and TP were 79.9%、19.7% and 44.8%. After the effluent of the MFC was aerated with air, the removal efficiency increased. So, the diposal rates of TN and TP were 79.6% and 95.2%. At the same time, it was verified that the best time for aeration was 6 h. Struvite on the cathod was found and it mean that a portion of nitrogen and phosphorus was removed in this way. From the test, it was seen that the content of NO3--N and NO2--N was slowly rising while the content of NH4+-N decreased. And the change of TN was not evident. Based on the above, it was concluded that some NH4+-N transformed into NO3--N and NO2--N. Only a small part of phosphorus was removed by MFC and most of it was removed by aeration.Modified conditions had effect on the landfill leachate treatment of the MFC when its cathodic catalyst was modified activated carbon. The experiment demonstrated that the modified activated carbon worked well when treated it with 40%(volume fraction) H2SO4,10%(mass fraction) FeSO4 and shocked in the device for 24 h. The highest rates of COD and TN were 54.3% and 21.2%. The maximum voltage was 306 mV and the maximum power density was 94 mW/m2.At last, the paper gave a comparison of the landfill leachate treatment between the above two MFCs. The result was that the MFC using modified activated carbon showed better performance. It had better electrochemical performance and treatment effect.The output power density increased by 23.4% while its internal resistance increased by 12.9%.The two MFCs operated continuously for 4 days, the diposal rates of NH4+-N were 33% and21%. Also,the COD removal rates were 53% and 45%. The activated carbon had porus structure and the loaded Fe2+ obtained better effect. It made possible to replace platinum in the MFC technology.