Study on Improving the Efficiency of Wastewater Treatment using Microbial Fuel Cells —Electricity Output and Water Purification Capacity when changing the External Resistance—

Abstract

In order to develop an efficient water purification method using microbial fuel cells (MFCs), we experimentally investigated not only the time history of the electrical output and the I-V characteristics of MFCs with external resistance of 100Ω and 1000Ω, but COD changes of the artificial waste water whose types were set to acetic and butyric acid. There was almost no electrical output at the beginning of the experiment. The MFCs, however, had the electrical output as the experiment progresses since there were microorganisms that generate electricity. In addition, the electrical output of 100Ω was higher than that of the external resistance of 1000Ω. At this time, there was a correlation between the value of the electric output and the rate of decrease of COD, and the correlation becomes stronger when the electric output was high. Finally, it was confirmed that the value of the external resistance that maximizes the electrical output changes according to the state of the MFC cell. From the above results, it has been shown that controlling the external resistance to maximize the electrical output may accelerate the rate of COD reduction.