| Summary: | 碩士 === 國立臺灣大學 === 生物產業機電工程學研究所 === 99 === The microbial fuel cell (MFC) is a technology which could simultaneously treat the wastewater and also produce the electricity, with significant meaning in both environmental protection and energy production. This study adopted an air-cathode microbial fuel cell, no aeration requirement, using carbon cloth as the anode and platinum titanium net as the cathode, the anaerobic sludge of a three-stage swine wastewater treatment system was used as the seeding bacteria. The sludge and graphite powder were immobilized by entrapping with the cellulose acetate, after cutting into the proper size, these immobilized cells were packed homogeneously in the anodic compartment. Experiments were conducted using both the synthetic and swine wastewater as substrate. The objective of this study is to investigate the effect of different amount of graphite powder addition and the organic loading rate.
Experimental results showed, in tests of using synthetic wastewater as substrate, the maximum power density was increasing when organic loading rate increased except the test of not adding graphite powder when making the immobilized cells. The maximum power density of 113 mW/m2 was observed at the loading rate of 8 gL-1d-1 with 3 g of graphite powder addition. The maximum coulombic efficiency of 1.8% was observed at the organic loading rate of 2 gL-1d-1, with no addition of graphite powder when making the immobilized cells.
The tests of using swine wastewater as substrate used 3 g graphite powder when making the immobilized cells. The maximum coulombic efficiency of 1.5% was occurred at the organic loading rate of 6 gL-1d-1. However, its average coulombic efficiency was better than those tests of using synthetic wastewater as substrate. The optimal value 75.6 mW/m2 of the maximum power density was achieved at the organic loading rate of 2 gL-1d-1.
Comparing the COD removal efficiency, the test of using the swine wastewater dropped down to only 18% at a loading rate of 8 gL-1d-1, while the synthetic wastewater test still maintained a COD removal efficiency of 51% at the same loading rate, for it had much higher biodegradable COD than the swine wastewater.
This study successfully proved that addition of graphite powder when making the immobilized cells did improve the electricity production for the air-cathode microbial fuel cell and it was feasible using the swine wastewater as the substrate.
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