Optimization of Microbial Fuel Cells Operating Parameters for Better Removal of Organic Matter and Higher Energy Production from Wastewater

Abstract

In this study, four double-chambered Microbial fuel cells (MFCs) operated by primary effluent wastewater mixed with anaerobic sludge as substrate, was designed, built, and optimized for better higher energy production and subsequently better removal of organic matter. Optimized MFCs operating parameters as a function of energy produced include electrode material type, electrode size, salt bridge diameter, type of salt solution that used in salt bridge, and concentration of the salt solution used in the salt bridge. Three duplicates-MFCs for each parameter value were used. Output open-circuit voltage (OCV) was measured for each MFC one time daily and for one week for each tested operating parameter. Data obtained showed that (i) MFCs with copper electrodes produce output voltage significantly higher than MFCs with carbon brushes electrodes which, in turn, achieved output voltage significantly higher than both that achieved by MFCs with zinc electrodes and MFCs with manufactured carbon electrodes, (ii) MFCs with 10 mm salt bridge shown significantly higher output voltage than MFCs with both 16 and 24 mm salt bridges, (iii) KCl salt bridge in MFCs is significantly more efficient than NaCl salt bridges, and (iv) MFCs with 1M KCl salt bridges can produce output voltage significantly higher than that produced by MFCs with 3M KCl salt bridges.