Thermodynamic analysis of biohydrogen and microbial fuel cells

Three alternatives for converting organic wastes to energy: biohydrogen production, direct electricity production via microbial cells (MFC), and methane production were evaluated. Biohydrogen production, MFC, or a combination could triple the energy production from organic wastes, compared to methane production. Biohydrogen required increased hydrogen yield or a second process that utilizes the electrons present in the fermentation products; thus, efforts are best focused on optimizing the energy recovery from fermentative products. The MFC is the best option in terms of energy-production efficiency, as long as substrate conversion to electron flow at the anode is high. This is an abstract of a paper presented at the 228th ACS National Meeting (Philadelphia, PA 8/22-26/2004).