Application of a biochemical fuel cell to wastewaters

The system employed in the study was composed of a reactor for hydrogen production by the immobilized cells of C. butyricum, a fuel cell, and a reactor for wastewater treatment by the immobilized microorganisms. Industrial wastewaters were applied to the system. The rate of hydrogen production by the agar gel-entrapped whole cells was higher than that by the polyacrylamide gel-entrapped ones. The optimum flow rate for hydrogen production was observed with a packed-bed reactor. As the bacteria produced organic acids, the wastewater became acidic at the low flow rate. The rate of hydrogen production and the current increased when the flow rate and the BOD of the wastewater were increased. The diffusion of hydrogen to the electrode surface and the amount of hydrogen produced were the rate-determining steps of the current generation. The system was composed of three devices, the reactor for the hydrogen production, the fuel cell, and the reactor for wastewater reatment. This study provides an application of immobilized whole cells to energy conversion and wastewater treatment. 10 figures, 2 tables.