Biohydrogen Production by Modified Anaerobic Fluidized Bed Reactor (AFBR) Using Mixed Bacterial Cultures in Thermophilic Condition

Abstract

Anaerobic fluidized bed reactor (AFBR) with slight modifications was investigated to increase biohydrogen production at high temperature. The modifications include a decrease in the total liquid volume to 3.3 L, in addition to an external work in the form of high temperatures, high dilution rates and high rates of de-gassed effluent recycling. These modifications were applied to overcome the thermodynamic constrains preventing the simultaneous achievement of high hydrogen yield (HY) and hydrogen productivity (HP) in an (AFBR). Bacterial granulation successfully induced under a high temperature of 65^oC. The bacterial granules consisted of a multispecies bacterial consortium comprised of thermophilic clostridial and enterobacter species. Hydrogen production rate (HPR) of 7.57 L H₂/L/h and hydrogen yield of 5.82 mol H₂/ mol glucose were achieved at a hydraulic retention time (HRT) of 1 h and effluent recycle rate of 3.6 L/ min, with V/F_er equal to 0.91