Kinetic study of biohydrogen production by anaerobic fermentation in a modified UASB-FF reactor

Fermentative hydrogen production is a common anoxic process where the bacteria degrade organic matters to produce the required electron in the anaerobic reaction. Dark fermentation in the acidogenic phase utilizing obligated and facultative anaerobes leads to hydrogen (H2) production. This method usually achieves a much higher H2 production rate than other biological processes. The kinetic evaluation of biological hydrogen production using palm oil mill effluent as substrate was done in a modified up-flow anaerobic sludge blanket –fixed film (UASB-FF) reactor. In this study, the two factors of feed flow (QF) (1.7-10.2 l/d) and up-flow velocity (Vup) (0.5-3.0 m/h) were chosen as the independent variables to investigate the bioreactor performance. The maximum specific growth rate (μmax) of hydrogenesis bacteria grown on POME as substrate was obtained at 0.313 d^-1 (38 °C). The half-velocity constant (Ks) was 9.04 g/L when POME concentration was 15.0 g/L. In this study, the kinetic parameters of Y, Kd, and k calculated were 0.1 g/g, 0.0043 d^-1, and 3.13 g COD/g VSS.d, respectively.