Effect of substrate concentration and pH on biohydrogen production kinetics from food industry wastewater by mixed culture

Kinetics of batch anaerobic hydrogen production using mixed culture was investigated in this study. The mixed culture broth was the effluent from the CSTR which had been inoculated with the Li-Ming wastewater treatment sludge. The batch reactor had a volume of 2 L and was operated at a temperature of 35 °C. The initial volumes of the mixed culture broth and the substrate were 200 ml and 1800 ml, respectively. The initial substrate concentrations were controlled at 20, 30, 40, 60 and 100 g total sugar/L. The peak specific growth rate of the mixed culture (μ = 0.28 h−1) was obtained at a substrate concentration of 40 g total sugar/L and pH 5.5. Finally, three inhibition models were used to obtain the kinetic parameters by curve fitting. The Haldane model is appropriate in this study. The effect of pH was then studied for modifying the established biohydrogen production by the three-parameter model. The established model can be used for further designing of a biohydrogen production fermenter for food industry wastewater by mixed culture.