Agricultural Organic Wastes By Anaerobic Fermentation Of Biological Hydrogen Production Research

Biological hydrogen was generated with anaerobic batch culture from agricultural solid wastes by anaerobic composts and digested sludge. The limited eco-factors and pretreatment methods to affect hydrogen-production for substrates were investigated systemically.From the experimental results, the eco-factors have important effects on hydrogen generation by fermentation. While the wheat bran is utilized as a substrate, the optimal hydrogen-production pH, initial pH, substrate concentration and sludge concentration of wheat bran are 5.0, 7.0/50mg/ml and 80mg/ml, respectively. The optimal temperature, rotate speed and substrate concentration for deoiled cottonseed cake fermentation are 36 , 90r/min and 100g/L, respectively; those for deoiled peanut cake fermentation are 36 , 90r/min and 80g/L, respectively; And those for deoiled gingeli cake fermentation are 30 ,90r/min and 100g/L, respectively. The maximal hydrogen production potentials of wheat bran, deoiled cottonseed cake, deoiled peanut cake and deoiled gingeli cake are 103.6, 24.0, 27.4 and 24.1ml/g, respectively. The maximal hydrogen concentrations in the produced gas are 62%, 47.1%, 48.9% and 63.2% for wheat bran, deoiled cottonseed cake, deoiled peanut cake and deoiled gingeli cake, respectively. Compared with comparative experiments, the cumulative hydrogen of wheat bran, deoiled cottonseed cake, peanut cake and gingeli cake are increased by 72.7%, 32.5%, 3.5 times and 22.8% through the pretreatment of Method (1), respectively. The optimal synergism of rice wine was achieved at pH 5.0. For deoiled cottonseed cake and gingeli cake, the synergism of rice wine is superior to that of yeast, but for the deoiled peanut cake, the case is opposite.Analytic results from the fermentation ending products suggest a trend that alcohols were increased up to the stable concentration, but the VFAs were increased to zenith and then decreased gradually till the hydrogen-generation cessation. This indicates that the VFAs were transformed into alcohols by hydrogen-generation microorganism in the process of hydrogen generation.