Study On Characteristics Of Anaerobic Fermentation With Agricultural Products Processing Wastes

Anaerobic fermentation technology can treat agricultural products processing waste, whith could not only achieve biomass energy biogas but also apply the biogas slurry residues as fertilizer after fermentation. It is a effective way to realize the recycling of resources, to solve the problem of energy shortage and environmental pollution. First, this research analyzes the theoretical feasibility of sugarcane bagasse, sawdust, mushroom residue, brewer’s grains, sauce residue and cassava residue as anaerobic fermentation of raw material. Secondly, in order to investigate the effect of initial dry matter concentration on biogas conversion, liquid metabolites and degradation efficency of organic substance, the anaerobic fermentation experiments of six kinds of agricultural products processing waste was conducted to produce biogas under the condition of mid temperature with different initial dry matter concentration. Lastly, in order to analysis the potential of gas production and the degradation rule of organic matter of agricultural product processing waste, the gas production properties and the organic matter degradation of six kinds of agricultural products processing wastes was compared. It provides a theoretical basis for future research. The main research contents and achievements are as follow:(1)It is similar to the influence of initial dry matter concentration on the six agro-processing waste of biogas characteristics and organic matter degradation, with increasing of initial dry matter concentration increased first, then with the increase of initial dry matter concentration reduced after to achieve the best effect. the optimum initial dry matter concentration of sugarcane bagasse, sawdust, mushroom residue and brewer’s grains was 10%,then VS methane production rates were 144.97mL·g-1, 37.13 mL·g-1, 134 mL·g-1 and 394.63 mL·g-1,respectively; the degradation rate of VS were 42.54%, 30.21%, 43.91% and 66.07%,respectively. The optimum initial dry matter concentration of sauce residues was 6%, then VS methane production rates and VS degradation rate were 209 mL·g-1and 48.33%,respectively. The optimum initial dry matter concentration of cassava residues was 2.5%,then VS methane production rate and VS degradation rate were 157.97 mL·g-1 and 48.33%.(2)Anaerobic fermentation process of six kinds of agricultural products processing waste has characteristics:fermentation starts faster, end relatively slower; and the VS rate of gas production, VS rate of methane production were proportional to degradation rate of VS.(3)Comprehensive analysis from the degradation of the organic matter in the raw materials showed that:in a range of conditions, the higher the organic matter content, the greater the amount of degradation;It is a key factor determining the degradation of organic matter which was the equilibrium ratio of organic matter of composition and element in raw material; The content of cellulose was higher, the structure of cellulose was more complicated, it would inhibit the starch, protein and fat degradation in raw material; High starch content can obtain high degradation of starch and protein; High fat content can inhibit the degradation of starch and protein; The degradation of protein did not get very good when protein content was higher. Therefore, the effect of degradation of organic matter is related not only to the organic matter degradation rate of raw materials, but also to the structure, the content, the ratio and the interaction of organic matter.(4)Through the analysis of the degradation of lignocellulose on different raw materials by microorganism of biogas slurry, it was known that degradation of lignocellulose mainly came from cellulose of sugarcane bagasse, sauce residue and cassava residue; that degradation of lignocellulose mainly came from hemicelluloses of sawdust, mushroom residue and brewer’s grains. The degradation of cellulose and hemicellulose not only related with the structure of lignocellulose of raw materials, but also related with the factors of common environment of the raw material and microorganisms.