The Effect of Food-microorganism(F/M)Ratio on Gas Properties in Batch Biogas Fermentation with Walnut peel

摘要

In order to study the effect of food-microorganism(F/M)ratio on gas properties in batch biogas fermentation experiments with walnut peel, by batch fermentation under the condition of 30°C, with walnut peel as fermentation raw materials, and respectively choose F/M(vs/vs)=0.20, 0.15, the effect of food-microorganism(F/M)ratio on the gas properties was studied in biogas fermentation with walnut peel. The experimental results showed that in the fermentation with walnut peel as raw materials, the potential of TS and VS, the total volume and the time reaching to 80% gas production volume of the time of experimental group F/M(vs/vs)=0.20 were respectively 202ml/gTS, 226ml/gVS, 2840ml, 19d. However, the values of experimental group F/M(vs/vs)=0.15 were respectively 152ml/gTS, 170ml/gVS, 2140ml, 24d. Therefore, food-microorganism(F/M)ratio has a great influence on batch biogas fermentation with walnut peel as the fermentation raw material. Food-microorganism(F/M)ratio is the ratio of the TS or VS of the raw material to the TS or VS of inoculums in the liquid of the fermentation. In order to maintain the normal operation of the batch reactor, we must add materials into the reactor and a certain amount of inoculums. Some studies show that food-microorganism(F/M)ratio has a certain influence on the performance of anaerobic digestion gas. Wudi Zhang, etc[1] choosing human excrement as fermentation materials and under the condition of the same dosing quantity, adding different proportions of inoculums found that the quality and quantity of inoculums is close to startup and the gas production in the operation of the pool. Lopes, etc[2] found that, when studying the anaerobic digestion of urban organic waste with the cow stomach as its inoculums, it was very important to select the appropriate quality ratio of substrate and inoculums (F/M) for maintaining the stability of the system whose inoculums was cow stomach and urban organic waste was raw material. Guangqing Liu, etc[3] proved that the values of F/M have significant impact on gas production rate of the two kinds of materials, when they studied the batch anaerobic digestion of food waste, grass and their mixture, at the medium temperature (35±2°C) and the high temperature (50±2°C), and respectively controlling F/M at the value of 1.6, 3.1, 4.0 and 3.1. F. Raposo etc[4]found that the values of F/M which were 1/3, 1/2, 2/3 and 1 had a little effects on methane production rate in the anaerobic digestion process study of corn at the medium temperature. Walnut production of our country is the largest in the world. Walnut industry is one of the focus industries in China. However, the study of walnut peel is less. The effect of food-microorganism(F/M)ratio on gas properties in batch biogas fermentation experiments with walnut peel is not studied yet. This experiment by batch fermentation under the condition of 30°C, with walnut peel as fermentation raw materials, and respectively choose F/M(vs/vs)=0.20, 0.15, the effect of food-microorganism(F/M)ratio on the gas properties was studied in biogas fermentation with walnut peel.