The Research On Biogas Production Of Anaerobic Digestion Of Dairy Manure

In the late of1990s,with the effective adjustment of China’s agricultural structure,and the rapid advance of idustrialization of agriculture. Livestock production is increasing at a great scale. Resulting in animals waste is much more than the asorptive capacity of surroundings.Because of the management is relatively lag behind and the level of the natural decomposition is limited, animal waste pollute the ecological environment and landscape,and the health of residents severely.Anaerobic digestion technology treating animal waste of predominance of economical, ecology, energy and environment protection. So anaerobic digestion technology is used in animal waste treating widely.Based on the anaerobic digestion technology of dairy manure, exploring the key factor of this technology.This paper focuses on some aspects as followed:1. The effects of different temperature on anaerobic digestion:thermophilic fermentation (50±1℃mesophilic fermentation (35±1) and room temperature fermentation, fermentation time is30days.The fasting rate of starting is thermophilic fermentation, then is the mesophilic fermentation.Because of the instability of thermophilic fermentation, the biogas yield of thermophilic fermentation、mesophilic fermentation and room temperature fermentation is99669mL、99640mL and19690mL.And the lignocellulose degradation rate is inscreasing as the temperature is increasing.Considering both potential biogas yield and heat requirement, the optimum digester temperature setting is one of the most critical factors for the economically viable digester operation.And thermophilic fermentation is more vulnerable to the effects of toxic substances and the temperature fluctuation.Therefore, mesophilic fermentation is more economical and stabilizing.2.Dry anaerobic fermentation is set at (35±1)℃, with four TS of15%,20%,25%,30%in5L digester, the four anaerobic digestion period including gas production peaks, stationary phase and the tailend.the gas yield is largest at the TS of30%, the gas yield of the four tests is60887ml,84670ml,89977ml,122975ml, the removal of VS is32.9%,25.3%,21.9%,16.45%, respectively. pH is6.8-7.4, the start-up period is successfully, the highest rate of lignocellulose degradation is at TS of20%. Dry anaerobic fermentation is set at (35±1)℃, with four inoculum concentration25%,30%,35%,40%in5L digester,the best "supply-demand relation" is30%. Ntrient solution,active carbon and FeSO4.7H2O were added to the500mL anaerobic digester.The results showed that nutrient solution,active carbon and FeSO4.7H2O could promot the anaerobic fermentation of cattle manure.Compared with the blank control group,the gas yield was increased by8%,22%and11%.3.An orthogonal experiment program was carried out,to determine the effect of TS、temperature、inoculation concentration and additives on total biogas yield.The results showed that:the temperature effect the total biagas yield the most,followed by TS、inoculation concentration and additives.4.Extract the microbial DNA from the activated sludge,compared five methods,the results indicate that liquid nitrogen grinding method and TENP methods are best.The DNA from the activated sludge has high yield、pure and not need further purification.Get specific bands by polymerase chain reaction(PCR).