The Study Characteristics Of The Anaerobic Fermentation For The Organic Waste

Adopting suitable pretreatment methods is critical technic to boost biogas production during the process of anaerobic fermentation of agricultural waste. Marinate methods is adopted to pretreat agricultural waste in experiment. The result shows that organic solid waste pretreated has the advantage of rapid degradation, short start-up time of reactor, high utilizing rate of feedstock, two-bit cost and so on.First, single batches anaerobic process is built in laboratory, and the rigorous anaerobic conditions are provided. The process of fermentation is carried through under medium temperature condition which water is heated to 35℃ to ensure .The influence of pressure is taken into account for the biogas production.Second, sludge taken from Weal village in Haerbin is domesticated. Sludge is used as cultures whose dynamic changes of microorganism are analyzed by Monod equation, at the same time, the marching relation between cultures and materials is analyzed. By electron microscope, the result shows that the cultures have been changed as sludge is domesticated.Third, about pretreatment, the straw has been marinated in water for 3 days, 9 days, 15 days respectively or the straw marinated in 3% and 6% sodium hydroxide for 15 days.The untreated and the treated are sliced up in experiment. The contrast conclusion shows that the more marinating time is adopted, the more remarkable changes of structure phase and digestion effect occur. The pretreatment effect of sodium hydroxide is better than that of distilled water, because cellular wall and fibre fall to more pieces for sodium hydroxide pretreatment.Fourth, the pre-experiment of biomass anaerobic digestion is designed. The result shows that the biogas production of feedstock is improved to adopt the sludge domesticated. To gain more biogas, it is the key to adopt the feedstock pretreated.Fifth, the contrast experiment on the straw and horse dung is designed. The rules of fermentation parameters like VFA, COD, PH, biogas production are studied, when the straw is dipped in water for different time or by different consistences of sodium hydroxide for 15 days. When TS(Total solid rate)is 41. 8%, the COD reduction of the straw dipped in water for 15 days is 63.1%, and the biogas productivity rate is 88.5ml/gTS.The fermentation effect of the straw pretreated for 15 days is better than that of other marinating time. The biogasproduction of the straw pretreated with 6% NaOH is more 4% than that of the straw pretreated with water for 15 days.Sixth, the contrast experiment about cattle dung dealt with different consistences of sodium hydroxide solution is designed .The rules of parameters such as VFA, PH, biogas production during the process of fermentation is studied. The study shows that the fermentation effect is remarkable to adopt cattle dung pretreated with sodium hydroxide solution. When TS is 35. 5%, the effect of cattle dung pretreated with 2. 5% sodium hydroxide solution is the most remarkable, the COD reduction is 66. 9%, and the biogas production rate is 126ml/gTS.Finally, the dynamical balance of microorganism is studied, and the regress equation which is analyzed variance about the relation between biogas production and fermentation time of straw marinated for 15 days is built. The result shows that the fermentation effect of the straw marinated for 15 days is remarkable.