Study On Dry Anaerobic Fermentation Technology Of Dairy Cow Manure In Shilin Xuelan Pasture

Cow manure is a kind of biomass resource with great potential for utilization.The dry anaerobic fermentation process can obtain a large amount of energy recovery and avoid pollutant discharge,which is an effective way.Due to the lack of relevant studies on anaerobic dry fermentation of cow manure,this study took cow manure from Xuelan dairy farm in Shilin county as the raw material to explore the process of anaerobic dry fermentation of cow manure,so as to realize the resource and energy utilization of ranch cow manure.In order to improve the methane production efficiency of anaerobic dry fermentation of cow dung,the suitable technological conditions(fermentation concentration and inoculation amount)were explored,and different additives(biochar,walnut shell ash,fly ash,magnetite powder and vermiculite)were tried to avoid the adverse effects in fermentation.The situation of methane content,daily methane production,organic matter degradation and organic acid change in the experiment were concerned the conclusions are as follows:(1)The best fermentation concentration and inoculum quantity were 22% and 40%,respectively.The higher the fermentation concentration,the worse the gas production effect,that is,the lower the methane production of vs.The larger the inoculation amount,the faster the start of dry anaerobic fermentation.The increase of inoculum quantity is beneficial to dry anaerobic fermentation.In the 50% inoculation group,the average methane content was the highest but the methane production was not high.(2)By adding adsorption additives,the methane production of dry anaerobic fermentation was increased.The most suitable group of biochar is 600 H group,and the most suitable amount of vermiculite is 5%.The addition of biochar enriched the anaerobic microorganism in the middle stage of fermentation,greatly promoted the methane production efficiency of dry anaerobic fermentation;the addition of vermiculite kept the organic acid at the appropriate fermentation level in the early stage of fermentation,advanced the fermentation peak,and improved the methaneproduction in the peak period of fermentation.Adding biochar and vermiculite increased methane production by 30.52% and 21.03% respectively.(3)By adding trace element additives,the methane production of dry anaerobic fermentation was increased.The most suitable addition of walnut shell ash and magnet powder was 2% and 5%,respectively.Adding appropriate amount of ash is beneficial to the protection of acid-base buffer equilibrium system in fermentation,while adding excessive ash(10%)can inhibit gas production.The addition of magnetic powder can obviously promote the methane content in dry anaerobic fermentation,which may be due to the role of trace element Fe.The addition of ash and magnet powder increased methane production by 20.85% and 17.99% respectively.The addition of fly ash,which has the effect of adsorption and trace elements,also increased the methane production of dry anaerobic fermentation.The effect is similar to that of ash.The most suitable addition is between 2% and 6%,and the highest methane production is 10.5% higher than that of the control group.