Effects Of Magnetite Powder On Anaerobic Fermentation Of Pig Manure And Wheat Straw

Energy utilization of biomass energy is an important measure to solve energy and environmental problems in rural areas of china.The biogas utilization in anaerobic fermentation can not only effectively solve the environmental hazards of rural waste,but also produce clean energy biogas,to meet the growing demand for energy.In this study,batch anaerobic fermentation texts were conducted.Pig manure and wheat straw as fermentation materials,magnetite powder(0 g,1.5 g,3 g,4.5 g and 6 g)were added to the reactents of per 700 mL,which were respectively arranged at 15℃,20℃,25℃,30℃,35℃ for 51 days.In order to study the efficiency of anaerobic fermentation of pig manure and wheat straw at low temperature,the relevant indicators of the fermentation process were determined and analysed.It can not only provide a theoretical basis and experimental support for the optimization of anaerobic fermentation in medium to low temperature,but also provide a feasible and easy operation way for household to improving the efficiency of biogas fermentation.The main conclusions are as follows:(1)When the single and mixed raw materials of pig manure and wheat straw were fermented at medium and low temperature,the optimum dosages of magnetite powder at different temperatures were obtained.The optimum amount of magnetite powder of pig manure fermentation during 15~35℃ were 4.5 g,3 g,3 g,3 g and 4.5 g respectively.The optimum amount of magnetite powder of wheat straw fermentation during 20~35℃ were 6 g,3 g,4.5 g,1.5 g respectively.The optimum amount of magnetite powder of mixed materials fermentation during 15~35℃ were 4.5 g,1.5 g,1.5 g,1.5 g and 3 g,respectively.(2)Magnetite powder with different degrees of effect on promoting methane production of pig manure,wheat straw and mixed fermentation.The best effect on promoting was abtained in pig manure,the second in wheat straw,and the lowest in mixed materials,and the best promotion were obtained at temperature of 35℃,30℃,and 15℃.(3)Adding proper dose of magnetite powder can make the pH value drop and recover quickly,and promote the start-up of fermentation system.It can make the alkalinity value rise faster and easier to maintain stability,and increase the buffer force of the fermentation system.(4)At different temperatures,the amount of magnetite powder in certain range can promote cellulase activity(CEA)and dehydrogenase activity(DHA).When different substrates were fermented at different temperatures,the dose ranges of magnetite powder to promote the activity of two enzymes were different.(5)In the fermentation of pig manure,the correlation between methane production and dehydrogenase activity higher than that with cellulose.In the fermentation of wheat straw,the correlation between methane production and cellulase activity decreased with the increasing of temperature,and that with dehydrogenase activity increased with the increase of temperature.In the fermentation of mixed,the higher correlation between methane production and the two kinds of enzymes was abtained at 20℃.The magnetite powder had no significant effect on the correlation between methane production and the activities of two enzymes.