Effect Of Ratios Of Human Feces Mixed With Different Materials In Anaerobic Fermention On Biogas Production

The survival and development of human has always been accompanied by a large number of organic waste generation, as improvement of people's living standards and the development of agricultural production, organic waste-human feces, crop residues, animal wastes, increasing emissions on the environment, and the pollution is also becoming increasingly serious.Therefore, to develop the technology of biogas, not only provided a biogas energy source for people, but also made use of human feces, crop straw, livestock manure and other organic waste, at same time also provided for the farmers with organic fertilizer, so the technology of biogas has significant energy, economic, ecological and environmental benefits.The research studies of the biogas production efficiency of human feces mixed with different materials in anaerobic fermentation. It is provide a scientific basis and technical support to solve the rural energy shortage, improve utilization of human feces, animal dung and crop residue of resource, achieve the controllability of biogas fermentation.A batch of experiments under the condition of 8% mass fraction of total solid were conducted in a self-manufactured anaerobic fermentation reactor, with human feces, cattle manure,chicken dung and corn straw rice straw as fermentation materials at different ratios(1:1,2:1,3:1), it chooses 15℃,20℃,25℃,30℃four constant temperature. Through research the main conclusions were draw as following:(1) Whether single human feces or human feces mixed with different raw material can make biogas.And it starts faster, it can occur production peak in a relatively short time, and the daily gas curve is basically similar. After the peak, the biogas production rate decreased rapidly, then usually there will be a number of small peaks, until the end. Under 15-30℃constant conditions, the average cumulative biogas production of human feces in order of 20℃>15℃>30℃>25℃.The best biogas-producting efficiency was observed at 25℃, and the cumulative biogas production can reach 20645 mL.(2)When human feces mixed with cattle dung, under 15-30℃, the best biogas-producting efficiency was observed when human feces mixed with cattle dung at the ratio of 1:1 at 20℃, and the cumulative biogas production is highest.It can reach 35820 mL. The average cumulative biogas production of human feces mixed with cattle dung in order of 20℃>15℃>30℃>25℃, the ratio of 3:1 was the best in the group of human feces with cattle dung at 15,25,30℃, and the duration peak of biogas production is the longest,but the ratio of 1:1 was the best in the group of human feces with cattle dung at 20℃, and the duration peak of biogas production is also the longest.(3)When human feces mixed with chicken dung, under 15-30℃, the best biogas-producting efficiency was observed when human feces mixed with chicken dung at the ratio of 1:1 at 20℃, and the cumulative biogas production is highest.It can reach 35850 mL. The average cumulative biogas production of human feces mixed with chicken dung in order of 20℃>25℃>30℃>15℃, the ratio of 3:1 was the best in the group of human feces with chicken dung at 15,30℃, and the duration peak of biogas production is the longest but the ratio of 1:1 was the best in the group of human feces with chicken dung at 20,25℃.and the duration peak of biogas production is also the longest.(4) When human feces mixed with corn straw, under 15-30℃, the best biogas-producting efficiency was observed when human feces mixed with corn straw at the ratio of 3:1 at 20℃, and the cumulative biogas production is highest.It can reach 46952 mL. The average cumulative biogas production of human feces mixed with corn straw in order of 20℃>15℃>30℃>25℃, the ratio of 3:1 was the best in the group of human feces with chicken dung at 20℃,25℃,30℃, and the duration peak of biogas production is the longest. But the ratio of 1:lwas the best in the group of human feces with corn straw at 15℃, and the duration peak of biogas production is also the longest.(5) When human feces mixed with rice straw, under 15-30℃, the best biogas-producting efficiency was observed when human feces mixed with rice straw at the ratio of 3:1 at 20℃,and the cumulative biogas production is highest.It can reach 32700 mL ml. The average cumulative biogas production of human feces mixed with rice straw in order of 20℃>25℃>15℃>30℃, the ratio of 3:1 was the best in the group of human feces with rice straw at 25℃,30℃, and the duration peak of biogas production is the longest, but the ratio of 1:1 was the best in the group of human feces with rice straw at 15℃,20℃,and the duration peak of biogas production is also the longest.(6) When human feces mixed with wheat straw, under 15-30℃, the best biogas-producting efficiency was observed when human feces mixed with wheat straw at the ratio of 1:1 at 20℃, and the cumulative biogas production is highest.It can reach 35657 mL. The average cumulative biogas production of human feces mixed with rice straw in order of 20℃>30℃>25℃>15℃, the ratio of 3:1 was the best in the group of human feces with wheat straw at 25℃,30℃, and the duration peak of biogas production is the longest, but the ratio of 1:1 was the best in the group of human feces with wheat straw at 15℃,20℃,and the duration peak of biogas production is also the longest.(7) Under 15-30℃When human feces mixed with five different material of three ratios in anaerobic fermentation, at 20℃the best biogas-producting efficiency was observed in the group of human feces mixed with corn straw and he ratio of 3:1 is the best in threes ratios, its cumulative biogas production is the highest,it can reach 46952 mL; at 15℃the best biogas-producting efficiency was observed in the group of human feces mixed with rice straw; at 25℃the best biogas-producting efficiency was observed in the group of human feces mixed with cattle dung; and at 30℃the best biogas-producting efficiency was observed in the group of human feces mixed with wheat straw. The same time at four temperatures, the biogas production of each group of human feces mixed with different materials was higher than that of the group of pure human feces.