Study On Biogas And Fertilizer Production Potential Of Wheat Straw Mesophilic Dry Anaerobic Fermentation

This paper is aided by national agricultural technology great-leap-forward plan project'Integration And Demonstration Of Recycle Agricultural Technology With Straw Energy Utilization As Core'(No.2130106-38). It surrounds tight the great demand in our country of vigorously developing and exploiting biomass energy, contraposes how to improve comprehensive utilization benefit of crop straw anaerobic dry fermentation, uses wheat straw which distributes widely as mesophilic anaerobic fermentation material, and mensurates biogas output and anaerobic fermentation residues (AFR) fertility of wheat straw mesophilic anaerobic dry fermentations in different conditions. This paper tries to make certain of the relationship between biogas output and the fermentation conditions and the relationship between AFR fertility and the fermentation conditions, aims to provide optimized technological parameters for co-production technology of biogas and organic fertilizer of crop straw mesophilic anaerobic dry fermentations and scientific references for further improving the theory and exploiting biogass and organic fertilizer co-production technology of straw mesophilic anaerobic dry fermentation.This paper studied mainly from the following aspects:(1) The relationship between total solid (TS) content of fermentation material and biogas output. Four anaerobic dry fermentation groups, TS25%, TS35%, TS45% and TS55%, which had same straw and inoculum content, showed that: the fermentation groups which had less TS content producted more biogas.(2) The relationship between the amount of inoculum and biogas output. Six mesophilic anaerobic dry fermentation groups with same amount of straw and TS25%,whose straw-residues ratio were 1:6, 1:8, 1:10, 1:12, 1:14 and 1:16, showed that: biogas output rose gradually while the amount of inoculum increased gradually; biogas output of per TS mass rose in the first and then being less, it was because that excessive inoculum was detrimental to efficiency of biogas production. The best straw-residues ratio was 1:10, and in this condition, biogas output of per TS mass was 75.4mL/g.(3) The relationship between the amount of inoculum and methane output. The experiments showed that: methane output and methane concentration rose gradually while the amount of inoculum increased gradually; methane output of per TS mass rose in the first and then being less, it was because excessive inoculum was helpful to increase methane output and methane concentration but detrimental to efficiency of methane production. The best straw-residues ratio was 1:10, and in this condition, methane output of per TS mass is 31.8mL/g.(4) Fertility of AFR producted by fermentations in different conditions. The experiments showed that: the AFR of wheat straw mesophilic anaerobic dry fermentation contained enough nutrient substances, its fertility met completely the requirements of National Microbial Organic Fertilizer Production Requirements (NO. NY 884-2004), and closed to National Organic Fertilizer Technical Index (NO. NY 525-2002). Under the condition, TS content of fermentation material was 55% and straw-residues ratio was 1:6, the fertility of AFR was the best.(5) Presented a set of biogas and organic fertilizer co-production process of straw anaerobic dry fermentation.Colligating conclusions of experiments above, the best fermentation condition of wheat straw mesophilic anaerobic dry fermentation was worked out: TS content of fermentation material should be 55%, straw-residues ratio was 1:10, and a set of biogas and organic fertilizer co-production process of straw anaerobic dry fermentation, using biogas as production energy, was presented.