Effect of temperature on the characteristics of anaerobic digestion_ of mixture of dung and crop straw | 温度对粪便与玉米秸秆混合厌氧消化产生特性的影响

Chinese. 探索牲畜粪便和玉米秸秆混合发酵的产气量与发酵时间和发酵温度之间的关系，确定农村户用沼气原料和最佳发酵温度，为提高农作物秸秆资源化利用效率提供科学依据。采用自行研究设计的可控性恒温发酵装置，以猪粪、牛粪和玉米秸秆作为发酵原料，以常温厌氧发酵池的底物为接种物，在总固体TS质量分数为8％条件下进行批量试验，在25～40 ℃，每5 ℃设一个温度梯度，研究不同发酵温度对猪粪、牛粪与玉米秸秆按不同比例（质量比为1∶1，2∶1，3∶1）配比混合发酵的产气速率、产气量及发酵时间的影响，并用SAS软件对各因素进行多元回归分析，建立回归方程，得出各影响因子的最优值。在一定温度范围内（25～40 ℃），厌氧发酵产气速率峰值出现的时间和发酵周期均基本随着温度的升高而缩短，峰值和产气量均基本随着温度的升高而增加。从总累积产气量来看，猪粪与玉米秸秆配比发酵优于牛粪与玉米秸秆配比，猪粪、牛粪与玉米秸秆混合厌氧发酵的最佳温度是34 ℃左右，发酵时间为58 d左右。确定了沼气的最佳原料、发酵温度和时间，为农作物秸秆的资源化利用提供了参考。

English. To approach the relationships between the biogas yield of mixed anaerobic fermentation of livestock dung and corn straw and fermentation duration and temperature is the key of selecting fermentation materials for rural household biogas, determining optimal fermentation temperature, and improving the reuse efficiency of agricultural residues. A batch of experiments under the condition of 8% mass fraction of total solid were conducted in a self-manufactured anaerobic fermentation reactor, with pig dung, cattle manure, and corn straw as fermentation materials,and the substrate of constant temperature fermentation pool as inoculation substance. The biogas production rate, biogas yield, and fermentation duration were determined with temperature increasing in increments of 5 ℃ from 25-40 ℃. Multiple regression analysis of the data was conducted and regression equations were established using SAS software. Based on these results, optimal values for temperature and digestion time were determined to maximize biogas yield per unit dry matter. The time to maximum biogas production rate and the overall length of the fermentation duration were shortened as temperature increased from 25 ℃ to 40 ℃ for all the three types of straws. In addition, maximum biogas production rate and biogas yield increased as temperature rose. The cumulative biogas yield of mixed anaerobic fermentation of pig dung and corn straw was higher than that of the fermentation of cattle manure and corn straw. The optimum fermentation temperature and digestion duration from mixture of manure and corn straw respectively were 34 ℃ and 58 d. The study determined optimal fermentation material, fermentation duration and temperature, and provide a reference for improving the reuse efficiency of agricultural residues.