菌剂预处理秸秆与牛粪混合对厌氧发酵产气的影响

Effect of Straw Microbial Agent Pretreatment on Biogas Production Performance by Anaerobic Co-digestion of Cow Manure and Straw

根据原料木质纤维素的降解程度及处理后的发酵产气试验,筛选适宜的菌剂和添加量。选取市场上常见的7种复合菌剂,将其活化后接到玉米秸秆中,对预处理后的玉米秸秆进行纤维素含量测定,结合滤纸条崩解试验结果得出,菌剂1和菌剂5的纤维素、半纤维素降解率较高,分别为21.98%,19.86%,故选取菌剂1和菌剂5作为产气发酵潜力试验的预处理剂。将2种菌剂分别设置5个接种浓度(0.2%,0.5%,1.0%,2.0%,5.0%)处理,以未处理的秸秆发酵组合作为对照,将玉米秸秆与牛粪(VS)比为5∶5比例后混合进行厌氧发酵,经测定,菌剂1和菌剂5最佳预处理量为菌占干秸秆量的2.0%。菌剂1在此用量下,累积产气量、VS产气量及产甲烷总量是所有组合里最高的,分别为10403.4 mL,326.52 mL·g^(-1),5892.66 mL,高出对照18.83%,19.32%,21.44%。菌剂5在此用量下,日产气量为647.34 mL·d^(-1),累积产气量为10329.13 mL,产甲烷总量为5807.28 mL。综上,菌剂对玉米秸秆预处理后,可加快降解纤维素、半纤维素的分解速度,和牛粪混合后进行厌氧发酵,对累计产气量、VS产气量和产甲烷总量均有促进效果,对提高厌氧发酵效率,提升畜禽粪污处理速度,降低环境污染具有重要意义。

The optimum microbial agent and additive amount were determined in this study according to the degradation of lignocellulose and biogas production performance of anaerobic co-digestion of straw pretreated with microbial agent and cow manure.Seven groups of microbial agent were selected,activated and added to the corn straw.The results of cellulose-hemicellulose content determination and filter paper strip disintegration test of pretreated corn straw indicated that microbial agent 1 and microbial agent 5 showed the highest cellulose-hemicellulose degradation rate of 21.98%and 19.86%,respectively.Therefore,microbial agent 1 and agent 5 were selected as pretreatment agents for the biogas potential test.Experiments with cow manure and corn straw(mixture with volatile solid)ratio 5∶5 at different inoculation concentration 0.2%,0.5%,1.0%,2.0%,5.0%of agent 1 and agent 5 were carried out,while the experiment with cow manure and untreated corn straw was set as the control group.A series of indicators were determined,it could be concluded that the best pretreatment amount of both agent 1 and agent 5 was 2.0%of the dry straw amount.The cumulative biogas production,VS biogas production and methane production of agent 1 at inoculation concentration of 2.0%were the highest,reached 10403.4 mL,326.52 mL·g^(-1),5892.66 mL,which were 18.83%,19.32%and 21.44%higher than that of the control group,respectively.While the agent 5 was inoculation concentration of 2.0%,the daily biogas production cumulative biogas production and methane production were 647.34 mL·d^(-1),10329.13 mL,5807.28 mL,respectively.In conclusion,the pretreatment of corn straw with microbial agent can accelerate the degradation rate of cellulose as well as hemicellulose,anaerobic co-digestion of cow manure and pretreated corn straw can promote the cumulative biogas production,VS biogas production and total methane production,which is of great significance to improve the efficiency of anaerobic digestion,promote the processing speed of livestock manure,and reduce environmental pollution.