The Effect Of Methane-Producing By Adding Biochar On Corn Straw Bar And Cow Dung Anaerobic Fermentation Under Alkaline Conditions

In today’s society,with the continuous progress of science and technology and the increasing awareness of environmental protection,the treatment and utilization of agricultural waste has become a topic of great concern.Among them,corn stover as a common agricultural waste,due to its hard texture,difficult to degrade and other characteristics,facing the problem of difficult to be effectively used.The difficult utilization of straw not only causes waste of resources,but also brings negative impact to the environment,therefore,we urgently need to find an effective solution.In order to improve the utilization rate of straw during anaerobic fermentation,this experiment firstly added NaOH,KOH and biochar to different mixed ratios of straw and cow manure substrate to observe the effect of methane production during fermentation,and used Box-Behnken The design was carried out to investigate the effects of straw and cow manure solid mass concentration(TS),fermentation temperature,NaOH,on gas production efficiency with the response value of biogas production from mixed anaerobic fermentation of straw and cow manure,and secondly,to improve the speed and efficiency of experimental data processing,a database of straw and cow manure substrates with different mixing ratios was established,and finally,a waste anaerobic fermentation plant was designed that could improve the fermentation rate of straw and cow manure substrates.equipment that can improve the fermentation rate of straw and cattle manure substrate.The specific research contents are as follows:(1)Experimental study on the effect of adding lye and biochar on the methanogenic efficiency of straw and cow manure in anaerobic fermentation.Since the change of pH during fermentation can reflect the microbial metabolism,and the stability of microbial metabolic process has an important influence on methane concentration and cumulative methane production,the experimental substrate pH,methane production content,total methane production,methanogens population and other indicators were evaluated,and it was found that in different mixing ratios of straw and cow manure methane reactors 0:1(S1),1:2(S2),and 2:1(S3),1:3(S4)and 3:1(S5),the best methane yield of 196.3 mL/g TS was observed for the mixed addition of biochar and NaOH(S4),which increased the highest total methane production by 8.2%compared to the control group.The anaerobic microbial consortium of straw and cow manure substrate with the addition of biochar and NaOH had more stable pH changes and higher bacterial population,which was more favorable to improve methane production.Since the addition of KOH,NaOH and biochar obtained a large amount of methane production data with different mixing ratios of straw and cow manure,the resulting data were used to build a database to improve the speed and efficiency of data processing.(2)The single-factor static experiment method was used to optimize the mixed anaerobic fermentation technology of straw and cow dung for gas production,and the Box-Behnken design method was applied to investigate the effects of,straw and cow dung solids concentration,temperature,and NaOH concentration on gas production efficiency.The results predicted that the best mixed substrate conditions were 11.67% substrate solids concentration,40.37 ℃fermentation temperature,and 2.115% NaOH concentration optimal mixed gas production of2161.92 mL,and the overall gas production was 2050±100 mL after multiple sets of validation experiments,with an error within 5%.(3)In order to test the feasibility of laboratory biogas process industrialization.Experimental research and development of anaerobic fermentation equipment of corn straw and cow manure,using multi-layer stirring paddle and stirring gear structure,increase the surface area of anaerobic fermentation stirring equipment,promote the mixing of organic materials such as corn straw and cow manure.In the experiment,the equipment was used to simulate industrial production conditions for scale-up production.Under normal temperature conditions,the results showed that the highest concentration of methane could reach 67.2%,and the methane production was 121.3 mL/g TS.In this study,the efficiency of methane production from anaerobic fermentation of straw and cow manure was optimized using the addition of biochar and NaOH,and was evaluated and validated using various experimental tools.By establishing a database and using the Box-Behnken design method,optimal mixed substrate conditions were found and the waste anaerobic fermentation equipment was redesigned to further improve straw utilization in anaerobic fermentation.Experimental data and optimization schemes were provided for the application of anaerobic fermentation technology,and also provided some reference for waste treatment and resource utilization.