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Effects Of Inoculum On Start-up Perfor-Mance Of Anaerobic Digestion Of Corn Stover And Itsmicrobial Characteristics

Posted on:2019-04-17Degree:MasterType:Thesis
Country:ChinaCandidate:J CaiFull Text:PDF
GTID:2371330551961949Subject:Environmental Science and Engineering
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In the start-up phase of large and medium-sized biogas projects,adding appropriate and high-quality anaerobic active microorganisms as inoculants can increase the degradation rate of anaerobic digestion,shorten the start-up time,increase biogas production,and achieve efficient and stable operation of the project.The type of inoculum at the stage and the characteristics of anaerobic microorganisms in the process are of great significance.In this experiment,the influence of anaerobic digestive performance of corn stover under different inoculum amounts on the influent of pig manure slurry and laboratory corn stover slurry inoculum was studied,and the structure and succession of microbial community in anaerobic system were studied.The content and results are as follows:The effect of inoculum on batch anaerobic digestion performance of corn stover was studied.Six groups of inoculum gradients were set up.It was found that under the same inoculation quantity,the pig manure biogas slurry was earlier than the peak of gas production of corn stover biogas slurry,and the highest cumulative gas production was 17.4%higher than that of corn stover slurry solution.The material removal efficiency of pig manure slurry as an inoculum was also significantly higher than that of corn sorghum slurry.The increase of inoculum volume within a certain range can lead to the peak of gas production in advance,increase the daily gas production of raw materials and anaerobic digestion efficiency.The effect of inoculum on the start-up performance of batch anaerobic digestion of corn stover was studied.The performance of sequential batch anaerobic digestion was compared between the two groups of inoculants under three different inoculum gradients.The results showed that the same inoculum,the growth of inoculum size can increase the gas production and methane production at the start-up phase,but the effect on the methane content was not significant.In the first HRT,the inoculum volume had no obvious effect on gas production performance and material conversion rate.influences.Compared with corn sorghum slurry,pig manure slurry can be used as an inoculum to reach the peak of gas production and methane production faster.The duration of the acidification phase is shorter,and the VFAs accumulated in the early start-up period are transformed more quickly and during the start-up phase.There are higher TS,VS,and cellulose removal rates.3.The PCR-DGGE technique was used to analyze the succession of inoculants during the initiation of anaerobic digestion of sequencing batches.Before and after domestication,the difference in dominant microorganism species was not significant,but the abundance varied greatly.The two types of bacteria in the system,Firmicutes and Clostridiales,have been dominant in the anaerobic digestion system,but Bacteroidetes and Verrucomicrobia have also emerged.Lactospiraceae and other bacteria that are more suitable for anaerobic digestion.4.At the microbiological level,the high-throughput sequencing method was used to compare the anaerobic conditions in the early and late start-up systems.Microbial community structure characteristics.The results showed that there were significant differences in the distribution and abundance of bacteria and archaea during the anaerobic digestion of the two types of inoculum.The richness,diversity and evenness of bacteria and archaea community increased in the pig manure slurry group,but decreased in the corn straw biogas slurry group.In the distribution of bacteria,Bacteroidetes and Firmicutes have always been dominant bacteria in the system.Methanosarcina and Methanobacterium are dominant methanogenic archaea in all systems.
Keywords/Search Tags:corn stover, anaerobic digestion, Inoculum, microbial-community, PCR-DGGE, high-throughput sequencing
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