| China is a large agricultural country and produces a lot of pig manure every year,and these pig manures are not fully utilized.Pig manure contains a large amount of organic matter,which can be used as a high-quality material for anaerobic digestion.Using anaerobic digestion technology to convert the organic matter in pig manure into clean energy biogas can not only improve the existing environmental problems,but also have economic benefits.BMP is an important parameter in the evaluation of anaerobic digestion technology.The default value can be consulted through the IPCC,but the default value is suitable for regional inventory studies,and there are often large uncertainties in the evaluation of methane in pig manure management in pig farms.Although the actual measurement can get a more accurate BMP value.However,the BMP experiment has relatively complicated experimental conditions,long test cycles,high cost,and low feasibility.It is difficult for most pig companies to complete.At the same time,the organic components in pig manure are more complex,and the organic components in different types of pig manure are also different,which also has special significance for the study of the potential of pig manure for methanogenesis.This article takes nursery pigs,growing pigs and pregnant sows as the research objects,using Fourier infrared change analysis,three-dimensional fluorescence spectroscopy analysis,thermogravimetric analysis,ultraviolet-visible spectroscopy analysis and other qualitative analysis methods for organic matter,headspace-meteorological chromatography,etc.Quantitative detection methods to study the relationship between the organic components of pig manure and the methanogenic potential,establish a mathematical model,and get the following conclusions.(1)Through the experiment and analysis of the biogenic methanogenic potential of organic components in pig manure at different growth phases,the results show that the BMP values of the nursery pigs and growing pig manures are 273 ml CH4 / g VS and 272CH4 / g VS,respectively.Close to,the BMP of pregnant sows is 220 ml CH4 / g VS,which is the lowest among the three pig manures.Fourier infrared spectrometer and thermogravimetric analyzer were used to detect organic matter in pig manure samples,and ultraviolet-visible spectrophotometer spectroscopy and fluorescence spectrometer were used to detect organic components in fecal DOM extract.Through testing,it is found that the content and composition of organic matter in nursery pigs and growing pig manure are similar,while the content of organic matter in pregnant sows is low,and contains more cellulose,lignin,and aromatic compounds.The substance is highly humified and difficult to degrade,so its methane generation potential is low.(2)Through the establishment of a model for estimating the potential for methanogenesis of volatile fatty acids,it is calculated that the correlation coefficient R2 of the model is 0.94,which proves that the model has a good correlation.The p value is 0.0038,which is less thanthe significance level,which proves that the regression model is established.And compared with the model made by the predecessors,it is concluded that the volatile fatty acid prediction model has the characteristics of quasi and fast.(3)Through the migration and transformation experiments of pig manure organic matter under normal temperature anaerobic digestion conditions,the results show that the cumulative methane production of pig manure samples is 151.12 ml / g VS,and the maximum daily methane production is 3.75 ml / g VS;the concentration of organic matter in the digestive juice decreases,However,the content of humin and tyrosine increased;cellulose and hemicellulose in the raw materials were continuously decomposed,and lignin was deposited in the digestive juice. |
