The Correlation Between Volatile Fatty Acid And Gas Production During Solid-state Fermentation Of Food Waste

In this study,sequencing batch anaerobic digestion of food waste was carried out to analyze methane concentration and methanogenic potential in anaerobic digester,and then perform continuous solid state fermentation on the basis of sequencing batch anaerobic digestion experiments.The correlation of volatile fatty acids?VFAs?with gas production during the solid-state fermentation of kitchen waste,observation of changes in pH,ammonia nitrogen,VFAs and other parameters during the whole solid-state fermentation process;finally,the data were used to derive and apply the acid production model.The results showed that under the condition of medium temperature,daily production of methane in anaerobic digestion of food waste with different substrate concentrations varied in different ways.With the increase of substrate concentration,the number of gas production peaks increases and the highest daily production rate gradually increases.The daily output of methane was correlated with p H,VFAs and the contents of various components;COD content of food waste with different substrate concentrations was in line with the daily output of methane Negative correlation trend.With the increase of substrate concentration,the anaerobic biodegradation firstly increased and then decreased,while the concentrations of biogas methane produced by anaerobic digestion of 4%,5%and 6%,the highest values were74.95%,61.39%,and 56.42%,respectively.According to the changes of gas production and other parameters of VFAs,the process of solid-state fermentation of food wastes was divided into four stages:adaptation stage,startup stage,inhibitory stage,and recovery and stabilization stage.The volumetric gas production rate,VFAs and the various parameters showed different stages of change in different periods:the gas production and the feeding intensity were relatively low during the adaptation and inhibition stage,and the VFAs content was stable between 20 and 22 g·L^-1 in the recovery and stabilization stages.Gas production increased significantly,TS reached over 20%,the system volume gas production and biodegradation rate remained relatively stable;VFAs output and components with pH and volume gas production rate influence each other.Finally,the model of gas production and acid production was deduced based on the cumulative gas production and VFAs production in continuous solid state fermentation experiments.