Kinetics Of Hydrolysis And Biogas Production For Kitchen Waste Dry Anaerobic Fermentation

The sequence batch and continuous anaerobic fermentation experiment for kitchen waste and its component（starch, protein, cellulose and fat） were performed at 37℃. The sequence batch experiment for single component and kitchen waste lasted 50 days and 30 days, respectively, the continuous anaerobic fermentation experiment conducted for 121 days, the latter achieved dry fermentation stable operation. Models were deduced and used based on the data.Fat had the longest lag phase time, followed by protein and cellulose with the lag phase time. Starch almost had no lag phase time. The experimental data and fitting data of models showed that the hydrolysis of starches preferred to follow the model of cylindrical particulates, and that of celluloses, fats and proteins preferred to follow the model of plat particulates. For biogas production, starches exhibited highest rate, followed by protein and fats, and celluloses exhibited lowest rate, respectively. Accumulated biogas production per gram volatile solid followed zero order hydrolysis kinetics for protein and celluloses and that of fat follow cubic function model for fat within the lag phase time. Based on the composite analysis, biogas production kinetics model was obtained during the whole experimental period for starches, proteins, celluloses and fats, which can provide the theoretical basis for anaerobic digestion. The model which contains this item（lnym+lnk） was used to analyze the characteristics of biogas production in organic waste anaerobic digestion process. Starch had the best characteristics of biogas production, followed by protein, fat and celluloses.Kitchen waste anaerobic fermentation biogas production model was obtained on the basic of single component biogas production model. Kitchen waste anaerobic fermentation conform to the first order model. The whole process can be divided into 4 periods depending on the gas production rate: start-up period（1²8d）, Inhibition period（29⁵1d）, restoration period（52⁷2d） and stabilization period（73¹21d）, and also can be divided into 3 stages（quadratic function stage: 1³0d; power function, 31⁶5d; linear function, 66¹21d） depending on the different function relationship. In dry kitchen waste fermentation, depending on the hydraulic retention time（HRT）, organic loading rate（OLR）, and maximum gas production rate of kitchen waste at different fermentation phases, the reaction rate constant k was found to be 0.3434d^-1,and biodegradation kinetic model was obtained.