Mechanism and kinetics model of hydrolysis in anaerobic digestion of kitchen wastes

The profile of hydrolysates during the anaerobic digestion of kitchen wastes was investigated. The experimental results show that the hysteresis of hydrolytic rate is mainly controlled by the diffusion effect. The hydrolytic mechanism of kitchen wastes is elaborated by taking the diffusion effect into consideration. A segment model of the hydrolysis for kitchen waste is formulated including the coefficient of diffusion resistance in the model. The coefficients of diffusion resistance for different particle sizes are 1.42, 2.12 and 2.78 respectively based on the experimental data, in which the coefficients of diffusion resistance conform an exponential function. So, the partitioning kinetic model could be integrated as a unified experience model. The model is verified with experimental data, which shows that the model could predict the concentration of organic substances during the anaerobic digestion of kitchen wastes.