Mathematical modeling and simulation of the composting process in a pilot reactor

Abstract

 In this paper, a mathematical model for composting process with an engineering approach was presented. The model describes the n-th order kinetics of composting process (mesophilic-thermophilicphase) with mass and heat balances in the process. Verification of the model was performed using experimental data obtained from a pilot reactor. Measured dynamic state variables used for a verification of the model were: organic matter mass, water mass in a mixture, amount of oxygen and carbon dioxide, temperature of mixture and the temperature of gas phase. The developed mathematical model was implemented in numerical software package MATLAB. Three kinetic parameters were estimated using the Marquardt method. Global sensitivity analysis and statistical F-test showed that the model is valid for predicting the change in five dynamic state variables. The advantage of the model is that it can be applied to the composting process with mixtures of different compositions in reactors with different volumes.