Effect of substrate pretreatment on biogas production through anaerobic digestion of food waste

Abstract

This work presents the effect of autoclave, microwave and ultrasonication pretreatment on anaerobic digestion of food waste co-digested with poultry manure. Four batch reactors with 2 L volume each were used for the study. The reactors were operated with a hydraulic retention time of 30 days and stirred twice a day. The daily biogas production, cumulative biogas production, methane and carbon dioxide composition were measured. The pretreatment of the substrates with autoclave, microwave and ultrasonication caused an increase in cumulative biogas production of approximately 4.67, 6.43 and 10.12% respectively. The degradation efficiency also showed positive result for substrates with pretreatment. The highest cumulative biogas yield was obtained with ultrasonication technique (9926 ml), followed by autoclave, microwave and untreated substrates. The results obtained from the experiments were evaluated to determine the kinetic constants of the process. Modified Gompertz model and Logistic model were used to determine the kinetic parameters of the reaction. The results obtained with the modified Gompertz model was more suitable than the result obtained with the Logistic model for describing the process kinetics.