Kinetics of batch biomethanation process of jatropha and pongamia oil cakesand their co-digested substrates

624-629Batch anaerobic digestion of substrates of jatropha and pongamia oil cakes and mixtures with cattle dung (1:1, oil cake:fresh cattle dung) were carried in aspirator bottles (5 l each) for 60 day hydraulic retention time (HRT). A first order equationhas been derived for kinetic behavior under batch anaerobic digestion. A simple method to fit constants of model using only onesingle linear regression is presented and these constants are used to determine and compare kinetic rates of each mixture. Mostproductive biogas yield corresponds to mixture of jatropha cake and pongamia cake co-digested with 50% cattle dung, havingdilution ratio of 3.5-4, with former mixture giving highest daily biogas yield. This is due to co-digestion with cattle dung, whichoffered good startup to biomethanation process. Kinetic rate constant of biomethanation process of jatropha and pongamiacake substrate are high in comparison to biodegradation of cattle dung, due to presence of more volatile solids in oil cake, leadingto higher conversion efficiency of volatile solids into biogas