Predicting Biogas Production by Anaerobic Digestion of Organic Wastes through Kinetic Modeling

The objective of this work is to test the capability of the first order kinetic model and Gompertz model to describe the volume of biogas produced by anaerobic digestion of organic solid waste versus time. The test was done by two ways: first, by using data obtained experimentally form the codigestion of Prosopis Juliflora sawdust with camel, chicken, cow manure and wastewater sludge at 37degree celsius for a period of 60 days and second by using experimental data available in open literature. The adequacy of the models was assessed by calculating R-2 and the residual sum of squares (RSS). The results showed that Gompertz model is more successful in representing the volume versus time data. The first order kinetic model was not capable of doing so for most of the cases studied. Codigestion of Prosopis Juliflora sawdust with animal manure showed that codigestion with chicken manure gave the highest amount of biogas whereas codigestion with camel manure gave the lowest amount of biogas. The amount of biogas produced upon codigestion of Prosopis Juliflora sawdust with animal manure follow the following order: P. Juliflora + chicken manure > P. Juliflora + wastewater sludge > P. Juliflora + cow manure > P. Juliflora + camel manure.