Simulation of an anaerobic digestion system for agricultural residuals generated in the province of Manabí

Abstract

The agricultural sector each year generates a large amount of organic waste, which generally does not receive proper management, producing environmental pollution. Rice straw and banana peel (BP) are among the most produced agricultural residues in Manabi, Ecuador. Anaerobic digestion is an ideal alternative for the treatment of these residuals, the purpose of which is to produce methane. The objective of this work is to propose a model for estimating methane yield from anaerobic digestion of organic waste generated from the elemental characterization. The developed dynamic model is based in the consumption of volatile solids (VS) according to first order kinetics. MATLABR was the software used for the implementation of the model. The statistical criteria for the model implementation were Root Mean Square of Errors (RMSE) and Average Relative Error (ARE). It was possible to represent the anaerobic digestion process of various organic substrates by using the dynamic model based on VS consumption with RMSE values lower than 0.13. Another aspect considered is the estimation of the annual energy generation (48.59 GWh) and fuel savings (3 - 7.5 million USD/year) from the results of the model. Likewise, a factor proposal for the evaluation of the residual and the generation of methane with respect to its biodegradability.