Influence of kinetic variables on biogas production evaluated with a simplified mathematical model

Abstract

Currently, society in general depends heavily on energy that is limited, due to this, the generation of sustainable energy is being sought and one of these is the production of biogas through anaerobic digestion (AD), where bacteria degrade organic matter. This process has shown great advances; however, it is necessary to continue studying the behaviour of bacteria in the face of the great variability of the environment to which they are exposed. To evaluate the kinetics of growth and consumption of microorganisms when using residual sludge from the Juan Diaz WWTP, which supplies the city of Panama, an experimental DA test was carried out for a period of 15 days, in order to know the biogas production, and consequently, a model based on differential equations describing the process was used to understand how the microorganisms reacted to the imposed conditions. The model used employed initial parameters extracted from literature and was later calibrated to real conditions where it was possible to demonstrate that the influence of temperature, for example, has a strong impact on the increase in the speed with which the microorganisms degrade the material and the conversion factor to biogas, despite this, it is extremely important to know the substrate that will be used, constantly monitor and study continuously how to reduce the effect of inhibitions that can complicate the development of the process.