Synergistic and antagonistic effects in anaerobic co-digestion. Analysis of the methane yield kinetics

Abstract

Anaerobic digestion (AD) is a process of decomposition of organic matter in which the main product is a gaseous mixture called biogas, which has potential as a fuel. Anaerobic co-digestion (ACoD) is a technological alternative to improve the performance of the process, focused on balancing the C/N ratio and diluting inhibitory components. The literature highlights the increase in methane yield through ACoD. This investigation analyzed the mixing effects on methane yield kinetics, using articles that report kinetic coefficients in Cone and Gompertz models modified for binary and ternary mixtures. The analysis of the mixtures considered the sum of the contributions for each mixture using the adjusted kinetic coefficients for the monosubstrates. The mixing effects analysis compared the additive model fitted to the modified Cone and Gompertz models. The comparison made with the coefficients for the additive model and the experimental data presented relevant variations of 10%. This allowed to establish that the mixing effects can influence the methane yield as well as the kinetic constants of the process.