Comprehensive Local Sensitivity Analysis of the ADM1-Based Anaerobic Digestion Process

Abstract

Anaerobic digestion is a popular method for treating waste and producing biogas. It remains challenging to automate and optimize the operation of the digester because of its complex process and suffering from great uncertainty. Therefore, it is extremely crucial to understand the influence of different model parameters on the output variables. Although anaerobic digestion processes have been studied extensively, few of these have performed sensitivity analyses. The present study explores the potential effects of varying 48 stoichiometric and kinetic parameters and input variables in the well-known Anaerobic Digestion Model No. 1 (ADM1) on the 35 output variables. The sensitivity analysis enables the identification of key parameters and variables relevant to the model uncertainty. The python implementation of ADM1 was used to identify the system behavior and sensitivity to the input parameters and variables from the mathematical point of view. The analysis provides all the correlations and sensitivity indexes between input variables/parameters and output variables. pH, as one of the critical output variables, shows the highest sensitivity to Tbase, kdec,ac, and San.in, among all parameters and input variables. As another example, methane concentration in the gas phase is sensitive to temperature bases variables, namely Tbase and Top.