A generic and systematic procedure to derive a simplified model from the anaerobic digestion model No. 1 (ADM1)

Abstract

The anaerobic digestion model No.1 (ADM1) developed by the IWA Task Group for mathematical modelling of anaerobic digestion processes Batstone et al. [1] is a structural model which describes the main biochemical and physicochemical processes. For such purposes, other models have been proposed to describe anaerobic processes with a reduced set of parameters, state variables and processes. Among them, the anaerobic model No. 2 (AM2) proposed by Bernard et al. [2] which describes the degradation of soluble organic compounds, appears as a model well-suited for control and optimization applications.In this work, we aimed at obtaining a model of reduced dimensions on the basis of which to synthesize regulators or observers with guarantees of performance, stability and robustness. Specifically, our contribution is twofold. First, a modified version of the AM2 is proposed while preserving the simplicity of the new model “AM2HN”. Second, we propose a systematic and generic state association procedure in order to obtain such a simplified model from any validated ADM1.Simulations and comparisons with the predictions of the ADM1 for a case study involving the anaerobic digestion of waste sludge are presented along with satisfactory results.