Publication

Risk index to monitor an anaerobic digester using a dynamic model based on dilution rate, temperature, and pH

Journal Article (2020)

Journal

Nonlinear Engineering

Pages

35-50

Volume

9

Doc link

https://doi.org/10.1515/nleng-2018-0055

File

Download the digital copy of the doc pdf document

Authors

Abstract

In this work, a risk index to monitor an anaerobic digestion process is established. The index is derived from the dynamical analysis of the system and it is composed of two conditions ensuring an optimum operating conditions inside bioreactor. The analysis is performed using bifurcation theory in order to study the effects of dilution rate, temperature and pH parameters at behavior system. For these purpose an extended version of the mathematical model proposed by Bernard [1] involving the dependence of growth kinetics on temperature and pH is used. The analysis shows both microbial growth and the performance of the bioprocess, when is highly affected by these parameters, indeed the washout condition occurs by combining a fold bifurcation and a transcritical bifurcation. From bifurcation diagrams both safety and optimal operation regions of the bioreactor are defined. Consequently, based on two conditions of stability a risk index to monitor the bioprocess on-line is proposed. The index is evaluated via numerical simulations allowing to detect system destabilization. The results obtained in this work may provide a useful methodology to monitor an anaerobic process and to guarantee the optimal performance of the bioreactor given that the model is sufficiently accurate.

Categories

automation, control nonlinearities, control system synthesis, control theory.

Author keywords

Anaerobic digestion, bioreactor, dynamic analysis, bifurcation theory, risk analysis

Scientific reference

A.M. Alzate, C. Ocampo-Martínez, C. Cardona and V. Trejos. Risk index to monitor an anaerobic digester using a dynamic model based on dilution rate, temperature, and pH. Nonlinear Engineering, 9: 35-50, 2020.