Modeling and simulation of anaerobic digestion process

Anaerobic digestion (AD) is an important technology that can be used to produce renewable energy and valuable chemicals from biodegradable waste and thereby contribute to the circular economy and mitigation of environment pollution. The purpose of this book chapter is to present a practical introduction to the modeling and simulation of AD process. First, an introduction to the widely used Anaerobic Digestion Model no. 1 (ADM1), originally developed by a task group at the International Water Association (IWA), is included using a general approach. This approach provides a mechanistically inspired modeling framework that incorporates all the major biochemical, chemical and physicochemical processes involved in anaerobic digestion in a well-mixed reactor. Next, a specific case study on AD process of readily degradable substrate in a batch reactor is presented and the corresponding model development is discussed in a step-by-step manner. Subsequently, simulation results are discussed showing time evolution of various components in the liquid and gas phase. Finally, the effect of various important process parameters such as pH, batch time, initial substrate and microorganism concentrations etc on the various products are reported. It is hoped that this book chapter will be useful for researchers looking at exploring modeling for simulation, optimization and design of AD processes.