PhD Defence: A DE NOVO Implementation of the Anaerobic Digestion Model 1 with Application to Selected Model Extensions

CANDIDATE: Courtney Allen

ABSTRACT: The Anaerobic Digestion Model 1 (ADM1) was developed in 2002 to model the processes of anaerobic digestion and is widely employed by wastewater treatment plants to predict and optimize the production of methane for collection as a biofuel. With 105 model parameters and 35 state variables, ADM1 is a versatile model, but does not describe every process of anaerobic digestion. For example, it only describes a continuously stirred tank reactor, where the substrate is constantly in motion, preventing the formation of biofilms on the tank’s surfaces. It also does not consider the production of gasses such as hydrogen sulphide or ammonia. To that end this thesis presents a de novo implementation of ADM1 that improves computational efficiency, and makes modifications to that base ADM1 model. The results of these modifications are analysed in order to understand which modifications make significant changes to the production of methane. These analyses show that both the inclusion of biofilm formation, through a zero-dimension biofilm model, and sulfur reduction processes have a large impact on the production of methane.