PhD defence Agung Prawira Negara: "Modeling and analysis of microbial activities in industrial wastewater treatment plant"

Promotors: Prof B. Jayawardhana and Prof G.J.W. Euverink

Abstract: Wastewater treatment plants (WWTP) treat wastewater which involves several different processes at different stages. To understand the complex interconnection of various processes in WWTP, one way to do this is through a mathematical model. For the modeling of WWTP dynamics, several Activated Sludge Models have been developed and acknowledged by the International Water Association (IWA) as standard models of WWTP. While it’s true that these models can be used to model an existing WWTP, there are still some improvements that can be made to these well-known models. This thesis addresses several problems that arise while performing the enrichment of the model. In this dissertation, we studied an existing industrial WWTP in the Netherlands and focused on using ASM1. We summarized the work in this thesis as mentioned in the following lines. First, a method is established to analyze the (local) sensitivity of each modeled state variable to each microorganism, where an indication of the influence of the microbial structure on process performance was found. Second, we performed a top-down approach by proposing a modified ASM1 (mod-ASM1) and enriching it with the NGS data by making two of the parameters time-varying and coupling them using the microbial population provided by the NGS data. Third, we performed a bottom-up approach by mimicking the selected industrial WWTP and aiming to produce a similar result as in the full-scale plant through a lab-scale experiment. Lastly, we propose the Kron reduction approach to get reduced-order models of open chemical reaction networks (CRN), e.g., WWTP, with mass-action kinetics.

Dissertation