Chapter 2 - Modeling Microbial Activity in Wastewater Treatment

Abstract

Mathematical modeling is a powerful tool in design, operation, optimization, prediction, and assessment of various processes in wastewater treatment. The majority of the key microbial processes comprises of mixed anaerobic microbial communities, where a fundamental understanding of the mechanisms of these microbial ecosystems is critical for efficient treatment of wastes. This review provides a comparison of approaches to model microbial activities in wastewater treatment, starting with traditional approaches and then proceeding toward more complex systems considering the effects of reversibility and thermodynamic equilibrium in kinetic rate expressions, maintenance requirements for microbial growth, as well as alternative metabolic models based on metabolic reaction networks. The current knowledge, state of the art of modeling applications in wastewater treatment systems, and future trends are discussed. The selection of a model depends on various factors including the available data, objective of the application, or problem under consideration and the required level of accuracy. While complex structure of models may be necessary for analysis of complex systems and technology development, simpler models may be sufficient to use for design purposes. The incorporation of reversible kinetic expressions for the simulation of product inhibition, thermodynamic factors and maintenance energy requirements within the existing wastewater treatment models may be recommended for further future development, as needed. This review chapter can prove useful for modeling microbial processes for a variety of applications in wastewater treatment systems, including the design of optimal bioreactors for bioremediation applications, start-up and shut-down periods of various reactor applications, resource recovery, and understanding the processes for optimal waste treatment.