Mathematical Modelling and Computer Simulation of Activated Sludge Systems

This international, comprehensive guide to modeling and simulation studies in activated sludge systems leads the reader through the entire modeling process – from building a mechanistic model to applying the model in practice.

This book will:

• enhance the readers’ understanding of different model concepts for several (most essential) biochemical processes in the advanced activated sludge systems,
• provide extensive and up-to-date coverage of experimental methodologies of a complete model parameter estimation (longitudinal dispersion coefficient, influent wastewater fractions, kinetic and stoichiometric coefficients, settling velocity, etc.),
• summarize and critically review the ranges of model parameters reported in literature,
• compare the existing protocols aiming at a systematic organization of the simulation study,
• outline the capabilities of the existing commercial simulators,
• present documented, successful case studies of practical model applications as a guide while planning a simulation study.

The book is organized to provide a general background and some basic definitions, then theoretical aspects of modeling and finally, the issues important for practical model applications.

Mathematical Modelling and Computer Simulation of Activated Sludge Systems can be used as supplementary material for a graduate level wastewater engineering courses and is useful to a wide audience of researchers and practitioners.  Experienced model users such as consultants, trained plant management staff may find the book useful as a reference and as a resource for self-guided study.

Contents

Introduction
Model building
Components of a complete model of an activated sludge system
Hydraulic configuration model
Influent wastewater characterization model
Bioreactor model
- Hydrodynamic mixing model
- Biokinetic model
- Oxygen transfer model
- Process temperature model
Sedimentation/clarification model
Complex biokinetic models
Development and evolution of complex biokinetic models
Model presentation
Approaches to modeling specific biochemical processes occurring in activated sludge systems
- Growth of microorganisms
- Disappearance (loss) of microorganism biomass and other cell internal components
- Storage of substrates
- Adsorption of substrates
- Hydrolysis of slowly biodegradable organic compounds
- Fermentation (conversion of “complex” readily biodegradable substrate to VFA)
- Nitrification
- Denitrification (including the addition of external carbon sources)
- Enhanced biological phosphate removal (EBPR)
- Bulking sludge (growth of Microthrix parvicella)
- Anammox

Organization of the simulation study
Data quality control (collection, verification and reconciliation)
Approaches to a systematic organization of the simulation study
Model calibration/validation procedures
- Selection of a hydrodynamic mixing model
- Influent wastewater and biomass characterization
- Estimation of kinetic and stoichiometric parameters in the biokinetic models
- Estimation of settling parameters
Sensitivity analysis

 Simulation platforms
Relationship between a real system, mathematical model and simulator
Characteristics of the existing simulators
- AQUASIM (Switzerland)
- BioWin (Canada)
- GPS-X (Canada)
- SIMBA (Germany)
- STOAT (UK)
- WEST (Belgium)

Practical model applications – case studies
Optimization of process performance
Expansion and upgrade of existing facilities
Design of new facilities
Development of new treatment concepts
Operator training