The use of models in activated sludge design and operation is increasing, with a similar trend seen in education. Starting with the original IAWPRC Activated Sludge Model no 1 (ASM1) and the subsequent ASM2 and ASM2D, the first generation of activated sludge models have played an important role in practice. With the development of the latest IWA Activated Sludge Model no 3 further progress has been made, and given the concurrent development of new methods for characterization of biomass and wastewater, this is a field of vigorous activity at present. The fifth Kollekolle Seminar brought together many of the world's leading experts on the activated sludge process, who have been working with activated sludge models in practice and research. The aim, as with previous seminars was to present the latest research findings, putting them into the proper perspective. From this high-quality programme 22 papers have been selected and revised to provide the best collection of papers on the state of the art of activated sludge modeling. Papers cover the following topics: modeling developments; wastewater and biomass characterization and parameter identification; modeling in practices.

Mathematical Modelling and Computer Simulation of Activated Sludge Systems – Second Edition provides, from the process engineering perspective, a comprehensive and up-to-date overview regarding various aspects of the mechanistic (“white box”) modelling and simulation of advanced activated sludge systems performing biological nutrient removal. In the new edition of the book, a special focus is given to nitrogen removal and the latest developments in modelling the innovative nitrogen removal processes. Furthermore, a new section on micropollutant removal has been added. The focus of modelling has been shifting in the last years to models that can describe the performance of a whole plant (plant-wide modelling). The expanded part of this new edition introduces models describing the most important processes interrelated with the mainstream activated sludge systems as well as models describing the energy balance, operating costs and environmental impact. The complex process evaluation, including minimization of energy consumption and carbon footprint, is in line with the present and future wastewater treatment goals. By combining a general introduction and a textbook, this book serves both intermediate and more experienced model users, both researchers and practitioners, as a comprehensive guide to modelling and simulation studies. The book can be used as a supplemental material at graduate and post-graduate levels of wastewater engineering/modelling courses.

Mathematical modelling of activated sludge systems is used widely for plant design, optimisation, training, controller design and research. The quality of simulation studies varies depending on the project objectives, finances and expertise available. Consideration has to be given to the model accuracy and the amount of time required carrying out a simulation study to produce the desired accuracy. Inconsistent approaches and insufficient documentation make quality assessment and comparison of simulation results difficult or almost impossible. A general framework for the application of activated sludge models is needed in order to overcome these obstacles. The genesis of the Good Modelling Practice (GMP) Task Group lies in a workshop held at the 4th IWA World Water Congress in Marrakech, Morocco where members of research groups active in wastewater treatment modelling came together to develop plans to synthesize the best practices of modellers from all over the world. The most cited protocols were included in the work, amongst others from: HSG (Hochschulgruppe), STOWA, BIOMATH and WERF. The goal of the group is to set up an internationally accepted framework to deal with the ASM type models in practice. This framework shall make modelling more straightforward and systematic to use especially for practitioners and consultants. Additionally, it shall help to define quality levels for simulation results, a procedure to assess this quality and to assist in the proper use of the models. The framework will describe a methodology for goal-oriented application of activated sludge models demonstrated by means of a concise guideline about the procedure of a simulation study and some illustrative case studies. The case studies shall give examples for the required data quality and quantity and the effort for calibration/validation with respect to a defined goal. The final report will include an extended appendix with additional information and details of methodologies. Additional features in Guidelines for Using Activated Sludge Models include a chapter on modelling industrial wastewater, an overview on the history, current practice and future of activated sludge modelling and several explanatory case studies. It can be used as an introductory book to learn about Good Modelling Practice (GMP) in activated sludge modelling and will be of special interest for process engineers who have no prior knowledge of modelling or for lecturers who need a textbook for their students. The STR can also be used as a modelling reference book and includes an extended appendix with additional information and details of methodologies. Scientific and Technical Report No. 22

Activated sludge is the most vital wastewater process today. Now, this recent book provides a comprehensive guide to the modelling and design of activated sludge systems. Written by two leaders in the wastewater field, the book presents extensive and up-to-date coverage of all areas in the activated sludge process microbiological basis, reactor kinetics, and design methodologies. The book is organized for easy reference and is ideal as a text or desktop guide.