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

This title is only available as a free copy to download from the WaterWiki. To download your free copy of the eBook, click here. The manual can be used independantly but when used in combination with the CD-ROM, it makes a unique tool for process operators to diagnose and solve operational problems. It is also a valuable educational and training package for universities and post experience courses. Click here for more details about the CD-ROM Process stability and final effluent quality largely depend upon the composition of the biomass in an activated sludge plant. Operational problems such as bulking and scum formation occur when the wrong micro-organisms are dominating the sludge population. Microscopic sludge investigation is therefore essential for process control and stable plant operation. The manual outlines the theoretical framework, extensively illustrated with full-colour micrographs. Contents Microscopy Microscopic sludge investigation Characteristics of activated sludge flocs Filamentous micro-organisms Protozoa and metazoa Conclusions of microscopic sludge investigation The activated sludge process Operational problems Bulking sludge Scum formation

Activated Sludge Separation Problems: Theory, Control Measures, Practical Experiences, Second Edition, describes the most common activated sludge separation problems and explains the main reasons for the growth of the different filamentous microorganisms in activated sludge. The book summarizes the identification techniques for important groups of activated sludge microorganisms both based on conventional microscopic analysis and using the biological molecular tools available today (FISH and PCR). This new edition, with 70% new and updated material, also provides explanation of basic activated sludge process principles and of parameters necessary for process control and operation. The theory of secondary clarifies is described to the extent necessary for understanding the construction and operation of secondary clarifiers. The activated sludge reactor and secondary clarifies are treated as one system and the interactions are explained. The wide range of experiences around the world is documented and the methods to avoid the proliferation of these organisms are presented and critically reviewed. Activated Sludge Separation Problems consists of six chapters, presenting up-to-date technical and scientific aspects of these processes. The new edition also features an extended list of literature references for further reading. The book will be a valuable help for students of environmental engineering, wastewater specialists, plant operators and designers of activated sludge plants. It is also useful for specialists in wastewater operation laboratories, especially for those studying activated sludge separation properties.

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.