Activated Sludge Wastewater Treatment

Process Control & Optimization for the Operations Professional

Eric J. Wahlberg, Ph.D.

978-1-60595-333-5, ©2019, 538 pages, 6×9, hardcover

    • Contains information relevant to all levels of operator certification
    • Scientific and data-driven process controls for activated sludge
    • Includes a comprehensive list of common abbreviations and acronyms
    • New ways for understanding, monitoring clarifiers, digesters, aeration basins and more
    • Simplified math problem solving and statistics for control
    • Strategies for reducing costs and recovering resources
    • A handy reference, a valuable textbook, an operations manual


This book is a milestone in the evolution of wastewater treatment operations. It explains the science of treatment framed within an ethics where wastewater personnel are seen as protectors of public health, preservers of the environment, and stewards of public monies. Written by a former plant operator with a Ph.D., the book presents the fundamental science behind the unit processes in wastewater treatment plants, including biological nutrient removal. In so doing, it challenges longstanding operational doctrines enshrined by habit and tradition, such as being careful not to remove too many influent organics in a primary clarifier for fear of starving the microorganisms in the aeration basin, or using the MLSS concentration to control effluent quality, or cutting the growth rate of microorganisms in anticipation of their slower growth rate in winter. Dispelling much of the prevailing that’s-the-way-we’ve-always-done-it dogma is achieved through an elegant and understandable presentation of the biology, chemistry, and physics that explain the phenomena of wastewater treatment. At the same time, the book is intensely practical. It offers detailed and data-based process control solutions to stabilize plant performance, maintain consistent effluent quality, and reduce energy costs. Powerful, easily implemented statistical techniques are given to unlock the meaning of plant performance data and make informed process control decisions. The book’s approach is learning-focused, including numerous examples of a failsafe, foolproof arithmetical method that enables operations professionals to define, set up, and solve problems.


From the Foreword by Biju George, Chief Operating Officer, DC Water

I had the privilege of working with Dr. Eric Wahlberg while I was managing the operations at Greater Cincinnati Metropolitan Sewer District. At the time, I was looking for a training program that would bridge the gap between the typical training available for operator certification and the coursework offered only at a university. Dr. Wahlberg tailored a program for our staff that addressed this need, and what he developed is reflected in this inventive book. His program consisted of fundamental elements such as: building basic math skills, understanding unit processes from the perspective of basic science, explaining the purpose of each unit process as an input to the following process, and identifying process bottlenecks to maximize throughput while minimizing operating cost and sludge inventory. This approach has proven invaluable for wastewater treatment plants with combined sewer overflows and those that treat high-strength waste to maximize revenue from idle capacity.

List of Abbreviations

Chapter 1. Operations Professionals
1.1. Introduction
1.2. Key Points
1.3. Review and Study Questions

Chapter 2. Wastewater and Wastewater Treatment Overview
2.1. Pollutants
2.2. Wastewater Treatment Plants
2.3. Model Wastewater Treatment Plant
2.4. Key Points
2.5. Review and Study Questions
2.6. References

Chapter 3. Primary Clarifier
3.1. Raw Wastewater Characteristics
3.2. Non-settleable TSS and BOD (TSSnon/BODnon) Test
3.3. Primary Clarifier Performance and Wastewater Characteristics
3.4. Primary Clarifier Performance Optimization
3.5. Chemically Enhanced Primary Treatment (CEPT)
3.6. Summary
3.7. Key Points
3.8. Review and Study Questions
3.9. References

Chapter 4. Aeration Basin
4.1. Process Objective
4.2. Bacterial Energetics and Growth
4.3. Measuring Conversion
4.4. Measuring Biomass Separation
4.5. Factors Affecting Conversion
4.6. Factors Affecting Biomass Separation
4.7. Summary
4.8. Key Points
4.9. Review and Study Questions
4.10. References 

Chapter 5. Nutrient Removal
5.1. Ammonia Oxidation
5.2. Nitrogen Removal
5.3. Biological Phosphorus Removal
5.4. Nutrient Recovery
5.5. Summary
5.6. Key Points
5.7. Review and Study Questions
5.8. References

Chapter 6. Secondary Clarifier
6.1. Compaction
6.2. Solids Mass Balance
6.3. Process Objective
6.4. State Point Analysis
6.5. Settling Flux Curve Development
6.6. RAS Pumping Optimization
6.7. Summary
6.8. Key Points
6.9. Review and Study Questions
6.10. References

Chapter 7. Anaerobic Digester
7.1. Process Objective
7.2. Microbiology
7.3. Process Control and Performance
7.4. Seeding
7.5. Thickening
7.6. Summary
7.7. Key Points
7.8. Review and Study Questions
7.9. References

Chapter 8. Data Validity
8.1. Why Statistics?
8.2. Normal Curve
8.3. Central Limit Theorem
8.4. Statistical Process Control
8.5. Cumulative Summary Chart
8.6. Data Checks
8.7. Summary
8.8. Key Points
8.9. Review and Study Questions
8.10. References

Chapter 9. Optimization
9.1. The Goal
9.2. Primary Clarifier Optimization
9.3. Aeration Basin Optimization
9.4. Secondary Clarifier Optimization
9.5. Anaerobic Digester Optimization
9.6. Summary
9.7. Key Points
9.8. Review and Study Questions
9.9. References


  1. (verified owner):

    Eric J. Wahlberg has written a book that deserves a prominent place in every operator’s library. His early introduction and explanation of the ‘solution bridge’ is a great orientation for operators preparing for certification exams. The book is very well organized, from the primary clarification process through data validation and optimization. Each chapter begins with a discussion of the importance of the concepts discussed, and concludes with “Key Points” and “Review and Study Questions”. Along the way, Eric has included diagrams and other visualizations that simplifies and reinforces the underlying concepts.

    This handbook is my “go to” book about the activated sludge and anaerobic digestion processes. His emphasis of operators as stewards of the environment and ratepayer dollars is acknowledgement of the importance of this field. If this book was available when I started my wastewater career, it would have flattened my learning curve and helped me advance as a manager of processes and people.

    Tim Truax, CFM, Manager
    Bend Oregon Water Reclamation Facility

  2. (verified owner):

    Dr. Eric J. Wahlberg’s book entitled Activated Sludge Wastewater Treatment should take the industry by storm. It destroys historical, yet many baseless claims about how and why we do what we do at wastewater plants. Dr. Wahlberg lays out the wastewater framework that will lead to effective and efficient operations. The book reads very well for most technical minds with real world examples, supporting science and math principles, and some humor and character. We’ve passed our copy around at all of our wastewater facilities and the managers thoroughly enjoyed the read and have already incorporated some of the theories. Godspeed to you, Dr. Wahlberg!

    Jason Tincu
    Director of Sanitary Engineering
    Incoming OWEA Vice President

  3. :

    This is a wonderful book. What I love most about this book is that it is written not only for operations professionals but it is also a great read/reference for the engineers that work with operations professionals. It is thorough and readable and that is not easy to do. After 25 years of wastewater treatment design and engineering, seldom have I found a text that speaks so simply about topics that can be so complex and intimidating. In addition to just the great readability, the collection of examples that follow the concept discussions in each chapter, provide a clear pathway to understanding. It’s simply a great text.

    Bill Eleazer
    Portfolio Chief Engineer
    Brown and Caldwell

  4. :

    I came across Activated Sludge Wastewater Treatment: Process Control & Optimization for the Operations Professional while searching for books to add to my collection of reference material for wastewater treatment. The title jumps out at you: It is what all operators strive for in their plants, to control their plant while optimizing it to its full potential. So I took the plunge and purchased the book not knowing what the contents included.

    This was the first book I have read cover to cover as it caught my attention from the moment I opened it. It deals with optimization of a wastewater treatment plant at the level of operators, but explains it in a way that gives you the excitement of working out the technical detail yourself for your particular plant. The language used in the book is excellent and I have used various sentences and paragraphs when trying to get my point across to other water professionals as to the reason we are doing what we are doing to optimize the process. The equations and formulas used collaborate well with the text, are easy to understand, and are excellently presented in the book. All the examples used can be replicated to suit the reader, while most of the examples used are US, (and I’m EU-metric), this didn’t reduce their importance in any way, it just made me get out my pen and paper and make it relevant to the treatment plant I am responsible for.

    I have recommended this book to many people, and in my mind should become a key addition in any wastewater engineer’s, scientist’s, or operator’s library on treatment plant control and optimization.

    Séamus Walsh, Water & Wastewater Process Optimization Specialist, Ireland

Activated Sludge Wastewater Treatment (Entire eBook)
$95.00 Save: $54.50
Chapter 1: Operations Professionals
Chapter 2: Wastewater and Wastewater Treatment Overview
Chapter 3: Primary Clarifier
Chapter 4: Aeration Basin
Chapter 5: Nutrient Removal
Chapter 6: Secondary Clarifier
Chapter 7: Anaerobic Digester
Chapter 8: Data Validity
Chapter 9: Optimization

After college, Dr. Wahlberg worked for seven years as an operator in Colorado. He then earned a Ph.D. at Clemson University in environmental systems engineering and went on to conduct ASCE-sponsored research on clarifiers at the Los Angeles County Sanitation District. After a 20-year tenure at Brown and Caldwell, he and his wife purchased WasteWater Technology Trainers from its founder, Mr. Keith Boger. Since 2011, Dr. Wahlberg has been actively engaged in course development and instruction for professionals in areas such as process control, statistics, and certification review.

978-1-60595-333-5, ©2019, 538 pages, 6×9, hardcover

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