Aeration Control System Design: A Practical Guide to Energy and Process Optimization

Learn how to design and implement successful aeration control systems Combining principles and practices from mechanical, electrical, and environmental engineering, this book enables you to analyze, design, implement, and test automatic wastewater aeration control systems and processes. It brings together all the process requirements, mechanical equipment operations, instrumentation and controls, carefully explaining how all of these elements are integrated into successful aeration control systems. Moreover, Aeration Control System Design features a host of practical, state-of-the-technology tools for determining energy and process improvements, payback calculations, system commissioning, and more. Author Thomas E. Jenkins has three decades of hands-on experience in every phase of aeration control systems design and implementation. He presents not only the most current theory and technology, but also practical tips and techniques that can only be gained by many years of experience. Inside the book, readers will find: Full integration of process, mechanical, and electrical engineering considerations Alternate control strategies and algorithms that provide better performance than conventional proportional-integral-derivative control Practical considerations and analytical techniques for system evaluation and design New feedforward control technologies and advanced process monitoring systems Throughout the book, example problems based on field experience illustrate how the principles and techniques discussed in the book are used to create successful aeration control systems. Moreover, there are plenty of equations, charts, figures, and diagrams to support readers at every stage of the design and implementation process. In summary, Aeration Control System Design makes it possible for engineering students and professionals to design systems that meet all mechanical, electrical, and process requirements in order to ensure effective and efficient operations.

Preface xi Acknowledgments xiii List of Figures xv List of Tables xxi 1 Introduction 1 1.1 Basic Concepts and Objectives / 2 1.2 Safety / 9 1.3 The Importance of an Integrated Approach / 10 1.4 Importance of Operator Involvement / 13 1.5 The Benefits of Successful Aeration Process Automation / 14 1.5.1 Energy Cost Reduction / 14 1.5.2 Treatment Performance / 18 1.5.3 Improved Equipment Life / 18 Example Problems / 19 2 Initial System Assessment 21 2.1 Define Current Operations / 24 2.1.1 Energy Cost / 25 2.1.2 Energy Consumption Patterns / 29 2.1.3 Influent and Effluent Process Parameters / 35 2.1.4 Treatment Performance / 36 2.2 Evaluate Process and Equipment / 37 2.3 Benchmark Performance / 40 2.4 Estimate Potential Energy Savings and Performance Improvement / 42 2.5 Prepare Report / 45 Example Problems / 47 3 Aeration Processes 49 3.1 Process Fundamentals / 49 3.1.1 Peripheral Equipment and Processes / 55 3.1.2 BOD Removal / 62 3.1.3 Nitrification / 66 3.1.4 Denitrification / 67 3.2 Loading Variations and Their Implications / 68 3.3 Process Limitations and Their Impact on Control Systems / 70 Example Problems / 74 4 Mechanical and Diffused Aeration Systems 77 4.1 Oxygen Transfer Basics / 78 4.2 Types of Aerators / 87 4.2.1 Mechanical Aerators / 88 4.2.2 Mechanical Aeration Control Techniques / 90 4.2.3 Diffused Aeration / 95 4.2.4 Diffused Aeration Control Techniques / 103 4.3 Savings Determinations / 106 Example Problems / 111 5 Blowers and Blower Control 113 5.1 Common Application and Selection Concerns / 114 5.1.1 Properties of Air / 114 5.1.2 Effect of Humidity / 119 5.1.3 Pressure Effects / 123 5.1.4 Common Performance Characteristics / 125 5.2 Positive Displacement Blowers and Control Characteristics / 134 5.2.1 Types and Characteristics / 134 5.2.2 Lobe Type PD Blowers / 134 5.2.3 Screw Blowers / 138 5.2.4 Control and Equipment Protection Considerations / 141 5.3 Dynamic Blowers / 143 5.3.1 Types and Characteristics / 144 5.3.2 Multistage Centrifugal Blowers / 150 5.3.3 Geared Single Stage Centrifugal Blowers / 152 5.3.4 Turbo Blowers / 154 5.3.5 Control and Protection Considerations / 155 Example Problems / 157 6 Piping Systems 161 6.1 Design Considerations / 162 6.1.1 Layout / 162 6.1.2 Pipe Size / 172 6.1.3 Pipe Material / 174 6.2 Pressure Drop / 178 6.3 Control Valve Selection / 182 Example Problems / 187 7 Instrumentation 191 7.1 Common Characteristics and Electrical Design Considerations / 192 7.2 Pressure / 202 7.3 Temperature / 205 7.4 Flow / 209 7.5 Analytic Instruments / 216 7.5.1 Dissolved Oxygen / 217 7.5.2 Offgas Analysis / 221 7.5.3 pH and ORP / 224 7.6 Motor Monitoring and Electrical Measurements / 224 7.7 Miscellaneous / 226 Example Problems / 230 8 Final Control Elements 233 8.1 Valve Operators / 234 8.2 Guide Vanes / 238 8.3 Motor Basics / 239 8.4 Motor Control / 247 8.5 Variable Frequency Drives / 251 Example Problems / 259 9 Control Loops and Algorithms 261 9.1 Control Fundamentals / 264 9.1.1 Discrete Controls / 264 9.1.2 Analog Control / 267 9.1.3 Proportional–Integral–Derivative / 271 9.1.4 Deadband Controllers / 274 9.1.5 Floating Control / 276 9.2 Dissolved Oxygen Control / 280 9.3 Aeration Basin Air Flow Control / 287 9.4 Pressure Control / 288 9.5 Most–Open–Valve Control / 291 9.6 Blower Control and Coordination / 293 9.7 Control Loop Timing Considerations / 302 9.8 Miscellaneous Controls / 303 Example Problems / 305 10 Control Components 309 10.1 Programmable Logic Controllers / 310 10.1.1 System Architecture / 314 10.1.2 Program Structure / 315 10.1.3 Communications Networks / 318 10.1.4 Accommodating Instrument Inaccuracy and Failure / 322 10.2 Distributed Control Systems / 323 10.3 Human Machine Interfaces / 323 10.3.1 Supervisory Control and Data Acquisition / 325 10.3.2 Touchscreens / 327 10.4 Control Panel Design Considerations / 328 Example Problems / 330 11 Documentation 333 11.1 Specification Considerations / 335 11.2 Data Lists / 338 11.3 Process and Instrumentation Diagrams / 341 11.4 Ladder and Loop Diagrams / 342 11.5 One–Line Diagrams / 344 11.6 Installation Drawings / 345 11.7 Loop Descriptions / 347 11.8 Operation and Maintenance Manuals / 348 Example Problems / 349 12 Commissioning 351 12.1 Inspection / 354 12.2 Testing / 357 12.3 Tuning / 361 12.4 Training / 365 12.5 Measurement and Verification of Results / 368 Example Problems / 369 13 Summary 371 13.1 Review of Integrated Design Procedure / 371 13.2 Potential Problem Areas / 374 13.3 Benefits / 375 Example Problems / 375 Appendix A: Example Problem Solutions 377 Appendix B: List of Equations and Variables 447 Bibliography 485 Index 487

THOMAS E. JENKINS, PE, is an owner and President of JenTech Inc., where he provides consultation services to the wastewater treatment industry, including control systems, aeration systems, energy conservation, blower systems, and process equipment design. He also cofounded Energy Strategies Corporation in 1984. Mr. Jenkins is a Professor of Practice in the Department of Civil and Environmental Engineering at the University of Wisconsin-Madison. He also teaches water and wastewater treatment classes in the University's Department of Engineering Professional Development.