Explains the fundamental theory and mathematics of water and wastewater treatment processes
By carefully explaining both the underlying theory and the underlying mathematics, this text enables readers to fully grasp the fundamentals of physical and chemical treatment processes for water and wastewater. Throughout the book, the authors use detailed examples to illustrate real-world challenges and their solutions, including step-by-step mathematical calculations. Each chapter ends with a set of problems that enable readers to put their knowledge into practice by developing and analyzing complex processes for the removal of soluble and particulate materials in order to ensure the safety of our water supplies.
Designed to give readers a deep understanding of how water treatment processes actually work, Water Quality Engineering explores:
- Application of mass balances in continuous flow systems, enabling readers to understand and predict changes in water quality
- Processes for removing soluble contaminants from water, including treatment of municipal and industrial wastes
- Processes for removing particulate materials from water
- Membrane processes to remove both soluble and particulate materials
Following the discussion of mass balances in continuous flow systems in the first part of the book, the authors explain and analyze water treatment processes in subsequent chapters by setting forth the relevant mass balance for the process, reactor geometry, and flow pattern under consideration.
With its many examples and problem sets, Water Quality Engineering is recommended as a textbook for graduate courses in physical and chemical treatment processes for water and wastewater. By drawing together the most recent research findings and industry practices, this text is also recommended for professional environmental engineers in search of a contemporary perspective on water and wastewater treatment processes.
Table of Contents
Preface xxi
Acknowledgments xxv
Part I Reactors and Reactions In water Quality Engineering
1 Mass Balances 3
1.1 Introduction: The Mass Balance Concept 3
1.2 The Mass Balance for a System with Unidirectional Flow and Concentration Gradient 7
1.3 The Mass Balance for a System with Flow and Concentration Gradients in Arbitrary Directions 20
1.4 The Differential Form of the Three-Dimensional Mass Balance 24
1.5 Summary 25
2 Continuous Flow Reactors: Hydraulic Characteristics 29
2.1 Introduction 29
2.2 Residence Time Distributions 30
2.3 Ideal Reactors 42
2.4 Nonideal Reactors 48
2.5 Equalization 62
2.6 Summary 70
3 Reaction Kinetics 81
3.1 Introduction 81
3.2 Fundamentals 82
3.3 Kinetics of Irreversible Reactions 88
3.4 Kinetics of Reversible Reactions 99
3.5 Kinetics of Sequential Reactions 107
3.6 The Temperature Dependence of the Rates of Nonelementary Reactions 114
3.7 Summary 115
4 Continuous Flow Reactors: Performance Characteristics with Reaction 121
4.1 Introduction 121
4.2 Extent of Reaction in Single Ideal Reactors at Steady State 121
4.3 Extent of Reaction in Systems Composed of Multiple Ideal Reactors at Steady State 130
4.4 Extent of Reaction in Reactors with Nonideal Flow 135
4.5 Extent of Reaction Under Non-Steady-Conditions in Continuous Flow Reactors 141
4.6 Summary 146
Part II Removal of Dissolved Constituents From Water
5 Gas Transfer Fundamentals 155
5.1 Introduction 155
5.2 Types of Engineered Gas Transfer Systems 159
5.3 Henry’s Law and Gas/Liquid Equilibrium 162
5.4 Relating Changes in the Gas and Liquid Phases 170
5.5 Mechanistic Models for Gas Transfer 170
5.6 The Overall Gas Transfer Rate Coefficient KL 179
5.7 Evaluating kL kG KL and a: Effects of Hydrodynamic and Other Operating Conditions 187
5.8 Summary 196
6 Gas Transfer: Reactor Design and Analysis 207
6.1 Introduction 207
6.2 Case I: Gas Transfer in Systems with a Well-Mixed Liquid Phase 207
6.3 Case II: Gas Transfer in Systems with Spatial Variations in the Concentrations of Both Solution and Gas 226
6.4 Summary 241
7 Adsorption Processes: Fundamentals 257
7.1 Introduction 257
7.2 Examples of Adsorption in Natural and Engineered Aquatic Systems 262
7.3 Conceptual Molecular-Scale Models for Adsorption 266
7.4 Quantifying the Activity of Adsorbed Species and Adsorption Equilibrium Constants 268
7.5 Quantitative Representations of Adsorption Equilibrium: The Adsorption Isotherm 269
7.6 Modeling Adsorption Using Surface Pressure to Describe the Activity of Adsorbed Species 296
7.7 The Polanyi Adsorption Model and the Polanyi Isotherm 306
7.8 Modeling Other Interactions and Reactions at Surfaces 314
7.9 Summary 320
8 Adsorption Processes: Reactor Design and Analysis 327
8.1 Introduction 327
8.2 Systems with Rapid Attainment of Equilibrium 328
8.3 Systems with a Slow Approach to Equilibrium 340
8.4 The Movement of the Mass Transfer Zone Through Fixed Bed Adsorbers 354
8.5 Chemical Reactions in Fixed Bed Adsorption Systems 356
8.6 Estimating Long-Term Full-Scale Performance of Fixed Beds from Short-Term Bench-Scale Experimental Data 357
8.7 Competitive Adsorption in Column Operations: The Chromatographic Effect 359
8.8 Adsorbent Regeneration 365
8.9 Design Options and Operating Strategies for Fixed Bed Reactors 366
8.10 Summary 369
9 Precipitation and Dissolution Processes 379
9.1 Introduction 379
9.2 Fundamentals of Precipitation Processes 380
9.3 Precipitation Dynamics: Particle Nucleation and Growth 384
9.4 Modeling Solution Composition in Precipitation Reactions 394
9.5 Stoichiometric and Equilibrium Models for Precipitation Reactions 397
9.6 Solid Dissolution Reactions 422
9.7 Reactors for Precipitation Reactions 426
9.8 Summary 428
10 Redox Processes and Disinfection 435
10.1 Introduction 435
10.2 Basic Principles and Overview 435
10.3 Oxidative Processes Involving Common Oxidants 441
10.4 Advanced Oxidation Processes 469
10.5 Reductive Processes 486
10.6 Electrochemical Processes 488
10.7 Disinfection 488
10.8 Summary 502
Part III Removal of Particles From Water
11 Particle Treatment Processes: Common Elements 519
11.1 Introduction 519
11.2 Particle Stability 521
11.3 Chemicals Commonly Used for Destabilization 532
11.4 Particle Destabilization 535
11.5 Interactions of Destabilizing Chemicals with Soluble Materials 542
11.6 Mixing of Chemicals into the Water Stream 544
11.7 Particle Size Distributions 546
11.8 Particle Shape 551
11.9 Particle Density 552
11.10 Fractal Nature of Flocs 552
11.11 Summary 553
12 Flocculation 563
12.1 Introduction 563
12.2 Changes in Particle Size Distributions by Flocculation 564
12.3 Flocculation Modeling 565
12.4 Collision Frequency: Long-Range Force Model 572
12.5 Collision Efficiency: Short-Range Force Model 581
12.6 Turbulence and Turbulent Flocculation 589
12.7 Floc Breakup 592
12.8 Modeling of Flocculation with Fractal Dimensions 594
12.9 Summary 596
13 Gravity Separations 603
13.1 Introduction 603
13.2 Engineered Systems for Gravity Separations 605
13.3 Sedimentation of Individual Particles 607
13.4 Batch Sedimentation: Type I 612
13.5 Batch Sedimentation: Type II 618
13.6 Continuous Flow Ideal Settling 622
13.7 Effects of Nonideal Flow on Sedimentation Reactor Performance 639
13.8 Thickening 644
13.9 Flotation 655
13.10 Summary 669
14 Granular Media Filtration 677
14.1 Introduction 677
14.2 A Typical Filter Run 680
14.3 General Mathematical Description of Particle Removal: Iwasaki’s Model 683
14.4 Clean Bed Removal 684
14.5 Predicted Clean Bed Removal in Standard Water and Wastewater Treatment Filters 694
14.6 Head Loss in a Clean Filter Bed 698
14.7 Filtration Dynamics: Experimental Findings of Changes with Time 700
14.8 Models of Filtration Dynamics 709
14.9 Filter Cleaning 714
14.10 Summary 717
Part IV Membrane-Based Water and Wastewater Treatment
15 Membrane Processes 731
15.1 Introduction 731
15.2 Overview of Membrane System Operation 732
15.3 Membranes Modules and the Mechanics of Membrane Treatment 734
15.4 Parameters Used to Describe Membrane Systems 742
15.5 Overview of Pressure-Driven Membrane Systems 749
15.6 Quantifying Driving Forces in Membrane Systems 752
15.7 Quantitative Modeling of Pressure-Driven Membrane Systems 759
15.8 Modeling Transport of Water and Contaminants From Bulk Solution to the Surface of Pressure-Driven Membranes 773
15.9 Effects of Crossflow on Permeation and Fouling 792
15.11 Modeling Dense Membrane Systems Using Irreversible Thermodynamics 834
15.12 Summary 838
References 839
Problems 841
Index 847
