Page 8 - Fundamentals of Water Treatment Unit Processes : Physical, Chemical, and Biological

Contents vii

3.5 Examples of Models.................................................................................................................................. 52
3.6 Summary.................................................................................................................................................... 54
Problems............................................................................................................................................................... 54
Glossary................................................................................................................................................................ 54
References ............................................................................................................................................................ 56

Chapter 4 Unit Process Principles......................................................................................................................................... 57
4.1 Unit Processes............................................................................................................................................ 57
4.1.1 Spectrum of Unit Processes and Technologies............................................................................ 57
4.1.2 Matching Unit Process with Contaminant ................................................................................... 57
4.1.2.1 Contextual Changes and New Treatment Demands..................................................... 57
4.2 Principles ................................................................................................................................................... 57
4.2.1 Sinks ............................................................................................................................................. 57
4.2.2 Transport....................................................................................................................................... 59
4.2.2.1 Macro Transport: Sedimentation .................................................................................. 59
4.2.2.2 Macro Transport: Advection......................................................................................... 59
4.2.2.3 Macro Transport: Turbulent Diffusion ......................................................................... 59
4.2.2.4 Macro Transport: Porous Media Dispersion................................................................. 59
4.2.2.5 Molecular Transport: Diffusion .................................................................................... 59
4.2.2.6 Mathematics of Diffusion, Turbulence, and Dispersion............................................... 60
4.2.3 Summary....................................................................................................................................... 62
4.3 Reactors ..................................................................................................................................................... 62
4.3.1 Examples of Reactors................................................................................................................... 62
4.3.2 Types of Reactors......................................................................................................................... 62
4.3.3 Mathematics of Reactors.............................................................................................................. 62
4.3.3.1 Materials Balance: Concept.......................................................................................... 62
4.3.3.2 Comments on Materials Balance.................................................................................. 63
4.3.3.3 Materials Balance: Mathematics................................................................................... 63
4.3.4 Materials Balance: Special Conditions.........................................................................................66
4.3.4.1 Batch Reactor: Complete Mixed .................................................................................. 66
4.3.4.2 Steady State Reactor: Complete Mixed........................................................................ 66
4.3.4.3 Zero Reaction: Complete Mixed .................................................................................. 67
4.3.4.4 Nonsteady State Reactor............................................................................................... 67
4.3.4.5 Spreadsheet Method to Solve Finite Difference Form of Mass Balance Equation ..... 68
4.3.4.6 Utility of Finite Difference Equation and Tracer Tests................................................ 71
4.4 Kinetic Models .......................................................................................................................................... 71
4.4.1 First-Order Kinetics...................................................................................................................... 71
4.4.2 Second-Order Kinetics ................................................................................................................. 72
4.4.3 Examples of Kinetic Equations.................................................................................................... 72
4.4.3.1 Example: Gas Transfer ................................................................................................. 72
4.4.3.2 Example: Biological Degradation of Substrate ............................................................ 72
4.4.3.3 Example: Trickling Filter.............................................................................................. 72
Problems............................................................................................................................................................... 73
Glossary................................................................................................................................................................ 74
References ............................................................................................................................................................ 76

PART II Particulate Separations

Chapter 5 Screening .............................................................................................................................................................. 79
5.1 Theory of Screening .................................................................................................................................. 79
5.2 Types of Screens ....................................................................................................................................... 79
5.2.1 Bar Screens................................................................................................................................... 79
5.2.1.1 Cleaning ........................................................................................................................ 80
5.2.1.2 Manually Cleaned Bar Screens..................................................................................... 80