Table Of Contents

PARTA

NITROGEN IN THE ENVIRONMENT

CHAPTER 1

NITROGEN COMPOUNDS AS POLLUTANTS 3 S.E. Jorgensen and B. Halling-Sorensen

1.1 The Role of Nitrogen in the Environment 3

1.2 The Nitrogen Cycle 6

1.3 Sources of Nitrogen Pollution 9

1.4 The Effect of Nitrogen Discharge 12

1.5 Treatment Processes for the Removal of Nitrogen 21

1.6 The Major Processes in the Removal of Nitrogen 22

1.7 Summary 25

1.8 Some Useful Definitions 39

PART B

BIOLOGICAL UNIT PROCESSES FOR THE REMOVAL OF NITROGEN 41

CHAPTER 2

BIOLOGICAL NITRIFICATION AND DENITRIFICATION 43 B. Halling-S0rensen

2.1 Introduction 43

2.2 Classification of Unit Processes in Nitrification and Denitrification 44

2.3 Terminology Used in Waste Water Treatment 46

2.4 Comparison of the Biofilm and Activated Sludge Unit

Processes 48

2.5 Comparison of the Nitrification Rate for Different Unit

Processes 50

2.6 Conclusions 53

CHAPTER 3

PROCESS CHEMISTRY AND BIOCHEMISTRY OF NITRIFICATION 55 B. Halling-Serensen

3.1 Introduction 55

3.2 Nitrification 55

3.3 The Biochemical Pathway in the Nitrification Process 56

3.4 The Energy and Synthesis Relationship 58

3.5 Kinetics of the Nitrification Process 61

3.6 The Kinetic Expressions for the Nitrification Process 61

3.7 Relationship Between Growth Rate and Oxidation Rate 66

3.8 The Influence of Temperature on the Nitrification Rate 71

3.9 The Influence of Dissolved Oxygen on the Nitrification Rate 84

3.10 The Influence of pH on the Nitrification Rate 87

3.11 A Kinetic Expression Combining Several Limiting Factors of the Nitrification Process 93

3.12 Bacterial Population Dynamics Applied in the Nitrification

Process 95

3.13 Effects of Inhibitors on Nitrification 102

CHAPTER 4

PROCESS CHEMISTRY AND BIOCHEMISTRY OF DENITRIFICATION 119 B. Halling-Serensen

4.1 Introduction 119

4.2 Types of Bacteria Accomplishing Denitrification 120

4.3 Biochemical Pathways 122

4.4 Energy and Synthesis Relationship 124

4.5 Alternative Electron Donors and the C/N Relationship 128

4.6 Kinetic Expression for the Denitrification Process 137

4.7 Relationship Between Growth and Removal Rate 138

4.8 Kinetic Constants in the Denitrification Process 138

4.9 The Influence of Oxygen on the Denitrification Rate 139

4.10 The Influence of Temperature on the Denitrification Rate 139

4.11 The Influence of Carbon Concentration on the Denitrification Rate 142

4.12 The Influence of pH on the Denitrification Rate 145

4.13 Combined Kinetic Expression for the Denitrification Process 147

4.14 Bacterial Population Dynamics for the Denitrification Bacteria 149

4.15 Influence of Toxic Substances on the Denitrification Process 150

4.16 Conclusion 151

CHAPTER 5

ATTACHED GROWTH REACTORS 153 B. Halling-Sorensen

5.1 Introduction 153

5.2 The Biofilm 154

5.3 The Development of a Bacterial Biofilm 155

5.4 Modelling the Transport and Reactions within a Biofilm 159

5.5 A Mass-balance Equation for a Biofilm Plant 165

5.6 The Nitrifying Trickling Filters (NTF) 170

5.6.1 The Performance of Trickling Filters 171

5.6.2 Equations for Modelling the Nitrifying Trickling

Filter (NTF) 177

5.6.3 The Application of the Trickling Filter 182

5.6.4 Recent Developments in the Technology of the Nitrifying

Trickling Filters (NTF) 186

5.6.5 Nitrogen Loading Capacity and Removal Efficiency of the

Different NTF-Applications 186

5.6.6 Advantages and Disadvantage of the NTF 192

5.7 Rotating Biological Contactors (RBC) 193

5.7.1 The Performance of the RBC 193

5.7.2 Equations for Modelling the RBC Reactor 198

5.7.3 The Application of the RBC 206

5.7.4 Recent Development in the RBC Technology 207

5.7.5 Nitrogen Loading Capacity and Removal Efficiency of the

RBC Process 208

5.7.6 Advantages and Disadvantages of the Nitrifying RBC 213

5.8 Submerged Filters 215

5.8.1 Case Study; Simultaneous Nitrification and Denitrification (SND) as Tertiary Treatment Step, using a Submerged BiofiIter of Clinoptilolite 216

CHAPTER 6

SUSPENDED-CULTURE REACTORS 235 B. Halling-Serensen

6.1 Activated Sludge Unit Processes 235

6.2 Process Design 237

6.3 Activated-sludge Process Configurations 245

6.4 The Kinetics of the Activated Sludge Process 252

6.5 Modification of Activated Sludge Plants for the Biological

Removal of Nitrogen 252

6.6 Modelling the Activated Sludge Process 256

6.7 Advantages and Disadvantages of the Separate and Combined Activated Sludge Processes 256

PART C

PHYSICO-CHEMICAL UNIT PROCESSES FOR THE REMOVAL OF NITROGEN

S.E. Jergensen

CHAPTER 7

AIR STRIPPING 261 S.E. Jergensen

7.1 Physico-chemical Principles of Air Stripping 261

7.2 Process Variables 265

7.3 Gas Transfer 270

7.4 Design of Stripping Tower 275

7.5 Practical Experience 288

7.6 Application of Stripping 292

CHAPTER 8

BREAKPOINT-CHLORINATION 295 S.E. Jorgensen

8.1 Principles of Breakpoint-Chlorination 295

8.2 Process Variables 299

8.3 Design of Breakpoint-Chlorination Units 300

8.4 Application of Breakpoint-Chlorination for the Removal of Nitrogen 301

CHAPTER 9

ION-EXCHANGE 305 S.E. Jergensen

9.1 Principles of Ion Exchange 305

9.2 Process Variables 313

9.3 The Sequential and Continuous Ion Exchange Operation 320

9.4 Application of Ion Exchange 334

CHAPTER 10

MEMBRANE PROCESSES 337 S.E. Jargensen

10.1 Principles of Membrane Processes 337

10.2 Process Variables 341

10.3 Design of the Reverse Osmosis Unit 348

10.4 The Reverse Osmosis System 350

10.5 Application of Reverse Osmosis and Ultrafiltration 352

CHAPTER 11

PRECIPITATION 355 S.E. Jorgensen

11.1 Principles of Precipitation 355

11.2 Process Variables 372

11.3 Design of Plants for Precipitation of Nitrogen Compounds 378

11.4 Application of Nitrogen Removal by Precipitation 389

APPENDICES Of PART:

B Determination of Kinetic Coefficients for Activated Sludge Processes 393

C Design Examples for: 399

The Stripping Column 401

The Ion Exchange Column 403

The Reverse Osmosis Unit 407

The Sedimentation Tank 409

References 413

index 439

Part A

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