Practical Approach to Water Conservation for Commercial and Industrial Facilities (eBook)

Cover 1
Copyright Page 5
Table of Contents 8
Foreword 17
About the Author 19
Acknowledgement 20
Chapter 1 Water Conservation – A Priority for Business 22
1.1 Introduction 22
1.2 Global Water Resources Availability 23
1.3 Human Need for Safe Drinking Water and Proper Sanitation 24
1.4 Meeting Agricultural Needs 27
1.5 The Impact of Climate Change 29
1.6 Business Sector Water Usage 32
1.7 Nine Reasons for Business to Reduce Their Water Consumption 36
1.8 Conclusion 43
References 43
Chapter 2 Basic Water Chemistry 46
2.1 Overview 46
2.2 Solubility Principles 47
2.3 Common Substances Found in Water 47
2.3.1 pH 47
2.3.2 Dissolved Gases 49
2.3.2.1 Carbon dioxide and Alkalinity 49
2.3.2.2 Oxygen (O2) 50
2.3.2.3 Ammonia (NH3) 50
2.3.2.4 Hydrogen Sulphide (H2S) 51
2.3.3 Dissolved Ions 51
2.3.3.1 Conductivity and Total Dissolved Solids 51
2.3.3.2 Hardness, Calcium and Magnesium 53
2.3.3.3 Chlorides 56
2.3.3.4 Sodium 57
2.3.3.5 Iron 57
2.3.3.6 Manganese 57
2.3.3.7 Silica 58
2.3.3.8 Phosphate 58
2.3.3.9 Nitrate 58
2.3.3.10 Boron 58
2.3.3.11 Cyanide 59
2.3.4 Suspended Solids and Turbidity 59
2.3.5 Colour 59
2.3.6 Organics in Water 60
2.3.6.1 Biochemical Oxygen Demand 60
2.3.6.2 Chemical Oxygen Demand 60
2.3.7 Micro-organisms 61
2.3.7.1 Viruses 61
2.3.7.2 Bacteria 61
2.3.7.3 Protozoa 62
2.3.7.4 Algae 63
2.3.7.5 Helminths 63
2.3.7.6 Fungi 63
2.3.8 Heavy Metals 63
2.3.8.1 Chromium 63
2.3.8.2 Cadmium 64
2.3.8.3 Lead 64
2.3.8.4 Mercury 65
2.3.9 Radionuclides 65
References 65
Chapter 3 Saving Water: Step by Step 67
3.1 Developing a Sustainable Water Management Plan 67
3.2 Step 1: Seek Senior Management Commitment 71
3.3 Step 2: Appoint A Water Conservation Manager 72
3.3.1 Responsibilities of the Water Conservation Manager 72
3.4 Step 3: Gather Baseline Data and Review Usage 73
3.5 Step 4: Identify Improvement Opportunities 76
3.5.1 Carry Out an Assessment of Management Systems 76
3.5.1.1 One-2-Five Water® – Management Diagnostic System 76
3.5.2 Technical Assessment 77
3.5.2.1 How Detailed Should the Water Audit Be? 78
3.5.2.2 Estimating Water-Saving Potential 80
3.5.2.3 Complying with Regulatory Standards 81
3.5.2.4 Carrying out a Water Audit 83
3.5.2.5 Develop a Water Balance 86
3.5.2.6 Identifying Other Opportunities to Reduce Water Use 86
3.6 Step 5: Preparing the Plan Prioritising the Opportunities 88
3.7 Step 6: Report the Results 89
3.8 Conclusion 92
References 92
Chapter 4 Measuring Flow and Consumption 94
4.1 Flow Measurement 94
4.2 Types of FlowMeters 96
4.2.1 Positive Displacement Meters (volumetric) 96
4.2.2 Velocity Meters 97
4.2.2.1 Mechanical Meters 98
4.2.2.2 Non-Mechanical Meters 99
4.3 Selecting a Flowmeter 101
4.4 Dataloggers 101
4.5 Chemical Methods of Flow Measurement 103
4.6 Conclusion 103
Chapter 5 Cooling Water Systems 104
5.1 Introduction 104
5.2 Types of Cooling Systems 105
5.2.1 Open Recirculating Cooling Water Systems 106
5.2.1.1 Recirculating Cooling Water Systems – Operational Principles 107
5.2.1.2 Recirculating Cooling Water Systems – Basic Concepts 109
5.3 Types of Cooling Towers 113
5.3.1 Induced Draught Cross-flow Cooling Towers 114
5.3.2 Induced Draught Counter-flow Cooling Towers 114
5.3.3 Forced Draught Wet Cooling Towers 115
5.3.4 Evaporative Condensers 115
5.4 Water Conservation Opportunities 115
5.4.1 Reducing Involuntary Water Loss 116
5.4.1.1 Minimising Overflow of Water from Cooling Tower Basins 116
5.4.1.2 Incorrect Piping Configuration 117
5.4.1.3 Leakage from Pipes, Joints and Pump Glands 117
5.4.1.4 Drift Loss 117
5.4.1.5 Splash 117
5.4.2 Reducing Voluntary Water Loss 117
5.4.2.1 Increasing Cycles of Concentration 118
5.4.2.2 Install Flowmeters on Make-up and Blowdown Lines and Conductivity Meters in Blowdown Lines 119
5.4.2.3 Operate Blowdown in Continuous Mode 119
5.4.2.4 Install Sidestream Filtration 120
5.4.3 Improving Operating Practices 121
5.4.3.1 Shut Off the Unit When not in Operation 121
5.4.3.2 Minimise Process Leaks to the Cooling System 122
5.5 Alternative Water Sources 122
5.5.1 Maximum Allowable Concentrations 122
5.6 Cooling Water Treatment for Recirculating Water Systems 125
5.6.1 Scaling 126
5.6.1.1 Scaling Indices 128
5.6.1.2 What the LSI is Not 129
5.6.1.3 Scale-control Methods 129
5.6.2 Fouling 130
5.6.3 Corrosion 130
5.6.4 Biofouling and Microbial Growth 132
5.6.4.1 Microbiological Control 133
5.7 Role of Water Treatment Contractors in Water Conservation 135
5.8 Conclusion 136
References 136
Chapter 6 Alternatives to Wet Cooling Towers 138
6.1 Air-conditioning and Refrigeration Systems 138
6.2 Energy Conservation = Water Conservation 139
6.3 Alternative Heat Rejection Systems 144
6.3.1 Air-Cooled Condensers 145
6.3.2 Hybrid Cooling Towers 146
6.3.3 Combination Cooling Systems 148
6.3.4 Geothermal Cooling Systems 150
References 151
Chapter 7 Steam Systems 153
7.1 Introduction 153
7.2 Steam System Principles 154
7.2.1 Pre-treatment 155
7.2.2 Steam Generation 160
7.2.2.1 Firetube Boilers 160
7.2.2.2 Watertube Boilers 161
7.2.2.3 Waste Heat Recovery Boilers 164
7.2.3 Steam Distribution System 164
7.2.3.1 Thermostatic Traps 165
7.2.3.2 Mechanical Traps 165
7.2.3.3 Thermodynamic Traps 165
7.2.3.4 Fixed Orifice Condensate Discharge Traps (FOCDT) 166
7.3 Steam and Energy Conservation Opportunities 167
7.3.1 Repair Steam Leaks 168
7.3.2 Maximise Condensate Recovery 169
7.3.2.1 Condensate Quality and System Protection 171
7.3.2.2 Minimise Water Logging of Pipes 172
7.3.3 Minimising Boiler Water Blowdown 172
7.3.3.1 Blowdown Control 172
7.4 Calculating the “True” Cost of Steam 175
References 176
Chapter 8 Industrial Water Reuse Technologies 178
8.1 Introduction 178
8.2 A Step-by-Step Approach to Water Reuse 180
8.2.1 Establishing the Goals of the Study 181
8.2.1.1 Goals 181
8.2.1.2 Project Boundaries 181
8.2.2 Gather Data 182
8.2.3 Identify the Project 182
8.2.4 Technical Assessment 185
8.2.5 Implementation 185
8.3 Pollutants Found in Reuse Streams 185
8.4 Removal of Pollutants 186
8.4.1 Order of Removal 188
8.5 Removal of Suspended Solids 188
8.5.1 Screening 189
8.5.2 Sedimentation 191
8.5.3 Settling 192
8.5.4 Chemically Aided Settling – Coagulation 193
8.5.5 Filtration 194
8.6 Removal of Fats, Oils and Greases 196
8.6.1 Sources of Fats, Oil and Grease 196
8.6.2 Free FOG Removal – Skimming 197
8.6.3 Emulsified FOG Removal 197
8.6.3.1 Air Flotation 198
8.6.3.2 Ultrafiltration 200
8.7 Removal of Biodegradable Organics 201
8.7.1 Activated Sludge Process 205
8.7.2 Anaerobic Processes 209
8.7.2.1 Performance 211
8.7.3 Membrane Bioreactors 212
8.8 Removal of Heavy Metals 213
8.8.1 Chemical Precipitation 214
8.8.2 Ion Exchange 217
8.9 Adsorption 218
8.10 Membranes for Removal of Dissolved Ions 219
8.10.1 Overview 219
8.10.2 Dead-End and Cross-Flow Filtration 222
8.10.2.1 Dead-end Filtration 222
8.10.2.2 Cross-flow Filtration 222
8.10.3 Membrane Types 223
8.10.3.1 Microfiltration 223
8.10.3.2 Ultrafiltration 226
8.10.3.3 Nanofiltration 226
8.10.3.4 Reverse Osmosis 227
8.10.4 Membrane Structure 227
8.10.5 Membrane Configurations 228
8.10.5.1 Spiral Wound 228
8.10.5.2 Hollow Fibre 228
8.10.5.3 Tubular 229
8.10.5.4 Plate and Frame 230
8.10.6 Membrane Performance Monitoring 234
8.10.6.1 Silt Density Index 235
8.10.6.2 Assessment of Scaling Tendencies 236
8.10.6.3 Membrane flux 236
8.10.6.4 Permeate Recovery 237
8.10.7 Disposal of Brine Streams 238
8.10.8 Considerations When Selecting Membrane Systems 238
8.10.9 Electrodialysis and Electrodialysis Reversal 240
References 240
Chapter 9 Making a Financially Sound Business Case 242
9.1 Introduction 242
9.2 Management Functions 243
9.3 Making a Good Business Case 243
9.3.1 Identifying Hidden Costs 245
9.4 Computing Cash Flows 247
9.5 Investment Appraisal Methods 249
9.5.1 Payback Method 249
9.5.2 Return on Investment Method 251
9.5.3 Discounted Cash Flow Methods 251
9.5.4 Net Present Value Analyses 252
9.5.5 Internal Rate of Return 254
9.6 Assessing Project Risk 254
References 256
Chapter 10 The Hospitality Sector 257
10.1 Introduction 257
10.2 Benchmarking Water and Energy Consumption 258
10.2.1 Benchmarking Water Consumption 258
10.2.2 Benchmarking Energy Consumption 259
10.3 Steps to Achieve Water Savings 261
10.3.1 Water Management Policy 261
10.3.2 Gathering Consumption and Billing Data and Metering Water Consumption 262
10.3.3 Identifying the Best Opportunities 262
10.3.3.1 Guest Rooms 262
10.3.3.2 Public Amenities 265
10.3.3.3 Kitchens 273
10.3.3.4 Cooling Tower: Air-Conditioning and Refrigeration 279
10.3.3.5 Laundry 280
10.3.3.6 Ice-Making Machines 280
10.3.3.7 Swimming Pools 283
10.3.3.8 Staff Rooms 283
10.3.3.9 Irrigation 283
10.4 Staff Awareness Programmes 285
10.5 Guest Awareness Programmes 285
References 286
Chapter 11 Commercial Buildings, Hospitals and Institutional Buildings 288
11.1 Introduction 288
11.2 Commercial Property – Office and Retail 288
11.2.1 Industry Structure and Water Usage 288
11.2.2 Water-Usage Benchmarks 290
11.2.2.1 Energy Consumption 291
11.2.2.2 Shopping Centres 292
11.2.3 Water-Saving Opportunities 293
11.3 Hospitals 296
11.3.1 Benchmarking Water Usage 297
11.3.2 Benchmarking Energy Consumption 298
11.3.3 Water Conservation Opportunities 299
11.3.3.1 Monitor Leakage 299
11.3.3.2 Air-conditioning and Refrigeration Systems 300
11.3.3.3 Steam Systems 300
11.3.3.4 Taps, Toilets and Urinals 300
11.3.3.5 Food Preparation 301
11.3.3.6 In-house Laundries 301
11.3.3.7 Medical Equipment 302
11.3.3.8 Increase Staff Awareness 306
11.3.3.9 Floor cleaning 306
11.4 Correctional Centres 306
11.4.1 Water Usage Benchmarks 307
11.4.2 Water Conservation Opportunities 307
References 309
Chapter 12 Swimming Pools 312
12.1 Introduction 312
12.1.1 Swimming Pool Benchmarks 312
12.2 Water Conservation Opportunities 313
12.2.1 Reducing Leakage 314
12.2.2 Water-Efficient Fixtures 314
12.2.3 Optimising Filter Backwash Cycles 315
12.2.4 Minimising Evaporation 317
References 320
Chapter 13 Food Processing and Beverage Industry 321
13.1 Introduction 321
13.2 Water and Energy Usage 322
13.2.1 Water Usage 322
13.2.2 Energy Usage 324
13.3 Understanding the Process and Where Water is Used 327
13.4 Benchmarking Water Usage and Comparing it Against Best Practice 328
13.5 Water Minimisation Measures in the Food-Processing Industry 331
13.5.1 Avoiding Water Usage 331
13.5.2 Reducing Water Usage – Spray Nozzles 333
13.5.3 Reducing Water Usage – Washing 337
13.5.4 Reducing Water Usage – Clean-in-Place 337
13.5.5 Reducing Water Usage – Liquid Ring Vacuum Pumps 341
13.5.6 Reducing Water Usage – Amenities Blocks 346
13.5.7 Reducing Water Usage – Evaporative Condensers and Cooling Towers 346
13.5.8 Reducing Water Usage – Steam Systems 347
13.5.9 Reusing Water 347
13.5.10 Notes on Water-Reuse Applications 348
References 349
Chapter 14 Oil Refining 351
14.1 Introduction 351
14.2 Oil Refining Processes 353
14.2.1 Desalting, Crude Distillation and Vacuum Distillation 353
14.2.2 Thermal and Catalytic Cracking 353
14.2.3 Hydrotreating 354
14.2.4 Reforming 354
14.2.5 Alkylation and Polymerisation 354
14.2.6 Coking 354
14.2.7 Blending 354
14.3 Water Usage 356
14.3.1 Cooling Water Systems 356
14.3.2 Steam Systems 356
14.3.3 Wastewater Systems 358
14.3.4 Energy Usage 359
14.4 Water Conservation Opportunities 360
14.4.1 Reduction in water consumption 362
References 363
Chapter 15 Laundries 364
15.1 Introduction 364
15.2 Industry Structure 365
15.2.1 Large Commercial Laundries 365
15.2.2 Large Hospital Laundries 365
15.2.3 Large and Small On-premise Laundries 365
15.3 Types of Laundry Equipment 366
15.3.1 Washer-Extractor 367
15.3.2 Continuous Batch Washers or Tunnel Washers 368
15.4 Benchmarking 369
15.5 Water Conservation 370
15.5.1 Water and Energy Reuse 370
15.5.2 Reuse for Wash Water Quality 371
15.5.3 Reuse for Rinse Water Quality 372
15.5.4 Ozone Disinfection 374
References 376
Glossary of Terms 378
Appendix 385
Worksheets 385
Conversions 390
Index 393