Aquaculture has been expanding at a rate of 8% per year for more than 30 years, and is projected to continue growing at a very rapid rate into the foreseeable future. In this completely updated and revised new edition of Aquaculture Engineering, a highly successful, best–selling and well received book, Odd–Ivar Lekang provides the latest must–have information of commercial importance to the industry, covering the principles and applications of all major facets of aquaculture and engineering.
Every aspect of the growing field and its new developments has been addressed in this Second Edition, with coverage spanning water transportation and treatment; feed and feeding systems; fish transportation and grading; cleaning and waste handling; and instrumentation and monitoring. There have also been major changes incorporated into the book, in the following subject areas: removal of particles; aeration and oxygenation; recirculation and water reuse systems; ponds; and the design and construction of aquaculture facilities. Also included is coverage of land–based fish farms and cage farms, and the book concludes with a very practical chapter on systematic methodology for planning a full aquaculture facility.
Fish farmers, aquaculture scientists and managers, engineers, equipment manufacturers and suppliers will find the Second Edition of Aquaculture Engineering an invaluable resource. The book will be an important addition to the shelves of all libraries in universities and research establishments where aquaculture, biological sciences and engineering are studied and taught.
Table of Contents
Preface xv
1 Introduction 1
1.1 Aquaculture engineering 1
1.2 Classification of aquaculture 1
1.3 The farm: technical components in a system 2
1.3.1 Land–based hatchery and juvenile production farm 2
1.3.2 On–growing sea cage farm 4
1.4 Future trends: increased importance of aquaculture engineering 5
1.5 This textbook 6
References 6
2 Water Transport 7
2.1 Introduction 7
2.2 Pipe and pipe parts 7
2.2.1 Pipes 7
2.2.2 Valves 11
2.2.3 Pipe parts: fittings 12
2.2.4 Pipe connections: jointing 12
2.2.5 Mooring of pipes 13
2.2.6 Ditches for pipes 14
2.3 Water flow and head loss in channels and pipe systems 15
2.3.1 Water flow 15
2.3.2 Head loss in pipelines 16
2.3.3 Head loss in single parts (fittings) 18
2.4 Pumps 19
2.4.1 Types of pump 19
2.4.2 Some definitions 19
2.4.3 Pumping of water requires energy 22
2.4.4 Centrifugal and propeller pumps 23
2.4.5 Pump performance curves and working point for centrifugal pumps 26
2.4.6 Change of water flow or pressure 28
2.4.7 Regulation of flow from selected pumps 29
References 31
3 Water Quality and Water Treatment: An Introduction 32
3.1 Increased focus on water quality 32
3.2 Inlet water 32
3.3 Outlet water 33
3.4 Water treatment 35
References 36
4 Fish Metabolism, Water Quality and Separation Technology 37
4.1 Introduction 37
4.2 Fish metabolism 37
4.2.1 Overview of fish metabolism 37
4.2.2 The energy budget 38
4.3 Separation technology 39
4.3.1 What are the impurities in water? 39
4.3.2 Phosphorus removal: an example 41
References 42
5 Adjustment of pH 43
5.1 Introduction 43
5.2 Definitions 43
5.3 Problems with low pH 44
5.4 pH of different water sources 44
5.5 pH adjustment 45
5.6 Examples of methods for pH adjustment 45
5.6.1 Lime 45
5.6.2 Sea water 47
5.6.3 Lye or hydroxides 47
References 48
6 Removal of Particles: Traditional Methods 50
6.1 Introduction 50
6.2 Characterization of the water 51
6.3 Methods for particle removal in fish farming 51
6.3.1 Mechanical filters and microscreens 52
6.3.2 Depth filtration: granular medium filters 55
6.3.3 Settling or gravity filters 58
6.3.4 Integrated treatment systems 60
6.4 Hydraulic loads on filter units 62
6.5 Purification efficiency 62
6.6 Dual drain tank 63
6.7 Local ecological solutions 64
References 64
7 Protein Skimming, Flotation, Coagulation and Flocculation 66
7.1 Introduction 66
7.1.1 Surface tension, cohesion and adhesion 68
7.1.2 Surfactants 70
7.2 Mechanisms for attachment and removal 71
7.2.1 Attachment of particles to rising bubbles by collision, typically in flotation 72
7.2.2 Improving colloid and particle removal rates: pretreatment 73
7.2.3 Attachment of surface–active substances, typically in protein skimmers 78
7.2.4 Particle attachment by nucleation 80
7.3 Bubbles 80
7.3.1 What is a gas bubble? 80
7.3.2 Methods for bubble generation 80
7.3.3 Bubble size 82
7.3.4 Bubble coalescence 83
7.4 Foam 83
7.4.1 What is foam? 83
7.4.2 Foam stability 84
7.4.3 Foam breakers 85
7.5 Introduction of bubbles affects the gas concentration in the water 85
7.6 Use of bubble columns in aquaculture 85
7.7 Performance of protein skimmers and flotation plants in aquaculture 86
7.7.1 What is removed in inlet or effluent aquaculture water with the use of protein skimmers? 86
7.7.2 Factors affecting the efficiency of protein skimming in aquaculture 87
7.7.3 Use of ozone 89
7.7.4 Bubble fractionation 89
7.8 Design and dimensioning of protein skimmers and flotation plants 90
7.8.1 Protein skimmers: principles and design 90
7.8.2 Protein skimmers: dimensioning 92
7.8.3 Flotation plant 92
7.8.4 Important factors affecting design of a DAF plant 93
References 95
8 Membrane Filtration 99
8.1 History and use 99
8.2 What is membrane filtration? 100
8.3 Classification of membrane filters 101
8.4 Flow pattern 103
8.5 Membrane shape/geometry 104
8.6 Membrane construction/morphology 105
8.7 Flow across membranes 106
8.8 Membrane materials 106
8.9 Fouling 107
8.10 Automation 108
8.11 Design and dimensioning of membrane filtration plants 108
8.12 Some examples of results with membranes used in aquaculture 112
References 112
9 Sludge Production, Treatment and Utilization 114
9.1 What is the sludge? 114
9.2 Dewatering of sludge 114
9.3 Stabilization of sludge 115
9.4 Composting of the sludge: aerobic decomposition 115
9.5 Fermentation and biogas production: anaerobic decomposition 117
9.6 Addition of lime 118
9.7 Utilization of sludge 118
References 118
10 Disinfection 120
10.1 Introduction 120
10.2 Basis of disinfection 121
10.2.1 Degree of removal 121
10.2.2 Chick s law 121
10.2.3 Watson s law 121
10.2.4 Dose response curve 122
10.3 Ultraviolet light 122
10.3.1 Function 122
10.3.2 Mode of action 122
10.3.3 Design 123
10.3.4 Design specification 124
10.3.5 Dose 125
10.3.6 Special problems 125
10.4 Ozone 125
10.4.1 Function 125
10.4.2 Mode of action 125
10.4.3 Design specification 126
10.4.4 Ozone dose 127
10.4.5 Special problems 127
10.4.6 Measuring ozone content 128
10.5 Advanced oxidation technology 129
10.5.1 Redox potential 129
10.5.2 Methods utilizing AOT 130
10.6 Other disinfection methods 131
10.6.1 Photozone 131
10.6.2 Heat treatment 131
10.6.3 Chlorine 131
10.6.4 Changing the pH 132
10.6.5 Natural methods: ground filtration or constructed wetland 132
10.6.6 Membrane filtration 132
References 132
11 Heating and Cooling 134
11.1 Introduction 134
11.2 Heating requires energy 134
11.3 Methods for heating water 135
11.4 Heaters 136
11.4.1 Immersion heaters 136
11.4.2 Oil and gas burners 137
11.5 Heat exchangers 138
11.5.1 Why use heat exchangers? 138
11.5.2 How is the heat transferred? 138
11.5.3 Factors affecting heat transfer 139
11.5.4 Important parameters when calculating the size of heat exchangers 140
11.5.5 Types of heat exchanger 141
11.5.6 Flow pattern in heat exchangers 144
11.5.7 Materials in heat exchangers 144
11.5.8 Fouling 145
11.6 Heat pumps 146
11.6.1 Why use heat pumps? 146
11.6.2 Construction and function of a heat pump 146
11.6.3 Log pressure enthalpy (p H) 147
11.6.4 Coefficient of performance 148
11.6.5 Installations of heat pumps 148
11.6.6 Management and maintenance of heat pumps 149
11.7 Composite heating systems 149
11.8 Chilling of water 153
References 154
12 Aeration and Oxygenation 155
12.1 Introduction 155
12.2 Gases in water 155
12.3 Gas theory: aeration 157
12.3.1 Equilibrium 157
12.3.2 Gas transfer 158
12.4 Design and construction of aerators 159
12.4.1 Basic principles 159
12.4.2 Evaluation criteria 160
12.4.3 Example of designs for different types of aerator 161
12.5 Oxygenation of water 165
12.6 Theory of oxygenation 166
12.6.1 Increasing the equilibrium concentration 166
12.6.2 Gas transfer velocity 166
12.6.3 Addition under pressure 166
12.7 Design and construction of oxygen injection systems 166
12.7.1 Basic principles 166
12.7.2 Where to install the injection system 167
12.7.3 Evaluation of methods for injecting oxygen gas 168
12.7.4 Examples of oxygen injection system designs 169
12.8 Oxygen gas characteristics 172
12.9 Sources of oxygen 172
12.9.1 Oxygen gas 173
12.9.2 Liquid oxygen 173
12.9.3 On–site oxygen production 175
12.9.4 Selection of source 175
Appendix 12.1 177
Appendix 12.2 177
References 177
13 Ammonia Removal 179
13.1 Introduction 179
13.2 Biological removal of ammonium ion 179
13.3 Nitrification 180
13.4 Construction of nitrification filters 181
13.4.1 Flow–through system 182
13.4.2 The filter medium in the biofilter 183
13.4.3 Rotating biofilter (biodrum) 183
13.4.4 Moving bed bioreactor (MBBR) 184
13.4.5 Granular filters/bead filters 185
13.5 Management of biological filters 185
13.6 Example of biofilter design 186
13.7 Denitrification 186
13.8 Chemical removal of ammonia 187
13.8.1 Principle 187
13.8.2 Construction 187
References 188
14 Traditional Recirculation and Water Re–use Systems 190
14.1 Introduction 190
14.2 Advantages and disadvantages of re–use systems 190
14.2.1 Advantages of re–use systems 190
14.2.2 Disadvantages of re–use systems 191
14.3 Definitions 191
14.3.1 Degree of re–use 191
14.3.2 Water exchange in relation to amount of fish 192
14.3.3 Degree of purification 193
14.4 Theoretical models for construction of re–use systems 193
14.4.1 Mass flow in the system 193
14.4.2 Water requirements of the system 193
14.4.3 Connection between outlet concentration, degree of re–use and effectiveness of the water treatment system 195
14.5 Components in a re–use system 196
14.6 Design of a re–use system 197
References 200
15 Natural Systems, Integrated Aquaculture, Aquaponics, Biofloc 201
15.1 Characterization of production systems 201
15.2 Closing the nutrient loop 201
15.3 Re–use of water: an interesting topic 201
15.4 Natural systems, polyculture, integrated systems 203
15.4.1 Integrated multitropic aquaculture 203
15.4.2 Biological purification of water: some basics 203
15.4.3 Examples of systems utilizing photoautotrophic organisms: aquaponics 204
15.4.4 Examples of systems utilizing heterotrophic bacteria: active sludge and bioflocs 205
15.4.5 The biofloc system 206
References 208
16 Production Units: A Classification 210
16.1 Introduction 210
16.2 Classification of production units 210
16.2.1 Intensive/extensive 210
16.2.2 Fully controlled/semi–controlled 213
16.2.3 Land based/tidal based/sea based 213
16.2.4 Other 214
16.3 Possibilities for controlling environmental impact 215
17 Egg Storage and Hatching Equipment 216
17.1 Introduction 216
17.2 Systems where the eggs stay pelagic 217
17.2.1 The incubator 217
17.2.2 Water inlet and water flow 218
17.2.3 Water outlet 218
17.3 Systems where the eggs lie on the bottom 219
17.3.1 Systems where the eggs lie in the same unit from spawning to fry ready for start feeding 219
17.3.2 Systems where the eggs must be removed before hatching 221
17.3.3 Systems where storing, hatching and first feeding are carried out in the same unit 223
References 223
18 Tanks, Basins and Other Closed Production Units 224
18.1 Introduction 224
18.2 Types of closed production unit 224
18.3 How much water should be supplied? 226
18.4 Water exchange rate 227
18.5 Ideal or non–ideal mixing and water exchange 228
18.6 Tank design 228
18.7 Flow pattern and self–cleaning 231
18.8 Water inlet design 233
18.9 Water outlet or drain 235
18.10 Dual drain 237
18.11 Other installations 237
References 237
19 Ponds 239
19.1 Introduction 239
19.2 The ecosystem 239
19.3 Different production ponds 240
19.4 Pond types 241
19.4.1 Construction principles 241
19.4.2 Drainable or non–drainable 242
19.5 Size and construction 243
19.6 Site selection 243
19.7 Water supply 244
19.8 The inlet 245
19.9 The outlet: drainage 245
19.10 Pond layout 247
References 247
20 Sea Cages 249
20.1 Introduction 249
20.2 Site selection 250
20.3 Environmental factors affecting a floating construction 251
20.3.1 Waves 251
20.3.2 Wind 257
20.3.3 Current 257
20.3.4 Ice 259
20.4 Construction of sea cages 259
20.4.1 Cage collar or framework 260
20.4.2 Weighting and stretching 260
20.4.3 Net bags 262
20.4.4 Breakwaters 263
20.4.5 Examples of cage constructions 264
20.5 Mooring systems 266
20.5.1 Design of the mooring system 267
20.5.2 Description of the single components in a pre–stressed mooring system 269
20.5.3 Examples of mooring systems in use 274
20.6 Calculation of forces on a sea cage farm 274
20.6.1 Types of force 275
20.6.2 Calculation of current forces 276
20.6.3 Calculation of wave forces 279
20.6.4 Calculation of wind forces 280
20.7 Calculation of the size of the mooring system 280
20.7.1 Mooring analysis 280
20.7.2 Calculation of sizes for mooring lines 281
20.8 Control of mooring systems 283
References 283
21 Feeding Systems 286
21.1 Introduction 286
21.1.1 Why use automatic feeding systems? 286
21.1.2 What can be automated? 286
21.1.3 Selection of feeding system 286
21.1.4 Feeding system requirements 286
21.2 Types of feeding equipment 287
21.2.1 Feed blowers 287
21.2.2 Feed dispensers 287
21.2.3 Demand feeders 287
21.2.4 Automatic feeders 289
21.2.5 Feeding systems 293
21.3 Feed control 295
21.4 Feed control systems 296
21.5 Dynamic feeding systems 296
References 297
22 Internal Transport and Size Grading 299
22.1 Introduction 299
22.2 The importance of fish handling 299
22.2.1 Why move the fish? 299
22.2.2 Why size grade? 300
22.3 Negative effects of handling the fish 304
22.4 Methods and equipment for internal transport 305
22.4.1 Moving fish with a supply of external energy 305
22.4.2 Methods for moving fish without the need for external energy 315
22.5 Methods and equipment for size grading of fish 316
22.5.1 Equipment for grading that requires an energy supply 316
22.5.2 Methods for voluntary grading (self–grading) 326
References 326
23 Transport of Live Fish 328
23.1 Introduction 328
23.2 Preparation for transport 328
23.3 Land transport 329
23.3.1 Land vehicles 329
23.3.2 The tank 329
23.3.3 Supply of oxygen 330
23.3.4 Changing the water 331
23.3.5 Density 331
23.3.6 Instrumentation and stopping procedures 332
23.4 Sea transport 332
23.4.1 Well boats 332
23.4.2 The well 332
23.4.3 Density 333
23.4.4 Instrumentation 334
23.4.5 Recent trends in well boat technology 334
23.5 Air transport 335
23.6 Other transport methods 336
23.7 Cleaning and re–use of water 336
23.8 Use of additives 337
References 337
24 Instrumentation and Monitoring 339
24.1 Introduction 339
24.2 Construction of measuring instruments 340
24.3 Instruments for measuring water quality 340
24.3.1 Measuring temperature 341
24.3.2 Measuring oxygen content of the water 341
24.3.3 Measuring pH 342
24.3.4 Measuring conductivity and salinity 342
24.3.5 Measuring total gas pressure and nitrogen saturation 342
24.3.6 Other 343
24.4 Instruments for measuring physical conditions 344
24.4.1 Measuring the water flow 344
24.4.2 Measuring water pressure 347
24.4.3 Measuring water level 347
24.5 Equipment for counting fish, measuring fish size and estimation of total biomass 349
24.5.1 Counting fish 349
24.5.2 Measuring fish size and total fish biomass 350
24.6 Monitoring systems 352
24.6.1 Sensors and measuring equipment 353
24.6.2 Monitoring centre 353
24.6.3 Warning equipment 354
24.6.4 Regulation equipment 355
24.6.5 Maintenance and control 355
References 355
25 Buildings and Superstructures 357
25.1 Why use buildings? 357
25.2 Types, shape and roof design 357
25.2.1 Types 357
25.2.2 Shape 358
25.2.3 Roof design 358
25.3 Load–carrying systems 359
25.4 Materials 359
25.5 Prefabricate or build on site? 362
25.6 Insulated or not? 362
25.7 Foundations and ground conditions 362
25.8 Design of major parts 363
25.8.1 Floors 363
25.8.2 Walls 363
25.9 Ventilation and climate control 364
References 366
26 Design and Construction of Aquaculture Facilities: Some Examples 367
26.1 Introduction 367
26.2 Land–based hatchery, juvenile and on–growing production plant 367
26.2.1 General 367
26.2.2 Water intake and transfer 367
26.2.3 Water treatment department 377
26.2.4 Production rooms 378
26.2.5 Feed storage 383
26.2.6 Disinfection barrier 383
26.2.7 Other rooms 383
26.2.8 Outlet water treatment 383
26.2.9 Important equipment 384
26.3 On–growing production, sea cage farms 385
26.3.1 General 385
26.3.2 Site selection 387
26.3.3 The cages and the fixed equipment 387
26.3.4 The base station 390
26.3.5 Net handling 391
26.3.6 Boat 392
References 393
27 Planning Aquaculture Facilities 394
27.1 Introduction 394
27.2 The planning process 394
27.3 Site selection 395
27.4 Production plan 395
27.5 Room programme 397
27.6 Necessary analyses 397
27.7 Drawing up alternative solutions 398
27.8 Evaluation of and choosing between the alternative solutions 399
27.9 Finishing plans, detailed planning 399
27.10 Function test of the plant 399
27.11 Project review 402
References 402
Index 403
