Preface xvii
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 6
1.5 This textbook 6
References 7
2 Water Transport 9
2.1 Introduction 9
2.2 Pipe and pipe parts 9
2.2.1 Pipes 9
2.2.2 Valves 12
2.2.3 Pipe parts: fittings 14
2.2.4 Pipe connections: jointing 15
2.2.5 Mooring of pipes 15
2.2.6 Ditches for pipes 16
2.3 Some basic hydrodynamics 17
2.3.1 Boundary layer theory 17
2.3.2 Bernoulli’s equation 18
2.4 Water flow and head loss in channels and pipe systems 19
2.4.1 Water flow 19
2.4.2 Head loss in pipelines 20
2.4.3 Head loss in single parts (fittings) 23
2.4.4 Gravity feed pipes 23
2.5 Pumps 26
2.5.1 Types of pump 26
2.5.2 Some definitions 26
2.5.3 Pumping of water requires energy 29
2.5.4 Centrifugal and propeller pumps 30
2.5.5 Pump performance curves and working point for centrifugal pumps 32
2.5.6 Change of water flow or pressure 35
2.5.7 Regulation of flow from selected pumps 37
References 39
3 Water Quality and Water Treatment: An Introduction 41
3.1 Increased focus on water quality 41
3.2 Inlet water 41
3.3 Outlet water 43
3.4 Water treatment 44
References 46
4 Fish Metabolism, Water Quality and Separation Technology 47
4.1 Introduction 47
4.2 Fish metabolism 47
4.2.1 Overview of fish metabolism 47
4.2.2 The energy budget 49
4.3 Separation technology 49
4.3.1 What are the impurities in water? 50
4.3.2 Phosphorus removal: an example 51
References 53
5 Controlling pH, Alkalinity and Hardness 55
5.1 Introduction 55
5.2 pH 55
5.2.1 Water dissolves in water 55
5.2.2 What is pH 56
5.2.3 The carbonate system 57
5.2.4 Total carbonate carbon 60
5.2.5 Open or closed system 60
5.2.6 A mathematical approach 63
5.2.7 pH of different water sources 64
5.2.8 Recommended pH for aquaculture 64
5.3 Alkalinity 65
5.3.1 How to avoid pH fluctuations 65
5.3.2 Titration is necessary 65
5.3.3 A buffer 66
5.3.4 The term equivalent weight 68
5.3.5 Alkalinity given as mg/L CaCO3 68
5.3.6 Alkalinity of different water sources 69
5.3.7 Recommended alkalinity for aquaculture 69
5.4 Hardness 69
5.4.1 The concentration of bivalent cations 69
5.4.2 Hardness may lead to precipitation 70
5.4.3 Hardness of different water sources 71
5.4.4 Recommended hardness 71
5.5 Chemical agents to use for regulation of pH, alkalinity and hardness 72
5.6 Examples of methods for pH adjustment 73
5.6.1 Lime 73
5.6.2 Sea water 75
5.6.3 Lye or hydroxides 76
5.6.4 pH regulation in RAS 76
References 77
6 Removal of Particles: Traditional Methods 79
6.1 Introduction 79
6.2 Characterization of the water 80
6.3 Methods for particle removal in fish farming 80
6.3.1 Mechanical filters and microscreens 81
6.3.2 Depth filtration: granular medium filters 84
6.3.3 Settling or gravity filters 87
6.3.4 Integrated treatment systems 90
6.4 Hydraulic loads on filter units 91
6.5 Purification efficiency 92
6.6 Dual drain tank 92
6.7 Local ecological solutions 94
References 94
7 Protein Skimming, Flotation, Coagulation and Flocculation 97
7.1 Introduction 97
7.1.1 Surface tension, cohesion and adhesion 99
7.1.2 Surfactants 102
7.2 Mechanisms for attachment and removal 102
7.2.1 Attachment of particles to rising bubbles by collision, typically in flotation 103
7.2.2 Improving colloid and particle removal rates: pretreatment 105
7.2.3 Attachment of surface?active substances, typically in protein skimmers 111
7.2.4 Particle attachment by nucleation 112
7.3 Bubbles 113
7.3.1 What is a gas bubble? 113
7.3.2 Methods for bubble generation 113
7.3.3 Bubble size 115
7.3.4 Bubble coalescence 115
7.4 Foam 116
7.4.1 What is foam? 116
7.4.2 Foam stability 117
7.4.3 Foam breakers 118
7.5 Introduction of bubbles affects the gas concentration in the water 118
7.6 Use of bubble columns in aquaculture 118
7.7 Performance of protein skimmers and flotation plants in aquaculture 119
7.7.1 What is removed in inlet or effluent aquaculture water with the use of protein skimmers? 119
7.7.2 Factors affecting the efficiency of protein skimming in aquaculture 121
7.7.3 Use of ozone 122
7.7.4 Bubble fractionation 123
7.8 Design and dimensioning of protein skimmers and flotation plants 123
7.8.1 Protein skimmers: principles and design 123
7.8.2 Protein skimmers: dimensioning 125
7.8.3 Flotation plant 126
7.8.4 Important factors affecting design of a DAF plant 127
References 129
8 Membrane Filtration 135
8.1 History and use 135
8.2 What is membrane filtration? 136
8.3 Classification of membrane filters 137
8.4 Flow pattern 139
8.5 Membrane shape/geometry 140
8.6 Membrane construction/morphology 142
8.7 Flow across membranes 143
8.8 Membrane materials 143
8.9 Fouling 144
8.10 Automation 146
8.11 Design and dimensioning of membrane filtration plants 146
8.12 Some examples of results with membranes used in aquaculture 149
References 150
9 Sludge 153
9.1 What is sludge 153
9.2 Utilization of the sludge 154
9.3 Dewatering of sludge 155
9.4 Stabilization of sludge 156
9.5 Composting of the sludge: aerobic decomposition 156
9.6 Fermentation and biogas production: anaerobic decomposition 158
9.7 Addition of lime 159
9.8 Drying of sludge 159
9.9 Combustion of sludge 160
9.10 Other possibilities for treatment and utilization of the sludge 161
References 161
10 Disinfection 163
10.1 Introduction 163
10.2 Basis of disinfection 164
10.2.1 Degree of removal 164
10.2.2 Chick’s law 164
10.2.3 Watson’s law 165
10.2.4 Dose–response curve 165
10.3 Ultraviolet light 165
10.3.1 Function 165
10.3.2 Mode of action 165
10.3.3 Design 166
10.3.4 Design specification 166
10.3.5 Dose 168
10.3.6 Special problems 168
10.4 Ozone 168
10.4.1 Function 168
10.4.2 Mode of action 169
10.4.3 Design specification 169
10.4.4 Ozone dose 170
10.4.5 Special problems 170
10.4.6 Measuring ozone content 172
10.5 Advanced oxidation technology 172
10.5.1 Redox potential 172
10.5.2 Methods utilizing AOT 173
10.6 Other disinfection methods 175
10.6.1 Photozone 175
10.6.2 Heat treatment 175
10.6.3 Chlorine 175
10.6.4 Changing the pH 176
10.6.5 Natural methods: ground filtration or constructed wetland 176
10.6.6 Membrane filtration 176
References 176
11 Heating and Cooling 179
11.1 Introduction 179
11.2 Heating requires energy 179
11.3 Methods for heating water 180
11.4 Heaters 181
11.4.1 Immersion heaters 181
11.4.2 Oil and gas burners 183
11.5 Heat exchangers 183
11.5.1 Why use heat exchangers? 183
11.5.2 How is the heat transferred? 184
11.5.3 Factors affecting heat transfer 184
11.5.4 Important parameters when calculating the size of heat exchangers 185
11.5.5 Types of heat exchanger 187
11.5.6 Flow pattern in heat exchangers 189
11.5.7 Materials in heat exchangers 190
11.5.8 Fouling 191
11.6 Heat pumps 192
11.6.1 Why use heat pumps? 192
11.6.2 Construction and function of a heat pump 192
11.6.3 Log pressure–enthalpy (p–H) 193
11.6.4 Coefficient of performance 194
11.6.5 Installations of heat pumps 194
11.6.6 Management and maintenance of heat pumps 196
11.7 Composite heating systems 196
11.8 Chilling of water 199
References 201
12 Gas Exchange, Aeration, Oxygenation and CO2 Removal 203
12.1 Introduction 203
12.2 Gas exchange in fish 203
12.3 Gases in water 204
12.4 Gas solubility in water 206
12.5 Gas transfer theory: aeration 210
12.5.1 Equilibrium 210
12.5.2 Gas transfer 212
12.6 Design and construction of aerators 213
12.6.1 Basic principles 213
12.6.2 Change of gas composition in the water for testing purposes 214
12.6.3 Evaluation criteria 215
12.6.4 Example of designs for different types of aerator 217
12.7 Oxygenation of water 223
12.8 Theory of oxygenation 224
12.8.1 Increasing the equilibrium concentration 224
12.8.2 Gas transfer velocity 224
12.8.3 Addition under pressure 224
12.9 Design and construction of oxygen injection systems 225
12.9.1 Basic principles 225
12.9.2 Where to install the injection system 225
12.9.3 Evaluation of methods for injecting oxygen gas 227
12.9.4 Examples of oxygen injection system designs 227
12.10 Oxygen gas characteristics 231
12.11 Sources of oxygen 231
12.11.1 Oxygen gas 231
12.11.2 Liquid oxygen 232
12.11.3 On?site oxygen production 234
12.11.4 Selection of source 235
References 236
13 Removal of Ammonia and Other Nitrogen Connections from Water 239
13.1 Introduction 239
13.1.1 Nitrogen connections 239
13.1.2 Total nitrogen: Kjeldahl nitrogen 239
13.1.3 Amount of NH3 in the water is pH dependent 239
13.1.4 NH4+?N 240
13.1.5 Nitrogen, a part of a cycle 241
13.1.6 Measurement of nitrogen compounds 241
13.1.7 Reference values for aquaculture 241
13.2 Biological removal of ammonium ion 242
13.3 Nitrification 242
13.4 Construction of nitrification filters 244
13.4.1 Flow?through system 244
13.4.2 The filter medium in the biofilter 245
13.4.3 Rotating biofilter (biodrum) 246
13.4.4 Moving bed bioreactor (MBBR) 246
13.4.5 Granular filters/bead filters 248
13.5 Management of biological filters 248
13.6 Example of biofilter design 248
13.7 Denitrification 249
13.8 Other bacteria cultures 250
13.9 Inoculation and boosting of biological filters 251
13.10 Chemical removal of ammonia 251
13.10.1 Principle 251
13.10.2 Construction 251
13.11 Other methods 253
References 253
14 Recycling Aquaculture Systems: Traditional Recirculating Water Systems 257
14.1 Introduction 257
14.2 Advantages and disadvantages of re?use systems 257
14.2.1 Advantages of re?use systems 257
14.2.2 Disadvantages of re?use systems 258
14.3 Definitions 259
14.3.1 Degree of re?use 259
14.3.2 Water exchange in relation to amount of fish or to supplied amount of feed 260
14.3.3 Degree of purification 260
14.3.4 Intensity of the RAS 261
14.4 Theoretical models for construction of re?use systems 261
14.4.1 Mass flow in the system 261
14.4.2 Water requirements of the system 261
14.4.3 Connection between outlet concentration, degree of re?use and effectiveness of the water treatment system 262
14.5 Components in a re?use system 264
14.5.1 Freshwater, brackish water and seawater RAS 267
14.6 Accumulation of substances, hydrogen sulphide problem and earthy taste removal 267
14.6.1 Accumulation of substances 267
14.6.2 Earthy taste removal 267
14.6.3 The hydrogen sulphide problem 268
14.7 Water maturation, disinfection and use of probiotics 269
14.8 Design of a re?use system 270
14.9 Evaluation of performance of a RAS 272
References 273
15 Natural Systems, Integrated Aquaculture, Aquaponics, Biofloc 275
15.1 Characterization of production systems 275
15.2 Closing the nutrient loop 275
15.3 Re?use of water: an interesting topic 275
15.4 Natural systems, polyculture, integrated systems 277
15.4.1 Integrated multitropic aquaculture 277
15.4.2 Biological purification of water: some basics 278
15.4.3 Examples of systems utilizing photoautotrophic organisms: aquaponics 279
15.4.4 Examples of systems utilizing heterotrophic bacteria: active sludge and bioflocs 279
15.4.5 The biofloc system 281
References 283
16 Production Units: A Classification 285
16.1 Introduction 285
16.2 Classification of production units 285
16.2.1 Intensive/extensive 288
16.2.2 Fully controlled/semi?controlled 288
16.2.3 Land based/tidal based/sea based 288
16.2.4 Other 289
16.3 Possibilities for controlling environmental impact 290
17 Egg Storage and Hatching Equipment 291
17.1 Introduction 291
17.2 Systems where the eggs stay pelagic 292
17.2.1 The incubator 293
17.2.2 Water inlet and water flow 293
17.2.3 Water outlet 294
17.3 Systems where the eggs lie on the bottom 294
17.3.1 Systems where the eggs lie in the same unit from spawning to fry ready for start feeding 295
17.3.2 Systems where the eggs must be removed before hatching 298
17.3.3 Systems where storing, hatching and first feeding are carried out in the same unit 298
References 299
18 Tanks, Basins and Other Closed Production Units 301
18.1 Introduction 301
18.2 Types of closed production unit 301
18.3 How much water should be supplied? 303
18.4 Water exchange rate 304
18.5 Ideal or non?ideal mixing and water exchange 305
18.6 Tank design 306
18.7 Flow pattern and self?cleaning 308
18.8 Water inlet design 310
18.9 Water outlet or drain 312
18.10 Dual drain 314
18.11 Other installations 315
References 315
19 Ponds 317
19.1 Introduction 317
19.2 The ecosystem 317
19.3 Different production ponds 318
19.4 Pond types 320
19.4.1 Construction principles 320
19.4.2 Drainable or non?drainable 320
19.5 Size and construction 321
19.6 Site selection 322
19.7 Water supply 322
19.8 The inlet 322
19.9 The outlet: drainage 323
19.10 Pond layout 324
References 325
20 Sea Cages 327
20.1 Introduction 327
20.2 Site selection 328
20.3 Environmental factors affecting a floating construction 329
20.3.1 Waves 329
20.3.2 Wind 336
20.3.3 Current 336
20.3.4 Ice 338
20.3.5 Site classification 339
20.4 Construction of sea cages 339
20.4.1 Cage collar or framework 340
20.4.2 Weighting and stretching 341
20.4.3 Net bags 342
20.4.4 Breakwaters 346
20.4.5 Examples of cage constructions 347
20.5 Mooring systems 351
20.5.1 Design of the mooring system 352
20.5.2 Description of the single components in a pre?stressed mooring system 354
20.5.3 Examples of mooring systems in use 360
20.6 Calculation of forces on a sea cage farm 360
20.6.1 Types of force 362
20.6.2 Calculation of current forces 363
20.6.3 Calculation of wave forces 367
20.6.4 Calculation of wind forces 367
20.6.5 Calculation of weight on materials in water 368
20.7 Calculation of the size of the mooring system 368
20.7.1 Mooring analysis 368
20.7.2 Calculation of sizes for mooring lines 369
20.8 Control of mooring systems 371
References 371
21 Feeding Systems 375
21.1 Introduction 375
21.1.1 Why use automatic feeding systems? 375
21.1.2 What can be automated? 375
21.1.3 Selection of feeding system 375
21.1.4 Feeding system requirements 376
21.2 Types of feeding equipment 376
21.2.1 Feed blowers 376
21.2.2 Feed dispensers 376
21.2.3 Demand feeders 378
21.2.4 Automatic feeders 378
21.2.5 Feeding systems 383
21.3 Feed control 385
21.4 Feed control systems 385
21.5 Dynamic feeding systems 386
References 386
22 Internal Transport and Size Grading 389
22.1 Introduction 389
22.2 The importance of fish handling 390
22.2.1 Why move the fish? 390
22.2.2 Why size grade? 391
22.3 Negative effects of handling the fish 394
22.4 Methods and equipment for internal transport 395
22.4.1 Moving fish with a supply of external energy 395
22.4.2 Methods for moving fish without the need for external energy 405
22.5 Methods and equipment for size grading of fish 406
22.5.1 Equipment for grading that requires an energy supply 406
22.5.2 Methods for voluntary grading (self?grading) 416
References 416
23 Transport of Live Fish 419
23.1 Introduction 419
23.2 Preparation for transport 419
23.3 Land transport 420
23.3.1 Land vehicles 420
23.3.2 The tank 420
23.3.3 Supply of oxygen 421
23.3.4 Changing the water 422
23.3.5 Density 422
23.3.6 Instrumentation and stopping procedures 423
23.4 Sea transport 423
23.4.1 Well boats 423
23.4.2 The well 424
23.4.3 Density 425
23.4.4 Instrumentation 425
23.4.5 Recent trends in well boat technology 426
23.5 Air transport 426
23.6 Other transport methods 427
23.7 Cleaning and re?use of water 428
23.8 Use of additives 429
References 429
24 Instrumentation and Monitoring 431
24.1 Introduction 431
24.2 Construction of measuring instruments 432
24.3 Instruments for measuring water quality 432
24.3.1 Measuring temperature 433
24.3.2 Measuring oxygen content of the water 433
24.3.3 Measuring pH 434
24.3.4 Measuring conductivity and salinity 435
24.3.5 Measuring total gas pressure and nitrogen saturation 435
24.3.6 Spectrophotometers for water analysis 436
24.3.7 Other 439
24.4 Instruments for measuring physical conditions 439
24.4.1 Measuring the water flow 440
24.4.2 Measuring water pressure 442
24.4.3 Measuring water level 443
24.5 Equipment for counting fish, measuring fish size and estimation of total biomass 444
24.5.1 Counting fish 444
24.5.2 Measuring fish size and total fish biomass 445
24.6 Monitoring systems 448
24.6.1 Sensors and measuring equipment 449
24.6.2 Monitoring centre 449
24.6.3 Warning equipment 451
24.6.4 Regulation equipment 451
24.6.5 Maintenance and control 451
24.7 Remotely operated vehicle (ROV) technology 451
References 452
25 Buildings and Superstructures 455
25.1 Why use buildings? 455
25.2 Types, shape and roof design 455
25.2.1 Types 455
25.2.2 Shape 456
25.2.3 Roof design 457
25.3 Load?carrying systems 457
25.4 Materials 458
25.5 Prefabricate or build on site? 460
25.6 Insulated or not? 460
25.7 Foundations and ground conditions 461
25.8 Design of major parts 461
25.8.1 Floors 461
25.8.2 Walls 462
25.9 Ventilation and climate control 463
References 465
26 Design and Construction of Aquaculture Facilities: Some Examples 467
26.1 Introduction 467
26.2 Land?based hatchery, juvenile and on?growing production plant utilizing flow?through technology 467
26.2.1 General 467
26.2.2 Water intake and transfer 468
26.2.3 Water treatment department 477
26.2.4 Production rooms 479
26.2.5 Feed storage 483
26.2.6 Disinfection barrier 484
26.2.7 Other rooms 484
26.2.8 Outlet water treatment 484
26.2.9 Important equipment 484
26.3 Land?based juvenile and on?growing production plant utilizing RAS technology 486
26.3.1 Introduction 486
26.3.2 Fish tanks and production department 488
26.3.3 Water treatment department 489
26.3.4 Retention time and number of turnover per day 492
26.3.5 Heating/chilling 493
26.3.6 H2S problem 493
26.3.7 Sludge treatment system 493
26.3.8 Fish handling 494
26.3.9 Others 494
26.4 On?growing production, sea cage farms 494
26.4.1 General 494
26.4.2 Site selection 494
26.4.3 The cages and the fixed equipment 495
26.4.4 The base station 498
26.4.5 Net handling 499
26.4.6 Boat 500
References 501
27 Planning Aquaculture Facilities 503
27.1 Introduction 503
27.2 The planning process 504
27.3 Site selection 504
27.4 Production plan 505
27.5 Room programme 505
27.6 Necessary analyses 505
27.7 Drawing up alternative solutions 508
27.8 Evaluation of and choosing between the alternative solutions 511
27.9 Finishing plans, detailed planning 511
27.10 Function test of the plant 511
27.11 Project review 511
References 511
Index 513
