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