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

About the Author

Odd-Ivar Lekang is Associate Professor of Aquaculture Engineering at the Department of Mathematical Sciences and Technology at the Norwegian University of Life Sciences in As.