AQU AQUACULTURE ENGINEERING ENGINEERING SECOND EDITION ODD-IVAR LEKANG AC Aquaculture has been expanding at a rate of 9% per year for more than 20 years, and is projected to AQUACULTURE continue growing at a very rapid rate into the foreseeable future. In this completely updated and revised new edition of a highly successful, best-selling and well-received book, Odd-Ivar Lekang provides the latest ULTURE must-have information of commercial importance to the industry, covering the principles and applications of all major facets of aquaculture engineering. ENGINEERING Every aspect of the growing field has been addressed with coverage spanning water transportation and treatment; feed and feeding systems; fish transportation and grading; cleaning and waste handling; and instrumentation and monitoring. Also included in this excellent new edition are comprehensive details of major changes to the following subject areas: removal of particles; aeration and oxygenation; recirculation and water reuse systems; ponds; and the design and construction of aquaculture facilities. Chapters providing information on how equipment is set into systems, such as land-based fish farms and cage farms, are also included, and the book concludes with a practical chapter on systematic methodology for planning S a full aquaculture facility. ECOND Fish farmers, aquaculture scientists and managers, engineers, equipment manufacturers and suppliers to the aquaculture industry will all find this book an invaluable resource. Aquaculture Engineering, Second Edition, will be an essential addition to the shelves of all libraries in universities and research establishments where aquaculture, biological sciences and engineering are studied and taught. E DITION 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 Ås. SECOND EDITION ALSO AVAILABLE FROM WILEY-BLACKWELL Aquaculture and Behavior Aquaculture LEKANG Edited by F Huntingford, M Jobling & S Kadri Second Edition ODD-IVAR LEKANG 9781405130899 Edited by J Lucas and P Southgate Aquaculture Production Systems 9781405188586 Edited by J Tidwell Journal of the World Aquaculture Society 9780813801261 Print ISSN: 0893-8849, Online ISSN: 1749-7345 ISBN 978-0-470-67085-9 9 780470 670859 Lekang_Aquaculture_9780470670859_hb.indd 1 17/12/2012 16:52 Aquaculture Engineering Aquaculture Engineering Second Edition Odd-Ivar Lekang Associate Professor of Aquaculture Engineering Department of Mathematical Sciences and Technology Norwegian University of Life Sciences Drobakveien 31 1432 Ås Norway A John Wiley & Sons, Ltd., Publication This edition first published 2013 © 2013 by John Wiley & Sons, Ltd. First edition published 2007 © 2007 by Odd-Ivar Lekang Wiley-Blackwell is an imprint of John Wiley & Sons, formed by the merger of Wiley’s global Scientific, Technical and Medical business with Blackwell Publishing. Registered Office John Wiley & Sons, Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK Editorial Offices 9600 Garsington Road, Oxford, OX4 2DQ, UK The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, UK 2121 State Avenue, Ames, Iowa 50014-8300, USA For details of our global editorial offices, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com/wiley-blackwell. The right of the author to be identified as the author of this work has been asserted in accordance with the UK Copyright, Designs and Patents Act 1988. All rights reserved. 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It is sold on the understanding that the publisher is not engaged in rendering professional services and neither the publisher nor the author shall be liable for damages arising herefrom. If professional advice or other expert assistance is required, the services of a competent professional should be sought. Library of Congress Cataloging-in-Publication Data Lekang, Odd-Ivar, author. Aquaculture engineering / Odd-Ivar Lekang, Department of Mathematical Sciences and Technology, Norwegian University of Life Sciences, Drobakveien, Norway. – Second Edition. pages cm Includes bibliographical references and index. ISBN 978-0-470-67085-9 (hardback) – ISBN (invalid) 978-1-118-49607-7 (obook) – ISBN (invalid) 978-1-118-49861-3 (emobi) 1. Aquacultural engineering. I. Title. SH137.L45 2013 639′.8–dc23 2012040911 A catalogue record for this book is available from the British Library. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Cover images: Main image: Large land-based on-growing fish farm. Smaller images (from left to right): Fish distribution in a tank with optimal flow conditions; UV light used for disinfection of inlet water to a fish farm (see figure 10.2 in chapter 10 for more details); Well boat collecting fish from sea cages for slaughtering. Cover design by Meaden Creative Set in 9.5/11.5pt Times Ten by SPi Publisher Services, Pondicherry, India 1 2013 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 v vi Contents 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 Contents vii 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