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The Potential of Mangroves in the Treatment of Shrimp Aquaculture Effluent on the Eastern Coast of Thailand

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The Potential of Mangroves in the Treatment of Shrimp Aquaculture Effluent on the Eastern Coast of Thailand The Potential of Mangroves in the Treatment of Shrimp Aquaculture Effluent on the Eastern Coast of Thailand 7 Nina Fancy B. Sc.(Horn), Queen's University, 1999 A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE in the Department of Geography O Nina Fancy, 2004 University of Victoria AII rights reserved. This thesis may not be reproduced in whole or in part, by photocopy or other means, without the permission of the author. Supervisor: Dr. Mark Flaherty ABSTRACT This thesis examines the potential of low-cost, low-maintenance mangroves in the treatment of nutrient-rich effluent originating from a shnmp fmon the coast of Thailand's Chanthaburi province. The objective of this thesis is to identify the environmental impact of shnmp aquaculture effluent and to determine if mangrove wetlands can be used as effective biofiltration areas to remove significant quantities of nitrate, ammonia and nitrite from shrimp wastewater. The study mangrove was found to remove an average of 44.5% of nitrate, 46.6% of ammonia and 59.0% of nitrite from shrimp effluent. The ratio of mangrove treatment area to shrimp fmrequired to adequately treat daily effluxes of wastewater from shrimp fmswas calculated to . be 1: 14. This ratio is significantly less spatially demanding than ratios calculated by .-: P 0 previous researchers and reveals the potential of mangroves to be used as large-scale wastewater treatment areas in shrimp-producing nations. TABLE OF CONTENTS .. ABSTRACT ..............................................................................................................11 ... TABLE OF CONTENTS ....................................................................................... UI LIST OF TABLES................................................................................................... vi .. LIST OF FIGURES................................................................................................ WI ... ACKNOWLEDGEMENTS .................................................................................. WIN CHAPTER 1 ............................................................................................................. 1 INTRODUCTION ....................................................................................................1 1.1 NATUREOF THE PROBLEM ................................................................................. 1 1.2 PURPOSE OF THE STUDY..................................................................................... 4 1.3 THESIS OUTLINE ............................................................................................... -5 CHAPTER 2 .............................................................................................................7 BACKGROUND....................................................................................................... 7 2.1 GLOBALAQUACULTURE TRENDS ....................................................................... 7 2.2.1 Geographical ShiJi................................................................................... 13 2.2.2System %iJi .............................................................................................. 16 2.3 MANAGEMENTPRACTICES ............................................................................... 17 2.3.1 Site Selection............................................................................................ 17 2.3.2Pond Preparation and Stocking ................................................................19 2.3.3 Feeding ....................................................................................................20 2.3.4 Aeration and Water Exchange ..................................................................22 2.3.5 Harvesting ...............................................................................................23 2.4 ENVIRONMENTALIMPACTS .............................................................................. 23 2.4.1 Land Requirements ..................................................................................23 2.4.2 Water Supplies .........................................................................................26 2.4.3 Chemical Discharge .................................................................................26 2.4.4 Organic Outputs ......................................................................................27 2.5 BESTMANAGEMENT PRACTICES ......................................................................30 2.5.1 Planning and Management .......................................................................31 2.5.2 Physical Techniques............................................................................... 31 2.5.3 Feed Related Practices............................................................................. 33 2.5.4 Policy Options .........................................................................................34 2.5.5 Biological Practices ................................................................................. 35 2.6 SUMMARY....................................................................................................... 38 CHAPTER 3 ........................................................................................................... 40 MANGROVE ECOLOGY ......................................................... .. .......................... 40 3.1 DEFINITION..................................................................................................... 40 3.2 GEOGRAPHICALDISTRIBUTION ....................................................................... 41 3.3 BIOL~GYOF MANGROVES................................................................................ 42 3.3.1 Anatomy ...................................................................................................42 3.3.2 Environmental Adaptations ......................................................................44 3.3.3Nutrient Dynamics ...................................................................................47 3.3.4Associated Hora and Fauna ....................................................................49 3.3.5 Natural and Anthropogenic Impacts .........................................................52 3.4 USESOF MANGROVES...................................................................................... 54 3.4.1 Local Subsistence..................................................................................... 54 3.4.2 Coastal Function ......................................................................................55 3.4.3 Tourism................................................................................................... -56 3.4.4 Wastewater Filtration ..............................................................................56 3.5 CONSTRUCTED AND MODIFIED MANGROVES .................................................... 60 3.5.1 Design..................................................................................................... 60 3.5.2 Can Mangroves be Constructed?A Question of Environmental Feasibility ......................................................................................................................... 61 3.5.3 Economic Feasibility................................................................................ 64 3.6 SvMMARY .......................................................................................................66 CHAP'lXR 4 ...........................................................................................................67 STUDY AREA AND METHODOLOGY .............................................................. 67 4.1 REGIONAL CONTEXT........................................................................................ 67 4.2 FARMAREA ................................................................................................... -70 4.3 MANGROVEDESCRIPTION ................................................................................ 74 4.4 EXPERTMENTALDESIGN ................................................................................... 76 4.5 DATACOLLECTION OVERVIEW ........................................................................ 77 4.5.1 Pre-TreatPnent Samples: Mondays ............................................................77 4.5.2 Post-Treatment Samples: Wednesdays .....................................................78 4.6 INSTRUMENTATION AND LABORATORYANALYSES ...........................................79 4.7 LIMITATIONS................................................................................................... 80 CHAPTER 5 ........................................................................................................... 82 RESULTS AND DISCUSSION .............................................................................82 5.1 SAMPLEID~CATION ................................................................................. 82 5.2 PH AND RAWFALLDATA................................................................................. 83 5.3 BOD ANALYSIS.............................................................................................. 86 5.4 PJUSE ANALYSIS .............................................................................................89 5.5 PRE-TREATMENT DATA:EFFLUENT SAMPLES ................................................. -92 5.6 PRE-TREATMENT DATA:MANGROVE ............................................................... 97 5.7 POST-TREATMENTDATA ................................................................................
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