Difference between revisions of "DCOM Volume I"

From Ministry of Water DCOM Manual
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{| class="wikitable"
 
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! Header text !! Header text !! Header text
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! # !! Title !! Page
 
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| 1 || [[CHAPTER ONE: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || 1
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| 1 || [[Preface|Preface]] || i
 
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| 2 || [[CHAPTER TWO: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 2 || [[Acknowledgements|Acknowledgements]] || ii
 
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| 3 || [[CHAPTER THREE: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 3 || [[List_of_Special_Committee_Members|List of Special Committee Members]] || iii
 
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| 4 || [[CHAPTER FOUR: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 4 || [[List_of_Abbreviations|List of Abbreviations]] || iv
 
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| 5 || [[CHAPTER FIVE: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 5 || [[Chapter_One:_Introduction|Chapter One: Introduction]] || 1
 
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| 6 || [[CHAPTER SIX: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 6 || [[Chapter Two: Project Planning|Chapter Two: Project Planning]] || 17
 
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| 7 || [[CHAPTER SEVEN: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 7 || [[Chapter Three: Water Sources Analysis|Chapter Three: Water Sources Analysis]] || 35
 
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| 8 || [[CHAPTER EIGHT: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 8 || [[Chapter Four: Water Demand Assessment|Chapter Four: Water Demand Assessment]] || 56
 
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| 9 || [[CHAPTER NINE: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 9 || [[Chapter Five: Pipelines Design|Chapter Five: Pipelines Design]] || 76
 
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| 10 || [[CHAPTER TEN: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 10 || [[Chapter Six: Pumping Systems|Chapter Six: Pumping Systems]] || 91
 
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| 11 || [[CHAPTER ELEVEN: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 11 || [[Chapter Seven: Water Treatment|Chapter Seven: Water Treatment]] || 96
 
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| 12 || [[CHAPTER TWELVE: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 12 || [[Chapter Eight: Treatment of Waters With Special Contaminants|Chapter Eight: Treatment of Waters With Special Contaminants]] || 148
 
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| 13 || [[CHAPTER THIRTEEN: INTRODUCTION|CHAPTER ONE: INTRODUCTION]] || Example
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| 13 || [[Chapter Nine: Design of Water Structures|Chapter Nine: Design of Water Structures]] || 159
 
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| 14 || [[APENDICES: APPENDICES]] || Example
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| 14 || [[Chapter Ten: Application Software|Chapter Ten: Application Software]] || 203
|}
 
 
 
{| class="wikitable"
 
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! Chapter #!! Chapter Title!! Page
 
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| i || LIST OF SPECIAL COMMITTEE MEMBERS || V
 
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| 1|| CHAPTER ONE: INTRODUCTION || 1
 
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| 1.1|| Global Considerations on Water Supply and Sanitation || 1
 
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| 1.1.1 || Global Considerations on Water Supply and Sanitation || 1
 
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| 1.1.2 || Climate Change and Resilience to Climate Change || 2
 
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| 1.1.3 || Public-Private Partnership in Water Supply and Sanitation Projects in Developing Countries || 3
 
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| 1.1.4 || International Water Law || 4
 
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| 1.2 || Development Agenda and Water and Sanitation Sector in Tanzania || 5
 
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| 1.2.1 || National Water Policy || 7
 
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| 1.2.2|| Legal and Institutional Framework for Water Supply and Sanitation Services || 8
 
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| 1.2.3 || Coverage and Access to Water Supply Services || 9
 
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| 1.2.4|| Policy Environment for Water and Sanitation Services in Tanzania || 9
 
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| 1.2.5 || Major Stakeholders in  Water Supply and Sanitation Projects || 10
 
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| 1.2.6 || Water Supply and Sanitation Public Private Partnership in Tanzania || 11
 
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| 1.3 || Rationale for Preparation of the Fourth Edition DCOM Manual || 13
 
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| 1.4 || About the Fourth Edition of the DCOM Manual || 13
 
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| 1.5 || Organisation of the 4th edition of the DCOM Manual || 14
 
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| 1.6 || Purpose of this Volume || 14
 
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| 1.7 || References || 15
 
 
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| Example || Example || Example
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| 15 || [[Chapter Eleven: Metering|Chapter Eleven: Metering]] || 208
 
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| Example || Example || Example
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| 16 || [[Chapter Twelve: Design Standards and Specifications|Chapter Twelve: Design Standards and Specifications]] || 217
 
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| Example || Example || Example
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| 17 || [[Chapter Thirteen: Role of Stakeholders in Design of Water Supply Projects|Chapter Thirteen: Role of Stakeholders in Design of Water Supply Projects]] || 228
 
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| Example || Example || Example
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| 18 || Apendices: Appendices
 +
* [[DCOM Volume I Appendix A|Appendix A: Climate Change and Resilience to Climate Change ]]
 +
* [[DCOM Volume I Appendix B|Appendix B: Minimum Water Flow Requirement for Fire Fighting ]]
 +
* [[DCOM Volume I Appendix C|Appendix C: Example: Estimating The Capacity Of Tank ]]
 +
* [[DCOM Volume I Appendix D|Appendix D: Structural Design of Concrete ]]
 +
* [[DCOM Volume I Appendix E|Appendix E: Supply Pumping Systems ]]
 +
* [[DCOM Volume I Appendix F|Appendix F: Source of Pumping Power ]]
 +
* [[DCOM Volume I Appendix G|Appendix G: Additional Details of Various Unit Oprations ]]
 +
* [[DCOM Volume I Appendix H|Appendix H: Methods for Disinfecting Water ]]
 +
* [[DCOM Volume I Appendix I|Appendix I: Measurements of Water Hardness ]]
 +
* [[DCOM Volume I Appendix J|Appendix J: Basic Statistics Used in Estimation of Design of Flood Events ]]
 +
* [[DCOM Volume I Appendix K|Appendix K: Dams Detail Design ]]
 +
* [[DCOM Volume I Appendix L|Appendix L: Standard Drawings ]]
 +
* [[DCOM Volume I Appendix M|Appendix M: Selected Intake Designs ]]
 +
* [[DCOM Specification|Appendix O: Standard Specifications ]]
 +
|| 231
 
|}
 
|}
 
 
* CHAPTER TWO 17
 
* PROJECT PLANNING 17
 
* 2.1 Planning Considerations for Water Supply Projects 17
 
* 2.2 Project Planning Steps 18
 
* 2.3 Pump Protection 18
 
* 2.3.1 Initiation 18
 
* 2.3.1.1 Community Assessment Steps 20
 
* 2.3.1.2 Methods of conducting community assessment 20
 
* 2.3.1.2.1 Comprehensive community assessment 20
 
* 2.3.1.2.2 Strategic community assessment 20
 
* 2.3.2 Pre-feasibility Study 21
 
* 2.3.3 Feasibility Study 21
 
* 2.3.3.1 Water Supply Projects Ranking and Technology Selection Criteria 22
 
* 2.3.3.1.1 Ranking of Projects 22
 
* 2.3.3.1.2 Choice of Technology 23
 
* 2.3.4 Preliminary and Detailed Design 23
 
* 2.3.4.1 Detailed Engineering Drawings 24
 
* 2.3.4.2 Detailed estimates of capital costs 24
 
* 2.3.4.3 Detailed estimates of recurrent costs 24
 
* 2.3.4.4 Anticipated revenue 25
 
* 2.3.4.5 Detailed design report 25
 
* 2.3.4.6 Project write-up to be submitted to potential financiers 25
 
* 2.3.5 Project Phasing 25
 
* 2.3.6 Procurement 26
 
* 2.3.6.1 2.2.6.1 Preparation of Tender Documents 26
 
* 2.3.6.2 Tendering process 27
 
* 2.3.7 Implementation/Construction Stage 27
 
* 2.3.7.1 Contract Management 27
 
* 2.3.7.2 Contract supervision and administration 27
 
* 2.3.8 Operation and Maintenance Stage 28
 
* 2.3.9 Performance Monitoring 28
 
* 2.4 Consulting the Integrated Water Resources Management and Development (IWRMD) Plans 28
 
* 2.4.1 Status of Development and Implementation of IWRMD Plans 29
 
* 2.4.2 Components of IWRMD Plans 30
 
* 2.5 Consult Guidelines for Preparation of Water Safety Plans - Resilient to Climate Change 30
 
* 2.6 Environmental and Social Impact Assessment Compliance 30
 
* 2.6.1 Procedures for Conducting ESIA in Tanzania 31
 
* 2.6.2 Strategic Environmental and Social Assessment (SESA) Compliance 31
 
* 2.7 Potential Impacts of Climate Change on Water Supply Projects 32
 
* 2.8 Participation of Community Based Water Supply Organizations (CBWSO) in Various Planning Stages 32
 
* 2.9 References 32
 
* CHAPTER THREE 35
 
* WATER SOURCES ANALYSIS 35
 
* 3.1 Availability of Water Resources in Tanzania Mainland 35
 
* 3.2 Water Sources Available in Tanzania Mainland 38
 
* 3.2.1 Rainwater and fog harvesting 39
 
* 3.2.2 Surface Water 39
 
* 3.2.2.1 Rivers or streams 39
 
* 3.2.2.2 Impoundments 39
 
* 3.2.2.3 Springs 39
 
* 3.2.2.4 Lakes 39
 
* 3.2.2.5 Dams 40
 
* 3.2.3 Groundwater 40
 
* 3.2.3.1 Infiltration galleries/wells 40
 
* 3.2.3.2 Well 40
 
* 3.2.3.3 Classification of wells based on the aquifer tapped 41
 
* 3.2.3.3.1 Shallow wells 41
 
* 3.2.3.3.2 Deep wells 41
 
* 3.2.3.3.3 Artesian wells 41
 
* 3.3 Quality Suitability of Water Sources for Water Supply Projects 42
 
* 3.4 Pilot Testing of Water Sources for Establishment of Appropriate Treatment 42
 
* 3.5 General Considerations for Selection of Water Sources 42
 
* 3.5.1 Adequacy and reliability 42
 
* 3.5.2 Quality of water sources 43
 
* 3.5.3 Technical Requirements 43
 
* 3.5.4 Cost implications to develop a water source 43
 
* 3.5.5 Protection of water sources 43
 
* 3.5.6 Legal and management requirements 44
 
* 3.5.7 Distance of water supply source 44
 
* 3.5.8 Topography of the project area and its surroundings 44
 
* 3.5.9 Elevation of a source of water supply 44
 
* 3.6 Determination of water source yield 44
 
* 3.6.1 Rainwater and fog harvesting 45
 
* 3.6.1.1 Rainwater harvesting 45
 
* 3.6.1.1.1 Types of rainwater harvesting 45
 
* 3.6.1.1.2 Components of rainwater harvesting system 46
 
* 3.6.1.1.3 Estimation of the yield 47
 
* 3.6.2 Hydrological Analysis of Surface Waters 47
 
* 3.7 Other considerations for various water sources 55
 
* 3.7.1 Water permits Considerations 55
 
* 3.7.2 Conservation of water sources 55
 
* 3.8 References 55
 
* CHAPTER FOUR 56
 
* WATER DEMAND ASSESSMENT 56
 
* 4.1 Water Demand Assessment 56
 
* 4.2 General Factors Affecting Water Demand Assessment 57
 
* 4.3 Determination of Water Demand for Different Uses 58
 
* Step 7. Establish Net Water Demand 67
 
* Step 9: Establish Operational water consumption 67
 
* Step 10: Establish System water losses 68
 
* Step 11 Establish Non-Revenue Water 69
 
* 4.4 Variations in Water Consumption 70
 
* 4.4.1 Definitions 70
 
* 4.4.2 Variation in the Rate of Consumption 71
 
* 4.4.2.1 Diurnal variation in demand 71
 
* 4.4.3 Peak Factors 72
 
* 4.4.4 Predicting Demand 74
 
* 4.4.5 Design Demand 75
 
* 4.5 References 75
 
* CHAPTER FIVE 76
 
* PIPELINES DESIGN 76
 
* 5.1 Design Requirements of pipelines 76
 
* 5.2 Types of pipelines 76
 
* 5.3 Security considerations for pipelines 76
 
* 5.3.1 Methods of water transmission and distribution 76
 
* 5.3.2 Gravity flow 77
 
* 5.3.3 Pumping with storage 77
 
* 5.3.4 Direct pumping to the distribution system 77
 
* 5.4 Pipeline Hydraulics Assessment 77
 
* 5.4.1 Pressure 77
 
* 5.4.2 Determination of Head Losses 77
 
* 5.5 Water supply transmission system 79
 
* 5.5.1 Determination of Transmission Pipe Size 79
 
* 5.5.2 Maximum Pressure 79
 
* 5.6 Distribution system 80
 
* 5.6.1 Branched System 80
 
* 5.6.2 Looped System 81
 
* 5.7 Pipe network analysis 82
 
* 5.7.1 Network analysis by Conventional method (Hardy Cross) 82
 
* 5.7.2 Network Analysis by Computer Software 82
 
* 5.7.2.1 EPANET Software 82
 
* 5.7.3 Pipeline design criteria 85
 
* 5.8 Pipeline materials selection 86
 
* 5.8.1 Considerations in Selecting Pipeline Materials 86
 
* 5.8.1.1 Flow Characteristics 86
 
* 5.8.1.2 Pipe Strength 86
 
* 5.8.1.3 Durability 87
 
* 5.8.1.4 Type of Soil 87
 
* 5.8.1.5 Availability 87
 
* 5.8.1.6 Cost of Pipes 87
 
* 5.8.2 Types of Pipe Materials Available 87
 
* 5.8.2.1 Galvanized Iron (GI) Pipes 87
 
* 5.8.2.2 Plastic Pipes 87
 
* 5.9 Appurtenances for transmission and distribution mains 88
 
* 5.9.1 Valves 89
 
* 5.9.1.1 Isolation Valves 89
 
* 5.9.1.2 Check Valves 89
 
* 5.9.1.3 Float Valves 89
 
* 5.9.1.4 Air Release Valves 89
 
* 5.9.1.5 Pressure Reducing Valves 89
 
* 5.9.1.6 Washout valves 89
 
* 5.9.2 Fittings 89
 
* 5.10 References 90
 
* CHAPTER SIX 91
 
* PUMPING SYSTEMS 91
 
* 6.1 Introduction 91
 
* 6.2 Rationale 91
 
* 6.3 Common Types of Pumps used in water supply 91
 
* 6.4 Pumping System Setup 91
 
* 6.5 Source of Pumping Power 92
 
* 6.6 Pumping system design pump selection 92
 
* 6.7 Pump Protection 95
 
* 6.8 References 95
 
* CHAPTER SEVEN 96
 
* WATER TREATMENT 96
 
* 7.1 Introduction 96
 
* 7.1.1 Classification of the qualities of water sources found in Tanzania according to the complexity of its treatment 96
 
* 7.1.2 Classification of Unit Operations to achieve water treatment levels 99
 
* 7.2 Recommended overall design approach for treatment plant components 99
 
* 7.3 Documents and websites consulted and those which are hyper-linked to the DCOM Manual 100
 
* 7.4 Water treatment design considerations 100
 
* 7.5 Water treatment levels and units 101
 
* 7.5.1 Pre-treatment 101
 
* 7.5.1.1 Scum and Floating Materials Skimmer 101
 
* 7.5.1.2 Screening or straining 101
 
* 7.5.1.3 Grit Removal 103
 
* 7.5.1.3.1 Design criteria 103
 
* 7.5.1.4 Sand Traps 105
 
* 7.5.1.5 Pre-chlorination 107
 
* 7.5.1.6 Water pre-conditioning (pH adjustment) 108
 
* 7.5.2 Primary Treatment 108
 
* 7.5.2.1 Sedimentation 108
 
* 7.5.2.2 Primary Filtration 114
 
* 7.5.2.2.1 Slow Sand Filtration 114
 
* 7.5.2.2.2 Rapid Gravity Sand Filtration 117
 
* 7.5.2.2.3 Comparison between Slow Sand Filters and Rapid Sand Filters 118
 
* 7.5.2.2.4 Other Types of Filters 119
 
* 7.5.2.3 Floatation 124
 
* 7.5.2.3.1 Dissolved-Air Floatation 124
 
* 7.5.2.3.2 Electrolytic Floatation 125
 
* 7.5.2.3.3 Dispersed-Air Floatation 125
 
* 7.5.2.4 Aeration 125
 
* 7.5.2.4.1 Falling Water Aerators 126
 
* 7.5.2.4.2 Spray Aerators 127
 
* 7.5.3 Secondary Treatment 130
 
* 7.5.3.1 Clarification 130
 
* 7.5.3.2 Coagulation 130
 
* 7.5.3.3 Flocculation 131
 
* 7.5.3.4 Filtration 131
 
* 7.5.4 Tertiary Treatment 132
 
* 7.5.4.1 Disinfection 132
 
* 7.5.4.1.1 Disinfection Methods 132
 
* 7.5.4.1.2 Chlorinators 132
 
* 7.5.4.1.3 Design considerations for chlorinators 133
 
* 7.5.4.2 Ozonation 133
 
* 7.5.4.3 Water softening 134
 
* 7.5.4.3.1 Methods of Softening 135
 
* 7.5.4.4 Defluoridation of Water 139
 
* 7.5.4.4.1 Fluorides 139
 
* 7.5.4.4.2 Defluoridation 139
 
* 7.5.4.5 Water Conditioning 141
 
* 7.5.5 Managemen
 

Revision as of 14:03, 31 March 2020