WATER SUPPLY SYSTEM
BASIC OPERATIONS
Prepared by RCAP Solutions
For PADEP
Introduction
 Basics of Water Supply
1
Drinking Water Sources
 Surface Water
 Groundwater
2
Surface Water: Advantages
 Easily accessible
 Large volumes of water
 Surface reservoirs for storage
3
Surface Water: Disadvantages
 Exposure to contaminants
 Expensive filtration
4
Groundwater: Advantages
 Less treatment
 Consistency
 Availability
5
Groundwater: Disadvantages
 Chemical contamination
 Hardness
 Multiple wells
 Location
6
Groundwater Treatment Processes
7
Groundwater Treatment Processes
 Not very complex
 Mainly disinfection
 Covered later
8
Surface Water Treatment Processes
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Racks and Screens
10
Racks and Screens
 Prevent debris
 Pipes and pumps
 Straining pasta
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Mixing
12
Mixing
 Coagulant
 Suspended particles
13
Coagulation and Flocculation
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Coagulation and Flocculation
 Reduces solids
 Prevents bacterial “hiding”
 Like making cheese
15
Sedimentation
16
Sedimentation
 Presedimentation
 Basins
 Solids loading reduction
 Sludge removal
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Filtration
18
Filtration
 Solids and floc removal
 Physical
 Chemical
 Biological
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Types of Filtration
 Slow Sand
 Conventional Filtration
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Types of Filtration
 Direct Filtration
 Diatomaceous Earth
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Types of Filtration
 Membrane Filtration
 Bag and Cartridge Filters
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Disinfection
23
Disinfection
 Disease-causing organisms
 Chlorine
 Ozone and Ultraviolet Radiation
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Disinfection: Chlorine
 Chlorine Gas
 Sodium Hypochlorite
25
Disinfection: Chlorine
 Calcium Hypochlorite
 Chlorine may form carcinogens
26
Disinfection: Ultraviolet Light
 Penetrates most cell walls
 No toxic residuals
 Short contact times; easy to operate
 Unsuitable for some water sources
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Disinfection: Ozone
 O3
 Shorter contact time
 Capital costs
 O&M
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Other Typical Treatment Processes
 Iron and manganese removal
 Corrosion control
 These are source dependent
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Iron and Manganese Removal
 Various techniques
 Aeration
 Sequestration
 Ion exchange
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Corrosion Control
 Prevents degradation
 Adjust water characteristics
31
Exercise
 Exercise!!!
 Complete the fill-in-the blank questions
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Distribution System Facilities
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Pumps
Storage facilities
Transmission mains
Valves and hydrants
Meters
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Pumps
 Provide lift
 Do not generally create pressure
 Major part of O&M costs
34
Storage Facilities
 Clear wells
 Stand pipes
 Elevated storage tanks
35
Clear Wells
36
Clear Wells
 Large concrete reservoirs
 Constant rate of operation
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Stand Pipes
 Located on the ground
 Require little maintenance
38
Elevated Storage Tanks
 Supporting structures
 Use gravity
 Filled in off-peak hours
39
Transmission Mains
System Design
 Branching systems
 Loop or grid systems
40
Transmission Mains
Materials
 Cast iron
 Ductile iron
 Plastic (polyvinylchloride – PVC)
41
Valves and Hydrants
 Valves
 Wet barrel hydrants
 Dry barrel hydrants
42
Meters
 Throughout the system
 Used for billing and to identify loss
 Lowers usage
 Replacement program
43
Exercise
 Exercise time!!!
 Fill in the graphic and answer the questions
44
Summary
 Key points
45
References and Resources
 See your workbooks for details
46