Transcript fin1_water_supply_slides

WATER SUPPLY SYSTEM
BASIC OPERATIONS
Prepared by RCAP Solutions
For PADEP
Introduction
 Basics of Water Supply
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Drinking Water Sources
 Surface Water
 Groundwater
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Surface Water: Advantages
 Easily accessible
 Large volumes of water
 Surface reservoirs for storage
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Surface Water: Disadvantages
 Exposure to contaminants
 Expensive filtration
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Groundwater: Advantages
 Less treatment
 Consistency
 Availability
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Groundwater: Disadvantages
 Chemical contamination
 Hardness
 Multiple wells
 Location
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Groundwater Treatment Processes
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Groundwater Treatment Processes
 Not very complex
 Mainly disinfection
 Covered later
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Surface Water Treatment Processes
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Racks and Screens
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Racks and Screens
 Prevent debris
 Pipes and pumps
 Straining pasta
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Mixing
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Mixing
 Coagulant
 Suspended particles
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Coagulation and Flocculation
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Coagulation and Flocculation
 Reduces solids
 Prevents bacterial “hiding”
 Like making cheese
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Sedimentation
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Sedimentation
 Presedimentation
 Basins
 Solids loading reduction
 Sludge removal
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Filtration
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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
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Disinfection
 Disease-causing organisms
 Chlorine
 Ozone and Ultraviolet Radiation
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Disinfection: Chlorine
 Chlorine Gas
 Sodium Hypochlorite
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Disinfection: Chlorine
 Calcium Hypochlorite
 Chlorine may form carcinogens
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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
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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
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Storage Facilities
 Clear wells
 Stand pipes
 Elevated storage tanks
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Clear Wells
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Clear Wells
 Large concrete reservoirs
 Constant rate of operation
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Stand Pipes
 Located on the ground
 Require little maintenance
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Elevated Storage Tanks
 Supporting structures
 Use gravity
 Filled in off-peak hours
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Transmission Mains
System Design
 Branching systems
 Loop or grid systems
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Transmission Mains
Materials
 Cast iron
 Ductile iron
 Plastic (polyvinylchloride – PVC)
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Valves and Hydrants
 Valves
 Wet barrel hydrants
 Dry barrel hydrants
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Meters
 Throughout the system
 Used for billing and to identify loss
 Lowers usage
 Replacement program
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Exercise
 Exercise time!!!
 Fill in the graphic and answer the questions
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Summary
 Key points
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References and Resources
 See your workbooks for details
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