water supply

1. WATER SUPPLY SYSTEM
BASIC OPERATIONS
Prepared by RCAP Solutions
For PADEP

2. 1
Introduction
 Basics of Water Supply

3. 2
Drinking Water Sources
 Surface Water
 Groundwater

4. 3
Surface Water: Advantages
 Easily accessible
 Large volumes of water
 Surface reservoirs for storage

5. 4
Surface Water: Disadvantages
 Exposure to contaminants
 Expensive filtration

6. 5
Groundwater: Advantages
 Less treatment
 Consistency
 Availability

7. 6
Groundwater: Disadvantages
 Chemical contamination
 Hardness
 Multiple wells
 Location

8. 7
Groundwater Treatment Processes

9. 8
Groundwater Treatment Processes
 Not very complex
 Mainly disinfection
 Covered later

10. 9
Surface Water Treatment Processes

11. 10
Racks and Screens

12. 11
Racks and Screens
 Prevent debris
 Pipes and pumps
 Straining pasta

13. 12
Mixing

14. 13
Mixing
 Coagulant
 Suspended particles

15. 14
Coagulation and Flocculation

16. 15
Coagulation and Flocculation
 Reduces solids
 Prevents bacterial “hiding”
 Like making cheese

17. 16
Sedimentation

18. 17
Sedimentation
 Presedimentation
 Basins
 Solids loading reduction
 Sludge removal

19. 18
Filtration

20. 19
Filtration
 Solids and floc removal
 Physical
 Chemical
 Biological

21. 20
Types of Filtration
 Slow Sand
 Conventional Filtration

22. 21
Types of Filtration
 Direct Filtration
 Diatomaceous Earth

23. 22
Types of Filtration
 Membrane Filtration
 Bag and Cartridge Filters

24. 23
Disinfection

25. 24
Disinfection
 Disease-causing organisms
 Chlorine
 Ozone and Ultraviolet Radiation

26. 25
Disinfection: Chlorine
 Chlorine Gas
 Sodium Hypochlorite

27. 26
Disinfection: Chlorine
 Calcium Hypochlorite
 Chlorine may form carcinogens

28. 27
Disinfection: Ultraviolet Light
 Penetrates most cell walls
 No toxic residuals
 Short contact times; easy to operate
 Unsuitable for some water sources

29. 28
Disinfection: Ozone
 O3
 Shorter contact time
 Capital costs
 O&M

30. 29
Other Typical Treatment Processes
 Iron and manganese removal
 Corrosion control
 These are source dependent

31. 30
Iron and Manganese Removal
 Various techniques
 Aeration
 Sequestration
 Ion exchange

32. 31
Corrosion Control
 Prevents degradation
 Adjust water characteristics

33. 32
Exercise
 Exercise!!!
 Complete the fill-in-the blank questions

34. 33
Distribution System Facilities
 Pumps
 Storage facilities
 Transmission mains
 Valves and hydrants
 Meters

35. 34
Pumps
 Provide lift
 Do not generally create pressure
 Major part of O&M costs

36. 35
Storage Facilities
 Clear wells
 Stand pipes
 Elevated storage tanks

37. 36
Clear Wells

38. 37
Clear Wells
 Large concrete reservoirs
 Constant rate of operation

39. 38
Stand Pipes
 Located on the ground
 Require little maintenance

40. 39
Elevated Storage Tanks
 Supporting structures
 Use gravity
 Filled in off-peak hours

41. 40
Transmission Mains
System Design
 Branching systems
 Loop or grid systems

42. 41
Transmission Mains
Materials
 Cast iron
 Ductile iron
 Plastic (polyvinylchloride – PVC)

43. 42
Valves and Hydrants
 Valves
 Wet barrel hydrants
 Dry barrel hydrants

44. 43
Meters
 Throughout the system
 Used for billing and to identify loss
 Lowers usage
 Replacement program

45. 44
Exercise
 Exercise time!!!
 Fill in the graphic and answer the questions

46. 45
Summary
 Key points

47. 46
References and Resources
 See your workbooks for details