WATER SUPPLY SYSTEM

coriandercultureMechanics

Feb 22, 2014 (2 years and 9 months ago)

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WATER SUPPLY SYSTEM
BASIC OPERATIONS

Prepared by RCAP Solutions

For PADEP

1

Introduction



Basics of Water Supply

2

Drinking Water Sources


Surface Water



Groundwater

3

Surface Water: Advantages


Easily accessible



Large volumes of water



Surface reservoirs for storage

4

Surface Water: Disadvantages


Exposure to contaminants



Expensive filtration

5

Groundwater: Advantages


Less treatment



Consistency



Availability

6

Groundwater: Disadvantages


Chemical contamination



Hardness



Multiple wells



Location

7

Groundwater Treatment Processes

8

Groundwater Treatment Processes


Not very complex



Mainly disinfection



Covered later

9

Surface Water Treatment Processes

10

Racks and Screens

11

Racks and Screens


Prevent debris



Pipes and pumps



Straining pasta

12

Mixing

13

Mixing


Coagulant



Suspended particles

14

Coagulation and Flocculation


15

Coagulation and Flocculation


Reduces solids



Prevents bacterial “hiding”



Like making cheese

16

Sedimentation

17

Sedimentation


Presedimentation



Basins



Solids loading reduction



Sludge removal

18

Filtration

19

Filtration


Solids and floc removal



Physical



Chemical



Biological

20

Types of Filtration


Slow Sand



Conventional Filtration

21

Types of Filtration


Direct Filtration



Diatomaceous Earth

22

Types of Filtration


Membrane Filtration



Bag and Cartridge Filters

23

Disinfection

24

Disinfection


Disease
-
causing organisms



Chlorine



Ozone and Ultraviolet Radiation

25

Disinfection: Chlorine


Chlorine Gas



Sodium Hypochlorite


26

Disinfection: Chlorine


Calcium Hypochlorite



Chlorine may form carcinogens

27

Disinfection: Ultraviolet Light


Penetrates most cell walls



No toxic residuals



Short contact times; easy to operate



Unsuitable for some water sources

28

Disinfection: Ozone


O
3



Shorter contact time



Capital costs



O&M

29

Other Typical Treatment Processes


Iron and manganese removal



Corrosion control



These are source dependent

30

Iron and Manganese Removal


Various techniques



Aeration



Sequestration



Ion exchange

31

Corrosion Control


Prevents degradation



Adjust water characteristics

32

Exercise


Exercise!!!



Complete the fill
-
in
-
the blank questions

33

Distribution System Facilities


Pumps


Storage facilities


Transmission mains


Valves and hydrants


Meters

34

Pumps


Provide lift



Do not generally create pressure



Major part of O&M costs


35

Storage Facilities


Clear wells



Stand pipes



Elevated storage tanks


36

Clear Wells

37

Clear Wells


Large concrete reservoirs



Constant rate of operation

38

Stand Pipes


Located on the ground



Require little maintenance

39

Elevated Storage Tanks


Supporting structures



Use gravity



Filled in off
-
peak hours

40

Transmission Mains

System Design


Branching

systems




Loop or grid systems

41

Transmission Mains

Materials


Cast

iron



Ductile

iron



Plastic

(polyvinylchloride



PVC)


42

Valves and Hydrants


Valves




Wet

barrel

hydrants




Dry

barrel

hydrants

43

Meters


Throughout

the

system




Used

for

billing

and

to

identify

loss



Lowers

usage



Replacement

program


44

Exercise


Exercise

time!!!



Fill

in

the

graphic

and

answer

the

questions

45

Summary


Key

points

46

References and Resources


See your workbooks for details