This document discusses various water treatment methods. It begins by introducing hard water and soft water, and the requirements and issues with boiler feed water. It then describes several external and internal water softening methods, including lime-soda, zeolite, and ion exchange. Lime-soda involves using lime and soda ash to precipitate hardness ions from water. Zeolite and ion exchange use ion exchange resins to remove hardness. The document provides details on the principles, processes, equipment used and regeneration for each method. It also discusses other water treatment issues like boiler troubles, scale formation, corrosion prevention and domestic water treatment.

1. 1
Unit – 1. Water Treatment

2. Unit -1 Water Treatment
1. Introduction- Importance of water and its source.
2. Hard water and soft water- Definition.
3. Boiler Feed water- requirements, scale and sludge
formation, priming and foaming, Caustic
embrittlement and boiler corrosion.
4. Softening/ Conditioning methods-Internal &
External methods.
5. External methods- Lime-soda method, zeolite
method and ion exchange method.
6. Internal conditioning methods- carbonate,
phosphate and calgon conditioning.
7. Domestic treatment of water.
2

3. Introduction
Purity and quality of
water is important
3

4. 4

5. 5
Introduction

6. 6
Introduction

7. 7
Introduction

8. 8
Hard water and soft water
Hardness – It is defined as Soap Consuming Capacity of water

9. 9
Types of Hardness

10. Units of hardness-
10
Hardness(ppm) Type
< 150 Good
150 to 350 Fair
350 onwards Bad
Classification of water types on the basis of hardness

11. Effects of hard water on domestic and industrial
purpose
1) Domestic purpose
Washing Wastage of soap and formation of sticky
precipitate
Bathing Wastage of soap, production of sticky ppt,
cleaning quality is reduced, darkening of
skin.
Cooking Elevation of boiling point, wastage of fuel,
consumption of time, incomplete cooking.
Drinking Harmful effects on health
Laundry Wastage of soap, patches on clothes
Bakery Poor quality products
11

12. 2) Industrial purpose
Textile Industry Wastage of soap and formation of sticky
precipitate, Poor quality of fabrics
Sugar Industries Difficulties in crystallization of sugar,
decomposition, impurities.
Dyeing Industries Impurities, uneven shades, uneven spots,
uneven coloring .
Paper industries Discoloration of paper
Concrete making Affects hydration of cement, reduction of
strength.
Pharmaceutical
industries.
Contamination, impurities.
Effects of hard water on domestic and industrial
purpose
12

13. 13
Quality of water for domestic and industrial
purpose

14. 14

15. Industrial requirement of water
15

16.  A boiler isa devicefor generating steam
 The furnace, which provides heat, usually by burning a fuel, and the boiler
proper, a devicein whichthe heat changes water into steam.
 The steam Applications :water heating, central heating, boiler-based power
generation, cooking,and sanitation.
 Proper treatment of boiler feed water is an important part of operating and
maintaining a boiler system. As steam is produced, dissolved solids become
concentratedand form depositsinsidethe boiler.
 Thisleadsto poor heat transferand reducesthe efficiencyof the boiler.
Boiler
16
Boiler Pressure
Low pressure
boilers
Up to 15 kg/cm2
Medium
pressure
boilers
Up to 15 to 30 kg/cm2
High pressure
boilers
30 kg/cm2 and above

17. 17

18. Boiler Troubles
18
1. Priming, foaming and carry over,
2. Sludge and scale formation,
3. Corrosion,
4. Caustic embrittlement are collectively known
as boiler troubles

19. 1. Priming
Priming can be controlled by:
19

20. Foaming
Foaming can be controlled by:
20

21. Priming and foaming collectively called as carry over
Carry over
21

22. Water in boiler is continuously heated causes the increase
in the concentration of dissolved and suspended solids.
•The precipitation in the form of soft loose and slimy deposits
(sludge)
•The precipitation in the form of hard deposits, which are
sticky on the walls of boilers (scale)
sludge & Scale formation process 22

23. Scale & sludge formation
23

24. Blow down operation for boiler
24

25. 25
Scale & sludge formation

26. 26
Scale & sludge formation

27. 27
Effect of scale formation of Heat

28. 28
Difference between Scale & sludge

29. 29
Corrosion
•Corrosion of boiler metal is a serious problem and takes place if unsuitable
water is used.
•The disadvantage of corrosion are
•Reducing life of the boiler.
•Leakage of joints and rivets.
•Increased cost of repairs and maintenance.

30. 30
Prevention of Corrosion due to oxygen

31. 31
Mechanical de-areation method

32. 32
Prevention of Corrosion due to carbon dioxide

33. 33
Prevention of Corrosion due to dissolved salts

34. 34
Caustic Embrittlement

35. 35
Boiler water treatment

36. 36
Boiler water treatment
Boiler water treatment
External Treatment Internal Treatment
1. Lime- soda treatment
2. Ion exchange process
3. Zeolite process
1. Phosphate conditioning
2. Carbonate conditioning
3. Calgon conditioning

37. Softening of water
 Softening of water: The process of removing or reducing
concentrations of hardness causing salts from water is
called as softening of water.
Zeolite process or permutit
Ion-exchange or deionization or
Demineralisation process
Lime soda process
Methods
used for
softening of
water
37

38. (a). Zeolite process of water
treatment
38

39. 39

40. Zeolite process
Zeolite is hydrated sodium aluminosilicate capable of exchanging
reversibly their sodium ions for hardness producing ions in water. They
are also known as permutits
40

41. 41
Types of Zeolite

42. Principle of zeolite-permutit process
42

43. Process of zeolite-permutit process
43

44. Regeneration
44

45. Types of zeolite water softener
45

46. 46

47. 47

48. Applications
•Used for removing Hardness of water
•To remove toxic metal ions and dye cations from the polluted
water
•To recover valuable trace metals from the industrial waste
water e.g. Ni, Cr, Pb, Cu, Ag, etc
•Simple, convenient method for removal of hard water or with
low cost operation
48

49. (b)Ion exchange process of
water softening
49

50. 50

51. 51
Ion- exchange process

52. Ion exchange resins
 Ion exchange resins are insoluble, crosslinked, long-
chain high molecular weight organic polymers which
are permeable due to their micro porous structure and
functional groups attached to the chains are involved
in the ion exchanging properties.
52

53. Ion exchange resins
1. Cation Exchange
resins(RH2)/(RH+)
2. Anion Exchange
resins(ROH)2
53

54. 54
Principle of ion-exchange process

55. 55
Structures of ion exchange resins

56. Properties of ion exchangers for
effective water treatment
1. Non toxic.
2. It should not discolor water being treated.
3. Possess high ion exchange capacity.
4. Physically durable
5. Resistance to chemical attack.
6. Cheap and commonly available.
7. Capable of being regenerated and back washed easily
and economically.
8. Should possess large surface area.
56

57. Ion exchange resins
Cation exchange resins
Resins containing acidic functional groups (-COOH, -SO3H
etc) exchange their H+ ions which comes in their contact
The reactions of these with cations like Ca2+ and Mg2+ are
RH2 +Ca2+ RCa + 2H+
RH2 +Mg2+ RMg + 2H+
Eg. DVB copolymer, Zeocarb, Amberlite IR-120
57

58. Ion exchange resins
Anion exchange resins
Resins containing basic functional groups (-NH2, =NH etc)
exchange their anions with other anions, which comes in
their contact are anion exchange resins.
The reactions of these with anions are:
R’ (OH)2 +H2SO4 R’ SO4 + 2H2O
R’ (OH)2 + 2HCl R’ Cl2 + 2H2O
Eg. Amino formaldehyde resins, Amberlite 400
58

59. Types of ion exchange Functional group
1) Cation exchangers
(a) Strongly acidic
(b) Weakly acidic
-SO3H
-COOH or -OH
2) Anion exchangers
(a) Strongly Basic
(b) Weakly Basic
-NR3+, -CH3,
-NH2 ,-(C2H4)x
59

60. 60

61. Water softening by ion exchange method
61

62. Regeneration
62

63. 63

64. 64

65. (c)Lime soda process of
water softening
65

66. 66

67. 67

68. 1. Lime removes dissolved CO2
Lime (Calcium Hydroxide) Calcium carbonate
2. Lime removes Temporary hardness
Calcium Hydroxide Calcium bicarbonate Calcium carbonate
Calcium Hydroxide Magnesium bicarbonate Calcium
carbonate
Magnesium
carbonate 68

69. 3. Lime removes free mineral acids
2HCl + Ca(OH)2 CaCl2 + H2O
H2SO4 + Ca(OH)2 CaSO4 + 2H2O
Calcium Hydroxide Magnesium
carbonate
Calcium
carbonate
Magnesium
hydroxide
Calcium Hydroxide
Calcium Hydroxide
Calcium chloride
Calcium sulphate
69

70. 4. Lime removes permanent magnesium, dissolved iron
and aluminium hardness
MgCl2 + Ca(OH)2 Mg(OH)2 + CaCl2
FeSO4 + Ca(OH)2 Fe(OH)2 + CaSO4
Al2(SO)4 + 3Ca(OH)2 2 Al2(OH)3 + 3CaSO4
Lime reactions with permanent hardness produces calcium permanent
hardness
Magnesium chloride Magnesium hydroxide
Calcium Hydroxide
Calcium Hydroxide
Calcium
Hydroxide
MgSO4 + Ca(OH)2 Mg(OH)2 + CaSO4
Magnesium sulphate Magnesium hydroxide
Calcium Hydroxide
Ferrous
sulphate
Aluminium
sulphate
Calcium sulphate
Calcium sulphate
Calcium chloride
Ferric
hydroxide
Calcium sulphate
Aluminium hydroxide
70

71. Reactions with Soda (Na2CO3)
CaSO4 + Na2CO3 CaCO3 +NaSO4
CaCl2 + Na2CO3 CaCO3 + 2NaCl
Soda removes all the soluble permanent hardness due
to calcium salts
Calcium chloride
Calcium sulphate
Calcium
carbonate
Calcium
carbonate
Sodium chloride
Sodium Suphate
Sodium
carbonate
Sodium
carbonate
71

72. Quantity of lime-soda for softening
72

73. Quantity of lime-soda for softening
73

74. Types of Lime-Soda process
Types of Lime-Soda process
74

75. Cold Lime-Soda process
(Precipitation Technique)
•When the lime and soda are added to hard water at
room temperature, the process is known as cold lime
soda process.
•At room temperature, the precipitates does not settle
down easily, and can not be easily filtered.
•Thus it is necessary to add coagulants like alum,
sodium sulphate and sodium aluminate.
75

76. Cold Lime-Soda process
76

77. 1. Intermittent type cold Lime-Soda process
77

78. 2. Conventional type cold Lime-Soda process
78

79. 2. Conventional type cold Lime-Soda process
79

80. 3. Catalyst or
spiractor type cold
Lime-Soda process
80

81. 4. The sludge blanket type cold Lime-Soda
process
•In this type, the sludge blanket is made up of previously
formed precipitates through which treated water is
filtered upwardly.
•Sludge blanket type of water softening equipment,
owing to its higher efficiency, shorter detention period
and smaller space requirements, is rapidly replacing the
conventional type
81

82. Hot Lime-Soda process
82

83. Hot Lime-Soda process
83

84. Difference between Hot Lime-Soda process
84

85. Advantages of Lime-Soda process
85

86. Comparison of Zeolite, Ion exchange and Hot Lime-Soda
process
Sr.no. Lime-Soda process Permutit (Zeolite) Process Ion exchange (de-
ionization) process
1. Lower initial
investment but
running cost is
high.
High initial investment but
low running cost.
High initial
investment but low
running cost.
2. Residual Hardness
is 50 to 60 ppm.
Residual Hardness is
about 10 ppm.
Treated water
contains almost zero
to 2 ppm hardness.
3. Treated water
contains lesser
quantity of total
dissolved solids
than original water
sample.
Treated water contains
almost equal quantity of
total dissolved solids than
original water sample.
Treated water
contains almost zero
quantity of total
dissolved solids
than original water
sample.
4. Water containing
suspended,
colloidal impurities
can be softened.
Water containing
suspended, colloidal
impurities can not be
softened.
Water containing
suspended, colloidal
impurities can not
be softened.
86

87. Comparison of Zeolite, Ion exchange and Hot Lime-Soda
process
Sr.no. Lime-Soda process Permutit (Zeolite)
Process
Ion exchange (de-
ionization) process
5. Large scale
treatment is
possible.
Method is applicable for
small scale treatment of
water.
Method is applicable
for small scale
treatment of water.
6. Involves problem
of settling, filtration
and disposal of
precipitates
formed.
Involves no precipitates. Involves no
precipitates.
7. Acidic water can be
treated.
Acidic water can not be
treated.
Acidic water can not
be treated.
87

88. Water characteristics- Hardness
88

89. 89
Boiler water treatment

90. 90
Boiler water treatment

91. 91
Boiler water treatment

92. 92
Boiler water treatment

93. 93
Domestic water treatment

94. 94

95. 95

96. 96
Domestic water treatment

97. 97

98. 98

99. 99

100. 100

101. 101

102. 102
Thank You
Dr. Sushma Pardeshi Singh,
Assistant Professor,
Department of Basic Science&
Humanities,
J.D. College of Engineering &
Management, Nagpur
Email- pardeshisushma@gmail.com