WATER TECHNOLOGY
AND
PURIFICATION PROCESS
OF WATER
, 11 INTRODUCTION TO WATER
TECHNOLOGY (HARDNESS OFWATER)
N
E 12. BOILER TROUBLES
1.3 TREATMENT OF BOILERFEED
WATER
1.4. DOMESTIC VWATER
TREATMENT
, 1.1 INTRODUCTION TO WATER TECHNOLOGY
Water is nature's most wonderful, abundant and useful compound. Water is not only essential for
the lives of animals and plants, but also occupies a unique position in industries. It is widely used for
drinking, bathing, sanitary, washing, irrigation, fire-fights, air-conditioning and also production of
industrial materials. Its most important use is as an engineering material in the steam generation. Water is
also used as a coolant in power and chemical plants. It is also used in other fields such as production of
steel, rayon, paper, atomic energy, textiles, chemicals,etc.
The distribution of water on the earth's surface is extremely uneven. About 80% of the earth's
surface is occupied by water. Only 3% of the earth's water is fresh.2.5% of the earth's freshwater is
unavailable(locked up in glaciers,oceans, polar ice caps, atmosphere and soil) or Only 0.5% of the earth's
water is available as fresh water.
SOURCES OF WATER
The main sources of water are
Surface water rain(purest form of natural water), rivers, lakes, seas(most impure form of
natural water)
Groundwater - wells, springs
Since surface and underground water are normally used for domestic and industrial purposes it must be
free from undesirable impurities. The process of removing all types of impurities from water and making
it fit for domestic or industrial purposes is called water treatment or water technology.
TYPES OF IMPURITIES PRESENT IN WATER
The natural water is usually contaminated by different types of impurities. They are mainly three types,
Physical impurities
Chemical impurities
Biological impurities
, 1. Physical impurities:
Colour: Colour in water is caused by metallic substances like salts.
fine suspensions such as insoluble
Turbidity: Turbidity is due to the colloidal, extremely
substances like clay, slit, and micro-organisms.
produces taste. Bitter taste can be due to the
Taste: Presence of dissolved minerals in water
Al, Mn, Sulphates and lime. Soap taste can be due to the presence of large amount
presence of Fe,
of sodium bicarbonate.
Odour: Odour in water is undesirable for domestic as well as industrial purpose.
2. Chemical impurities:
Inorganic chemicals: Cations(Al", Ca, Mg*, Fe", Zn*, Cu Na", K), Anions(CI, SO,2, NO,,
HCO, F, NO,)
Organic chemicals: Dyes, paints, petroleum products, pesticides, detergents, drugs textile materials,
other organic related materials.
3. Biological Impurities:
Biological impurities are algae, pathogenic bacteria, fungi, viruses, pathogens, parasite-worms.
1.1.1 HARD WATER AND SOFT WATER
Soft Water
The water which gives lather with soap solution is called soft water.
C17H3sCOONa + H,O C7HssCOOH + NaOH
(soap) (water) (stearic acid)
AND
PURIFICATION PROCESS
OF WATER
, 11 INTRODUCTION TO WATER
TECHNOLOGY (HARDNESS OFWATER)
N
E 12. BOILER TROUBLES
1.3 TREATMENT OF BOILERFEED
WATER
1.4. DOMESTIC VWATER
TREATMENT
, 1.1 INTRODUCTION TO WATER TECHNOLOGY
Water is nature's most wonderful, abundant and useful compound. Water is not only essential for
the lives of animals and plants, but also occupies a unique position in industries. It is widely used for
drinking, bathing, sanitary, washing, irrigation, fire-fights, air-conditioning and also production of
industrial materials. Its most important use is as an engineering material in the steam generation. Water is
also used as a coolant in power and chemical plants. It is also used in other fields such as production of
steel, rayon, paper, atomic energy, textiles, chemicals,etc.
The distribution of water on the earth's surface is extremely uneven. About 80% of the earth's
surface is occupied by water. Only 3% of the earth's water is fresh.2.5% of the earth's freshwater is
unavailable(locked up in glaciers,oceans, polar ice caps, atmosphere and soil) or Only 0.5% of the earth's
water is available as fresh water.
SOURCES OF WATER
The main sources of water are
Surface water rain(purest form of natural water), rivers, lakes, seas(most impure form of
natural water)
Groundwater - wells, springs
Since surface and underground water are normally used for domestic and industrial purposes it must be
free from undesirable impurities. The process of removing all types of impurities from water and making
it fit for domestic or industrial purposes is called water treatment or water technology.
TYPES OF IMPURITIES PRESENT IN WATER
The natural water is usually contaminated by different types of impurities. They are mainly three types,
Physical impurities
Chemical impurities
Biological impurities
, 1. Physical impurities:
Colour: Colour in water is caused by metallic substances like salts.
fine suspensions such as insoluble
Turbidity: Turbidity is due to the colloidal, extremely
substances like clay, slit, and micro-organisms.
produces taste. Bitter taste can be due to the
Taste: Presence of dissolved minerals in water
Al, Mn, Sulphates and lime. Soap taste can be due to the presence of large amount
presence of Fe,
of sodium bicarbonate.
Odour: Odour in water is undesirable for domestic as well as industrial purpose.
2. Chemical impurities:
Inorganic chemicals: Cations(Al", Ca, Mg*, Fe", Zn*, Cu Na", K), Anions(CI, SO,2, NO,,
HCO, F, NO,)
Organic chemicals: Dyes, paints, petroleum products, pesticides, detergents, drugs textile materials,
other organic related materials.
3. Biological Impurities:
Biological impurities are algae, pathogenic bacteria, fungi, viruses, pathogens, parasite-worms.
1.1.1 HARD WATER AND SOFT WATER
Soft Water
The water which gives lather with soap solution is called soft water.
C17H3sCOONa + H,O C7HssCOOH + NaOH
(soap) (water) (stearic acid)
