Unit-1 WATER TECHNOLOGY
INTRODUCTION:
Water is one of the most abundant commodities in nature. About 80% of earth surface is covered by
water. Out of this about 97% of total water is locked in the oceans and sea which is too saline to
drink & for direct use for agricultural or industrial purposes. 2-4% is trapped in polar ice caps &
gaunt glaciers. About 10% is locked in rock crevices & minerals laying below the earth crust. Thus
only about 0.3% of worlds water resources are available for domestic, agricultural & industrial use.
Water is essential for the growth of animal & plants. It is a basic material of industries also as an
engineering material. it is used in steam generation in boiler hydro electric power generation . civil
work. It also used as a cooler, solvent in so many industries like textile, paper, sugar,
pharmaceutical, ice etc.
In so many industries water requirement is very much. In steel industries 30 million liter of water
needed per 1000 tones of production. In paper industries half million liters of water is needed per
tone of paper production. In automobile industries 1.5 tones liter of water is required per automobile
production.
Water is used for municipal & industrial purpose. The largest water requirement of is for municipal
use , but standard of purify required for this purpose is quite different demanded for industrial use.
SOURCES OF WATER:
In nature water occurs in abundantly as:-
1. Water vapors in atmosphere
2. As liquid water in inland water & ocean
3. As ice in Polar Regions.
The chiefs sources of water are divide into two groups.
a) Surface Water
b) Underground Water
a) Surface water- This is found on surface. It is of several types.
1. Rain water - It is consider as a purest form of water, since it obtained as a result of
evaporation from surface water. However rain water during its down ward journey dissolves
considerable amount of gases like C02, NO2, SO2, & suspended solid particles present in
atmosphere.
2. River Water -Rain and spring water go into river. Water from these sources flow over the earth
surface. Thus river water contains considerable amount of dissolved salts of bicarbonates, chlorides,
sulphate, nitrates of sodium, calcium, magnetic, potassium & iron etc.
3. Sea Water - it is most impure form of natural water. The impurities carried by river water are
accumulated into sea water. Due to contentious evaporation of water from the surface of sea It
contains 3.5% dissolved salts, out of which 2.5%is sodium chloride. Other salts like bi-carbonate of
Potassium Magnesium &Na2SO4 are present in it.
b)Under ground water -Spring & well water are clearest form of water. It is percolated rain water,
which on reaching the ground passes through various strata of the soil .Thus it contains high
percentage of dissolved salt. Thus it is extremely hard .
Water Technology by SN
, IMPURITIES IN NATURAL WATER AND ITS ILL EFFECTS:
Water obtained from different sources is associated with large number of impurities. The impurities
present in water can be broadly classified as follows:
(1) Suspended impurities (3) Colloidal impurities
(2) Dissolved impurities (4) Biological impurities.
The solids present in water can be classified on their size as follows
Dissolved Colloidal Suspended
10-5 10-4 10-3 10-2 10-1 1 10 100 (µm)
10-8 10-7 10-6 10-5 10-4 10-3 10-2 0.1 (mm)
1) Suspended Impurities: - These are the dispersion of solid particles in water and can be removed by
filtration or on settling.
The suspended impurities include:
(a) Inorganic Impurities: Clay (< 0.002mm), Silt (0.002-0.075mm) and Sand (0.075-0.43mm). These
impurities cause turbidity.
(b) Organic Impurities: Oil globules, vegetable and animal waste. These are responsible for taste,
colour, release of germs and bacteria.
(c) Bacterial Impurities: Bacteria, micro organisms, other forms of animal and vegetable life,
algae protozoa. They cause colour, odour and turbidity and some causes diseases.
2) Dissolved Impurities:- Some impurities like atmospheric gases and mineral salts are dissolved in
water, when it moves through air and flows over the rocks, soil etc. Normally the salts like chlorides,
sulphate, nitrate, bicarbonate, fluoride, phosphate, nitrite of sodium, potassium, calcium, magnesium and
traces of zinc exist in raw water. Such types of impurities with their effects are given as follows:
3)
SN Nature of impurity Effect of impurities on quality of water
1 Carbonates
2 Bicarbonates Causes Alkalinity & Hardness
Calcium &
3 Magnesium Chlorides
4 Sulphate Causes Hardness
5 Carbonates
6 Bicarbonates Causes Alkalinity & Softness
Sodium
7 Chlorides Causes salty taste
8 Fluorides Causes bone & teeth problems
Water Technology by SN
INTRODUCTION:
Water is one of the most abundant commodities in nature. About 80% of earth surface is covered by
water. Out of this about 97% of total water is locked in the oceans and sea which is too saline to
drink & for direct use for agricultural or industrial purposes. 2-4% is trapped in polar ice caps &
gaunt glaciers. About 10% is locked in rock crevices & minerals laying below the earth crust. Thus
only about 0.3% of worlds water resources are available for domestic, agricultural & industrial use.
Water is essential for the growth of animal & plants. It is a basic material of industries also as an
engineering material. it is used in steam generation in boiler hydro electric power generation . civil
work. It also used as a cooler, solvent in so many industries like textile, paper, sugar,
pharmaceutical, ice etc.
In so many industries water requirement is very much. In steel industries 30 million liter of water
needed per 1000 tones of production. In paper industries half million liters of water is needed per
tone of paper production. In automobile industries 1.5 tones liter of water is required per automobile
production.
Water is used for municipal & industrial purpose. The largest water requirement of is for municipal
use , but standard of purify required for this purpose is quite different demanded for industrial use.
SOURCES OF WATER:
In nature water occurs in abundantly as:-
1. Water vapors in atmosphere
2. As liquid water in inland water & ocean
3. As ice in Polar Regions.
The chiefs sources of water are divide into two groups.
a) Surface Water
b) Underground Water
a) Surface water- This is found on surface. It is of several types.
1. Rain water - It is consider as a purest form of water, since it obtained as a result of
evaporation from surface water. However rain water during its down ward journey dissolves
considerable amount of gases like C02, NO2, SO2, & suspended solid particles present in
atmosphere.
2. River Water -Rain and spring water go into river. Water from these sources flow over the earth
surface. Thus river water contains considerable amount of dissolved salts of bicarbonates, chlorides,
sulphate, nitrates of sodium, calcium, magnetic, potassium & iron etc.
3. Sea Water - it is most impure form of natural water. The impurities carried by river water are
accumulated into sea water. Due to contentious evaporation of water from the surface of sea It
contains 3.5% dissolved salts, out of which 2.5%is sodium chloride. Other salts like bi-carbonate of
Potassium Magnesium &Na2SO4 are present in it.
b)Under ground water -Spring & well water are clearest form of water. It is percolated rain water,
which on reaching the ground passes through various strata of the soil .Thus it contains high
percentage of dissolved salt. Thus it is extremely hard .
Water Technology by SN
, IMPURITIES IN NATURAL WATER AND ITS ILL EFFECTS:
Water obtained from different sources is associated with large number of impurities. The impurities
present in water can be broadly classified as follows:
(1) Suspended impurities (3) Colloidal impurities
(2) Dissolved impurities (4) Biological impurities.
The solids present in water can be classified on their size as follows
Dissolved Colloidal Suspended
10-5 10-4 10-3 10-2 10-1 1 10 100 (µm)
10-8 10-7 10-6 10-5 10-4 10-3 10-2 0.1 (mm)
1) Suspended Impurities: - These are the dispersion of solid particles in water and can be removed by
filtration or on settling.
The suspended impurities include:
(a) Inorganic Impurities: Clay (< 0.002mm), Silt (0.002-0.075mm) and Sand (0.075-0.43mm). These
impurities cause turbidity.
(b) Organic Impurities: Oil globules, vegetable and animal waste. These are responsible for taste,
colour, release of germs and bacteria.
(c) Bacterial Impurities: Bacteria, micro organisms, other forms of animal and vegetable life,
algae protozoa. They cause colour, odour and turbidity and some causes diseases.
2) Dissolved Impurities:- Some impurities like atmospheric gases and mineral salts are dissolved in
water, when it moves through air and flows over the rocks, soil etc. Normally the salts like chlorides,
sulphate, nitrate, bicarbonate, fluoride, phosphate, nitrite of sodium, potassium, calcium, magnesium and
traces of zinc exist in raw water. Such types of impurities with their effects are given as follows:
3)
SN Nature of impurity Effect of impurities on quality of water
1 Carbonates
2 Bicarbonates Causes Alkalinity & Hardness
Calcium &
3 Magnesium Chlorides
4 Sulphate Causes Hardness
5 Carbonates
6 Bicarbonates Causes Alkalinity & Softness
Sodium
7 Chlorides Causes salty taste
8 Fluorides Causes bone & teeth problems
Water Technology by SN
