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INTRODUCTION
WATER
Water is one of the basic needs and is required
by all life on earth. It dominates a majority of the
space on our planet, covering about 71% of the
total surface area of Earth. Hydrology is the
study of the distribution, availability,
consumption, and movement of ground water.
Water exists in all three of its states, namely,
solid (ice), liquid, and gas (stream)—explaining
the importance of understanding the science and
structure of water. It is a transparent colorless
chemical substance with one oxygen atom
covalently bonded to two hydrogen atoms. Water
is cycled continuously on Earth through
evaporation, transpiration, condensation,
precipitation, and other means. Water
consumption and use is defined as the water that
is drawn continuously from surface or ground
and that is utilized in such a way that it is no
longer available for further use. Many industrial
processes, such as power generation, irrigation,
mining, bleaching, paper and pulp production,
textile manufacturing, and food processing,
require water as one of the main constituents of
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the process. The term water pollution refers to
water that has been contaminated by
anthropogenic substances and not fit for human
consumption. Industries also contribute to this
pollution and, as a result, many treatment plants
that have primary, secondary, and tertiary
treatment processes have been set up for
treating the contaminated water. Pathogens in
this polluted water can cause waterborne
diseases in living beings. Population growth and
technological improvement are the main factors
for water pollution. Life will be impossible on
Earth if the present situation continues as a
great demand for water, and a scarcity of it, may
occur.
IMPORTANCE OF
WATER
Water is one of the most important resources
on Earth because all living things depend on it to
survive. Humans, animals, and plants all need
water for various daily functions. People use
water for drinking, cooking, cleaning, farming,
and in industries. Our bodies need it to stay
healthy, regulate temperature, and support
digestion. In farming, water is necessary for
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growing crops and raising animals. Clean water
also helps maintain good hygiene and prevents
the spread of diseases. Even though water
covers a large part of the Earth, only a small
amount is fresh and safe to use. That’s why it’s
so important to use water carefully and avoid
wasting it. If we protect and conserve our water
today, we can make sure that future generations
have enough of it too. Simple actions like turning
off taps when not in use and fixing leaks can
make a big difference. Being aware of how we
use water is the first step toward saving it.
TYPES OF WATER
There are different types of water based on their
chemical, physical and biological
characteristics. The main types of water are:
1 . Potable water:
Potable water or drinking water is water fit for
human consumption, which has undergone
appropriate treatment and can be consumed
without any risks. It is clean, transparent, has no
unpleasant odour or taste and is free of any
contaminants.
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2 . Fresh water:
Fresh water is found naturally on the Earth's
surface as ice, as water in wetlands, ponds,
lakes, rivers and streams, and as groundwater in
aquifers. It usually has a low concentration of
dissolved salts and solids.
3 . Salt water:
It is also called seawater, found in the Earth's
oceans and seas. It has a concentration of
dissolved salts of about 3.5%.
4 . Brackish water:
The salinity of brackish water is somewhere
between that of fresh water and seawater. The
salinity of brackish water is not accurately
defined; it can range between 0.5 to 30 grams of
salt per litre.
5 . Hard water:
Hard water has a high mineral content,
particularly magnesium and calcium salts. It is
also known as calcareous water.
6 . Soft water:
Soft water contains very small amounts of
dissolved salts. It may be defined as water with
less than 50 mg per litre of calcium carbonate.
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7 . Distilled water:
Distilled water is composed of H2O molecules,
having been purified or cleaned
through distillation.
8 . Wastewater:
Wastewater is any type of water whose quality
has been negatively affected by human
activity. According to the FAO, the water has no
immediate value for the purpose it was used or
produced because of its quality, quantity, or the
moment at which it is available.
9 . Black water:
Within the different kinds of used water, black
waters are those that have been polluted with
faeces or urine .
10 . Grey water:
Grey water is domestic wastewater. It has less
nitrogen and phosphorous than black water, and
contains organic and inorganic material, and
microorganisms. Grey water owes its name to its
murky appearance and because it is somewhere
between potable freshwater and wastewater.
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11 . Raw water:
Raw water is water that has not undergone any
treatment. It is found in natural sources and
reserves, in surface and groundwater bodies.
