Objective:- What is purification of water Definition Why to purify Process (Standard level for Class 9 below) Results if not purified

1. CHEMISTERY PROJECT
TERM I
BY
A.
HRUSHYANG
CLASS XI

2. DEFINATION
Water purification is the
process of removing
undesirable chemicals,
biological contaminants,
suspended solids and gases
from contaminated water
to make it fit for drinking.

3. Need for Water
Purification
 Although reasonably pure, it is
always variable due to seasonal
variations, regional variation in
water quality.
 For removing impurities and control
microbes to avoid contamination.
 The treatment of water majorly
depends on water’s chemistry and
contaminants, influenced by, e.g.
rainfall, erosion, pollution, etc.
IF PURIFICATION IS NOT DONE IT MAY
LEADS TO VARIOUS DISEASES DUE TO
THE MICROBES PRESENT IN IT.

4. Process of Purification
of Water
The process of purification
of the water majorly involves
four methods i.e. :-
 Sedimentation tank
 Loading tank
 Filtration tank
 Chlorination tank

5. Sedimentation Tank
Water entering into the
sedimentation tanks contains
suspended particles
(sediments). These sediments
settle to the bottom of the
tanks forms sludge which is
then driven to the outlet using
scrappers so that the water is
free from suspended material
like rocks, soil, etc.

6. Loading Tank
The addition of inorganic coagulants such
as aluminium sulphate (or alum) or iron (III) salts
such as iron(III) chloride cause several simultaneous
chemical and physical interactions on and among
the particles. Within seconds, negative charges on
the particles are neutralized by inorganic
coagulants. Also within seconds, metal hydroxide
precipitates of the aluminium and iron (III) ions
begin to form. These precipitates combine into
larger particles under natural processes such
as Brownian motion and through induced mixing
which is sometimes referred to as flocculation. The
term most often used for the amorphous metal
hydroxides is “floc.” Large, amorphous aluminium
and iron (III) hydroxides adsorb and enmesh
particles in suspension and facilitate the removal of
particles by subsequent processes of sedimentation.

7. Filtration Tank
In this tank the water moves vertically
through sand which often has a layer
of activated carbon or anthracite
coal above the sand. The top layer
removes organic compounds, which
contribute to taste and odour. The
space between sand particles is larger
than the smallest suspended particles,
so simple filtration is not enough.
Most particles pass through surface
layers but are trapped in pore spaces
or adhere to sand particles. Effective
filtration extends into the depth of the
filter.

8. Chlorination Tank
The most common disinfection
method involves Chlorination. Chlorine
is a strong oxidant that rapidly kills
many harmful micro-organisms.
Because chlorine is a toxic gas, there is
a danger of a release associated with
its use. This problem is avoided by the
use of sodium hypochlorite, which is a
relatively inexpensive solution that
releases free chlorine when dissolved
in water. Chlorine solutions can be
generated on site by electrolyzing
common salt solutions. After water
passing from this Chlorination tank the
water is supplied to our houses.

9. IF Water is not Purified
Water is another fertile source of disease, many organic
and inorganic impurities making their way into it. It is to
the former that its unhealthful is generally due. Nearly
all water from the earth contains some mineral
ingredients, few of which are harmful, some of which
are healthful. The waters of many mineral springs serve
as remedies for serious disorders of the system. The
chief source of water pollution lies in organic
impurities, which are carried through the soil from
cesspools, manure heaps, and similar sources into
wells, or are emptied by sewers into the rivers from
which many cities now derive their drinking water. The
lack of sufficient water may also be a cause of disease.
The person and clothes are not properly washed,
houses and streets are dirty, and the sewers become
clogged with filth. As a result there is a general lower
state of health of the community, and typhoid fever
and diarrhoea may be prevalent.

10. Diseases caused by Impure water
CHOLERA
Cholera, whose germs are now thought to be
conveyed only by water. The great epidemic
at Hamburg in 1892, was traced to sewage
water from cholera patients getting into the
river Elbe, which supplies the city with water.
This frequently, perhaps almost wholly,
comes from a like distribution of the bacterial
germs of the disease by water. Typhoid fever
has been traced to this cause in numerous
instances. This was the case at Over Darwin in
1874, when a drain containing the excreta of a
typhoid patient was blocked, and its contents
got in the main pipe of the water supply. As a
result, out of a population of22,000 there
were 2,035 cases of typhoid fever and 104
deaths. In Bangor, in 1882, there occurred an
epidemic of typhoid fever, affecting 540
persons out of a population of10,000, of
whom 42 died. This was found to be caused
by the excreta of a single typhoid patient
getting into a small stream which discharged
into the river supplying the town with water.

11. Diphtheria
Diphtheria is probably conveyed and
caused by impure water, but this is not yet
absolutely proved. Dysentery is well known
in tropical countries to be caused by impure
water, as was proved by an outbreak at
Cape Coast Castle, where it was caused by
the passage of sewage into one of the
drinking tanks. Diarrhoea has been caused
in epidemic form by impure water, as was
shown in the old Salford jail, where the
untrapped overflow pipe from a cistern of
drinking water communicated with a
sewer, and the water had thus absorbed
sewer gas, and probably germs.