Water purification

This
could be described as the process which involves the removal of contaminates
from raw water (untreated water) to make it safe for drinking purposes it includes
the various treatment procedures or processes. It can also be said as the
method employed in ensuring the quality and safety of water used for human
consumption. This is achieved by making sure the water is free from pathogenic
organisms and impurities that are harmful to human health.

The
following source or forms of water may need purification since they may occur
from doubtful sources:

i.
Stream

ii.
River

iii.
Pond

iv.
Shallow
wells

v.
Rain
water

Objectives of water purification

i.
To
destroy pathogenic organisms

ii.
To
remove faecal matter present in water

iii.
To
remove flat taste from water

iv.
To
prevent unpleasant odour in water

v.
To
prevent corrosion of pipes

vi.
To
prevent fluorosis of the teeth and caries

vii.
To
encourage long term storage of water

Method
of water treatment in the home the methods include:

a) Boiling

b) Coagulation and sedimentation

c) Filtration

d) Disinfection through chlorination

Boiling: Boiling of water and allowing it to
cool is another method of ensuring the wholesomeness of the water. The water
must be brought to a rolling boil; for 5-10 mins. It kills all bacteria,
spores, cysts and ova and yields sterilized water. Boiling also removes
temporary hardness by driving off carbon dioxide and precipitating the calcium
carbonate. The taste of water is altered, but this is harmless.

Coagulation and sedimentation: This method involves addition of aluminum
sulphate to water which leads to flocculation of finely suspended matter, the
larger particles settle more rapidly leaving a clear supernatant.

Filtration: Filtration with remove bacterial
protozoa cysts and other large particles present in water, but will not remove
viruses: viruses filters are used for filtration but great themselves do not
constitute a source of pollution.

Household water filters

Various
filtration devices used in houses for filtration of water are known as
household filters. These are the medium through which the processes of water
filtration passes example are:

i.
Thick
linen filter

ii.
Sand
filter (consisting of sand and stones at the bottom,

iii.
Simple
domestic cloth filter.

iv.
Porcelain
net.

However,
all filters require proper care and regular cleaning to remain effective.
Health education and regular supervision should be adhere to in other to
prevent them from been contaminated.

a) Disinfection: Chlorination is the most widely used
method of chemical disinfection of water it may be used in the form of chlorine
gas for large municipal schemes or as bleaching powder (chloride of lime),
liquid bleach or hypochloride. The need for chlorination in any location must
first be established and the precise requirement decided.

Super chlorination is the application
of dose of chlorine which considerably exceeds that required to disinfect the
water. After a suitable contact time, the water is dechlorinated.