Many
method can be employed for the storage of water been rain or borehole. The two
important are (1) above the ground storage method and below the ground storage
method. Whatever method choosing, it must ensure prevention/contamination of
the water from human, animals, dust leaves and other pollution that might enter
the storage containers.
method can be employed for the storage of water been rain or borehole. The two
important are (1) above the ground storage method and below the ground storage
method. Whatever method choosing, it must ensure prevention/contamination of
the water from human, animals, dust leaves and other pollution that might enter
the storage containers.
Ways by which drinking water could be
contaminated at household level
contaminated at household level
Drinking
water at household level could be contaminated as follows:
water at household level could be contaminated as follows:
i.
Using
contaminated vessel to collect or store water.
ii. Leaving drinking water open without
providing a tight fitting cover.
providing a tight fitting cover.
iii. Failure to use a stationed cup to draw
out water from the water cistern hence using different types of cup.
out water from the water cistern hence using different types of cup.
iv.
Placing
water where dust could be easily raised on water.
Placing
water where dust could be easily raised on water.
v. Drawing water from the cistern with
contaminated hands.
contaminated hands.
vi.
Coughing
and sneezing while opening water meant from human consumption.
Coughing
and sneezing while opening water meant from human consumption.
Criteria of a water treatment
plant
plant
Ø Population of the community
Ø Accessibility to the community the road
should be movable
should be movable
Ø Good motor-able road network
Ø Mobility mobilized
Ø Equipments
Ø Skilled and unskilled labour
Ø Nearness to a stream, river or ocean
Ø Availability of required chemical
Ø Finance money
Ø Political will of the government
Various step in water treatment in a
conventional plant:
conventional plant:
Ø Source
Ø Screening (wire screen or bar screen to
remove large suspended particle size from entry the treatment plant)
remove large suspended particle size from entry the treatment plant)
Ø Coagulation
Ø Sedimentation
Ø Filtration
Ø Chlorination/disinfections
Ø Chlorine testing
Ø Storage
Ø Distribution
Source: The source of water supply for
conventional treatment should either be from a stream, dam, flowing rivers, sea
or ocean depending on the population it is to serve.
conventional treatment should either be from a stream, dam, flowing rivers, sea
or ocean depending on the population it is to serve.
Screening: Is the process whereby suspended large
size of particles are prevented from entering into the treatment plant from the
source and to bar away aquatic living organism and large particles. This screening
is known as bar screen.
size of particles are prevented from entering into the treatment plant from the
source and to bar away aquatic living organism and large particles. This screening
is known as bar screen.
Aeration: This is the process of allowing water
to come into contact with air for purpose of oxidation. Aeration increases oxidation
thereby absorbing oxygen (O2) into water and expels carbon iv oxide
(co2). Aeration removes hydrogen sulphide, which causes odour in water,
it also oxdides iron and magnesium present in water which causes corrosion in
pipes, it also reduces ph greater than 7 and makes it alkaline (i.e. ph
correction takes place in tank.
to come into contact with air for purpose of oxidation. Aeration increases oxidation
thereby absorbing oxygen (O2) into water and expels carbon iv oxide
(co2). Aeration removes hydrogen sulphide, which causes odour in water,
it also oxdides iron and magnesium present in water which causes corrosion in
pipes, it also reduces ph greater than 7 and makes it alkaline (i.e. ph
correction takes place in tank.
Coagulation chamber: At this chamber chemical like lime or
alum aluminum Sulphate (AL2SO4) and magnesium carbonate (Mgco4),
ferric sulphate are added or introduced into the already screen and aerated water
to flocculate and enables the suspended and dissolved particle in water settle
down quickly to enhance easy sedimentation. Also the alum engulfs
micro-organisms and colloidal matter (those that can give colour) and also
suspended matter thereby removing turbidity, colour, taste and odour.
alum aluminum Sulphate (AL2SO4) and magnesium carbonate (Mgco4),
ferric sulphate are added or introduced into the already screen and aerated water
to flocculate and enables the suspended and dissolved particle in water settle
down quickly to enhance easy sedimentation. Also the alum engulfs
micro-organisms and colloidal matter (those that can give colour) and also
suspended matter thereby removing turbidity, colour, taste and odour.
Sedimentation chamber: After the coagulations of the water,
it passed into the sedimentation tank or chamber were water particles settle
down at the bottom of the tank due to precipitation or gravitational force without
adding anything or chemical. Settling down particles floc or sludge are then
remove by filtration process.
it passed into the sedimentation tank or chamber were water particles settle
down at the bottom of the tank due to precipitation or gravitational force without
adding anything or chemical. Settling down particles floc or sludge are then
remove by filtration process.
Filtration chamber: Water is allows to flow from the
sedimentation chamber to the filtration chamber by passing through different sand
and gravel, for the purpose of removing bacterial, colour, taste thereby
producing clear and sparking water. This
can be achieved by slow or rapid sand filter.
sedimentation chamber to the filtration chamber by passing through different sand
and gravel, for the purpose of removing bacterial, colour, taste thereby
producing clear and sparking water. This
can be achieved by slow or rapid sand filter.
Slow sand gravity filter: these are water tight shallows tanks lined
with fine gravels and sand. The sand and gravels to be used must be clean,
hard, durable and should be free from clay, shells and other foreign matter.
with fine gravels and sand. The sand and gravels to be used must be clean,
hard, durable and should be free from clay, shells and other foreign matter.
Rapid sand filter or pressure filter: It also made water tight and lined
with fine gravels and sand, the rate of filtration here is faster and it can be
backwashed when it needs cleaning.
with fine gravels and sand, the rate of filtration here is faster and it can be
backwashed when it needs cleaning.
Disinfection: This is very important in domestic and
urban supply treatment. It is safe guard against pathogeneses organisms that
may escape such treatment process as filtration, aeration, sedimentation and
those that may accidentally get in contact with the water. Chemical disinfection such as the use of chlorine is commonly use
to destroy any micro organism in the water. It also removes odours and taste to
some extent. Other chemicals used include ozone, iodine, Milton etc.
urban supply treatment. It is safe guard against pathogeneses organisms that
may escape such treatment process as filtration, aeration, sedimentation and
those that may accidentally get in contact with the water. Chemical disinfection such as the use of chlorine is commonly use
to destroy any micro organism in the water. It also removes odours and taste to
some extent. Other chemicals used include ozone, iodine, Milton etc.
Chlorine/ph testing: The disinfected water from the
chlorination chamber has to be tested to confirm the effectiveness of the
treatment. During this process, the acidity and alkalinity content of the water
is checked and balance with the use of colour comparator. PH of water ranges
between 6, 8 and 7.2.
chlorination chamber has to be tested to confirm the effectiveness of the
treatment. During this process, the acidity and alkalinity content of the water
is checked and balance with the use of colour comparator. PH of water ranges
between 6, 8 and 7.2.
Storage: After balancing the PH level of the water,
the water is pumped into temporary reservoirs and booster stations to serve the
community and individual.
the water is pumped into temporary reservoirs and booster stations to serve the
community and individual.
The
booster station is a mechanical mechanism put in place to equalize the pressure
of water flow.
booster station is a mechanical mechanism put in place to equalize the pressure
of water flow.
