Water purification

It explains about water, pollution, types of different treatment plant, purification of water procedure, methods of filtration, sources of water, waste water treatment eight steps in detail and last the role of individual towards the water conservation.

1. Water purification
DR. C. BEULAH JAYARANI
M.Sc., M.A, M.Ed, M.Phil(Edn), M.Phil(ZOO), NET, Ph.D(Edn)
ASST. PROFESSOR,
LOYOLA COLLEGE OF EDUCATION, CHENNAI -34

2. Water-introDuction
•Water, a substance composed of the
chemical elements hydrogenand
oxygenand existing in gaseous,
liquid, and solid states.
•It is one of the most plentiful and
essential of compounds.
•A tasteless and odorless liquid at
room temperature, it has the important
ability to dissolve many other
substances.
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3. Pollution is the
introduction of
contaminants into the
natural environment
that cause adverse
change.
What is pollution?
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4. Water pollution is the contamination of water bodies,usually
as a result of human activities. Water bodies include for
example lakes, rivers, oceans, aquifers and groundwater.
Water pollution results when contaminants are introduced
into the natural environment.
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5. Water pollution is measured by analysing the
water samples.
Physical,
chemical and
biological tests can be done.
Control of water pollution requires appropriate
infrastructure and management plans.
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6. Different treatMent plants are..
Wastewater treatment plants
Sewage treatment plants
Industrial treatment plants
Agricultural treatment for farms
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8. purification of Water
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9. Water purification is the process of removing undesirable chemicals,
biological contaminants, suspended solids and gases from water.
Most water is disinfected for human consumption (drinking water), but
water purification may also be designed for a variety of other purposes,
including fulfilling the requirements of medical, pharmacological,
chemical and industrial applications.
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10. MethoDs of filtration
1. Physical
processes
Filtration,
Sedimentation, Distillation
2. Biological
processes
Slow sand
filters
Biologically
active
carbon;
3. Chemical
processes
Flocculation Chlorination
Electromagnetic
radiation
MethoDs of filtration
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11. Simple techniques for treating water at homeare.,
chlorination
filters
solar disinfection
storing it in safe containers
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12. GrounD Water
The water emerging from some
deep ground water may have
fallen as rain many tens,
hundreds, or thousands of years
ago.
Soil and rock layers naturally
filter the ground water to a high
degree of clarity and often, it
does not require additional
treatment besides adding
chlorine or chloramines as
secondary disinfectants.
springs,
artesian springs
boreholes
wells
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13. •Upland lakes and reservoirs: Typically located in the headwaters
of river systems, upland reservoirs are usually sited above any
human habitation and may be surrounded by a protective zone
to restrict the opportunities for contamination. •Bacteria and pathogen levels are usually low, but some
bacteria, protozoa or algae will be present.
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14. •Surface Water:Freshwater bodies that are open
to the atmosphere and are not designated as
groundwater are termed surface waters
.
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15. other Water reserVoirs
•Rivers, canals and low land reservoirs
•Rainwater harvesting or fog collection
•Desalination of seawater by distillation or reverse
osmosis
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16. Step 1 –Screening Method
Screening removes objects such as
rags,
paper,
Plastics and
metals to prevent damage
WasteWater treatMent (
WWTPs)
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17. •Step 2 –Grit Removal :
Grit includes sand, gravel, cinder, or
other heavy solid materialsthat are
“heavier” (higher specific gravity)
than the organic biodegradable solids
in the wastewater.
Grit also includes eggshells, bone
chips, seeds, coffee grounds, and
large organic particles, such as food
waste.
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18. Step 3 –Sedimentation process :
. It is a large tank with low water velocities,
allowing floc to settle to the bottom. The water is
left undisturbed so that the waste are settled at
the bottom .
•WATER (grit chamber)
•Sedimentation basin (Clarifier)
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19. Step 4 : skimmer process
A skimming tank is a chamber so arranged that the
floating matter like oil, fat, grease etc., rise and
remain on the surface of the waste water (Sewage)
until removed, while the liquid flows out continuously
under partitions or baffles.
It is necessary to remove the floating matterfrom
sewage otherwise it may appear in the form of
unsightly scum on the surface of the settling tanks or
interfere with the activated sludge process of sewage
treatment.
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20. Step 5 : Aeration tank
The biological treatment of the wastewater takes place
in the aeration tank. Before the wastewater gets to this
tank, it is mixed with activated sludge.
This contains countless microorganisms, such as
bacteria, that are able to break down the colloidal,
organic contaminants dissolved in the wastewater.
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21. Step 6 : Filterationprocess :
The most common type of filter is a rapid sand filter.
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.
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22. Step 7: Slow Sand Filter :
Slow sand filters may be used where there is sufficient land and space,
as the water must be passed very slowly through the filters.
These filters rely on biological treatment processes for their action
rather than physical filtration.
The filters are carefully constructed using graded layers of sand, with
the coarsest sand, along with some gravel, at the bottom and finest
sand at the top.
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23. Step 8 : Disinfection Method
Disinfection is the final stage in drinking water treatment
before its distribution.
Disinfection is used to remove pathogenic micro-organisms
from the water.
However, it should be noted that disinfection is not the same
as sterilisation (sterilisation = destruction of all germs
present in a medium) and therefore a few common germs
may remain in the water following disinfection .
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24. Disinfection is usually the final stage in the water treatment
process in order to limit the effects of organic material,
suspended solids and other contaminants.
Primary methods of disinfection are chlorination,
chloramines, ozoneand ultraviolet light.
Other disinfection methods include chlorine dioxide,
potassium permanganateand nanofiltration.
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25. role of inDiViDual…
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26. REFERENCE
“SCIENCE READER”
Tamil Nadu text book
NCERT Books
Google images
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