SNS COLLEGE OF
ENGINEERING
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SESSION – 4
WATER POLLUTION
Water resources
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 The water cycle, through evaporation and
precipitation, maintains hydrological systems which
form rivers and lakes and support in a variety of
aquatic ecosystems.
 a large number of people for their daily needs such as
drinking water, washing, cooking, watering animals,
and irrigating fields.
Our liquid planet glows like a
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soft blue sapphire in the hardedged darkness of space. There
is nothing else like it in the
solar system. It is because of
water. – John Todd
Water availability on the planet
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 Water that is found in streams, rivers, lakes,
wetlands and artificial reservoirs is called surface
water.
 Water that percolates into the ground and fills the
pores in soil and rock is called groundwater.
 Porous water-saturated layers of sand, gravel or
bedrock through which ground water flows are called
aquifers
Water Pollution
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 When the quality or composition of water changes
directly or indirectly as a result of man’s activities
such that it becomes unfit for any purpose it is said
to be polluted.
 Any pollutant that is discharged onto the land above,
is also pulled into the aquifer and pollutes the
groundwater resulting in polluted water in the
nearby wells.
Point Vs Non- point sources of pollution
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 When a source of pollution can be readily identified
because it has a definite source and place where it
enters the water it is said to come from a point
source. Eg. Municipal and Industrial Discharge
Pipes.
 When a source of pollution cannot be readily
identified, such as agricultural runoff, acid rain, etc,
they are said to be non-point sources of pollution.
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Answer if possible
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 A little girl kicks a soccer ball. It goes 10 feet and comes
back to her. How is this possible?
 A is the father of B. But B is not the son of A. How’s that
possible?
 A 10 foot rope ladder hangs over the side of a boat with
the bottom rung on the surface of the water. The rungs
are one foot apart, and the tide goes up at the rate of 6
inches per hour. How long will it be until three rungs are
covered?
 An electric train is moving north at 100mph and a wind
is blowing to the west at 10mph. Which way does the
smoke blow?
Causes of water pollution
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 Disease-causing agents (pathogens)
 Oxygen depleting wastes – Organic wastes (The amount
of oxygen required to break down a certain amount of
organic matter is called the biological oxygen demand
(BOD))
 Inorganic plant nutrients (The excessive growth of algae
and aquatic plants due to added nutrients is called
eutrophication)
 Water soluble inorganic chemicals which are acids, salts
and compounds of toxic metals such as mercury and lead
 organic chemicals, which include oil, gasoline, plastics,
pesticides, cleaning solvents, detergent and many other
chemicals.
 Sediment of suspended matter is another class of
water pollutants (reduces
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 Water soluble radioactive isotopes - various tissues
and organs as they pass through food chains and
food webs- cause birth defects, cancer and genetic
damage
 Thermal pollution – Hot water
 Oil is washed into surface water in runoff from
roads and parking lots which also pollutes
groundwater
Groundwater pollution
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 Urban run-off of untreated or poorly treated waste water
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and garbage
Industrial waste storage located above or near aquifers
Agricultural practices such as the application of large
amounts of fertilizers and pesticides, animal feeding
operations, etc. in the rural sector
Leakage from underground storage tanks containing
gasoline and other hazardous substances
Leakage from landfills
Poorly designed and inadequately maintained septic
tanks
Mining wastes
Control measures
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 Setting up effluent treatment plants and treating
waste
 treated effluent can be reused for either gardening or
cooling purposes
 THERMAX
THERMAX
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 running contaminated water through the root zones of
specially designed reed beds
 REEDS- wetland plants have the capacity to absorb
oxygen from the surrounding air through their stomatal
openings
 oxygen is pushed through the porous stem of the reeds
into the hollow roots -enters the root zone , creates
conditions suitable for the growth of numerous bacteria
and fungi
 micro-organisms oxidize impurities in the wastewaters,
so that the water which finally comes out is clean
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SUMMARY
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1)Discharged pollutants at specific location through pipes,
ditches or Sewers into bodies of surface water is
___________
2) wetland plants have the capacity to absorb oxygen from
the surrounding are _______
3)Hot water is added by ________ pollution
4) When the ___________of water changes directly or
indirectly such that it becomes unfit for any purpose it is
said to be polluted
5) The amount of oxygen required to break down a certain
amount of organic matter is called _________
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Thank You