Thermal pollution is caused by the discharge of heated water or waste material into bodies of water, raising their temperature. Major causes include power plants using water for cooling, which is returned at higher temperatures. This decreases oxygen levels and harms ecosystems adapted to specific temperature ranges. Consequences are decreased oxygen, fish migration, increased toxins from waste, loss of biodiversity, and ecological impacts like loss of key species. Case studies examine impacts on a river's fish from a metal plant's heated discharge and potential environmental effects of a proposed coal power plant in India.

1. THERMAL POLLUTION-
CAUSES AND
CONSEQUENCES

2. • Pollution, also called environmental pollution, the
addition of any substance (solid, liquid, or gas) or any
form of energy (such as heat, sound, or radioactivity) to
the environment at a rate faster than it can be dispersed,
diluted, decomposed, recycled, or stored in some
harmless form.
• The major kinds of pollution, usually classified by
environment, are air pollution, water pollution, and
land pollution.
• Modern society is also concerned about specific types
of pollutants, such as noise pollution, light pollution,
and plastic pollution. Pollution of all kinds can have
negative effects on the environment and wildlife and
often impacts human health and well-being.

3. Thermal Pollution
• Thermal Pollution is the harmful increase in water
temperature in streams, rivers, lakes, or occasionally,
coastal ocean waters.
• It is the degradation of water quality by any process that
changes ambient water temperature.
• A temperature increase as small as 1 or 2 Celsius
degrees (about 2 to 4 Fahrenheit degrees) can kill native
fish, shellfish, and plants, or drive them out in favor of
other species, often with undesirable effects.

4. • When water used as a coolant is returned to the natural
environment at a higher temperature, the sudden change
in temperature decreases oxygen supply and
affects ecosystem composition.
• Fish and other organisms adapted to particular
temperature range can be killed by an abrupt change in
water temperature (either a rapid increase or decrease)
known as "Thermal shock."

5. CAUSES

6. • The major sources of thermal pollution are discharge of
heated water or hot waste material into water bodies
from :-
• Nuclear power plant
• Industrial effluents
• Domestic sewage
• Hydro-electric power
• Coal fired power plants
• Thermal shock
• Deforestation
• Soil erosion

7. 1. Nuclear power plant
• A common cause of thermal pollution is the use of
water as a coolant by power plants and industrial
manufacturers.
• When water used as a coolant is returned to the natural
environment at a higher temperature, the sudden change
in temperature decreases oxygen supply and affects
ecosystem composition.
• After the water is used, it is put back into a water supply
at 9-20°C warmer
• Emission from nuclear reactors increases the
temperature of water bodies.

8. Coal fired power plants
• Coal is utilized as a fuel.
• Condenser coils are cooled with water from nearby lake
or river.
• The heated effluents decrease the DO of water.

9. 2. Industrial effluents
• A common cause of thermal pollution is the use
of water as a coolant by power plants
and industrial manufacturers.
• When water used as a coolant is returned to the
natural environment at a higher temperature, the
sudden change in temperature decreases
oxygen supply and affects ecosystem
composition.

10. • Discharged water from steam-electric power
industry using turbo generators will have a
higher temperature ranging from 6 to 9˚C than
the receiving water.
• In modern stations, producing 100 MW, nearly
one million gallons are discharged in an hour
with increase in temperature of the cooling water
passing by 8 to 10 ˚C.

12. 3. Domestic sewage
• Sewage is commonly discharged into lakes, canals or
streams.
• Municipal sewage normally has a higher temperature
than the receiving water.
• Increase in temperature of the receiving water
decreases the dissolved oxygen of water.
• The foul smelling gases increased in water resulting in
death of marine organisms.

14. 4. Hydro-electric power
• Hydroelectricity is the term referring to electricity
generated by hydropower; the production of electrical
power through the use of the gravitational force of falling
or flowing water
• Hydropower plants derive energy from the force of
moving water and harness this energy for useful
purposes.
• Traditional uses include watermills. In modern
technology, hydropower moves turbines that pass on
their energy to a generator which then produces electric
power.

15. • Hydropower is a type of renewable energy, and once the
power plant is constructed it produces little to no waste.
• Globally, hydropower contributes more electricity than
any other renewable energy type.
• Generation of hydro electric power sometimes results in
negative thermal loading in water systems.
• Creates less heat on water sources less than nuclear
power plant.

17. 5. Thermal shock
• When a power plant first opens or shuts down
for repair or other causes, fish and other
organisms adapted to particular temperature
range can be killed by the abrupt change in
water temperature known as "thermal shock."
• At some point, this stress can exceed
the strength of the material, causing a crack to
form. If nothing stops this crack from
propagating through the material, it will cause
the object's structure to fail.

18. • Failure due to thermal shock can be prevented
by;
• Reducing the thermal gradient seen by the
object, by changing its temperature more slowly
or increasing the material's thermal conductivity
• Reducing the material's coefficient of thermal
expansion
• Increasing its strength
• Introducing built-in compressive stress, as for
example in tempered glass

20. 6. Deforestation
• Deforestation, clearance, or clearing is the
removal of a forest or stand of trees from land
which is then converted to a non-forest use.
• Trees and plants prevent sunlight from falling
directly on lakes, ponds or rivers.
• When deforestation takes place, these water
bodies are directly exposed to sunlight, thus
absorbing more heat and raising its temperature.

21. • Streams and small lakes are naturally kept cool
by trees and other tall plants that block sunlight.
• People often remove this shading vegetation in
order to harvest the wood in the trees, to make
room for crops, or to construct buildings, roads,
and other structures.
• Deforestation is also a main cause of the higher
concentrations of greenhouse gases i.e. global
warming in the atmosphere.

23. 7. Soil Erosion
• Soil erosion is another major factor that
causes thermal pollution. Consistent soil
erosion causes water bodies to rise, making
them more exposed to sunlight.
• The high temperature could prove fatal for
aquatic biomes as it may give rise to anaerobic
conditions.
• Removal of vegetation far away from a stream
or lake can contribute to thermal pollution by
speeding up the erosion of soil into the water,
making it muddy, which increases the light
absorbed.

25. CONSEQUENCES
• Decreased Dissolved Oxygen
• Migration
• Increased Toxins
• Loss of Biodiversity
• Ecological Impacts
• Reproductive Effects
• Increased Metabolic Rate

26. 1.Decreased Dissolved Oxygen
• Warm water holds less oxygen than cool water. If the
oxygen level drops animals that cannot move to another
area may begin to die.
• In deeper bodies of water, the injection of warm water
can keep oxygen from dispersing into deep water, which
is potentially good for bacteria but dangerous for aquatic
animals.
• The decreased oxygen can cause algae blooms that
pose a threat to aquatic plants and animals.
• This algae bloom problem is probably the most common
and best-known side effect of thermal pollution.

27. 2. Migration
• Fish and amphibians may move away from the
warm water to a more-suitable location,
disrupting the ecosystem for animals that
remain.
• Birds may also be forced to leave in search of
areas with more food. Plants and certain
animals will be stuck in the area, which can lead
to huge losses.
• Migration away from the polluted area
contributes to a dramatic loss of biodiversity at
sites where thermal pollution happens.

29. 3. Increased Toxins
• Toxins in the water are more a side effect of
dumping waste water than a direct effect of
thermal pollution.
• Chemical pollution is an almost inevitable side
effect of using water for cooling. Solvents, fuel
oil, and dissolved heavy metals end up in the
lake or river where the cooling water gets
dumped.
• Nuclear power plants can also release
slightly radioactive cooling water.

30. • The chemicals may have a range of toxic effects
on plants and animals, from fatal poisoning to
mutations and sterilization.

31.
4. Loss of Biodiversity
• The sudden heating can kill off vulnerable
organisms or drive them away.
• This is one of many serious issues for
threatened and endangered animal species.
• This loss can come from organisms dying from
the hot water, being unable to reproduce as
effectively as before, or simply leaving the area.
• We usually think of animals as casualties of
water pollution, but multi-celled aquatic plants
are also at risk when thermal pollution changes
the local aquatic ecosystem.

33. 5. Ecological Impacts
• The local aquatic ecosystem can be damaged
by thermal pollution, especially if it is dramatic,
as in copious amounts of warm water being
dumped into a chilly pond or bay or river.
• “Thermal shock” can kill off insects, fish, and
amphibians. This sudden loss of life causes
further issues with the ecosystem.

34. • Key food sources are no longer adequate.
A threatened or endangered local
population may be wiped out or put under
even more pressure.
• Coral reef bleaching has also been
observed when a power plant or factory is
dumped into coastal water.
• Coral bleaching happens when the coral
organisms die.

36. 6. Reproductive Effects
• A significant temperature increase in the water can
cause reproductive problems. Warmer water can reduce
the fertility of some organisms.
• Other species may suffer birth defects or lay deformed
eggs because of chemical changes in the body caused
by warmer water.
• Defective eggs and birth defects hurt the overall
reproductive fitness of the animal population and can
reduce the population.
• Thermal pollution can change the biology of aquatic
organisms in a variety of ways.

40. 7. Increased Metabolic Rate
• Warmer water may be good for cold-blooded fish and
amphibians, but only for a limited time.
• One of many real problems that warm water may cause
is faster metabolism, which means animals need more
food.
• The local ecosystem may not be able to support a
significant increase in food consumption.
• The warmer water gives an advantage to certain
organisms while it puts stress on others. The more-
adaptable organisms may unbalance the ecosystem
simply by out-competing other organisms and by eating
them or driving them to starvation.

41. CASE STUDY 2: Impact on
Loup River
a• The Bentley Manufacturing Company: The
Bentley Manufacturing Corporation maintains a
small scrap metal processing plant located on
the bank of the Loup River Power Canal.
• The canal was built 65 years ago to provide
water for a hydroelectric power plant, which
provides electricity for the region.

42. • The Loup River Canal draws water from the
Loop River several miles up stream from the
Bentley plant. The power plant is three miles
below the Bentley plant just below a small
storage lake.
• Over the years the canal has become an
important freshwater estuary. Several species of
catfish, perch, bluegill, and freshwater drum
inhabit the canal. It has been a popular area for
sport fishermen.

43. • A variety of ducks live in the marshes and
seepage ponds that are found next to the
canal.The Bentley Processing Plant was began
operations seven years ago. Its operations have
grown over the years and its demands for water
have increased substantially.
• The company has been very profitable and has
also been a good neighbor in the community.But
all is not well for the company. Biologists have
reported a steady decline in the fish population
in the canal.

44. • Many observers have blamed the discharge of
hot water from the Bentley plant for the problem.
Bentley is equally concerned because it would
like to expand its operations, but will not be able
to do so until the problem is resolved.
• Many people have maintained that the demise
of the fish population in the Loop Canal is the
result of Bentley's thermal pollution of the water.

45. • Bentley's management feels that the declining
fish populations are due to increased
concentrations of fertilizers and other agricultural
chemicals, which drain into the canal.
• Because Bentley would like to expand its
facilities to meet increasing business and it
faces a potential challenge from the State
Department of Fisheries as well as the
community

47. CASE STUDY 3: Environmental Impacts of
Thermal Power Plant: Case Study - Tamil Nadu
• Jayamkondam lignite Power Corporation (JLPC), a joint
sector company, to exploit the Jayamkondam lignite field
with a proposal to establish 3 X 500 MW lignite based pit
head thermal power station near Jayamkondam.
• Neyveli lignite corporation (NLC) is the consultant to the
preparation of the pre-feasibility report for opening a
mine of a capacity of a million tons per annum to feed
the proposed 3 X 500 MW thermal power station.
• The excavation of lignite and the consequent
commencement of the thermal power station will have
numerous impacts, calling for a detailed EIA of the lignite
mine and thermal power plant at Jayamkondam.

48. • The industrial sector is one of the major energy
consuming sectors in India. It uses about 50% of the
total commercial energy in the country. Apart from
• Environmental problems associated with urbanization,
the thermal power plant would have specific effects on
the environment and people living in the urban areas.
• Two scenarios were envisaged for the water pollution
from the thermal power plant.
• In the first scenario where there would be no controls of
the particulates using an ESP (Electro Static
Precipitator) an assumption was made that 50% of the
particulate matter from the thermal power plant would
deposited on the land whereas the other 50% would
deposit on the small ponds.

49. • In the second scenario, it was assumed that 90% of the
SPMs are dumped in the fly ash pond, 30% of this
leaches, of which 20% into the ground water aquifer and
10% leaching into the soil.
• After 10 years of mining and at a radius of 2 km from the
thermal power plant (thermal power plant), some of the
villages that could be affected are Rattinam,
Devamangalam, Nayaganaipiriyal, Vanathiraiyan,
Angarayanallur, Periyavalayam, Jayamkondam,
Pichanur, Elaiyaperunallur, Mathuservarmadam, Ulkottai
and T. Solankurichi.
• These villages would be affected as they lie to the east
of the fly ash pond and earlier studies indicate that the
aquifer slides towards the east and gently rises when it

50. • The analysis reveals that 0.0149 ppm of lead, 0.00118
ppm of cadmium would enter the ground water, 0.0097
ppm of chromium and 0.000661 ppm of mercury would
enter the ground water under the affected villages.
• The presence of these heavy metals in the water is
extremely poisonous, having chronic effects,
carcinogenic and can be fatal.
• Studies on the heavy metal abundance in aquatic
environment in and around Korba, Madhya Pradesh,
India, showed alarming concentrations of Fe (10000
µg/l), Cr (800 µg/l), Mn (560 µg/l), Zn (82 µg/l), Co (70
µg/l) and As (10 µg/l). (15).
• µg/l), Mn (560 µg/l), Zn (82 µg/l), Co (70 µg/l) and As (10
µg/l). (15)

51. • Thermal pollution leads to change in water quality
leading to death of organisms and the water bodies are
rendered unpotable. The environmental effects are
mostly localized and mostly on the fish. Most fish larvae
pass through the inlet screens and are killed.
• Fishes also cannot with stand sudden changes in
temperature caused by routing shut down and start up of
plants.
• Increase in the lake temperature will generally increase
the biological growth rate (which increases the oxygen
demand) but reduces oxygen diffusivity this could cause
the dissolved oxygen to drop below a critical level.

52. Neyveli lignite corporation
(NLC)

53. Cooling ponds
Spray ponds at the Volgodonsk Nuclear Power
Station.

54. Cooling tower

56. Artificial lake