“ “THERMALTHERMAL

POLLUTION” POLLUTION”

By:By:

NIKHIL PAKWANNENIKHIL PAKWANNE

What is Thermal What is Thermal Pollution?Pollution?

Increase in the normal temperatures Increase in the normal temperatures of natural waters caused by of natural waters caused by intervention of human activities.intervention of human activities.

Temperature is a physical Temperature is a physical characteristic of water which is characteristic of water which is characteristic of water which is characteristic of water which is regulated under the Clean Water regulated under the Clean Water Act.Act.

Thermal PollutionThermal Pollution

Major CausesMajor Causes

Nuclear power Nuclear power plantsplants

DeforestationDeforestation Soil erosionSoil erosion

Nuclear Power PlantsNuclear Power Plants

Nuclear power plants use water as a Nuclear power plants use water as a cooling agent.cooling agent.

After the water is used, it is put back After the water is used, it is put back into a water supply at 9-20into a water supply at 9-20ooC C warmerwarmer

This 1988 thermal image of the Hudson River highlights temperature changes caused by discharge of 2.5 billion gallons of water each day from the Indian Point power plant. The plant sits in the upper right of the photo — hot water in the discharge canal is visible in yellow and red, spreading and cooling across the entire width of the river. Two additional outflows from the Lovett coal-fired power plant are also clearly visible against the natural temperature of the water, in green and blue.

Waste Heat from Power Plants

DeforestationDeforestation

The decrease in vegetation increases The decrease in vegetation increases the amount of light that hits the the amount of light that hits the water, which increases the water, which increases the temperature of the watertemperature of the water

Deforestation also increases erosionDeforestation also increases erosion

Soil ErosionSoil Erosion

Erosion makes the water muddy, Erosion makes the water muddy, which increases the light absorbedwhich increases the light absorbed

Effects of Increased Water Effects of Increased Water TemperatureTemperature

Thermal shock – aquatic life adapted to a Thermal shock – aquatic life adapted to a certain water temperature can go into certain water temperature can go into shock when the temp is changed even 1 or shock when the temp is changed even 1 or 2 degrees.2 degrees.

Oxygen dissolved in water decreasesOxygen dissolved in water decreases Increases the rate of photosynthesis, Increases the rate of photosynthesis,

which increases the amount of plant which increases the amount of plant growthgrowth

Increases the metabolic rate of fish, which Increases the metabolic rate of fish, which increases their need for oxygen increases their need for oxygen

• Changes in the environment may also result in amigration of organisms to another, more suitable environment, and to in-migration of organisms that normally only live in warmer waters elsewhere. As a result one has the problem of compromising food chains of the old and new environments. Biodiversity can be decreased as a result.

Biotic Effects of Thermal Biotic Effects of Thermal PollutionPollution

• Changes of even one to two degrees Changes of even one to two degrees Celsius canCelsius can cause significant changes in organism cause significant changes in organism metabolismmetabolism and other adverse cellular biology and other adverse cellular biology effects.effects. Principal adverse changes can include Principal adverse changes can include renderingrendering cell walls less permeable to necessary cell walls less permeable to necessary osmosis,osmosis, coagulation of cell proteins, and coagulation of cell proteins, and alteration of enzyme metabolism. These alteration of enzyme metabolism. These cellular level effects can adversely affect cellular level effects can adversely affect mortality and reproduction.mortality and reproduction.

Dissolved Oxygen

vs

Temp

Control of thermal Control of thermal pollutionpollution

Cooling ponds, man-made bodies of Cooling ponds, man-made bodies of water designed for cooling water designed for cooling by evaporation, convection, and by evaporation, convection, and radiationradiation

Cooling towers, which transfer waste Cooling towers, which transfer waste heat to the atmosphere through heat to the atmosphere through evaporation and/or heat transferevaporation and/or heat transfer

Cogeneration, a process where waste Cogeneration, a process where waste heat is recycled for domestic and/or heat is recycled for domestic and/or industrial heating purposes industrial heating purposes

References: References: http://thermal.unl.edu/dmhttp://thermal.unl.edu/dm www.thermaleffects.comwww.thermaleffects.com www.google.comwww.google.com http://thermalpollution.usda.edu/dthttp://thermalpollution.usda.edu/dt