tell about control of thermal pollution and its effects
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control measures of thermal pollution ppt
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tell about control of thermal pollution and its effects
25-03-2017, 02:39 PM
Thermal pollution
Thermal pollution is defined as the addition of undesirable excess heat to water, making it harmful to human, animal or aquatic life. Thermal pollution can also lead to significant deviations from the activities of aquatic communities. Thermal pollution is the degradation of water quality by any process that changes the temperature of the ambient water. A common cause of thermal pollution is the use of water as a refrigerant by power plants and industrial manufacturers. When the water used as refrigerant is returned to the natural environment at a higher temperature, the temperature change decreases the oxygen supply and affects the composition of the ecosystem. Fish and other organisms adapted to a particular temperature range can be destroyed by an abrupt change in water temperature (either a rapid increase or decrease) known as a "heat shock".
Measures to control thermal pollution
The following methods can be adapted to control the high temperature caused by thermal discharges:
1. Cooling Towers: The use of water from water systems for cooling systems for cooling purposes, with a return to the waterway after passing through a condenser, is called the cooling process. Cooling towers transfer heat from hot water to the atmosphere by evaporation. Cooling towers are of two types:
(I) Wet cooling tower: The hot water leaving the condenser (reactor) is allowed to spray on the baffles. The fresh air, with high speed, is passed from the sides, which removes the heat and refreshes the water.
(Ii) Dry cooling tower: here, hot water is allowed to flow in long spiral pipes. Cold air with the help of a fan is passed over these hot pipes, which cools the hot water. This cold water can be recycled.
2. Cooling ponds: Cooling ponds are the best way to cool thermal discharges. Effluents heated on the surface of the water in the cooling ponds maximize the dissipation of heat to the atmosphere and minimize the area and volume of water. The wedhe warm water acts as a cooling pond.
3. Spray ponds: The water coming out of the condensers is allowed to pass through the sprayers to the ponds. Here the water is sprayed through nozzles like fine droplets. The heat of fine droplets dissipates into the atmosphere.
4. Artificial Lakes: Artificial lakes are man-made water bodies that offer one-time cooling. The heated effluents can be discharged into the lake at one end and the water for cooling can be withdrawn from the other end. The heat eventually dissipates by evaporation.
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