Aquatic life thermal pollution

Thermal pollution. Degradation of water quality by the introduction of a heated effluent. It is primarily a result of the discharge of cooling waters from industrial processes, particularly from electrical power generation. Even small deviations from normal water temperatures can affect aquatic life. Thermal pollution usually can be controlled by cooling towers. 

What is the minimum rate of heat deposition in a river by a 100-MW power plant operating with a boiler at 800°C and using the river water at 30°C to condense steam Such heat deposition is known as thermal pollution and can contribute to making rivers unsuitable for many forms of aquatic life. 

Memman, Daniel, "The Calefaction of a River", Scientific American, Vol. 222, No. 5, May 1970, Page 42 Clark, John R., "Thermal Pollution and Aquatic Life", Scientific American, Vol. 220, No. 3, March 1969, Page 18 Ellers, Fred S., "Advanced Offshore Oil Platforms", Scientific American, Vol. 246, No. 4, April 1982, Page 39... 

The fishes depend on dissolved oxygen in the water. If water temperature goes too high, the solubility of the oxygen may fall too low, and the fishes may die. That is one of the reasons thermal pollution from power plants can pose serious problems to aquatic life. ... 

What is thermal pollution Why is it harmful to aquatic life ... 

The decreased solubility of O2 in water as temperature increases is one of the effects of thermal pollution of lakes and streams. The effect is particularly serious in deep lakes because warm water is less dense than cold water. Warm water therefore tends to remain on top of cold water, at the surface. This situation impedes the dissolving of oxygen in the deeper layers, thus stifling the respiration of all aquatic life needing oxygen. Fish may suffocate and die under these conditions. 

Water that is returned to a waterway at a higher temperature than it was withdrawn contributes to thermal pollution of the waterway. Because the solubility of oxygen in water decreases with increased temperature, thermally polluted water cannot support aquatic life as well as cooler water can. 

People usually think of things like lead, mercury, toxic organic compounds, and bacteria as being major pollutants. However, heat can also be a major pollutant. The solubility of a gas in a liquid decreases as the temperature increases (see Chapter 13 for more about the solubility of gases). This means that warm water doesn t contain as much dissolved oxygen as cool water. And how is this related to pollution The amount of oxygen in water has a direct impact on aquatic life. The reduction of the dissolved oxygen content of water caused by heat is called thermal pollution. 

Gases in liquids For gases dissolving in liquids, such as oxygen dissolving in lake water, the solubility goes down cis the temperature increases. This is the basis of thermal pollution, the addition of heat to water that decreases the solubility of the oxygen and ciffects the aquatic life. 

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