STP442A: Chapter 8—Thermal Loading of Water Supplies

    Pages: 11    Published: Jan 1978


    Abstract

    The discharge of heated water to streams, lakes, esturies, and groundwater can cause various effects. Some of these are detrimental while others are beneficial for subsequent uses of the receiving water. The heated discharge has been recognized as a problem in water quality and it is attracting increasing attention. Although ill effects are relatively minor at present, they may eventually become serious where thermal loading is tending to increase. The term “thermal pollution” has been used to identify the detrimental effects of heated discharges. This is not a particularly good term because heat itself is not a pollutant. All matter contains heat, except when it has a temperature of absolute zero. The heat content of a substance is directly proportional to its mass, whereas its temperature is a measure of the intensity of the kinetic energy of its molecules. Thus it is the temperature of water that is of primary concern, rather than its heat content. There are two related reasons for the interest in thermal loading. The first is the fact that a change in temperature will modify the environment of aquatic flora and fauna, resulting in a change in the species that can live and propagate in a given body of water. This is caused largely by an increase in the rate of biological reactions that accompanies a rise in temperature. The second is a fear that the tendency for thermal loading to increase will, in time, exceed the capacity of surface water to dissipate the added heat and thus create permanent temperature elevations over considerable areas.


    Paper ID: STP47426S

    Committee/Subcommittee: D19.03

    DOI: 10.1520/STP47426S


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