What is Thermal pollution?
‘Thermal pollution may be defined as the output of heat by population and industry such as the natural temperature of water is increased. It is known that plants and animals thrive best in a particular range of temperature and that changes of the body of water will influence the types and number of organisms in aquatic system’
Effects: The use of river and water for cooling of industries may be able to raise the temperature of water enough to produce major changes in the ecosystem. The water is so hot some times that fish haven’t be able to survive in it. Elevated temperature typically decreases the level of dissolved oxygen of water
Impacts: This can harm aquatic animals such as fish, amphibians and other aquatic organisms. Thermal pollution may also increase the metabolic rate of aquatic animals, as enzyme activity, resulting in these organisms consuming more food in a shorter time than if their environment were not changed. An increased metabolic rate may result in fewer resources; the more adapted organisms moving in may have an advantage over organisms that are not used to the warmer temperature. As a result, food chains of the old and new environments may be compromised. Some fish species will avoid stream segments or coastal areas adjacent to a thermal discharge. Biodiversity can be decreased as a result.
Cooling ponds or reservoirs constitute the simplest method of controlling thermal discharges. Heated effluents on the surface of water in cooling ponds maximize dissipation of heat to the atmosphere and minimize the water area and volume. This is the simplest and cheapest method which cools the water to a considerable low temperature. However, the technique alone is less desirable and inefficient in terms of air-water contact.