WHAT IS THERMAL POLLUTION? ITS SOURCES, EFFECTS AND CONTROLS.

• Thermal pollution is the degradation of water quality by any process that changes ambient water temperature. It is a rise in temperature of water bodies due to discharging of hot industrial effluents.
• A common cause of thermal pollution is the use of water as a coolant to cool their equipments by power plants and industrial manufacturers.
• The sources of thermal Pollution :   

1. Nuclear Power Plant 
2. Coal-fired power Plant 
3. Industrial Effluents 
4. Domestic Sewage
5. Hydro-electric power 
6. Thermal Power Plant

• The discharged effluents of these sources have a higher temperature than the intake water that reduces the concentration of oxygen from the water which causes the deleterious effects on the marine ecosystem.
• Other causes of thermal pollution include soil erosion, deforestation, runoff of water by pavement, natural disasters like volcano eruption and geothermal activities.

Effects of thermal pollution :

1. Decrease in DO (Dissolved Oxygen) Levels: The warm temperature reduces the levels of DO (Dissolved Oxygen) in water. The warm water holds relatively less oxygen than cold water. The decrease in DO can create suffocation for plants and animals such as fish, amphibians and copepods, which may give rise to anaerobic conditions. Warmer water allows algae to flourish on surface of water and over the long term growing algae can decrease oxygen levels in the water.

2. Increase in Toxins: With the constant flow of high temperature discharge from industries, there is a huge increase in toxins that are being regurgitated into the natural body of water. These toxins may contain chemicals or radiation that may have harsh impact on the local ecology and make them susceptible to various diseases.

3. Loss of Biodiversity: A dent in the biological activity in the water may cause significant loss of biodiversity. Changes in the environment may cause certain species of organisms to shift their base to some other place while their could be significant number of species that may shift in because of warmer waters.  Organisms that can adapt easily may have an advantage over organisms that are not used to the warmer temperatures.

4. Increases Metabolic Rate: Thermal pollution increases the metabolic rate of organisms as increasing enzyme activity occurs that causes organisms to consume more food than what is normally required, if their environment were not changed. It disrupts the stability of food chain and alter the balance of species composition.

5. Migration: The warm water can also cause particular species of organisms to migrate to suitable environment that would cater to its requirements for survival. This can result in loss for those species that depend on them for their daily food as their food chain is interrupted.

Steps to control thermal pollution :

1. Heated water from the industries can treated before discharging directly to the water bodies.

2. Heated water from the industries can be treated by the installation of cooling ponds and cooling towers.

3. Industrial treated water can be recycled for domestic use or industrial heating.

4. Through artificial lakes: In this lake Industries can discharge their used or heated water at one end and water for cooling purposes may be withdrawn from the other end. The heat is eventually dissipated through evaporation.