Thermal Pollution

1.0)            INTRODUCTION

Pollution is the introduction of contaminant into the environment that dangerous to human or other living organisms. Pollution also makes human and other living organisms not comfortable with the environment. It also can damage our environment.

Pollution can occur in varies form such as air pollution, water pollution, noise pollution, light pollution, nuclear pollution, thermal pollution and so on. Pollution happens in many ways such as by natural ways, by human activities and so on. Pollution by natural ways occurs when there are floods, earthquake, eruption of volcano and many more. 

Pollution by human activities occurs when human doesn’t care about their environment. Normally, pollution made by human is the major cause to make the environment pollute. Example for human activities that can lead to pollution is throw the rubbish everywhere such as river. Besides that, wastes from their factory also contribute to pollution.

Pollution can classify into two categories. That is point source pollution and non-point source pollution.
        • Point source pollution: A single identifiable localized source of air, water, thermal, and noise or light pollution.
        • Nonpoint source pollution: Pollution that come from several different sources.
When pollution occurs, there are many effects that can harm our environment. Normally, it affects human and other organisms. Pollution can affect human health. It can make us have headache fatigue, skin irritation and cancer. When the pollution become worse, it also can make human and other organisms died. 

Today, pollution had become worst to our environment. We need to reduce or minimize all this pollution before our environment become worse. There are some ways to control pollution to become worse such as recycling for our waste, used public transport or car pooling to reduce air pollution and so on.

Thermal pollution is defined as the degradation of water quality by any process that changes water temperature. Thermal pollution also can be defined as the increases in the normal temperature of waters in a stream, lake, river or ocean that caused by human activities mainly. Some of human activities that can produce to thermal pollution are dumping hot water from factories and power plants to the source of water.

Besides that, there are many other sources that contribute to thermal pollution such as power plants creating electricity from fossil fuel, water as a cooling agent in industrial facilities, deforestation of the shoreline and soil erosion. Thermal pollution also refers to the addition of large amounts of waste heat to our environment, same as the causing of air pollution.
Thermal pollution is very harmful to human and aquatic biomes. When the thermal pollution is spread, it can affect many lakes, stream, rivers, and ocean also other parts of the world. If the temperature increases only in small value like 1 or 2 Celsius degrees or about 2 to 4 Fahrenheit degrees, it can kill aquatic organisms such as native fish, shellfish and plants.


Thermal pollution has become an increasing and the most current pollution in the world. There are many causes that cause thermal pollution. Some of the causes are:
3.1)            Water as a Cooling Agent

Water as a cooling agent is the major causes of thermal pollution. Water is the main thing that use as a cooling agent in many industries either in Malaysia or other country. When water is used as a coolant, the temperature of the water will become higher than usual. As we know, the changes in temperature can give impact mainly on aquatic organisms by
 3.1.1 Decrease Oxygen Supply
All plant and animal species that live in water are adapted to temperatures within a certain range. When the temperature is increasing even one to two degrees Celsius, it can give impact to aquatic organisms. Warm water temperature may lower the oxygen content in water.
Lower of the oxygen content can affect aquatic organisms’ respiration rate and aquatic organisms is needed oxygen consumption in fast rate. For example, when water in an area warms more than they can tolerate, species that cannot move, such as rooted plants and shellfish, will die. Species that can move, such as fish, will leave the area in search of cooler conditions but when they can’t find the cooler area, the aquatic organisms will die. 
When this conditions happen, aquatic organisms not only susceptibility to the harmful effects to toxic chemicals, parasites and diseases but they will die too. 

Its different in the Southern Hemisphere, thermal pollution is commonly caused by the release of very cold water from the base of reservoirs, with severe affects on fish normally eggs and larvae, macroinvertebrates and river productivity.

3.2)            Urban Runoff
Urban runoff is surface runoff of rainwater created by urbanization. The urban runoff is created for the flow of rainwater when raining day to make sure the rainwater not stay at parking lots, roads and sidewalks. But, during warm weather, urban runoff can have significant thermal impacts on a small stream with the stormwater passes over hot parking lots, hot roads and hot sidewalks.

When the stormwater is moved along the hot parking lots, hot roads and hot sidewalks, it can make the temperature of water increase. The runoff also increases temperatures in streams, harming fish and other organisms. This runoff is a major source of water pollution in United State.

3.3)            Deforestation on Shorelines and Soil Erosion
Soil erosion and deforestation on shorelines is two other major factors that can cause temperature increases. Plants and trees at the shorelines have their own advantages. It helps to shade the water and keep the temperatures of the water in normal rate by providing protection of the water from the sunlight. Normally, tall trees are used to cover water from the sunlight.
People like to remove the plants or trees in order to harvest the wood in the trees that used to cover the water from the temperature increase. When plants are removed from the shorelines, the water from the river, lake, ocean or sea will absorb more sunlight. Not only the water is absorb the sunlight but soil that hold by the root structure will falls into the river, lake, ocean or sea.
Soil erosion happened when no root from the trees or plants holds it. Soil erosion can cause river and lake beds to rise and make the surface of the water more shallow which can heated the water more quickly.

3.4)            Electric Power Plants 
An electric power plants or fossil fuels power plant is a power station that burns fossil fuels such as coal, natural gas or petroleum to produce heat. Heat is turned water to steam where the turbines is spins to produce electricity. After the steam us used, the steam must be cooled and condensed back into water. To make the steam back into water, cool water is brought into the plant and circulated next to the hot steam.
In this process, the temperature of the cool water increase to 5 to 10 degree Celsius. After the water us used, the water is dumped back into the river, lake or ocean from which it came.
An electric power plant can affect our environment too. When the heat is increase to the environment, it can be a serious threat to human, animals and also plant. Electric power plants also can contribute to thermal pollution because the combustion of fossil fuels is related to the increases in temperature of water.


As we know, thermal pollution can’t be avoided but this pollution can be reduced. When thermal pollution is happened, we need to find ways to overcome this pollution. People mainly researchers and engineers have made a research about this pollution and ways to overcome it.
4.1)            Industrial Wastewater

In the United States, thermal pollution is mainly come from industrial source. Industrial sources in United States mostly generate by power plants, petroleum refineries, pulp and paper mills, chemical plants, steel mills and smelters. All these industrial sources are form heat water. The heated water from these industrial sources can be controlled with:
4.1.1        Cooling Ponds
Cooling pond is made by human. The purpose of cooling ponds is to provide cooling water for a nearby power plant which is used water for cooling. Normally, in areas where the cooling pond is used, the pond also use as a recreation place by other people of the surrounding.
In a cooling pond, hot water is pumped through the pond to cool down. The heat is transferred through the water, bringing the temperature down so that the water can be used again.
            4.1.2    Cooling Towers
Cooling tower is a device that removes heat used to transfer heat to the atmosphere. Normally, cooling towers may use the evaporation process to remove heat of water. Common applications of cooling towers are provide cooled water for air conditioning, manufacturing and electric power generation.           
The smallest cooling towers are design to handle water streams only for a few gallons of water per minute. Normally is used at residence while the largest cooling towers are cool hundreds of thousands of gallons per minute.
            4.1.3    Cogeneration
Cogeneration is the combination of heat and power (combined heat and power, CHP). Cogeneration used of a heat engine or a power station to generate electricity and useful heat. Cogeneration is one of the common forms of energy recycling.

4.2)            Urban runoff
Urban runoff must be control with effective method involves reducing the velocity and the flow of stormwater. Based on this method, we also can reduce pollutant discharge. The variety of stormwater management practices and systems may be used to reduce this effect of urban runoff.

Stormwater management facilities that absorb runoff or direct it into groundwater, such as bioretention systems and infiltration basins, can reduce these thermal effects.
Retention basins tend to be less effective at reducing temperature, as the water may be heated by the sun before being discharged to a receiving stream.
5.3)            Prevent Shoreline From Devegetation
Prevent shoreline from devegetation is needed to prevent thermal pollution from happen. “Do Not Devegetate” is the simple prescription to lead people do not make deforestation on shoreline. Landowner can leave the strips of the trees along streams and shorelines.
But, this method is quite hard to control because it is may include many people and may be only minor people will be involve in this effort. So, Grazing management plans are need to produced to control this thermal pollution.