Water pollution occurs when harmful substances such as chemicals and waste materials like garbage are present in water that affect its quality and the presence of life in it.
The causes of Water Pollution
Waste from Industries – The industries often release chemicals directly into water bodies such as rivers and seas which contaminates it.
Sewage – The waste produced from households is often released into the water which gives rise to harmful bacteria in the water.
Mining Activities – The metal wastes obtained from mining activities harm the organisms present in water
Usage of Fertilizers and Pesticides – The chemicals present in fertilizers and pesticides are extremely harmful to aquatic animals, plants as well as animal consumption.
The Effects of Water Pollution
Addition of unwanted substances such as fertilizers pesticides and industrial wastes can make it poisonous and extremely harmful for consumption.
It can also lead to an increase in bacteria that causes severe diseases like Cholera.
Water pollution can lead to a decrease in the amount of Oxygen and nutrients in the water which affects the aquatic life.
Water pollution can cause changes in the temperature of water. An increase in temperature is not suitable for all the aquatic animals especially their eggs.
The water cycle refers to the continuous movement of water from the sky to the ground and then back again. The water cycle can be divided into different stages:
Evaporation- Water from the Earth evaporates into water vapours and travels up to the atmosphere.
Condensation – The water cools down and forms clouds up in the atmosphere.
Rainfall, Snowfall or Precipitation – The water then falls back to the ground
The water that falls on the earth and travels through different pathways before it finally falls back into the sea and oceans via rivers. Some of the water is also being utilized by the plants, animals and human beings present on the earth. But the journey of water continues in the form of the water cycle.
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List the events that reduce the Biological Oxygen Demand (BOD) of a primary effluent during sewage treatment.