Eutrophication: Process & Control Measures

eutrophication - Eutrophication: Process & Control Measures
  • The process of nutrient enrichment of water and consequent loss of species diversity is called eutrophication.
  • Water polluted with inorganic fertilizers containing nitrates and phosphates or containing organic wastes causes eutrophication in water bodies.
  • The Decomposition of organic wastes also increases nutrients in the water and causes eutrophication.
  • During eutrophication, there is a luxuriant growth of algae, particularly blue-green in water. These form floating scums and water blooms.
  • The algae use oxygen at night and may deoxygenate the water enough to kill the fish and other animals.
  • The algal mat at the water surface may block light to the submerged plant.
  • The algal species quickly complete their life cycle and die thereby adding a lot of dead organic matter, and feed the oxygen-consuming bacteria.
  • They may be pushed on the shore by the wind and decompose, releasing foul gases, such as hydrogen sulfide.
  • Silt and decaying matter may accumulate and finally fill the lake or pond. This process is called senescence. It is a natural stage in the change of a lake into dry land.
  • Depending upon the climate, the size of the lake, and other factors, the natural ageing of a lake may span thousands of years.
  • However, pollutants from man activities example- effluents from industries and residential premises, etc. can radically accelerate the ageing process. This phenomenon is termed as cultural or accelerated eutrophication.

Control of Eutrophication:

Following measures can be adopted to combat the phenomenon of Eutrophication-

  • Wastewater must be treated before its discharge into water bodies.
  • To reduce the amount of nutrients in the water body, bacterial growth should be stimulated.
  • The dissolved nutrients can be removed by physio-chemical methods. For example- phosphorous can be removed by precipitation and nitrogen by nitrification or denitrification, electrodialysis, and ion exchange methods.
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