ENVIRONMENTAL ISSUES

 

• Cultural or Accelerated Eutrophication:
  • Pollutants from man’s activities like effluents from the industries and homes can radically accelerate the aging process. This phenomenon is called Cultural or Accelerated Eutrophication.

Causes:

• Sewage and agricultural and industrial wastes.
• Prime contaminants are nitrates and phosphates.

Effects:

• Unsightly scum and unpleasant odors.
• Robbing the dissolved oxygen form water.
• Pollutant inflow kills the fish.
• Decomposition of dead fish causes further depletion of DO.
• Finally a lake can literally choke to death.

Thermal pollution:

Cause:

• Heated (thermal) waste waters flowing out of electricity-generating units. E.g. thermal power plants.

Effects:

• Thermal wastewater eliminates or reduces the number of organism sensitive to high temperature.
• Enhance the growth of plants and fish in extremely cold areas but only after causing damage to the indigenous flora and fauna.

A case study of integrated waste water treatment:

• Wastewater including sewage can be treated in an integrated manner, by utilizing a mix of artificial and natural process.
• It has been done in town of Arcata, in the northern coast of California.
• The treatment is done in two stages:-
  • The conventional sedimentation, filtering and chorine treatment are given.
  • The biologist developed a series of six connected marshes over 60 hectares of marshland.
  • Appropriate plants, algae, fungi and bacteria were seeded into this area, which neutralize, absorb and assimilate the pollutant
  • The water flows through the marshes, it get purified naturally.
  
  
• The marshes also constitute a sanctuary, with high level of biodiversity in the form of fishes, animals and birds that now reside there.
• A citizens group called Friends of the Arcata Marsh (FOAM) is responsible for the upkeep and safeguarding of this project.

Ecological sanitation:

• Ecological sanitation is a sustainable system for handling human excreta, using dry composting toilets.
• This is a practical, hygienic, efficient and cost-effective solution to human waste disposal.
• With this composting method human excreta can be recycled into are source (as natural fertilizer).
• ‘EcoSan’ toilets are being used in Kerala and Srilanka.

SOLID WASTES:

• Solid wastes refer to everything that goes out in trash.
• Municipal solid wastes are wastes from homes, offices, stores, schools, hospitals etc. It comprises paper, food wastes, plastics, glass, metals rubber, leathers, textiles etc.
• Open damp of these wastes serve as the breeding ground for rats and flies.
• Sanitary landfills were adopted as substitute for open-burning dumps.

Sanitary landfills:

• Wastes are dumped in a depression or trench after compaction and covered with dirt everyday.

Disadvantages:

• Shortage of space for huge garbage’s.
• Danger of seepage of chemicals, polluting the ground water resources.

Solution to solid wastes:

• All solid wastes are categorized into thee types:
  • Bio-degradable.
  • Recyclable.
  • Non-biodegradable.
  
  
• All the garbage generated is sorted first.
• Recyclable material to be separated and send for recycles.
• Biodegradable wastes can be put into deep pits in the ground and be left for natural breakdown.
• Only Non-biodegradable wastes are left and required to be disposed.

Prevention:

• The need to reduce our garbage generation should be a prime goal.
• Reduction in use of plastics and use of eco-friendly packaging.
• Carrying cloth or other natural fiber carry bags when we go shopping.
• Refusing polythene bags.

Case study of Remedy for Plastic wastes: (Ahmed Khan)

• Polyblend, a fine powder of recycled modified plastic, was developed by his company.
• Polyblend is mixed with bitumen that is used to lay roads.
• It increases the water repelling property of bitumen, and helped to increase road life by a factor of three.
• The raw material used for polyblend is plastic film waste.

 

CBSE Biology (Chapter Wise) Class XII ( By Mr. Hare Krushna Giri )
Email Id : harekrushnagiri@yahoo.com