Tuesday, August 4, 2020

Environmental Issues - Notes | Class 12 | Part 3: Wastes and their Effects

16. ENVIRONMENTAL ISSUES


WASTES AND THEIR EFFECTS

SOLID WASTES 

Solid wastes refer to everything that goes out in trash.

Municipal solid wastes are wastes from homes, offices, stores, schools, hospitals, etc. that are collected and disposed by the municipality.

All solid wastes cannot be completely burnt. Open dumps serve as the breeding ground for rats and flies.

Sanitary landfills are the substitute for open-burning dumps. In sanitary landfill, wastes are dumped in a depression or trench and covered with dirt.

Limitations of Landfills:
  • Amount of garbage especially in metros has increased so much that these sites are getting filled too.
  • Seepage of chemicals, from the landfills pollutes the underground water resources.
Solid wastes are 3 types:
  • Bio-degradable: They undergo natural breakdown.
  • Non-biodegradable: E.g. plastic packets, polybags, polystyrene etc.
Eco-friendly packaging can be used instead of plastics. E.g. Carrying cloth, natural fibre carry-bags etc.
  • Recyclable: E.g. Plastics, e-wastes etc.
Hospital wastes contain disinfectants, harmful chemicals, and pathogenic micro-organisms. They are incinerated.

E-wastes (electronic wastes):

All irreparable electronic goods are known as e-wastes.

They are buried in landfills or incinerated.

Recycling is the only eco-friendly solution for the treatment of e-wastes. But during recycling, the workers are exposed to toxic substances present in e-wastes.

Over half of the e-wastes in developed world are exported to developing countries (China, India, Pakistan etc.), where many metals (Cu, Fe, Si, Ni & Au) are recovered during recycling process.

Polyblend: A Remedy for Plastic Waste 

Ahmed Khan (A plastic sack manufacturer in Bangalore) developed Polyblend. 

It is a fine powder of recycled modified plastic. 

Polyblend is mixed with the bitumen and is used to lay roads.

Blend of Polyblend and bitumen enhances the bitumen’s water repellant properties and helps to increase road life.

AGRO-CHEMICALS AND THEIR EFFECTS 

Inorganic fertilisers, pesticides, herbicides, fungicides, etc. are toxic to non-target organisms that are important components of the soil ecosystem. These are biomagnified in the terrestrial ecosystems.

Chemical fertilisers cause eutrophication.

Integrated Organic Farming 

It is a cyclical, zero-waste procedure, where waste products from one process are cycled in as nutrients for other processes. 

This allows the maximum utilization of resource and increases the efficiency of production.

Ramesh Chandra Dagar (a farmer in Sonipat, Haryana) included bee-keeping, dairy management, water harvesting, composting & agriculture in Integrated Organic Farming. Its advantages are given below:
  • They support each other and allow an economical and sustainable venture.
  • No need of chemical fertilizers, as dung is used as manure.
  • Crop waste is used to create compost (natural fertilizer) or to generate natural gas (provides energy for the farm).
Dagar has created the Haryana Kisan Welfare Club, with a membership of 5000 farmers to spread information on the practice of integrated organic farming.

RADIOACTIVE WASTES 

Use of nuclear energy has two very serious problems:
  • Accidental leakage. E.g. Three Mile Island incident & Chernobyl incident.
  • Safe disposal of radioactive wastes.
Nuclear radiation causes mutations. It is lethal at high doses. At lower doses, it causes disorders such as cancer.

It is recommended to store nuclear wastes in shielded containers buried within rocks, about 500 m deep below the earth’s surface. But, the public opposes this method.
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