Relevance: GS III (Science & Tech – Energy / Environment) | Source: The Hindu

1. The Concept: Solving Two Problems at Once

Waste-to-Energy (WtE) is a technology designed to tackle two major urban headaches simultaneously: Overflowing Landfills and Energy Shortage.

  • The Process: Instead of dumping non-recyclable trash into a landfill where it rots and releases methane, WtE plants process it to generate Electricity or Heat.
  • The Impact: These facilities can reduce the physical volume of waste by nearly 90%, significantly extending the life of city landfills.

2. How Does It Work? (The Technologies)

The article highlights three main methods:

  • Incineration (Burning): The most common method. Trash is burned at high temperatures to boil water, create steam, and turn turbines. Risks: If not filtered, it can release toxic Dioxins.
  • Gasification: Instead of burning, waste is heated with very little oxygen. This doesn’t produce smoke but converts the solid waste into a combustible gas called Syngas (Synthetic Gas).
  • Biomethanation (Anaerobic Digestion): Best for wet/organic waste (like food scraps). Bacteria break down the waste in the absence of oxygen to produce Biogas (Methane) and bio-fertilizer.

3. The Challenge in India

While WtE works well in Europe, it faces hurdles in India due to the nature of our waste.

  • Low Calorific Value: Indian waste has high moisture (wet food waste) and high inert content (dust/sand).
  • The Problem: Wet waste doesn’t burn well. Without strict Segregation at Source, mixed waste lowers the efficiency of incinerators, often requiring extra fuel just to burn the trash.

UPSC Value Box

Concept / RuleRelevance for Prelims
Refuse Derived Fuel (RDF)A fuel produced by shredding and dehydrating solid waste (plastics, paper). It has a high calorific value and is often used in cement kilns or power plants as a substitute for coal.
Solid Waste Management Rules, 2016The primary legal framework in India. It mandates Segregation at Source (Wet, Dry, Hazardous) and encourages the use of RDF to reduce landfill burden.
Dioxins & FuransHighly toxic chemical compounds (Persistent Organic Pollutants) often released during the burning of plastic or chlorinated waste. Modern WtE plants use “scrubbers” to trap them.

Q. With reference to Waste-to-Energy technologies, consider the following statements:

  1. Gasification is a process that converts organic or fossil-based carbonaceous materials into carbon monoxide, hydrogen, and carbon dioxide.
  2. Incineration involves the combustion of organic substances contained in waste materials.
  3. Biomethanation is an aerobic process used primarily for the treatment of dry, inorganic waste.

Which of the statements given above is/are correct?

(a) 1 only

(b) 1 and 2 only

(c) 2 and 3 only

(d) 1, 2 and 3

Correct Answer: (b)

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