Waste Management – SWM Rules, EWM Rules, etc

Converting waste to energy

Note4Students

From UPSC perspective, the following things are important :

Prelims level : Refuse-derived fuel (RDF)

Mains level : MSW management

The new plant at Bidadi has several advantages but also some operational challenges.

Practice Question: Discuss the various benefits of waste to energy plants and challenges in running them successfully.

The prospectus of new plant

  • The new 5 MW waste-to-energy plant is going to set up near Bidadi, Karnataka.
  • This plant is expected to process 600 tonnes per day of inorganic waste.
  • The inorganic waste, which consists of bad quality plastics and used cloth pieces, can be processed as Refuse Derived Fuel (RDF). This material has a calorific value of more than 2,500 kJ/kg.
  • This can be used to generate steam energy, which can be converted into electric energy.

A well-planned plant

  • The waste-to-energy plants usually accept the RDF material generated in organic composting plants.
  • They also segregate the wet and inorganic material near the plant, convert organic waste to compost, and inorganic waste to energy.
  • About 50 tonnes of RDF generate 1 MW of power, which indicates that the plant at Bidadi has been appropriately designed.

A permanent solution

  • Handling inorganic waste that is not fit for recycling has always been a challenge.
  • At present, these high-calorific materials are landfilled or left unhandled in waste plants and cause fire accidents.
  • Attempts to send this material to cement kilns have not fructified.
  • The proposed plant can source 600 tonnes per day of this RDF and generate 11.5 MW of power equivalent to 2.4 lakh units of power per day.
  • This will reduce the dependence on unscientific landfills, reduce fire accidents, and provide a permanent solution to recover value from inorganic waste.

Challenges

  • Needed a good demonstration model – Over the last decade, several Indian cities have been trying to set up such plants but a good demonstration model is yet to be established.
  • Nature of waste – Technology suppliers are international organizations who struggle with the change in quality and nature of waste generated in Indian cities. A few plants in India have stopped operations for this reason.
  • The plants require fine inorganic material with less than 5% moisture and less than 5% silt and soil contents, whereas the moisture and inert content in the mixed waste generated is more than 15%-20%.
  • The sticky silt and soil particles can also reduce the calorific value.
  • Economic cost per unit of electricity – The other big challenge for this plant is the power tariff which is around ₹7-8 KwH which is higher than the ₹3-4 per KwH generated through coal and other means.

Way forward

  • For the successful running, the plant needs to ease the challenge of handling inorganic waste, the efficiency of organic waste processing/ composting plants.
  • With the increasing waste generation in the coming years, there is a need for more such plants which are environment friendly. 

Back2Basics: Refuse-derived fuel (RDF)

  • Refuse-derived fuel (RDF) is a fuel produced from various types of waste such as municipal solid waste (MSW), industrial waste or commercial waste.
  • It is selected waste and by-products with recoverable calorific value can be used as fuels in a cement kiln, replacing a portion of conventional fossil fuels, like coal, if they meet strict specifications.
  • Sometimes they can only be used after pre-processing to provide ‘tailor-made’ fuels for the cement process.
  • RDF consists largely of combustible components of such waste, as non-recyclable plastics (not including PVC), paper cardboard, labels, and other corrugated materials.
  • These fractions are separated by different processing steps, such as screening, air classification, ballistic separation, separation of ferrous and non-ferrous materials, glass, stones and other foreign materials and shredding into a uniform grain size, or also pelletized.
  • This produces a homogeneous material which can be used as a substitute for fossil fuels in e.g. cement plants, lime plants, coal-fired power plants or as a reduction agent in steel furnaces.
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