waste-to-wealth-sustainable-processing-of-municipal-solid-waste-summary

Context: With an ever increasing population and rapid pace of urbanization, India is facing a huge challenge of waste management. 

More on the news:

  • The volume of waste is projected to rise from the present 62 million tonnes to about 150 million tonnes by 2030. 
  • Indiscriminate dumping of garbage at the current rate without appropriate scientific treatment, would impose a huge requirement of landfill area per year. 
  • This necessitates the importance of scientific solid waste management in today’s context.

Municipal Solid Waste generation in India:

  • Studies suggest that the Municipal Solid Wastes generated in India mostly consists of a large fraction (> 50%) of organic wastes
  • Unscientific disposal of organic waste produces greenhouse gas (GHG) emissions and other air pollutants.
  • The ineffective processing of MSW also is the root cause of many diseases as the dumped landfills transform into Contamination Hubs for Pathogens, Bacteria and Viruses. 
  • The most commonly used processing "composting" also does not yield impactful economic returns for the entrepreneurs as it requires more land space, more labour, pasteurization for effective disinfection and has restricted utilization due to presence of heavy metals. 

Steps taken for Waste Management in India:

  • New Technology: The CSIR-CMERI developed Municipal Solid Waste Processing Facility has not only helped achieving decentralized decimation of solid wastes, but has also helped create value-added end-products such as dry leaves, dry grass etc. 
  • The Solid Waste Management Rules (SWM) 2016: The rules prescribed by Union Ministry of Environment, Forests and Climate Change (MoEF&CC), Government of India, mandates source segregation of waste to channelize the waste to wealth by recovery, reuse and recycling. 

Different methods/technologies used for Waste Management:

  • Plasma arc gasification process
    • The plasma gasification process uses electricity to generate a high temperature plasma arc (above 3000°C) inside the plasma reactor which converts the waste into syngas. 
    • The produced syngas when passed through a series of gas purification systems consisting of catalytic converter, redox reactor, cyclone separator, is ready for use in gas engines for generation of electricity.
    • The residual ash can be mixed with cement for preparation of recycled bricks for usage in construction. 
    • By this eco-friendly solid waste management in which large volume reduction of waste up to 95% is possible. ’.
    • Shortcoming: However, this technology is not economically viable as energy requirements for waste treatment using this technology is very high. 
  • Biomass Waste Disposal:
    • Biomass waste such as dry leaves, dead branches, dry grass etc. are disposed of by first shredding it to suitable size followed by mixing with the slurry of the biogas digester. 
    • This mixture is feedstock for briquette, which is utilized as fuel for cooking. 
    • These briquettes are also being utilized in gasifiers for production of syngas which can be utilized in gas engines for generation of electricity. 
    • The ash produced from burning briquettes is mixed with cement and water in an appropriate proportion for production of bricks which is used for construction work.
  • Polymer Waste Disposal
    • The polymer waste consisting of plastics, sanitary waste etc. is being disposed of through two main processes i.e. pyrolysis and plasma gasification. 
    • In the pyrolysis process, the polymer waste is heated to a temperature of 400 – 600°C in an anaerobic environment in presence of suitable catalyst. 
    • The volatile matter from the polymer waste comes out as a result of heating which on condensation gives pyrolysis oil. 
    • The non-condensed syngas and crude pyrolysis oil after purification are reused for heating purposes and it helps in obtaining self-sustainability. 
    • The solid residue known as char is mixed with the biogas slurry for production of briquette.
  • Sanitary Waste Disposal
    • The sanitary items including masks, sanitary napkins, diapers etc. are disposed-off utilizing high temperature plasma.

Significance of sustainable Solid Waste Management: 

  • Zero-Waste and Zero-Landfill Ecology: The technology of decentralized MSW and its sustainable processing opens-up the opportunities to realise the dream of generating 100 GW Solar Power.
  • Source of Job Creation: through both process-engagement and manufacturing, which can help support the MSEs, Start-Ups and numerous Small Entrepreneurs across the Nation.

Source: https://pib.gov.in/PressReleseDetail.aspx?PRID=1667099