GS Paper III

News Excerpt:

Delhi's biomining project to clear landfill sites is likely to miss the 2024 deadline. 

More about the news:

  • According to Municipal Corporation of Delhi (MCD) officials, the ongoing biomining project at two of the Capital’s three landfill sites Ghazipur and Bhalswa are likely to miss the latest deadline of 2024 to clear the sites.
    • The addition of fresh waste and weather challenges at the Ghazipur and Bhalswa sites is slowing down the biomining process.
  • MCD launched the biomining project to clear its three oversaturated landfill sites in July 2019 on directions of the National Green Tribunal.

Current status of the project:

  • At present MCD is in line to clear only the Okhla landfill in December this year, a deadline set in March 2023, as no fresh waste is being dumped on this location. 
  • In a progress taken report submitted to the Delhi Pollution Control Committee on February 17, 2024, the MCD admitted that the three landfill sites still have 17.2 million tonnes of legacy waste, due to which the deadline to clear the Ghazipur landfill has been pushed back from 2024 to 2026, while the Bhalswa landfill will be cleared by 2025.

What is Biomining:

  • Biomining is a process of separating various components of legacy waste such as plastic, paper, cloth, sand, and bricks by passing them through trommel machines, which act as cylindrical rotating sieves.
  • It is the process of using microorganisms (microbes) to extract metals of economic interest from rock ores or mine waste. 
  • Biomining techniques may also be used to clean up sites that have been polluted with metals.

What metals are currently biomined?

  • Most current biomining operations target valuable metals like copper, uranium, nickel, and gold that are commonly found in sulfidic (sulfur-bearing) minerals. 
  • Microbes are especially good at oxidizing sulfidic minerals, converting metals like iron and copper into forms that can dissolve more easily. 
    • Other metals, like gold, are not directly dissolved by this microbial process, but are made more accessible to traditional mining techniques because the minerals surrounding these metals are dissolved and removed by microbial processes.

What are the environmental risks of biomining?

  • Most current biomining operations use naturally occurring microbial communities. 
    • Because these types of organisms are already common in the environment, the risks from the release of the microbes themselves into the local environment are considered to be relatively small. 
  • The greatest environmental risks are related to leakage and treatment of the acidic, metal-rich solution created by the microbes, which is similar to the acid mine drainage from some abandoned mines. 
  • This risk can be managed by ensuring that biomining is conducted under controlled conditions with proper sealing and waste management protocols.

Significance of Biomining:

  • Biomining holds significant promise for sustainable resource recovery and environmental remediation. 
  • It offers a more environmentally friendly alternative to traditional mining, reducing the need for extensive excavation and minimizing environmental disruption. 
  • Biomining can help recover valuable metals from low-grade ores or mine waste that would otherwise be uneconomical to extract, thus contributing to resource efficiency and conservation. 
  • Biomining can be used to clean up sites contaminated with metals, offering a cost-effective and efficient solution for environmental remediation. 


Overall, biomining has the potential to play a key role in promoting a more sustainable and environmentally conscious approach to mining and waste management. But delay in Delhi's landfill sites biomining process will affect Delhi's pollution free goal.

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