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  • 26 September, 2022

  • 7 Min Read

Fly Ash

Fly Ash

  • The National Green Tribunal (NGT) has emphasised the urgent need for Chhattisgarh to increase the use and disposal of fly ash.



  • 15 state, national, and privately owned electricity generating units are concentrated in Korba, Chhattisgarh, makes the situation much more dire.

What is Fly Ash?

  • Burning pulverised coal in thermal power plants produces fly ash as a byproduct.
  • Clay, feldspar, quartz, and shale, mineral impurities in coal, fuse in suspension during combustion and float out of the combustion chamber with the exhaust gases.
  • Fly ash, which are spherical glassy particles, are formed as the fused material cools and solidifies as it rises.
  • Ash concentration ranges from 30-45% in low-grade coal used in thermal power generation. The low ash level of the imported high-grade coal is between 10% and 15%.
  • Since low-grade coal makes up the majority of the fuel used in thermal plants, a lot of ash is produced, which needs a lot of space to be utilised as a landfill or disposal ponds.
  • Depending on the chemical and physical characteristics of the fly ash as well as the cement, all fly ashes display cementitious qualities to varied degrees.
  • Fly ash is composed of silica dioxide (SiO2), aluminium oxide (Al2O3), ferric oxide (Fe2O3), and calcium oxide(CaO) in significant concentrations.
  • Uses: It is a top-notch material for producing building supplies such as hollow blocks, mosaic tiles, and bricks.
  • Fly ash bricks can significantly contribute to soil preservation.
  • There are a number of environmentally beneficial ways to use fly ash so that it doesn't contaminate the air and water.
  • It involves filling low-lying areas and mines, building roads, dams, and embankments, and using fly ash in the production of cement and ready-mix concrete.

Significant environmental and health risks

  • The majority of the heavy elements present in fly ash, such as lead, nickel, chromium, cadmium, and arsenic, are poisonous by nature.
  • Due to direct exposure, mangrove destruction, drastically reduced crop yields, groundwater pollution, etc., they seep into the surrounding soil and can cause respiratory problems, asthma, and other allergies in addition to entering food chains.

Uses of fly ash

  • Some of the Portland cement found in concrete can be replaced with fly ash. It is good for the environment since it requires less Portland cement, which is a major source of CO2 in concrete.
  • Currently, fly ash is used in the production of bricks, blocks, and tiles and has a long history of use in the construction industry.
  • The usage of fly ash bricks in construction projects 500 kilometres from thermal power plants is now required by the Union Government.

A new rule for thermal power plants' use of fly ash (TPPs)

  • Thermal Power Plants (TPPs) must guarantee fly ash use at 100% within three to five years.
  • The current regulations allow TPPs to stagger the full utilisation of fly ash over a four-year cycle.
  • As part of the "polluter pays principle," it also instituted fines of Rs 1,000 on non-compliant plants beginning on April 1 of the following year.
  • According to the widely accepted "polluter pays" principle, individuals who cause pollution should be responsible for paying the costs associated with controlling it in order to protect public health and the environment.
  • According to this, the Central Pollution Control Board's (CPCB) allocated account will receive the fines that have been collected.

Initiatives Developed

  • The government has created a web portal for tracking fly ash generation and utilization statistics of thermal power plants as well as a mobile application termed "ASH TRACK" to enable 100% ash utilisation by all coal-based thermal power plants.
  • Ash-Park has created a programme to raise awareness about the use of fly ash and its products on numerous platforms.
  • NTPC roles : The National Thermal Power Corporation (NTPC) has built a transportation system that makes it more affordable to move fly ash from power plants to cement manufacturers in large quantities.
  • The fly ash that NTPC generates will be turned into a by-product that will provide income.
  • One example of this is the development of geopolymer and nano aggregates from leftover fly ash for use in building buildings and roads.


  • Programs to raise awareness: The NGT ordered that Chhattisgarh's common people be made aware of the exploitation of fly ash for its own purposes.
  • Follow instructions: The state authority shall direct all carriers to follow instructions provided by the federal and state governments for the secure carriage of fly ash and bottom ash.
  • If the authorities received a report about an illegal disposal, strict action should be taken.
  • Pond ash supply: Thermal power plants should provide pond ash to brick producers and road construction projects.
  • Promoting R&D to improve power plant efficiency would also aid in lowering ash generation.

Read Also: Carbon Watch

Source: Down To Earth

  • 13 February, 2021

  • 5 Min Read

Fly Ash

Fly Ash

  • Definition: It is a byproduct of the burning of coal in electric power generating plants.
    • It is called fly ash because it is transported from the combustion chamber by exhaust gases.
    • It is collected from the exhaust gases by electrostatic precipitators or bag filters.
  • Composition: Fly ash includes substantial amounts of silicon dioxide (SiO2), aluminium oxide (Al2O3), ferric oxide (Fe2O3) and calcium oxide (CaO).
  • Properties:
    • Exhibit cement like properties.
  • Uses: It is used in concrete and cement products, road base, metal recovery, and mineral filler among others.
  • Harmful Effects: Fly ash particles are toxic air pollutants. They can trigger heart disease, cancer, respiratory diseases and stroke.
    • When combined with water they cause leaching of heavy metals in ground water.
    • It also pollutes the soil, and affects the root development system of trees.

Source: TH

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