Fly Ash

In News 

• Recently, the National Green Tribunal (NGT) made an urgent need to augment the utilisation and disposal of fly ash in Chhattisgarh.

About

• The situation in Chhattisgarh is even more critical because Korba is the hub of coal thermal power plants containing 15 state, central and private-owned electricity generating plants.

What is Fly Ash?

• About:
  • Fly ash is a by-product of burning pulverized coal in thermal power plants.
    • During combustion, mineral impurities in the coal (clay, feldspar, quartz, and shale) fuse in suspension and float out of the combustion chamber with the exhaust gases. As the fused material rises, it cools and solidifies into spherical glassy particles called fly ash. 
  • Low-grade coal used in thermal power generation carries 30-45% ash content. The high-grade imported coal has a low ash content of 10-15%. 
  • Since most of the coal used in thermal plants is low-grade, it generates a large quantity of ash which requires a large area as landfill or ponds for disposal.
  • All fly ashes exhibit cementitious properties to varying degrees depending on the chemical and physical properties of both the fly ash and cement.
• Composition:
  • Fly ash includes substantial amounts of silicon dioxide (SiO2), aluminium oxide (Al2O3), ferric oxide (Fe2O3) and calcium oxide (CaO).
• Uses:
  • It is an excellent material for making construction materials such as bricks, mosaic tiles and hollow blocks. 
  • Bricks made of fly ash can help conserve soil to a great extent.
  • There are several eco-friendly ways to utilize fly ash so that it does not pollute air and water.
    • It includes the use of fly ash in the manufacturing of cement, ready-mix concrete; constructing roads, dams and embankment, and filling of low-lying areas and mines.

Major Health and Environmental Hazards

• All the heavy metals found in fly ash like nickel, cadmium, arsenic, chromium, lead, etc—are toxic in nature. They leech into the surrounding soil and can enter food-chains, asthma and respiratory ailments due to direct exposure, destruction of mangroves, drastic reduction in crop yields, and the pollution of groundwater etc.

Utilization of Fly Ash

• Fly ash can be used as a replacement for some of the Portland cement contents of concrete. It is environmentally beneficial because it reduces the Portland cement, a major contributor of CO2, required in concrete.
• Fly ash is a proven resource material for many applications of construction industries and currently is being utilized in manufacturing of bricks/blocks/tiles.
• Union Government has made it mandatory for use of fly ash bricks in construction activities happening 500 km around thermal power plants.

New fly ash utilisation rule for Thermal Power Plants (TPPs)

• It is mandatory for Thermal Power Plants (TPPs) to ensure 100% utilisation of fly ash within three to five years. 
  • Existing provisions allow TPPs to fully utilise fly ash in a four-year cycle in a staggered manner. 
• It also introduced fines of Rs 1,000 on non-compliant plants under the ‘polluter pays principle’, taking into account utilisation targets from April 1 next year.
  • The ‘polluter pays’ principle is the commonly accepted practice that those who produce pollution should bear the costs of managing it to prevent damage to human health or the environment.
  • Under this, the collected fines will be deposited in the designated account of the Central Pollution Control Board (CPCB). 

Initiatives Taken

• Optimum utilization of fly ash: To facilitate 100% ash utilization by all coal based thermal power plants, a web portal for monitoring of fly ash generation and utilization data of Thermal Power Plants and a mobile based application titled “ASHTRACK” has been launched by the Government. 
  • Ash-park has developed, and awareness programme for utilisation of fly ash and its products conducted at various platforms.. 
• Roles played NTPC:  National Thermal Power Corporation (NTPC) has developed an infrastructure to transport fly ash from power plants in bulk to cement plants, at a cheaper cost.
  • NTPC intends to transform the fly ash it produces into a revenue-generating by-product.
  • It has developed geopolymer and nano aggregates from residual fly ash for use in the construction of roads and houses is a manifestation of this.

Suggestions/ Way forward

• Awareness programmes: NGT directed that awareness programmes needed to be organised for common people in Chhattisgarh about the utilisation of fly ash for its own use.
• Comply with guidelines: The state authority must instruct all transporters to comply with guidelines issued by the central and state governments for safe transportation of fly ash and bottom ash.
• Notice on vehicles: Every fly ash transporter must write on their vehicles that if any illegal dumping of fly ash by this vehicle is seen, please inform the collector.
• Strict action should be taken if any complaint regarding illegal disposal was received by the authorities.
• Supply pond ash: The thermal power plants should supply pond ash for road construction projects and brick manufacturers.
• Promoting R&D for increasing the efficiency of power plants will also help in reducing ash generation. 

Source: DTE