Introduction
The Union Ministry of Environment, Forests and Climate Change (MoEF&CC) recently released a new notification clarifying the compliance dates for the complete utilisation of fly ash by Thermal Power Plants (TPP). The latest move by the ministry has brought the topic of fly ash, its utilisation, and impact on the environment back into focus.
Understanding Fly Ash
Fly ash is an unwanted unburnt residue that results from coal combustion in a coal thermal power plant. It’s produced during the burning of coal in a furnace and collected using electrostatic precipitators to minimize fugitive dust emissions. The collected fly ash is converted into a wet slurry and then transported to scientifically designed ash ponds through slurry pipelines.
Composition and Properties of Fly Ash
The composition of fly ash depends upon the type of coal being burnt. It may contain elements like Beryllium, Arsenic, unburnt Carbon, Silicon Oxides, Dioxins, aluminium oxide, ferric oxide, calcium oxide etc. These components, however, make it a severe environmental pollutant. While fly ash resembles Portland cement, they are chemically different. A visible characteristic of fly ash is its cementitious properties, meaning it hardens when mixed with water.
Potential Uses of Fly Ash
Despite its environmental implications, fly ash is used in several industries due to its unique properties. It finds application in concrete and cement products, road base, metal recovery, and as a mineral filler among others. Innovations in construction technologies have also led to the use of fly ash bricks.
The Harmful Impact of Fly Ash
Fly ash is a acknowledged as a toxic air pollutant. It is linked with a range of health issues including heart disease, cancer, respiratory diseases, and stroke. When combined with water, fly ash causes the leaching of heavy metals in groundwater which can pollute the soil and affect the root development system of trees. Under-utilisation of this by-product has led to a massive accumulation of 1,670 million tonnes of fly ash.
Initiatives Related to Fly Ash
In 2021, the National Thermal Power Corporation (NTPC) Limited invited Expressions of Interest (EOI) for the sale of fly ash. As part of collaboration efforts, NTPC has tied up with cement manufacturers around the country to supply fly ash. Also, schemes like Pradhan Mantri Awas Yojana (Urban) has focused on new construction technologies such as using fly ash bricks that are innovative, and environmentally friendly. Some state governments have introduced their fly ash utilisation policies, with Maharashtra leading the way. The government has also launched a web portal and a mobile application named “ASHTRACK” for monitoring fly ash generation and utilisation. Furthermore, the Goods and Services Tax (GST) rates on fly ash and its products were reduced to 5%.
Questions from Previous UPSC Civil Services Examinations
Previous years’ UPSC Civil Services Examinations included questions related to fly ash and its implications. One such question from 2015 asked candidates to identify correct statements about fly ash. Another question from 2011 focused on the emissions from coal combustion at thermal power plants.
With increasing environmental concerns, it is crucial to understand the significance of fly ash, along with its potential applications and harmful effects. This awareness is not only critical for those preparing for competitive exams like the UPSC, but also for individuals in research, policy making, and general public concerned about climate change.
