Taming the ash: Strategies for fly ash management in India

The problem of fly ash from coal plants in India and recommended solutions

A fly ash dam near NTPC in Korba (Image: India Water Portal Flickr)

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Updated on:

20 May 2024, 10:31 am

8 min read

India is heavily reliant on coal for its energy needs, with coal-fired power plants contributing significantly to the country's electricity generation. However, this dependency comes with environmental and health challenges, one of the most pressing being the management of fly ash. Fly ash, a byproduct of coal combustion, poses severe risks if not managed properly.

India is the second-largest producer of coal in the world, and coal-fired power plants account for around 70% of its electricity generation. Consequently, the country produces a massive amount of fly ash annually. Furthermore, as per CEA (2023) Indian coal is of low grade with ash content ranging from 24% to 63%, compared to imported coal which has a lower ash content of 3% to 20%.

Consequently, a large quantity of ash is generated at coal/lignite-based thermal power stations in the country, requiring substantial areas of valuable land for disposal. In 2021-22 alone, India generated approximately 226 million tonnes of fly ash. Despite significant efforts to utilise this waste, a substantial portion remains unutilised, leading to various environmental and health hazards.

Fly ash particles, being very fine, can become airborne and contribute to air pollution. Inhalation of these particles can cause respiratory issues and other health problems. Fly ash contains toxic metals such as arsenic, lead, and mercury, which can exacerbate these health risks.
Improper disposal of fly ash can lead to the contamination of surface and groundwater. Fly ash contains heavy metals that can leach into water sources, posing a risk to aquatic life and human health. Incidents of fly ash pond breaches have led to the contamination of rivers and lakes.
When fly ash is used as a fill material or is improperly disposed of on land, it can lead to soil degradation. The toxic metals in fly ash can reduce soil fertility and negatively impact agricultural productivity.
Fly ash disposal requires significant land area. The establishment of ash ponds and landfills for fly ash storage not only consumes valuable land resources but also poses risks of land contamination and reduced land usability for other purposes.

Exposure to fly ash can cause several health issues:

Inhalation of fine fly ash particles can lead to respiratory issues such as asthma, bronchitis, and other lung diseases.
Studies have linked exposure to fly ash with cardiovascular diseases due to the presence of heavy metals and other toxic substances.
Long-term exposure to fly ash, particularly due to the presence of carcinogenic substances like arsenic, can increase the risk of cancer.

The Indian government has implemented several measures to manage fly ash. The Ministry of Environment, Forest, and Climate Change (MoEFCC) has mandated the use of fly ash in construction activities, such as in the production of cement, bricks, and road construction. Additionally, power plants are required to ensure 100% utilisation of fly ash within a specified timeframe.

However, despite these regulations, challenges in enforcement, lack of infrastructure, and economic factors have impeded the effective utilization and management of fly ash. The government has implemented a comprehensive strategy to tackle this issue, focusing on minimising environmental impact and promoting fly ash as a valuable resource. A key pillar of this approach is a strong regulatory framework. The amendments to Fly Ash Notification of 2021 mandates 100% fly ash utilisation from coal-based thermal power plants. This regulation prohibits the harmful practice of dumping fly ash in landfills or water bodies, pushing industries towards eco-friendly utilisation methods.

The Environmental Protection Act of 1986 provides the overarching legal foundation for these regulations. Additionally, government agencies like the Central Pollution Control Board (CPCB) and State Pollution Control Boards (SPCBs) play a crucial role in monitoring and enforcing fly ash utilisation rules. They have the authority to impose penalties on non-compliant industries.

Promoting fly ash utilisation is another key strategy. The government offers financial incentives, such as subsidies or tax benefits, to industries that incorporate fly ash into their products. This helps make fly ash a more attractive and cost-competitive alternative to virgin materials. Dedicated missions and task forces have also been established to explore innovative ways to utilise fly ash and create a robust market demand for these products. Investments are being made in developing infrastructure for fly ash storage, transportation, and processing. This could involve building silos for storage, creating rail networks for transportation, and establishing processing facilities to enhance the usability of fly ash in various applications.

The focus of fly ash management in India is on its beneficial use. The government encourages using fly ash in the construction sector for manufacturing bricks, blocks, tiles, and even concrete. In 2020, “only 9.94 percent of the total fly ash utilised is used for the production of building materials like bricks/blocks/tiles. According to calculations, around 2800 fly ash units are present in the country producing 6.65 billion bricks annually,” as per a report by the Development Alternatives. Still, this has the potential to not only reduce reliance on natural resources like clay but also promote a more sustainable and resource-efficient construction industry. Fly ash also has the potential for land reclamation and even for specific agricultural applications, subject to proper testing and regulations to ensure safety and effectiveness.

However, challenges remain. Creating a consistent market demand for fly ash-based products is crucial for sustained utilisation. Additionally, developing a robust and cost-effective transportation network for fly ash is essential, especially for areas far from power plants, as per the report of the committee to encourage the utilisation of fly ash in construction of hydro power projects, 2020. Finally, stringent monitoring and enforcement of regulations are needed to ensure responsible fly ash management and prevent illegal dumping practices.

By addressing these challenges and continuing to implement these strategies, the Indian government aims to transform fly ash from a waste product into a valuable resource. This approach has the potential to significantly reduce pollution and promote a more circular economy in construction and infrastructure sectors.

NTPC's fly ash management

The National Thermal Power Corporation (NTPC), India's largest energy conglomerate, has been at the forefront of fly ash management. NTPC has installed silos for storing dry fly ash at their coal-based thermal power plants. They have also developed rail loading facilities to facilitate bulk transportation, which is considered a cost-effective option. NTPC actively promotes using fly ash in various construction materials like bricks, blocks, tiles, and even ash-based building materials with proper branding initiatives. NTPC has supplied millions of tonnes of fly ash for such projects. This helps reduce reliance on natural resources and creates a market for fly ash.

Fly ash can be used for reclaiming mine voids, creating a sustainable solution for land management and potentially enabling future afforestation efforts. NTPC has achieved significant success in fly ash utilisation through various initiatives:

Cement manufacturing:
NTPC supplies fly ash to cement manufacturers, which use it as a raw material in cement production. This has not only reduced the need for virgin raw materials but also enhanced the quality of cement.
Road construction:
Fly ash from NTPC's plants has been used in the construction of highways and rural roads. This has demonstrated the potential of fly ash in infrastructure development.
Fly ash bricks:
NTPC has promoted the use of fly ash bricks in construction projects. These bricks are more durable and eco-friendlier compared to traditional clay bricks.

NTPC's efforts in fly ash management have been recognised. Their power plants have received awards for efficient fly ash utilisation, showcasing their commitment to responsible management practices. While NTPC prioritises utilisation, complete elimination of fly ash disposal might be difficult. There might be situations where the quality of fly ash or limitations in transportation infrastructure make utilisation impractical. Stringent regulations and proper monitoring are crucial to ensure safe disposal of fly ash when utilisation is not possible.

The state of Maharashtra has implemented a comprehensive fly ash utilization policy, which mandates the use of fly ash in construction activities within a 300-kilometer radius of coal power plants. Originally, fly ash could only be used within a 100-kilometer radius of the power plant that generated it. This policy has led to increased demand for fly ash in the construction sector, promoting its effective utilisation. The primary objective is to completely eliminate the need for disposal of fly ash generated by thermal power plants within the state. This policy looks to promote fly ash as a valuable alternative material (manufacturing bricks, blocks, tiles, wall panels, and even in cement production) in various construction projects.

The details regarding specific incentives or penalties for using fly ash are unclear at this time. The policy also mentions the potential role of dispute settlement committees to address any conflicts that may arise related to fly ash usage, but specifics on how these committees would function are not readily available. The Maharashtra Pollution Control Board (MPCB) is expected to play a key role in overseeing and enforcing the fly ash utilisation policy. Collaboration with local authorities such as District Magistrates will likely be crucial for ensuring compliance, especially in areas with a high concentration of brick kiln operations.

United States:

The U.S. Environmental Protection Agency (EPA) promotes the beneficial use of coal combustion residuals, including fly ash, through regulations and guidelines. The federal Resource Conservation and Recovery Act (RCRA) exempts fly ash from hazardous waste disposal regulations. The use of fly ash in concrete is widespread, contributing to the reduction of carbon emissions. There are also no mandatory national regulations for disposal. In the absence of strong federal rules, states have their own regulations, which can vary significantly. While some states may have stricter regulations, the overall approach is considered less stringent compared to how hazardous waste is typically handled.

European Union:

The European Union (EU) takes a different approach to fly ash compared to the USA. Here, the focus is on promoting the beneficial use of fly ash and ensuring its safe management when disposal is necessary. Member states have adopted various strategies to promote the use of fly ash in construction, soil stabilisation, and other applications

EU waste legislation prioritises reusing and recycling fly ash, diverting it from landfills. This applies to fly ash generated from both coal and biomass combustion. Fly ash itself is not automatically classified as hazardous waste. Instead, its specific properties determine the regulations that apply. The EU actively encourages using fly ash in construction materials, such as concrete. If fly ash meets specific quality standards, it can be a valuable and sustainable replacement for some raw materials. However, regulations are still in place to ensure safe management if fly ash cannot be beneficially used.

These regulations might involve setting limits on certain elements in fly ash intended for use in agriculture or outlining specific protocols for storage depending on its classification. Overall, the EU prioritises a balanced approach - promoting the safe and sustainable use of fly ash as a resource while ensuring proper management when disposal is unavoidable.

The problem of fly ash from coal plants in India is a significant environmental and health challenge. However, with concerted efforts from the government, industry, and other stakeholders, it is possible to mitigate the adverse impacts and harness the potential benefits of fly ash. Enhanced utilisation in construction, investment in research and development, strict regulatory enforcement, public-private partnerships, and awareness programs are key strategies that can drive effective fly ash management. The success stories from NTPC and Maharashtra, along with international best practices, provide a roadmap for achieving these goals.

Contamination, Pollution and Quality