Dust Control: Balancing Health and Sustainability

With governmental norms for reduction of dust emissions and technological advancements for dust control, the Indian cement industry is geared up to reduce the environmental and health hazards of dust emissions and to make cement processing more sustainable.

Dust emissions from cement plants can have significant environmental and health impacts, as well as affecting nearby communities. Cement plants generate dust during the production process, which can include raw material grinding, blending, preheating, kiln processes, clinker cooling and cement grinding.
Dust emitted from cement plants is a significant environmental and health concern in India, where the cement industry is a major contributor to air pollution. According to the Central Pollution Control Board (CPCB), the cement industry is one of the top five polluting industries in India, and dust emissions are a major contributor to this pollution. To address this issue, the Indian government has set emissions standards for the cement industry under the National Ambient Air Quality Standards (NAAQS) and the Environment Protection Act (EPA). The standards set limits on particulate matter (PM) emissions, which include dust particles, from cement plants.
The Indian cement industry has also implemented measures to reduce dust emissions such as using modern filters and control technologies, optimising production processes and providing training to employees on dust control practices. However, despite these efforts, the industry still faces challenges in meeting emissions standards, particularly for smaller, older plants. To further address the issue of dust emissions, the Indian government has launched initiatives such as the National Clean Air Program (NCAP) and the Swachh Bharat Abhiyan (Clean India Mission), which aim to reduce air pollution and improve environmental cleanliness.
“We have addressed fugitive emissions in the clinker tunnels at the cement plant where the clinker is stored in the silos and a lot of dust comes out when it is discharged onto the conveyor belts. Conventionally cement plants have used back filters which are connected to exhausts located besides the discharge point, but it is common knowledge that these systems were not entirely effective, resulting in a lot of dust in the tunnels. It also made it very difficult to get maintenance done in these tunnels because anyone who enters would have to breathe dust and that is a health hazard,” says Venkatesh Ravula, CEO, DCL Bulk Technologies.

DUST EMISSION HAZARDS
Dust hazards are a significant concern in Indian cement plants due to the high levels of dust generated during production processes. Exposure to cement dust can have negative health effects on workers, including respiratory issues such as bronchitis and asthma, as well as skin and eye irritation. Some of the major sources of dust hazards in Indian cement plants include raw material handling, clinker production, and cement grinding processes. Dust can also be generated during maintenance activities such as cleaning, repair, and replacement of equipment.
To address these hazards, Indian cement plants have implemented a variety of measures, including using personal protective equipment (PPE) such as respirators, dust masks, and goggles, as well as installing dust collection and control systems. In addition, training programs for employees on the safe handling and control of dust are often provided. The Indian government has also established regulations and guidelines to protect workers from dust hazards in the workplace. The Factories Act, 1948 and the Mines Act, 1952 set standards for occupational health and safety, including measures to control dust emissions and protect workers from exposure to hazardous materials.
“For achieving effective prevention and control of potential fugitive emission sources in cement manufacturing plants, specific requirements along with guidelines have been evolved by the central government. For the Indian cement industry, the Ministry of Environment Forest and Climate Change has notified the norms for reduction of dust emission from cement plants, which includes Particulate Matter, SOx and NOx. The notification clearly defines the limits for above mentioned emissions, particulate matter should be <30 milligram, SOx should be <100 milligram, NOx should be <1000, 800, 600 milligrams. It depends on the age of the plant or we can say that on the commissioning date of the plant,” says Anil Gupta, Technical Head – Nimbahera Plant, JK Cement.
It is important for Indian cement plants to prioritise the implementation of dust control measures and training programmes to protect the health and safety of their workers and nearby communities.

FILTRATION TECHNIQUES AT CEMENT PLANTS
Cement plants use various types of dust filtration equipment and techniques to control dust emissions and improve air quality. Some of the common methods used include:

• Bag filters: Bag filters are commonly used in Indian cement plants to capture dust particles from the production process. These filters consist of bags made of fabric material that trap dust particles as air passes through them.
• Electrostatic precipitators (ESPs): ESPs are another type of dust filtration equipment used in Indian cement plants. They use an electrostatic charge to attract and trap dust particles.
• Cyclones: Cyclones are a type of mechanical separator that can be used to remove larger dust particles from the air. They work by creating a cyclonic effect that causes particles to be separated from the air stream.
• Wet scrubbers: Wet scrubbers are used in some Indian cement plants to capture and remove dust particles from the air. They work by spraying water onto the particles, causing them to stick to surfaces and be removed from the air.
• High-efficiency particulate air (HEPA) filters: HEPA filters are highly efficient filters that can remove up to 99.97 per cent of particles as small as 0.3 microns. They are commonly used in cleanrooms and other sensitive environments.

In addition to these filtration techniques, Indian cement plants also use various operational and maintenance practices to reduce dust emissions, such as regular equipment cleaning and maintenance, optimising production processes to reduce dust generation, and providing training to employees on dust control practices.
“Modern mining equipment is deployed with dedicated dust separation systems. Electric/hydraulic equipped mining machinery is also being used to minimise the dust. The cement industry has been modernised by introducing specific dedusting equipment used in the production, transport, and storage processes. The installation is equipped with specific filters (bag filters or electrostatic filters). This has reduced the flue gas emission and amount of dust released into the atmosphere. The main dedusting machine is the state-of-the-art bag filter, which is available and guarantees a maximum emission of 10 mg/Nm3,” says Pankaj Kejriwal, Whole Time Director, Star Cement.
“Truck mounted road/area sweeping machines are also operated to clean the dusty area. High pressure water spray systems are used to clean the tyres of vehicles moving inside the plant to minimise the fugitive dust emission,” he adds.

DUST CONTROL NORMS IN INDIA
The Indian government has established norms and regulations to control dust and fugitive emissions from cement plants. Some of the key norms include:

• National Ambient Air Quality Standards (NAAQS): The NAAQS set by the Central Pollution Control Board (CPCB) establish limits on air pollutants, including particulate matter (PM) emissions, from all industries, including cement plants.
• Environment Protection Act (EPA): The EPA provides guidelines and regulations for controlling emissions from industries, including the cement industry.
• Cement Industry (Prevention and Control of Pollution) Rules, 2013: These rules set specific emission limits for cement plants in India. For example, the rules specify that PM emissions should not exceed 30 mg/Nm3 for dry kilns and 50 mg/Nm3 for wet kilns.
• Ministry of Environment, Forest and Climate Change (MoEFCC) guidelines: There are guidelines for the installation of pollution control equipment in cement plants, including bag filters, electrostatic precipitators and wet scrubbers.
• State pollution control boards: State pollution control boards are responsible for enforcing the norms and regulations related to dust and fugitive emissions at cement plants.

Cement plants in India are required to comply with these norms and regulations to minimise their impact on the environment and public health. Failure to comply can result in fines, legal action and suspension of operations.

Exposure to cement dust may lead to health hazards for workers like respiratory issues, and skin and eye irritation.

It is important for cement plants to prioritise reducing dust emissions to protect both the environment and nearby communities from potentially harmful effects. The future of dust emission in the Indian cement industry is likely to see a continued focus on reducing emissions to improve air quality and protect public health. The industry is under increasing pressure to adopt cleaner technologies and more sustainable production processes, and there is a growing demand for environmentally friendly cement.
To meet these challenges, Indian cement plants are likely to adopt a range of strategies and technologies to reduce dust emissions, such as using low-emission fuels, implementing more efficient production processes, and investing in advanced dust filtration and control technologies. There is also likely to be increased focus on recycling and reusing waste materials to reduce environmental impact.
The Indian government is also expected to continue to play an active role in regulating dust emissions from the cement industry. This may include strengthening existing regulations and standards, as well as developing new policies and initiatives to encourage the industry to adopt more sustainable and environmentally friendly practices.
Overall, while the Indian cement industry faces significant challenges in reducing dust emissions, there are also many opportunities for innovation and progress. With continued investment in new technologies and sustainable production processes, the industry can help to create a cleaner, healthier and more sustainable future for all.

–Kanika Mathur