Industrial development has created many opportunities for growth. However, it has also led to a huge increase in environmental pollution. One sector that plays a major role in pollution is the chemical industry, especially the dye and dye intermediates industry. Colourful products such as clothing, leather goods and plastics rely on dyes. However, the manufacture of dyes releases harmful chemicals into the air, water and land. In India, the government has been serious about protecting the environment. Strict regulations have been put in place to control pollution from industries. An important law for this is the Environment (Protection) Act, 1986. Under this Act, several rules have been made to set limits on emissions and discharges from industries. The Environment (Protection) (4th Amendment) Rules, 2014, mainly focused on the dye and dye intermediate industry, lay down strict standards to protect the environment.

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Overview of the Environment (Protection) Act, 1986

The Environment (Protection) Act, 1986, one of India’s most important environmental laws, was introduced in 1984 as a response to the Bhopal gas tragedy. Its main purpose is to provide a framework for protecting and improving the environment in the country. The Act empowers the Central Government to take decisive action against industries and individuals causing damage to the environment, including strict rules on pollution control. It covers a range of areas including industrial emissions, waste management and vehicle pollution. 

The Act empowers the government to make regulations to control hazardous wastes, emissions and discharges, ensuring that industries meet environmental standards. In addition, the Act enables the government to conduct inspections, test equipment, and enforce environmental standards. The Environment (Protection) Act is considered a “basic law” under which many rules have been framed, including the Environment (Protection) Rules, 1986. These regulations are regularly updated to address emerging environmental concerns, ensuring that the laws remain relevant and effective in protecting the environment.

Also Read: What are the Standards for Emission or Discharge of Environmental Pollutants for Man-Made Fibres (Synthetic)?

The Role of Dyes and Dye Intermediate Industry in Environmental Pollution

The dye and dye intermediate industry is a major part of the chemical sector. Dyes are used in textiles, leather, paper, food, cosmetics, and plastics. Dye intermediates are the raw materials used to make dyes. However, there is a dark side to the industry. Paint production uses many chemicals, heavy metals, and organic compounds. During manufacturing, harmful gases are released into the air. Liquid waste containing toxic substances is often dumped into rivers and lakes. Solid waste, if not handled properly, can contaminate land and groundwater. Some common pollutants from the dye industry include:

• Sulphur oxides
• Acid mist (HCl)
• Ammonia
• Chlorine
• Heavy metals like chromium, copper, and lead

Water pollution is especially concerning. Dye factories discharge wastewater that is often black in color, contains suspended solids, and contains toxic substances, including heavy metals such as chromium, copper, and lead. When this wastewater is released into rivers and lakes without treatment, it can damage aquatic ecosystems and contaminate drinking water sources. Additionally, improper disposal of solid waste can lead to land and groundwater pollution, further endangering human and environmental health. To mitigate these impacts, strict pollution control measures must be implemented. These are managed by CPCB (Central Pollution Control Board) or by SPCB (State Pollution Control Board). These include proper wastewater treatment, safe solid waste handling, and effective air emission control. Sustainable practices are essential to balance industrial development with environmental protection and public health.

Emission Standards for Dye and Dye Intermediate Industry

Air emissions from dye manufacturing processes can include harmful gases such as sulphur oxides, ammonia, hydrochloric acid mists, and chlorine. To reduce the impact of these emissions on air quality, the amendment specifies the following emission standards for the dye and dye intermediate industry. These standards aim to reduce the harmful effects of gaseous pollutants such as sulphur oxides, hydrochloric acid mists, and ammonia, which can cause respiratory problems, environmental acidification, and other health issues. Chlorine, a toxic gas, can be harmful if inhaled and pose a serious threat to the environment. The following limits apply to air emissions from the dye industry:

Note: The chimney height of all process vents must be at least two meters above the shed or building where the equipment is installed.

Effluent Standards for the Dye and Dye Intermediate Industry

Effluent discharge is another major environmental concern in the dye industry. These discharges can include toxic chemicals, suspended solids, and organic pollutants, all of which can seriously affect water quality and aquatic ecosystems. The amendment outlines the following standards for waste discharge. The following table shows the limiting concentrations for various parameters in dye and dye intermediate industry effluents.

Additional Terms:

• The temperature of the receiving water should not increase by more than 5 °C due to waste materials.
• Chloride and Sulphate standards for inland surface water are strict.
• For land disposal, the sodium absorption ratio (SAR) should not exceed 26.
• Groundwater must be monitored using piezometers, especially when discharging to the ground.
• Storage tanks must be designed to prevent groundwater contamination.

Also Read: What are the Standards for Emission or Discharge of Environmental Pollutants for Sugar Industry?

Regulations for Waste Incineration in the Dye Industry

Some of the waste from dye manufacturing must be incinerated. The regulations set out detailed requirements to ensure the safe and complete burning of hazardous substances.

Emission Standards for Captive Incinerators

Operational Requirements

• All values corrected to 11% oxygen on a dry basis.
• CO₂ concentration in tail gas must not be below 7%.
• Incinerator temperature must be 850 ± 25°C (primary chamber) and 950°C (secondary chamber) for <1% halogenated waste. 850 ± 25°C (primary) and 1100°C (secondary) for >1% halogenated waste.
• Minimum gas residence time in secondary chamber is 2 seconds.
• Scrubbers must not be used as quenchers.
• Residual ash must contain less than 3% TOC and 5% Loss on Ignition (LOI).
• Chimney height must be at least 30 meters.

Effluent Standards for Incinerator Wastewater

• Scrubber and floor wash water must be treated to meet the same standards listed under effluent limits.
• Total Dissolved Solids (TDS) in floor wash water must not exceed 1000 mg/l above raw water levels.

Stormwater Management

• Stormwater must not mix with wastewater.
• It must be collected separately using drains and stored in an HDPE-lined pit with a capacity to hold 10 minutes of rainfall.

Conclusion

The dye and dye intermediate industries play an important role in the economy. However, without proper environmental controls, it can cause severe damage to air, water, and land. Recognizing this, the Government of India amended the Environment (Protection) Rules in 2014 to set strict standards for emissions, effluent and waste management for this industry. Proper height of chimneys, strict limits on gases like SOX and HCl, strict control of wastewater discharge and safe incineration of waste are essential steps to protect the environment. Industries should strictly follow these regulations to achieve sustainable growth. Adhering to these standards not only helps the environment but also ensures that the industry operates responsibly and earns the trust of the public. Cleaner production and better waste management are key to a greener future.