The Government of India sets emission standards as a means to limit the levels of pollution from industrial sources. The minimum national standards for emissions have been notified for over 100 industries/activities, this also includes emission standards for air pollution from brick kilns.
Air pollution can be defined as the presence of toxic chemicals or compounds in the air, at levels that pose a health risk. These chemicals or compounds could be in a gaseous form (e.g. carbon monoxide, sulphur dioxide, etc.), or in a solid form (as particulate matter suspended in air).
Emission standards are developed through an elaborate process which usually takes several years. The process starts at the Central Pollution Control Board (CPCB), where draft standards are developed. Usually a detailed sector study by an independent consultant, along with inputs from industry and experts, forms the basis for the draft standards. The draft standards are then sent to the Ministry of Environment, Forest and Climate Change (MoEFCC), which reviews the standards and puts them for public consultation. The standards are also reviewed by the Law Ministry before they are notified. These are minimum national standards, but the State Pollution Control Boards (SPCBs) have the authority to set tighter standards if required.
The State Pollution Control Boards (SPCBs) have the main responsibility for the implementation of the emission standards.
India has emission standards for three types of brick kilns – Bull’s Trench Kiln, Down-Draft Kiln and Vertical Shaft Kiln. There are no emissions standards specifically for Clamp Kilns. The emission standards specify the maximum concentration of Particulate Matter in the flue gases in milligram/normal cubic metre (mg/Nm3), and the minimum chimney height in metre (m).
Type of Kiln |
Capacity |
Limiting concentration of Particulate Matter (mg/Nm3) |
Minimum Chimney Height (m) |
|
Natural Draft |
With fan operating with minimum draft of 50 mm WG |
|||
Bull’s Trench Kiln |
Small |
1000 |
22 |
12 |
|
Medium |
750 |
27 |
15 |
|
Large |
750 |
30 |
17 |
Down-Draft Kiln |
Small |
1200 |
12 |
NA |
|
Medium |
1200 |
15 |
NA |
|
Large |
1200 |
18 |
NA |
Vertical Shaft Kiln |
Small |
250 |
11 |
NA |
|
Medium |
250 |
14 |
NA |
|
Large |
250 |
16 |
NA |
The complete emission standards can be downloaded from
http://moef.gov.in/legis/ep/543_E.pdf.
In large brick producing countries like China and South Africa, the emission standards for brick kilns are more stringent. In South Africa, the emission standards for “new” brick kilns (excluding clamp kilns) for particulate matter emission are at 50 mg/Nm3, while for “existing” brick kilns (excluding clamp kilns) are at 150 mg/Nm3. Similarly, in case of China, the proposed emission standards for “new” brick kilns (drying and firing) are at 50 mg/Nm3, while for “existing” brick kilns (drying and firing) are at 100 mg/Nm3. The emission standards for brick kilns in the developed countries of Europe and North America apart from being more stringent, cover many more parameters. For example, the standard in USA covers emission limits for acid gases, mercury, and particulate matter.
The existing emission standards for brick kilns were notified in 2009. The process of revising the emission standards for brick kilns started in 2010. MoEFCC has till now put two versions of draft emission standards for public comments, once in 2015 and recently in 2018. The draft standards which were put for public comments in March 2018, propose to make the emission standards stringent by reducing the limiting concentration of Particulate Matter to 250 mg/Nm3 (normalized at 4% CO2) for several types of brick kilns, that includes, Bull’s Trench Kilns, Induced/High Draft Kilns, Hoffmann Kilns, Tunnel Kilns, Down-Draft Kilns, Vertical Shaft Kilns, and Zigzag Kilns.
After taking into account the public comments, the new emission standards are expected to be announced during 2018.