Out of the total estimated brick units, more than 60,000 are generally small-scale brick producers operating clamp firing technology, producing approximately 50,000 to 10,00,000 bricks per year. A variety of fuels such as coal, firewood, various types of agricultural residues, dung cakes, etc., are used in clamps. Such fuels have low energy efficiencies as most of the heat in the flue gases, fired bricks and kiln structure remains unutilized.

The brick kilns are classified into three categories according to the production capacity as per Gazette Notification on ‘Emission Standards for Brick Kilns’ under the Environment (Protection) Act, 1986:

The TARA EcoKiln is an appropriate technology solution to conventional Bulls Trench Kiln and open clamps. It was first introduced in India in 1996 at Datia, Madhya Pradesh. After initial adaptation to Indian soil conditions, it is now being disseminated in the states of Orissa, Chattisgarh, Rajasthan and Madhya Pradesh. More than 100 EcoKilns are now under operation in the above states.

The advantages of the TARA EcoKiln are:

The TARA EcoKiln technology economizes on fuel costs, with savings between 30 to 50% when compared with other common brick-firing technologies such as clamps or Bulls trench kiln with movable chimneys.

The construction of a TARA EcoKiln requires very little land. The building of multiple shaft production units further enhances the ratio of land use to production output. The TARA EcoKiln has been designed to be fired only with coal (or with coal dust), thus deforestation of rural areas can be controlled. Additionally, if a TARA EcoKiln is operated as per the recommended conditions, emissions are reduced by approximately 90% compared to common traditional brick-firing technologies.

Brick production using TARA EcoKiln technology is a profitable business and the overall initial investment is low (considering investment in permanent land). As the fired bricks in a TARA EcoKiln are produced in 24 hours, the working capital required is very little.

Unlike other brick-firing technologies where uniform quality of fired bricks is not possible due to heat losses, in TARA EcoKiln, the batches of fired bricks produced are 95% uniform in quality, segregated into a single class. Compared to the BTK, where second and third grade bricks are produced in significant quantities, a TARA EcoKiln produces mostly first-grade bricks. Breakage and wastage can be limited to even less than 5% through stable operation of the TARA EcoKiln and quality green brick making.

The TARA EcoKiln can be operated through the year and even during the monsoon, subject to availability of dried green (unfired) bricks. Weather factors are only a minor influence because a roof protects the kiln.

Through its use of internal fuel and measures of minimization of heat loss, TARA EcoKiln provides an enormous potential of coal savings which can be traded for providing carbon revenue. Entrepreneurs will be entitled for cash benefits, whereas the workers will benefit from on-site sanitation facilities and insurance against accidents.

TARA EcoKiln is an inherently fast firing process. Unlike conventional firing process of BTKs or clamps, where the firing time is measured in days (14-21 days), the TARA EcoKiln firing process is completed within 24–36 hours. Thus, the time for uniform heat distribution within the green brick is short. To ensure uniform heat distribution within the entire cross section of the mass, there is a need to provide heat from within the green brick also, apart from the external heat given. This heat distribution within the green brick is achieved through ‘internal fuel’.

Internal fuels generally comprise medium calorific value materials (1000–2000 KCal/kg) mixed with the soil during the green brick formation process. The various types of internal fuels recommended for use in the TARA EcoKiln are generally waste materials, e.g., boiler ash, sponge iron waste, bottom ash from thermal power plants, rice husk ash and other carbon-bearing wastes.

The advantages of using waste materials as internal fuel are:

The existing emission standards on brick kilns pertain only to annular kilns (BTKs and high-draught kilns) and were made before TARA EcoKiln emerged as a potential technology for firing bricks in India. Against this background, it was imperative to formulate new emission standards for TARA EcoKiln and relax the citing criteria for brick kilns, keeping in view the extremely low emission levels and reduced energy consumption.

The performance of VSBK can be compared with BTKs and other high-draught kilns. The important performance parameters of interest while comparing the environmental performance of brick kilns are:

There is some confusion regarding applicability of emission standards in brick kilns. Queries are received and clarifications issued time and again. The Emission Standards for Brick Kilns as notified (S. No. 74, vide GSR No. 176 (E), dated April 2, 1996) have some confusion regarding applicability. Queries are received and clarifications issued time and again. The Emission Standards for Brick Kilns as notified (S. No. 74, vide GSR No. 176 (E), dated April 2, 1996) are exclusively for Bulls Trench Brick Kiln. Emission standards notified for down draught kilns are in S. No. 61, vide GSR No. 475 (E), dated April 5, 1992. Emission standards proposed to Central Pollution Control Board for EcoKilns and are more stringent compared to all other brick firing technologies, are:

Guidelines for environmental performance of TARA EcoKiln

The set of guidelines which would help in further bringing down emission levels in TARA EcoKiln, as proposed to Central Pollution Control Board, are as under:

1. Use of internal fuel

Use of internal fuel during green brick moulding helps in reducing stack emissions, particularly particulate matter (PM).

Experiences in TARA EcoKiln operations have proved that boiler ash, sponge iron waste, fly ash coal powder can be used effectively as internal fuel in TARA EcoKilns.

The amount of internal fuel addition in green brick during moulding depends on the quality of soil and the desired quality of the fired product. It is generally observed that addition of internal fuel in soil varies between 3% - 10% by weight.

Bottom ash from thermal power plants can be used as an effective internal fuel in TARA EcoKilns, depending upon the soil quality.

2. Characteristics of external fuel

Low volatile content bituminous coal with low sulphur content is the preferred fuel for TARA EcoKiln. Use of fuel having volatile matter more than 25% results in higher emissions (soot, unburnt carbon and CO).

3. Ventilation at loading platform

Proper ventilation at the loading platform by providing sufficient openings on all the sides ensures good ventilation and reduces the exposure of workers to pollution.

Proposed pollution control guidelines for TARA EcoKilns

The rapidly industrialized states of Chattisgarh, Orissa and Jharkhand abound in all types of brick-firing technologies. In rural areas and district towns, traditional clamp firing technologies along with movable chimney BTKs are prevalent. In and around the capital and main cities, both fixed chimney and movable chimney kilns are in operation.

As per the energy and emission norms for brick-firing technologies, it is evident from the emission results that TARA EcoKiln is a vastly improved technology compared to the existing BTKs and traditional technologies. Rapid dissemination of TARA EcoKiln in all the above areas will certainly improve the environment by reducing the pollution levels and coal consumption in brick kilns, thus, saving natural resources. Adoption of TARA EcoKiln technology will also be using waste materials top soul energy both conserving.

Thus, the immediate need for the rapidly industrialized states is to relax the pollution control guidelines and consider waiver of Pollution NOC for TARA EcoKilns, because compared to other kilns, there is minimal pollution through this technology. This will not only help in faster adoption of pollution friendly technologies but also benefits the environment through lower carbon emissions and utilization of industrial waste materials.

Approvals from Regulatory Authorities

Realizing the environmental benefits of EcoKilns, approvals have been forthcoming from various regulatory agencies. The Building Material and Technology Promotion Council (BMTPC) has certified EcoKilns under its Performance Appraisal Certification Scheme (PACS).

In fulfillment of the assurance in the National Common Minimum Programme, Shri Mahabir Prasad, Union Minister for Small Scale Industries and Agro and Rural Industries, has announced a policy package for stepping up credit to micro, small and medium enterprises. This promotional package is projected to sustain economic growth of the country through small-scale industries thereby further generating employment.

The package states that for comprehensive and speedier development of clusters of micro and small enterprises, the existing guidelines of the Small Industries Cluster Development Programme (SICDP, to be renamed as ‘Micro and Small Enterprises Cluster Development Programme’ - MSECDP) will be reviewed to accelerate holistic development of clusters, including provision of Common Facility Centres, develop sites for new enterprises, upgradation of existing industrial infrastructure and provision of Exhibition Grounds/Halls and also for creation and management of infrastructure-related assets in the public-private partnership mode. The ceiling on the project cost will be raised to Rs.10 crore.

Under the Technology and Quality Upgradation Support, the Vertical Shaft Brick Kiln (VSBK) Technology will be promoted for adoption by MSEs engaged in manufacturing bricks to make them energy efficient and eco-friendly. For this, a one-time capital subsidy (limited to 30 per cent of the cost or Rs.2 lakh, whichever is less) will be provided to micro and small brick manufacturing enterprises.