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Promoting sustainable and efficient brick-making practices in India through ICIMOD–PCBA collaboration

Zig-zag technology promises cleaner and more efficient burning of fuel, resulting in better-quality bricks
Published: 21 Aug, 2023
⏲ 6 minutes Read

Assam, the largest economy in India’s northeast region, is home to some 2,000 brick kilns, many of which are unregistered and operate using traditional methods such as the ‘Fixed Chimney Bull’s Trench Kiln’ (FCBTK) and some clamp burning which are energy inefficient and polluting. As the brick-firing season kicks off every year, brick kilns on the outskirts of Guwahati, Assam’s state capital, belch out thick black plumes, made up of harmful particulate and gaseous air pollutants. The Pollution Control Board of Assam (PCBA) is keen to reinforce the central Indian government’s revised emission standards for the brick sector, which requires the brick sector to adopt the cleaner zig-zag technology as opposed to traditional methods. Zig-zag technology promises cleaner and more efficient burning of fuel, resulting in better-quality bricks.

Of the 2,000 brick kilns operating in Assam, hardly 20 have made the government-mandated switch to zig-zag technology. This technology involves stacking unfired bricks in a zig-zag pattern; when the bricks are fired, the air plumes are regulated in a zig-zag pattern, allowing a longer interaction with the stacked bricks and better heat transfer. This results in more efficient combustion, cleaner emissions, and ultimately, better-quality bricks. By adopting the cleaner zig-zag technology, brick entrepreneurs can save up to 20% on coal, and yield up to 90% ‘class A’ bricks which are top quality and demand the highest price, while also reducing emissions.

In March 2023, a team from ICIMOD comprising air quality specialists partnered with PCBA to organise a training on zig-zag technology for state pollution board officials and brick entrepreneurs from Assam, and other northeastern Indian states, Arunachal Pradesh, Meghalaya, and Tripura. At the three-day training, we introduced technologies and practices that can help replace traditional and polluting methods in brick kilns. The training covered theoretical and practical aspects, including raising awareness on the economic benefits of zig-zag technology; reducing fuel consumption and emissions; and operating the zig-zag technology, including firing, stacking, fuel selection, and application. In addition to ICIMOD and PCBA resource persons, two master trainers and brick entrepreneurs from Nepal led the training – Bikram Ratna Bajracharya and Rajkumar Lakhemaru – with the Nepal Federation of Nepal Brick Industries (FNBI).

Bikram Bajracharya demonstrates brick firing to participants at the training.
Bikram Bajracharya demonstrates brick firing to participants at the training.

“Done right, zig-zag kilns belch out white smoke, as opposed to black smoke from traditional kilns,” says Rajkumar Lakhemaru, a veteran brick entrepreneur with 40 years of experience under his belt.

bharai brick stacking in a zig zag pattern
Rajkumar Lakhemaru demonstrates “bharai” brick-stacking in a zig-zag pattern at the HMB brick unit.

White smoke, which is indicative of more complete combustion, is often considered ‘cleaner’ than black smoke – a sign of incomplete combustion, resulting in lower heat and more visible pollutants. In the specific context of brick kilns, white smoke is preferable to black; however, we we must remain mindful that all combustion of fossil fuels pollutes the air, and white smoke does contain pollutants.

Notwithstanding, zig-zag technology is proven to be more efficient, thus reducing the amount of fuel burned and the time that combustion takes place. Since adopting zig-zag technology, Rajkumar Lakhemaru has not looked back since.

Besides imparting theoretical lessons, the two master trainers also demonstrated correct zig-zag brick-stacking and brick-firing techniques in the field at the HMB brick unit in Chandrapur, Assam. Though the HMB unit was an early adopter of zig-zag technology for their kiln, they still struggle to produce quality bricks or reduce coal consumption.

Pankaj Gupta, owner-operator of HMB brick unit and a participant at the training confides that their experiences with the zig-zag approach have been sub-optimal as they lacked the technical know-how in operating the technology.

automated brick moulding machine
Pankaj Gupta (right), owner-operator at HMB brick unit demonstrates the automated brick moulding machine to Sagar Adhikari, Air Pollution Analyst at ICIMOD (left).

He says, “The training was a definite eye-opener for us. Our fire masters and brick-stacking supervisors observed the right techniques in-person and will be able to train other brick workers. Through this intervention, we will be able to benefit fully from the technology.”

In view of the new legislation/directive from the central government of India and PCBA, brick entrepreneurs must retrofit existing FCBTK to zig-zag technology soon. Consequently, participating brick entrepreneurs actively sought inputs on retrofitting existing kilns to zig-zag, stacking and firing techniques. They appreciated experience sharing by FNBI master trainers and reached out to ICIMOD resource persons for training materials on the technology.

ICIMOD’s Senior Atmospheric Environment Specialist, Bidya Banmali Pradhan, shares that this model of south-south learning worked well in Nepal and Pakistan. Both Lakhemaru and Bajracharya have experienced the technology work first hand and are the best available promoters. With support from ICIMOD, they trained fellow brick entrepreneurs in 10 cities across Pakistan in 2018.

“This model to promote zig-zag technology was a resounding success in Pakistan. Therefore, we are scaling this approach in Assam,” she adds.

The workshop was a great success, with enthusiastic participation from the brick entrepreneurs, and participants commended PCBA and ICIMOD for the training. The local media also covered the event, helping to spread awareness about the importance of sustainable and efficient brick-making practices.

“This training is a good step forward in raising awareness on the need to switch to the cleaner zig-zag approach,” says Shantanu Kumar Dutta, Member Secretary, Pollution Control Board, Assam. He adds, “We will work with ICIMOD to develop guidelines for brick entrepreneurs to adopt the technology.”

Overall, the workshop and training session was an important step towards promoting sustainable and efficient brick-making practices in Assam and beyond. Our collaboration with the PCBA and the brick entrepreneurs, has laid the foundation for future partnerships that will continue to promote these practices and create a cleaner, more sustainable brick-making industry.

Promoting cleaner bricks in the HKH region.

The training was organised under the framework of the Himalayan Resilience Enabling Action Programme (HI-REAP) funded by the UK Government’s Foreign, Commonwealth & Development Office (FCDO). Immediately after the training, we organised a national stakeholder dialogue with brick and tile manufacturers in India to address social challenges in India’s brick sector and training on internal fuel application for brick manufacturers in Nepal to reduce coal consumption.

ICIMOD PCBA FNBI All India Brick Tile Manufacturers Federation IIT–Guwahati and Central Pollution Control Board
Resource persons from ICIMOD, PCBA, FNBI, All India Brick & Tile Manufacturers Federation, IIT–Guwahati, and Central Pollution Control Board at the opening ceremony


Communication and digital media engagement officer, RECOFTC


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