During this dry season, the Real-time Air Quality Index (AQI) of Dhaka frequently crossed the 300 mark, indicating the 'hazardous' condition of Dhaka's air. In terms of air pollution, Dhaka nowadays competes with Delhi and Lahore to rank worst in the world.
Among other factors such as construction work, toxic vehicle emissions, and industrial air pollution, brick kilns are the top air polluters not only in Dhaka, but also in six other major cities of Bangladesh, especially during dry season when brick production peaks, according to a five-year-long survey by Department of Environment (DoE), which was done two years back.
While this is true for the most brick kilns in the country, there are interesting stories of overcoming the challenge of keeping brick production cleaner.
Kapita Auto Bricks Ltd, established in 2009, has seen success in this regard. The company has been earning carbon credits against its greenhouse gas (GHG) emission reduction. And Kapita is doing it by setting up a Hybrid Hoffman Kiln.
A Hoffmann kiln, or a ring oven, is a massive circular or elliptical brick-built oven used for producing bricks and tiles. The kiln was patented in Germany by Frederick Hoffmann in 1858.
This type of kiln allows for a uniform burning while using less fuel. Fire is made to travel in a circular path through the stacked bricks in this kiln while new green bricks are loaded and fired bricks are unloaded from the chambers in a continuous fashion. This allows such kilns to operate 365 days a year.
Later, the Chinese developed a modified version of the Hoffmann Kiln to fit local needs, which, instead of a circular shape, has a rectangular one with two parallel tunnels connected by curved tunnels at both ends. These are called Hybrid Hoffman Kiln (HHK).
Unlike fixed chimney brick kilns, HHKs do not emit the hot flue gases directly to the atmosphere. Instead, the exhaust gas is first diverted to the 'drying chambers' where green bricks get dried before the final baking in the kiln.
Particulate matters generated during combustion -- the prime air polluter of Dhaka and other cities in the country -- get deposited on green bricks at this stage, cutting the particulate emission by 75% or more compared to fixed chimney kilns (FCK).
Due to efficient combustion, HHKs also use less fuel.
"The exhaust gas of fixed chimney kilns carries unburnt coal particles that damages vegetation and harms livestock. But in an HHK, coal is almost fully burnt, so we can save around 40% coal," Chaklader Reza Alam, the managing director of Kapita Auto Bricks Ltd (KAB), told The Business Standard.
This emission cut allows KAB to earn carbon credits.
Under a Clean Development Mechanism (CDM) project titled "Improving Kiln Efficiency in the Brick Making Industry in Bangladesh", Industrial and Infrastructure Development Finance Company (IIDFC) made deals with the World Bank, the Government of Denmark and Asian Development Bank (ADB) to facilitate carbon trading. Nine HHK units under the CDM project umbrella cut 30,000 to 32,000 tonnes of GHG annually.
Kapita Bricks saves 8,000 tonnes of GHG each year, the company's General Manager Eugene Rodrigues informed.
Under the carbon trade arrangements, emission reducing industries from developing countries can earn carbon revenue from industrialised countries. According to IIDFC, Bangladesh has earned $1.5 million through the project involving the brick industry so far, starting in 2014.
Critics say that emission trading schemes provide industrialised nations a chance to continue emitting GHG in exchange of a little price and fail to contribute to the goal of net emission reduction.
However, the carbon revenue may motivate industries in the developing countries to adopt greener technology.
Despite fuel efficiency and the opportunity to receive carbon revenue, there are only around 25 HHKs in the country against more than 8,000 fixed chimney and zigzag kilns. Apparently, the biggest barrier with installing HHKs is the cost.
"The machinery and construction of factory etc is costlier than FCK and zigzags. Also, more land is required for the storage of coal, soil and finished product. While it takes Tk1 crore to Tk1.5 crore to set up an FCK, construction of an HHK only 40 km away from Dhaka will require around Tk40 crore," said Reza Alam.
Despite being interested, many people cannot convert their traditional kilns to HHKs because of the high setup cost, he added.
HHKs serve the environmental cause better, but it was not the only motivation for KAB to set up one.
"Apart from the environmental aspect, KAB wanted to create a better product. There is a middle market between 'Bangla' brick and ceramic brick. Our plan was to produce an appropriate product for that market," explained Reza Alam, whose father, Chaklader M Alam, started the company.
Although the brick produced at KAB costs Tk2.5 to Tk3 more than traditional brick, building with these bricks requires less mortar and saves time of brick masons due to the uniform shape of the brick, Reza said.
During a recent visit to KAB campus in Dhamrai, the smooth surface of the bare wall of an under-construction building inside the campus demonstrated the superior quality of the brick produced at the factory.
A supervisor at the construction site said there was no plan to plaster the outer walls. There was no need, indeed.
Is it the HHK that gives this smooth look to the brick?
Reza answered, "There are other factors as well, such as giving the soil a one-year maturing time to get rid of unwanted properties, crushing and mixing it three times to give it a fine quality, skilled workers, quality of coal, and team effort etc".
"Looks are important, but more than looks, other qualities of bricks are more important to a lot of developers. Whereas regular bricks have a strength of 2,500 to 2,800 psi, KAB's brick has a psi of 5,000 to 6,500," said Reza.
So, is it possible to make profit with all the expensive HHK and associated auto brick machineries without getting carbon payment?
"To me, it is 100% viable," stated Reza with confidence. "I consider the carbon credit funds only as a bonus. Our financial calculation is based on the price of raw materials, cost of production, and sales. Since 2014, our profitability each year has been larger than the year before, without the carbon credit."
Getting carbon credit is a matter of pride, the managing director of the brick manufacturing company said.
"Our industrial clients also keep a copy of our carbon credit certificate so they can show the compliance monitoring agencies that they bought bricks from a green company that receives carbon credit," said Reza adding, "It is a big marketing aspect for us."
Coming back to the need for more HHK-based brick factories, Reza Alam said that there is an annual demand for six billion bricks in the country with a 30% growth rate per year, and there is too small a number of HHKs to be able to sustainably produce this large amount of bricks.
He, therefore, underlined the need for green loans with lower interest rates so that more entrepreneurs can invest in setting up HHKs and contribute in the protection of the environment.
Although HHKs are a progressive means to reduce air pollution, the brick industry remains responsible for land degradation through removal of top soil.
Asked about his insight about shifting towards alternative building materials, Reza Alam admitted that there is a certain amount of risks involved in taking topsoil away as it does not get replenished by sediment carried by flood water like before.
"Our current demand for infrastructure, and hence, bricks, is more than what our top soil can give. So as a second part of our building construction product business, we are looking forward to producing a block made of fly ash, steam and a certain chemical," Reza Alam explained his future plan.
But for producing the steam, gas supply is essential for efficiency, Reza said. The problem is, getting a gas supply nowadays is hard, and for existing lines, gas pressure is often not appropriate for manufacturing the block.
Using coal is an option, but recycling the coal to reduce pollution is still a concern. Gasification of coal to create the steam is another option that Reza is currently considering.
"I am interested in this product because the polluting factor is very little, less space is needed to set up the factory, agrarian economy is not affected at all as no soil is removed, and what is more fascinating about it is that you can make products of different sizes with the same machine," said the managing director of KAB