Brick kiln

A brief fact about brick kiln in
Bangladesh: environment issue

ABSTRACT
Brick kiln industry is the emerging one sector in Bangladesh. This industry has
gotten momentum since 1980 when urbanization strategy was taken to develop
rural area through establishing upazila complex. Due to urbanization, the demand
for brick is increasing day by day. To keep pace with this huge demand large
numbers of kiln unit were established near cities and promising rural areas.
Bangladesh has about 6,000 authorized brickfields and numerous illegal ones.
(Bayron, 2009). A significant factor is that brick kilns are usually clustered near big
cities in different parts of Bangladesh. It should emphasize the need for energy
conservation and pollution control in brick industries of Bangladesh. Some of the
technical options are discussed in this literature as an effective means of energy
conservation and pollution control.

Introduction
Brick kiln industry is emerging one in Bangladesh. This industry has gotten
momentum since 1980 when urbanization strategy was taken to develop rural area
through establishing upazila complex. The government of the Peoples Republic of
Bangladesh has been spending a huge amount of money to construct infrastructures
of upzilas and connecting roads and culverts. At the same time per capita income
increased $50 in 1970 (BBS 1972) to $ 1800 in 2014 which changes lifestyle,
attitude and choice of rural people as well as middle-class urban people. Urban
people prefer dwelling house for their own to rented one. Resulting emerges of real
estate business as an industry. On the other hand, rural people prefer pacca
dwelling house to semi- pacca and tin shed house. Influence of all developmental
activities it creates a huge demand for bricks. About 4 to 5 lakh tons of bricks
required to meet up this demand every year. This demand also increases day by day.
To keep pace with this huge demand large numbers of kiln unit were established
near cities and promising rural areas. So, brick kiln becomes an indispensable part
of our life. This large numbers of brick kiln emit major pollutant to air among all
other sources of pollution. That is the contribution of the brick kiln to air pollution is
higher. Exposure to air pollution is the main environmental threat to human health
in towns and cities even promising local area. Numerous brick-making kilns
operating in the dry season are one of the major sources of air pollution in cities. A
significant factor is that brick kilns are usually clustered near big cities in different
parts of Bangladesh. The brickfields are typically small independent units and
operate 24 hours during the dry season. They are located near towns or major
construction sites. In Dhaka district, it is almost cover some part of Gabtali, Savar,
Ashuliya, Keraniganj, Narshingdi, Gazipur and Manikganj. In Dhaka, there are
around 4,500 brick kilns in operation, producing about 9.0 billion bricks per year.
The largest brick making zone is on the north of Dhaka city, where more than 1,000
brickfields are situated, therefore, the parts of the city in the immediate vicinity of
the brick-field clusters have serious air pollution problems.

Discussion
Bangladesh is the 8th largest populous country with 160 million people. Each year
3, 00,000 to 4, 00,000 rural people migrate in Dhaka. The existing people, as well as
new migrants, need housing facility. At present in our country, the annually
required shelter varies from 3 lakh to 5.5 lakh units. Bangladesh will need to
construct approximately four million new houses annually a to accommodate the
growing population (Rahim, 2011). Rapid urbanization in the country has created a
booming construction industry and spurred the production of 8.6 billion, bricks
each year, with demand for the bricks rising at an annual rate of about 5.28 percent
(UNDP, 2011).
Bangladesh has about 6,000 authorized brickfields and numerous illegal ones.
(Bayron, 2009). The illegal brickfields do not have proper resources to run and
proper license to keep the fields on the track. The brickfields are typically small
independent units and operate 24 hours during the dry season. They are located
near towns or major construction sites; i.e., Gabtali, Savar, Ashuliya, Keraniganj,
Narshingdi, Gazipur and Manikganj. In Dhaka, there are around 4,500 brick kilns in
operation, producing about 9.0 billion bricks per year. The largest brick-making
zone is on the north of Dhaka city, where more than 1,000 brickfields are situated
(Khan, 2009). The existing technology for firing kiln are fixed chimney kiln (FCK)
and bull's trench kiln (BTK); though the last one is banned in Bangladesh
contributes 16% of production. The main raw materials used in brick kilns to dry
bricks are firewood and coal. In case of unavailability of coal brick fields (about 33%)
use firewood illegally to dry bricks. As a result of a large number of trees like Keora,
chaila, sundari, mehguni, bain etc. are being felled indiscriminately. If Bangladesh
maintains its current economic growth rate, continued use of this outdated brick-
firing technology would raise the level of greenhouse gas emissions to 8.7 million
tons by 2014 by using coal for the purpose. Furthermore, using of firewood in kilns
also results in significant deforestation and this wood still account for about 25
percent of the fuel used in Bangladesh's brick making kilns every year. The

department of environment said that the 4,000 brick kilns burn nearly 20 lakh tons
of coal and another 20 lakh tons of wood every year to meet the demand for 400 to
1200 tons of fuel (Roy, 2004). Inquiry suggested that many brick manufacturers set
up their kilns near forests with the intention to plain the forests illegally. Another
investigation reveals that workers of the brick field not only cut many trees but also
built dikes to stop water from entering its premises during high tide which results in
a sudden flood in the adjacent areas. Beside this, people working in the brickfield
because of deadly air and poor water quality have to accept a subhuman life. On an
average, the workers receive 80 BDT every day for over 12 hours of extremely hard
or hazardous work (Akter, 2010).
In Bangladesh there are three major sources of air pollution; i.e. (a) vehicular
emission, (b) small industries like brick kilns and other biomass inclinators and (c)
re-suspended road dust (Ferdausi, Vaideeswaran & Akbar, 2008). In manufacturing
seasons of brick, October to March, pollution goes to peak in Dhaka and around the
city depending on the monsoonal rains. In the brick kilns, smokes are wafting out of
the chimneys polluting the environment of the area. According to the Brick Kiln
Control (amended Act -2001), there must be no establishment of brick kilns within a
three kilometer radius of human inhabitation as well as fruit garden. But lack of
proper monitoring, brickfields have sprung up like mushrooms and the situation has
created a serious threat to environment and biodiversity while the people in the
neighboring areas face health hazards and fertility of farms is going down (The Daily
Star, 2011).

Causes of pollution
The pollution is caused by following ways
1. The poor quality of fuel.
2. Improper design of chimneys and combustion chamber.
3. Abusing exiting law: Despite the existence of laws, thousands of brick kilns,
most of which are coal-based fixed chimney kilns (FCK), are using from wood
to even tires to burn bricks, thereby polluting air severely. Many brick kilns,
according to reports, have been operating just without the approval of the
concerned authorities. The existing law stipulates that no brickfield can be
set up within three kilometres of a residential or a forest area; however, the
law is more on paper.
4. Back dated technology: Special traits (all aspects) of FCK technology are:
cheap and simple technology; green brick making is a manual process; no
permanent roof is constructed over the baking area and this is why heat loss
is significant while more coal is needed that means the technology is highly
energy inefficient; environmentally damaging as black smoke from the kiln is
released to the atmosphere through chimney; operational only during the
dry season and as such job at this type of kiln is temporary; final product
(brick) is not of high quality; investment is less than a billion; most of the
FCKs are constructed on rented lands; working condition is poor; and child
labour is very much common in the FCKs and the like.

CHALLENGES
Pollutants such as oxides of carbon, sulfur dioxides oxides of nitrogen, (CO2, CO,
NOX, NO and SO2) all are hazardous gases, volatile organic components and
particulates matter (PM), are produced and emitted from the brickfields. The PM
concentration appears to be low but it is expected to have a long-term massive
impact on global environments as well as on human health.
The particulate matter consists of dust, smoke, fumes, and fly ash. It was found that
particulate matter was a major pollutant in that region. Moreover even under well-
controlled processes worldwide, 0.2 microgram toxic equivalents of each to of brick,
which is very harmful to lives.
Fig.1 Sources of fine particulate pollution in Dhaka City
1. Effects of Particulate Matter (PM)
Particulate is one of the major pollutants emitted from Brickfields. Two types of
particulate, settable and suspended are produced; both are harmful to human health
and the surrounding environment.

a. Effects on human health
At high concentration suspended particulate matter poses health hazards to humans,
particularly those susceptible to respiratory illness.
b. Effects on plants and animals
Dry brick kiln dust appears to cause little damage if deposited on a leaf surface, yet
in the presence of moisture; such dust imparts damage and consequential growth
inhibition to plant tissues. Dust coating of leaves reduces photosynthesis and the
increased plugging of stomata reduces plant growth. Animals who eat plants coated
with the particulate matter may suffer from some ill effects.Brickfield also causes
crop loss corrosion of metallic objects and soil fertility.
c. Effects on materials
Particulate matter can damage materials by soiling clothing and textiles, corroding
metals (especially at relative humidities above 75%), eroding building surfaces, and
discolouring and destroying painted surfaces. For example, at particulate matter
concentrations ranging from 130 to 180 μg/m3 and in the presence of SO2 and
moisture, corrosion of steel and zinc panels can be three to four times greater than
in areas close to background particulate levels (60 μg/m3).
d. Effects on global temperature
Brick kilns expose huge quantity of greenhouse gas to air which contributes to
increasing global temperature. A study shows that the rate at which global
temperature increases continues, the one-third area of Bangladesh will disappear at
the end of the century.
2. Effects of Sulfur Oxides
SO2 emission is one of the concerns of environmental pollution by the brick
industry. It may have some significant impact on the environment and human health.
SO2 is one of the principal pollutants, which gets emitted from brick industry.
Sulfuric acid (H2SO4), Sulfur dioxide (SO2) and sulfate salts tend to irritate the

mucous membrane of the respiratory tract and foster the development of chronic
respiratory diseases, particularly bronchitis, pulmonary emphysema and asthma.
Individuals who suffer from chronic respiratory diseases may experience coughing
and a difficulty in breathing when the SO2 concentration rises from 0.1 to 0.2 ppm.
Also, SO2 is the primary component of acid deposition and damages the ecosystem
both directly and indirectly.
3. Effects of oxides of nitrogen (NO2)
NO can combine with haemoglobin to reduce the oxygen-carrying capacity of the
blood. NO concentrations are generally less than 1.22 (1ppm) is the ambient air and
thus is not considered as a health hazard. This irritates the alveoli of the lungs; the
response of the human respiratory system to short-term exposure to nitrogen
dioxide. Other ill effects include heart tightness, barring eyes, and headaches. People
with asthma and bronchitis are particularly vulnerable to these effects. Recurrent
exposure to high concentration of NO.
4. Effects of CO2
CO2 at present ambient levels has little if any effect on property, vegetation or
materials. At high concentrations, it can seriously affect human aerobic metabolism,
owing to its high affinity for haemoglobin, the component of the blood responsible
for transport of oxygen. CO reacts with the haemoglobin (Hb) of blood to form
carboxyhemoglobin (COHb) thus reducing the capability of blood to carry oxygen.
Hence, more blood needs to be pumped to deliver the same amount of oxygen,
resulting in strain on the heart. This is fatal when inhaled at very high
concentrations, and heart disease patients, pregnant women, infants, senior citizens
and those especially susceptible to respiratory problems may exhibit symptoms of
poisoning at a relatively lower concentration.

WAY OUT
Brick kilns are one of the major sources of emission in Bangladesh. There is wide
scope to improve the traditional brick manufacturing process of Bangladesh. The
major issues in environmental improvement involve the increasing of the
combustion efficiency of existing kilns and upgrading kilns to newer and more
efficient process design, upgrading the design of the chimney so that it emits less
hazardous pollutants and the overall process technology upgrading. Process
technology upgrades are usually capital intensive. Combustion efficiency
improvement can be achieved with relatively lower costs in many kilns. Promoting
cleaner production in this industry requires extensive understanding of work with
brick making technical changes. Several low-cost ways to increase efficiency and to
reduce waste and pollution in brick making are described below.
Stack fuel around bricks to facilitate preheating:
Solid fuel is mixed with the bricks throughout the kiln, either as sawdust mixed into
the brick mass or as fuel channels in different levels of the kiln. By doing this, a
combustion zone can be generated in the kiln that gradually moves upwards, using
the residual heat in the lower, already burnt bricks for preheating of combustion air.
The residual heat in the flue gases is used for drying and preheating of the higher
levels of crude bricks.
Improve brick drying before firing:
Extended drying time reduces fuel requirements. Even drying throughout brick
stacks reduces defective firing of bricks.
Improve airflow control:
Stopping air leaks and controlling the kiln opening size allows better control of
airflow speed and direction to improve combustion.

Switch to propane or natural gas fuel:
If available and competitively priced, these fuels have significantly less emission and
can increase production quality and speed.
New kiln design:
Vertical shaft brick kiln allows increased production rate and significantly
decreased emissions through improved combustion airflow efficiency. Several kiln
designs have also proven to be relatively low-cost and much more efficient than
traditional ovens or kilns. Some newly developed technologies may be introduced in
Bangladesh. The Bull's Trench Kiln, which is common in Bangladesh, may improve
this technology by taking some measures. Most of the technology consists of the
movable metallic chimney, which can be replaced by the fixed chimney. A
gravitational settling chamber may be designed and set up at the chimney to reduce
suspended particulate in the flue gas passing through the chimney. The following
steps may be adapted to take necessary measures to upgrade the existing
technology.
 The traditional BTK technology could be upgraded by adding limestone
scrubbers to reduce sulfur dioxide emissions and filters for entrained
particulate removal.
 Mixing and pulverizing the fuel before combustion and adding insulation
would also result in higher energy efficiency. Fuels such as natural gas and
low sulfur coal could replace the current fuel mix of wood and poor quality
coal.
 A properly designed chimney of 120 feet height (as per the requirement of
the Department of Environment, Bangladesh) along with an integral
gravitational setting chamber should be provided.
 To supplement the chimney, the flue ducts are to be designed to provide the
least amount of resistance to the flue gases.

 Alternate building materials such as straw bales, block bricks, cement blocks
and reprocessed waste could also be employed to reduce the demand for
ceramic bricks.
 The properly designed chimney which provides required draught for
combustion fuel and transfer from cooling zone to firing zone and then to
pre-heating one.
 Gravitational settling chamber providing below the chimney which arrests
SPM.
 Space for valves providing in flue lines, which will fulfil the requirements of
factory acts.

Conclusion
Brick making is an energy-intensive process. It should emphasize the need for
energy conservation and pollution control in brick industries of Bangladesh. Some
of the technical options are discussed as an effective means of energy conservation
and pollution control. However, existing technologies are not energy efficient. On
the other hand, new technologies are not popular in Bangladesh and costly in terms
of initial investment. Following notes cannot be made from this study:
 If these existing approaches (e.g. Clamp, BTK etc.) are replaced overnight by
the modern but expensive and complicated technology like Hoffman’s kiln,
fixed chimney kiln or Zigzag kiln, those traditional brick kiln owners would
be wiped out and this incident will have a great impact to the national
economy of Bangladesh. As a result, consumers will have to buy bricks at a
higher rate which will create a negative impact on the rapid growth of the
urbanization. Therefore, a transition should be created between the existing
and proposed techniques.
 The government should come forward to establish a platform for stakeholder
interaction (industry representatives, policymakers, researchers and
financial institutions) to expedite the adoption of efficient kiln technologies
and should offer an incentive to the entrepreneurs of the new green
approach.
 A feasible alternative for the small investors might be Vertical Shaft Brick
Kiln (VSBK) method which consumes relatively smaller energy with lower
initial investment and can be operated against the natural calamities like rain
or flood.

References
Akter, B. (2010, November 25). Brick field: a deadly workplace. Retrieved from
http://www.demotix.com/news/518117/brick-field-deadly-workplace
Bayron, R.K. (2009, December 13). Brick kilns going green. The Daily Star. Retrieved
from http://www.thedailystar.net/newDesign/newsdetails.
php?nid=117503
Ferdausi, S.A., Vaideeswaran, S., & Akbar, S. (2008, November). Greening brick
making industries in Bangladesh. South Asia Social, Environment & Water
Resources Management Unit, the World Bank.
Rahim. (2011, November). Real Estate Business in Bangladesh: Opportunities and
Challenges. Vol.1. (issue V), pp. 2. 2011, June 20. Eco-friendly brick technique
helps build a cleaner Bangladesh. Retrieved from
http://www.beta.undp.org/undp/en/home/presscenter/articles/2011/06/
20/ecofriendly-brick-technique-helps-build-a-cleaner-bangladesh.html
UNDP. (2011, June 20). Eco-friendly brick technique helps build a cleaner
Bangladesh. Retrieved from
http://www.beta.undp.org/undp/en/home/presscenter/articles/2011/06/
20/ecofriendly- brick-technique-helps-build-a-cleaner-bangladesh.html
Roy, P. (2004, March 7). Spewing out eco time bomb Raising chimney heights of
brick kilns fails to stop grave air pollution. The Daily Star. Retrieved from
http://www.sos-arsenic.net/english/environment/toxic-fumes.html
The Daily Star. (2011, April 20). Brick kilns burn firewood, destroying CHT forest.
Retrieved from http://www.thedailystar.net/newDesign/newsdetails.
php?nid=18230

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