Impact of Brickkiln Pollution on Dhaka City

Presented by: Ijaz Hossain Chemical Engineering Department BUET ijaz@bangla.net

Snapshot of the Brick Making Industry in Bangladesh

Parameter Value (approximate) All Types of Coal-fired Kilns 5000 Natural Gas Fired Kilns 26 Kilns Within 25 kilometers of Dhaka 1200 Kilns in the Dhaka North Cluster 550 Annual Brick Production 15 Billion Value of Output in Taka 450 Billion Value of Output in US$ 640 Million Contribution to GDP 1% Coal Consumption 2.2 Million Tons Import Value of Coal 140 Million US$ Firewood Consumption 1.9 Million Tons GHG (CO2) Emission 8.75 Million Tons Clay 45 Million Tons Total Employment including supply of clay/coal, transport of bricks and marketing

Close to 1 million

Database of Brick KilnsBased on field surveys and interviews

with random brick field owners

Database of Brick Kilns

Database of Brick Kilns

Database of Brick Kilns

Database of Brick Kilns

2005-2006 Brick-burning season

Total Number of Brick Kilns = 4140

This is the minimum number – actual probably 10-15%

higher

Source: GEF-UNDP Study (2006)

Modeling:Ground level particulate concentration as

a result of emissions of 550 kilns in the North Dhaka Cluster were modeled

Technical Options:Alternative cleaner technologies were

identified and assessed

Main Data Requirement

Particulate emission from a typical kiln

Exact position of each kiln in the modeling domain

Chimney dimensions and flow of flue gas (collected and/or assumed)

Gas properties (assumed)

Meteorological data (WMO)

Stack Emissions Monitoring

Stack Emissions Monitoring

25'

Stack Emissions MonitoringTo improve understanding of the actual emissions from the industry

Stack Emissions Monitoring

Figure1:Total Hydrocarbon Concentration Vs. Time (Hours)

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THC Concentration 500 ppm

Stack Emissions Monitoring

Figure2: CO Concentration Vs. Time (Hours)

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CO Concentration 4000 ppm

Stack Emissions MonitoringParticulate Measurement

Stack Emissions MonitoringParticulate Measurement

Sampling Date Sampling Time SPM(mg/m3)

March 18, 2006 2:30 PM-5:20 PM 663.94

March 23, 2006 3:16 PM-6:35 PM 1173.77

Stack Emissions MonitoringParticulate Measurement

Bangladesh = 1000

Google Earth –Dhaka North Cluster

Hand Held GIS Meters

Modeling Domain –Dhaka North Cluster

Wind Direction In winter

(µg/m3)

Four-month (December-March) Average Particulate Profile [in micrograms/cubic meter]

SEASONAL AVERAGE OF WORST CASE SCENARIOOn a particular day/week, the pollution may be much more

(µg/m3)

December January

February March

Baseline

20% Less than Baseline

50% less than baseline

75% less than baseline

Particulate Concentration in µg/m3 % More or Less Than Baseline

LOCATION Baseline 20%

more

20%

less

50%

less

75% less

Baseline with

wind at 170o

1ZIA AIRPORT 27 32 21 13 7 81

2 UTTARA 53 64 42 27 13 171

7 GABTOLI 224 269 179 112 56 324

11

CITY CENTER 26 32 21 13 7 71

BAEC Apportionment Study

Found 15% of TSP to be from coal fired brickkilns

This study: 26 – 53 µg/m3 (except Gabtoli)

BAEC: Total TSP = 150 – 200 µg/m3

Therefore, 22% using BAEC’s total

1. Clamps – Very old traditional technology 2. BTK – Bull’s Trench Kilns (less than 10%) 3. FCK – Fixed Chimney Kilns (Baseline) 4. Improved FCK (gravity settling chamber, etc.) 5. Zigzag Kilns (less than 20% of existing kilns) 6. Hoffman Kilns (natural gas – only 26 kilns) 7. VSBK – Vertical Shaft Kilns 8. Hoffman (coal) + Internal Fuel (UNOPS) [HHK] 9. Tunnel Kilns

Clamps – Does not exist in Bangladesh BTK – Banned in Bangladesh

Market Share of the Four Types of Kilns (2005-06 season)

Kiln Type Number Percent of Kilns

Brick Production

(Billion)

Brick Production

(%)

FCK 3123 75.4 9.4 75.8

BTK 794 19.2 2.0 16.1

Zigzag Kiln 197 4.8 0.7 5.7

Hoffmann Kiln

26 0.6 0.3 2.4

Total 4140 100 12.4 100

Source: GEF-UNDP Study (2006)

FCK

FCK – Assessment

Simple and convenient technology

Ideally suited to the level of the present owners and workers

Is constructed in low lying land (cheap and abundant)

Profitability – High, IRR > 30%

Pollution – Very polluting

Zigzag Kiln

Zigzag Kiln – Assessment

The construction technology is not readily available, and expertise has to be procured from India Scrubbing water is not changed regularlyOperation procedure is more sophisticated than FCK – a badly operated kiln has the same energy consumption and hence pollution Requires electricity and standby diesel generatorPollution – 50% less assuming good design and proper operation

HOFFMAN KILN(30 Kilns use 5.5 MMcfd of Natural Gas )

Natural Gas Hoffman Kiln

Hoffman – Assessment

Initial investment 10 times that of the FCK (50% for land) Requires high land, natural gas connection, electricity and standby generator Requires more land compared to the FCK or Zigzag (at least 5 acres of high land close to a main road) Profitability low (IRR ~ 20%, 12-months operation needed to recover costs) Pollution – 80-90% reduction compared to the FCK

FCK – Modifications

Existing FCKs can be improved with one or all of the following – Gravity settling chambers– Improved coal feeding– Internal fuel (up to 50%)– Plugging air leakage

All of these options will require technical assistance in the early years. Once tried and tested, these can be easily replicated

Operation and maintenance aspect is not known

Some Indian data is available for gravity settling chamber modification along with improved coal feeding. The particulate emission can be reduced below 400 mg/m3 that would meet present and future emission standard

Coal Hoffman Hybrid Hoffman Kiln (HHK)

Coal Hoffman Hybrid Hoffman Kiln (HHK)

Permanent Roof and ID Fan +

Internal Fuel (up to 80%)

Hoffman Coal (HHK) –Assessment

The technology provider claims 80% coal can be mixed with clay. This needs to be demonstrated

Operational and maintenance issues from Bangladesh perspective is not known yet

Technology provider claims that the quality of the brick is better than FCK 1st class brick (but using extruder and drying chamber)

It is claimed that Hoffman (coal) can reduce pollution by 50% to 80% compared to the FCK

VSBK – Assessment According to available literature sources the bricks are of good quality. But, Bangladeshi brick makers have the following perception problems: – Existence of cracks in bricks

– Bricks do not make a good ringing sound when banged

About 70-80% reduction in emission compared to the FCK. Current standard is 1000 mg/m3 for 120-feet chimney. Emission is 200-300 mg/m3 for VSBK, but total height including chimney around 60 feet

Comparison of Particulate Emission of Different Kilns

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FCK Zigzag (medium) NG Hoffman FCK (+GSC+IF) Coal Hoffman VSBK Zigzag (good)

Part

icul

ates

(mg/

m3 )

Present Emission Standard

Probable Future Emission Standard

Cement Block Plant

Summary – Technology Options 1. Internal fuel

This appears to be a very promising option for reducing pollution. Both the HHK and VSBK employ this practice

+

Gravity Settling Chamber

FCK will be able to meet future emissions standard if it is set at 500 mg/m3 or more

2. Zigzag Kilns

Many operating in Bangladesh have notbeen constructed according to the design standards. As a result these will not be able to meet the 500 mg/m3 standard.

3. Coal Hoffman (HHK)

The HHK can meet future emissions standard. It will also lower coal consumption, but the exact amount will only be known after its commercial operation in Bangladesh.

5. VSBK

In terms of emissions the VSBK is the best coal burning option. But this is totally new, and there appears to be some hesitation and resistance from existing FCK owners in shifting to this technology.

6. Cement Blocks

In terms of service cement blocks are comparable to bricks, but there exists consumer resistance. Blocks use imported cement, while bricks use imported coal. However, the financial burdenfor importing Cement is 50 to 100% greaterthan that for importing coal from India.

• The DoE should use dispersion modeling for Permitting industries. Compliance only with stack standards is not enough.

• Significant efforts are underway for transforming the brick industry. Many of these will yield positive results in the next 2-3 years. The DoE should initiate a study to update standards, and gradually introduce tighter standards, and not hastily ban technologies and practices.

• Undertake project to determine the viability of using Gravity Settling Chambers and Internal Fuel in FCKsbecause if these options prove successful then FCKs may be able to meet future emission standards.

• Undertake study to evaluate the popular Zigzag Kiln’s design and emission.

• Undertake pilot projects of new technology (like VSBK) and assess operational (including product quality) and financial viability.