 |
Toolkit for Identification and Quantification of Releases of Dioxins, Furans and Other Unintentional POPs PART III Annexes |
Annex 37 Complementary information to source category 4c Brick Production
Overview of recent revisions
The results of an experimental programme in Kenya, South Africa and Mexico, including measurements of PCDD/PCDF, PCB and HCB emissions in Mexico were used to revise and amend emission factors to air, residues and products. From the experiments in Mexico, PCDD/PCDF, PCB and HCB emission factors to air, products (bricks) and residues (ashes) are available for two types of fuels (wood and heavy oil or “Combustoleo”). The resulting air emission factors found in Mexico confirmed the 2 classes of emission factors for air. Emission factors for PCB and HCB were equally generated. Emission factors for PCDD/PCDF, PCB and HCB in ashes and bricks were also developed. Emissions of HCB and marker PCB were shown to be more fuel related than PCDD/PCDF.
Table III.37.1 Dioxin like PCBs in WHO TEQ emission factors for source category 4c Brick Production
4c Brick Production Emission Factors (µg TEQ/t brick produced) Classification Air Water Land Product Residue* 1 No emission abatement in place and using contaminated fuels 0.015 - NA 0.01i 0.001iii 2 No emission abatement in place and using non-contaminated fuels
Emission abatement in place and using any kind of fuel
No emission abatement in place but state of the art process control0.001 - NA 0.001ii 0.0001iv * In countries with no waste management or no reuse of the residue for brick making, this often goes to Land
iDerived from field measurements at Mexican artisanal brick kilns using waste oil
iiDerived from coal and virgin wood fired brick kilns in Mexico, South Africa at industrial and artisanal scale
iiiDerived from Mexican artisanal brick kilns fired with contaminated fuels
ivDerived from virgin wood and coal fired kilns in Mexico, South Africa and Kenya at industrial and artisanal scaleTable III.37.2 HCB emission factors for source category 4c Brick Production
4c Brick Production Emission Factors (mg TEQ/t brick produced) Classification Air Water Land Product Residue* 1 No emission abatement in place and using contaminated fuels 225 - NA 100i 1iii 2 No emission abatement in place and using non-contaminated fuels
Emission abatement in place and using any kind of fuel
No emission abatement in place but state of the art process control32 - NA 20ii 0.1iv * In countries with no waste management or no reuse of the residue for brick making, this often goes to Land
iDerived from field measurements at Mexican artisanal brick kilns using waste oil
iiDerived from coal and virgin wood fired brick kilns in Mexico, South Africa at industrial and artisanal scale
iiiDerived from Mexican artisanal brick kilns fired with contaminated fuels
ivDerived from virgin wood and coal fired kilns in Mexico, South Africa and Kenya at industrial and artisanal scaleThe comparison of PCDD/PCDF, PCB and HCB levels in soil, ash and brick samples from Kenya and South Africa to the levels found in Mexico suggest that emission factors measured in Mexico fit the variety of installations and fuels used in developing countries and can be applied in general.
Finally, the existing classes were further refined to better reflect the specific processes and technologies used in developing countries. Consequently, class 2 was amended to include technologies with no emission abatement in place and using non-contaminated fuels, using emission abatement and any kind of fuel, and with no emission abatement in place but state of the art process control.
Some hot spot situations were encountered during the field study. Significantly high levels of PCDD/PCDF were detected in ash and bricks of some Mexican sites co-incinerating waste, and indicate the need to assess further whether these data represent another category. Furthermore, typical Asian kiln types could not be included in this study, and further work should be done to include information on these types of kilns as well.
As it is anticipated that brick making will increase in developing countries, opportunities exist for South-South exchange of technologies and BAT/BEP in order to further reduce emissions.
Derivation of emission factors
Release to Air
An emission factor of 0.02 μg TEQ/t of product is to be applied to brick making processes with good control, consistently high temperatures and controls over the fuels used. Higher emissions may occur if poor controls are in place and wastes or poor quality fuels burned; then class 1 should be applied. These emission factors have been confirmed by studies in Mexico, South Africa and Kenya (Umlauf et al. 2011).
Release to Water
No release to water is expected. Any effluent should be noted and its source recorded.
Release to Land
No release to land is expected.
Release in Products
Few data were available on levels of PCDD/PCDF in bricks, usually at or below the detection limit. The levels are generally expected to be low as the bricks have been subject to high temperatures. In one occasion in Mexico levels around 10 ng/kg TEQ were detected. However, it is assumed that most of the PCDD/PCDFs are immobilized within the bricks and should not be considered as an exposure relevant emission.
Release in Residues
PCDD/PCDF may be present in residues from the process. Apart from one exception with levels around 100 ng/kg TEQ, the concentrations were usually in the low ng/kg TEQ range or non detected. Since the ash production is in the range of some kg per ton of bricks, this release pathway is generally negligible (Umlauf et al. 2011).
