Toolkit for Identification and Quantification of Releases of Dioxins, Furans and Other Unintentional POPs
PART III Example Inventories
Example Inventory 5 Source Group 4 Mineral Products
The purpose of this case study is to illustrate the process of inventory development, update and revision. We will consider a hypothetical example of an inventory of country X, and describe the inventory process focusing on the source group 4 Mineral Products.
Let’s consider a hypothetical inventory of country X. The baseline inventory is developed in 2006, based on data collected for the reference year 2005 and by using the Toolkit 2005 methodology. The baseline inventory estimated that approximately 15,000 tons of bricks were manufactured each year based from statistical data obtained from the manufacturing industry. The technologies used in the manufacturing industry have no dust control systems in place and do NOT use contaminated fuels. The total annual releases for the baseline year were calculated based on the Toolkit 2005 methodology, by applying an emission factor for air of 0.2 µg TEQ/t of brick manufactured. The baseline releases to air from brick manufacturing were thus estimated at 0.003 g TEQ/year.
|Baseline PCDD/PCDF released to air in 2005 (g TEQ/year) =||Quantity of bricks manufactured x EFAir=|
|= 15,000 t/yr x 0.2 µg TEQ/t = 0.003 g TEQ/year|
The updated inventory is developed in 2013, based on data collected for the reference year 2010 and the Toolkit methodology as revised in 2013. Activity rates for this source had been assessed at around 15,000 tons of bricks produced annually for the baseline year. The corresponding emission factor has been revised since the first inventory and is much lower than the one used for the baseline inventory: EFAir is now 0.02 µg TEQ/t of brick produced using technologies that have no emission abatement technology in place and using non-contaminated fuels. This is in contrast to 0.2 µg TEQ/t that had previously been used for this technology. In addition in this category, there are new EFs for Products (0.006 µg TEQ/t) and Residues (0.002 µg TEQ/t). The total annual release based on the Toolkit 2013 methodology is determined as below:
|PCDD/PCDF released to air in 2010 (g TEQ/year) =||Quantity of bricks manufactured x EFAir=|
|= 15,000 t/yr x 0.02 µg TEQ/t = 0.0003 g TEQ/year|
This is approximated to 0g TEQ/year in the excel tables.
|PCDD/PCDF to products in 2010 (g TEQ/year)=||Quantity of bricks manufactured x EFProduct=|
|= 15,000 t/yr x 0.006 µg TEQ/t = 0.00009 g TEQ/year|
This is approximated to 0 g TEQ/ year in the excel tables.
|PCDD/PCDF to residues in 2010 (g TEQ/year) =||Quantity of bricks manufactured x EFResidue=|
|= 15,000 t/yr x 0.002 µg TEQ/t = 0.00003 g TEQ/year|
This is approximated to 0gTEQ/year in the excel tables.
TOTAL RELEASES IN 2010 = sum of TEQs released to the different for the media = 0 g TEQ/year
Thus based on the 2013 Toolkit methodology, the updated release levels for this category for the baseline year 2010, changes from 0.003gTEQ/yr to 0g TEQ/yr.
Based on new statistical data available, it was now possible to estimate the total brick production in the country which will include bricks from commercial production and artisanal brick production as opposed to baseline year which only had data from the commercial manufacturing industries. This will give a better estimate of activity rate arising from this source category. From statistical data 35,000 housing units are built per year and of these, approximately 16% are constructed using bricks. Assuming that each housing unit will use approximately 15,000 bricks and each weighing approximately 2.5kg, the resulting activity rate will be as follows:
Calculation of activity rate:
|Total number of housing units built per year||= 35,000|
|Total number of units built using bricks is 16% of total||= 35,000 x 0.16
= 5,600 units
|Bricks used per unit appx 15,000 and assuming 10% waste||= 15,000 + (15,000 x 0.1)
= 16,500 bricks
|Total number of bricks used for 5600 units||= 16,500 x 5,600
= 92,400,000 bricks
|Total tons of bricks produced/yr assuming 2.5kg per brick||= 92,400,000 x 2.5/1000 tons
= 231,000 tons
In determining the activity rates based on construction data, there is a level of uncertainty that is inherent because of use of a uniform size of house unit, assumed identical sizes for both commercial and artisanal bricks and also not taking into consideration other buildings that are not residential units but use bricks for construction.
Calculation of release estimates:
|Revised baseline PCDD/PCDF released to air (g TEQ/year) =||Quantity of bricks manufactured x EFAir=|
|= 231,000 t/yr x 0.02 µg TEQ/t = 0.005 g TEQ/year|
|Revised baseline PCDD/PCDF to products (g TEQ/year) =||Quantity of bricks manufactured x EFProduct=|
|= 231,000 t/yr x 0.006 µg TEQ/t = 0.001 g TEQ/year|
|Revised baseline PCDD/PCDF to residues (g TEQ/year) =||Quantity of bricks manufactured x EFResidue=|
|= 231,000 t/yr x 0.002 µg TEQ/t = 0.00046 g TEQ/year|
This is approximated to 0g TEQ/yr in the excel tables.
TOTAL RELEASES IN 2005 = 0.006 g TEQ/year
Based on the revised EFs in the 2013 Toolkit, and improved activity rate data, this is a better estimate of the releases from this category for the baseline year 2005.
Revising the release levels from this category is advised, since the revised emission factor values in the 2013 Toolkit may affect the release levels by one order of magnitude as compared with those that had been determined using the previous emission factors. It important to establish activity rates in artisan brick production especially in situations where there are no statistics for production rates and there are indications that the estimated artisan production rates are significantly high as compared to commercial production. Construction/building statistics may assist in arriving at a reasonable estimate. It is also important to establish the types of fuels used, as the use of contaminated fuels influences the emission factor by one order of magnitude.