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Toolkit for Identification and Quantification of Releases of Dioxins, Furans and Other Unintentional POPs PART III Example Inventories |
Example Inventory 10 Source Group 9 Disposal/Landfill
Country A has prepared its PCDD/PCDF inventory for the reference year 2005. For source group 9, data on the amount of wastes deposited on landfills and waste dumps, sewage collection, treatment and disposal were obtained from the National Department of Statistics and from the National Survey on Basic Sanitation, complemented by data from agencies and companies responsible for waste and sewage collection, treatment and disposal.
Category 9a Landfills and Waste Dumps
To estimate leachate releases generated by organic decomposition of municipal solid waste, the total amount of wastes disposed of in sanitary landfills - 1,011,780 t/year - and in waste dumps – 809,424 t/year – was considered, resulting in a total of 1,821,204 t wastes disposed of per year. Reliable studies were conducted by researchers at the National University in Country A, indicating generation of leachate from 0.1 to 0.2 cubic meter per ton of waste disposed of. Considering the intermediate value of 0.15 m³/t, the total volume of leachate generated in 2005 was of 273,181,000 liters.
Information for the calculation of leachate from hazardous waste releases does not exist. The surveyed companies reported that formation of leachate in landfills containing industrial hazardous waste is small, as special landfills are used for this type of waste, compliant with the legislation in force, with low amounts of degradable organic matter, and where rain is prevented from reaching the landfilled waste.
Municipal solid wastes are considered to contain 5% of hazardous wastes according to information given by the Federal Environment Agency. The total annual release was then calculated by multiplying the activity rates by the corresponding emission factors according to the Toolkit (2005). The results are shown in the following table:
Annual PCDD/PCDF releases for source category 9a (reference year 2005)
| Category | Class | Activity Rate | Annual release (g TEQ/a) | Total | ||||
|---|---|---|---|---|---|---|---|---|
| Air | Water | Land | Product | Residue | ||||
| Landfills and waste dumps | Hazardous wastes | 13,659,000 L/year leachate 91,060 t/year solid waste |
- | 0.003 | - | - | 4.6 | 14.9 |
| Non-hazardous wastes | 259,521,600 L/year leachate 1,730,144 t/year solid waste |
- | 0.008 | - | - | 10.4 | ||
Landfill mining and excavation
Landfill mining and excavation was not considered in the baseline inventory of Country A. Nonetheless a good example of emission from this source is given by Torres et al. (2012). It is the case of a company in Sao Paolo that produced acetylene/vinylchloride monomer (VCM), ethylenedichloride (EDC) and PVC since mid 1950s and deposited the related production wastes on a landfill. The VCM production via the acetylene method stopped in 1996. The corporate landfill has been used for approximately 40 years and was closed in 1996. Lime milk from the acetylene process was the main type of waste disposed of at this site, with approximately 1,400,000 tons of lime milk stored (Torres et al. 2012). In 1997, a company started to mine the lime waste from the site and put it on the construction market for neutralizing citrus pulp to produce citrus pulp pellets (CPP). The citrus pulp pellets were exported to Europe as feed for cattle, resulting in PCDD/PCDF contamination of milk and dairy products in several countries (Malisch et al. 2000, Torres et al. 2012). After the PCDD/PCDF contamination was discovered, mining of the PCDD/PCDF contaminated lime for CPP ceased. To evaluate the extent and type of PCDD/PCDF contamination of the landfill, 323 samples were taken from the site and analyzed. Concentrations ranged between 0 to 81,000 ng TEQ/kg, averaging around 1000 ng TEQ/kg. The total TEQ amount at the site was estimated at 1.4 kg TEQ. Patterns in the higher contaminated samples (1000 ng – 81,000 ng TEQ/kg) were similar to the EDC catalysts described by Carroll et al. (2000). During the last ten years, securing measures were installed including the construction of a hydraulic barrier. The site was also capped (Torres et al. 2012). This example demonstrates how PCDD/PCDF from reservoirs can enter via landfill mining in the food chain, directly into cattle feed and human nutrition.
Category 9b Sewage and Sewage Treatment
The National Statistics Department detains information on the volume and type of disposal and treatment given to sewage collected in Country A. The volume of sewage collected and treated was of 668,000 m³/day (243,820,000 m³/year). The amount of sludge generated in several types of treatment processes was of 175 g/m³ (calculated on the basis of 25 grams of dry sludge per person per day and a daily consumption of water of 0.143 m³/person).
It was estimated that 10% of the sewage collected (24,382,000 m³/year) contains industrial effluents with chlorine relevance; sewage treatment processes generate sludge, which is afterwards removed. The remaining 90% of the sewage collected (219,438,000 m³/year) are treated in systems with (93%) and without (7%) sludge removal. Treatment systems without removal of sludge are of the wetland type.
No statistics were available to calculate the activity rates for remote environments or with input control, and they were not included in the inventory. The results of the inventory are shown in the following table:
Annual PCDD/PCDF releases for source category 9b (reference year 2005)
| Category | Class | Activity Rate | Condition | Annual release (g TEQ/a) | Total | ||||
|---|---|---|---|---|---|---|---|---|---|
| Air | Water | Land | Product | Residue | |||||
| Sewage and sewage treatment | Mixed domestic and industrial inputs | 0.0 | No sludge removal | - | 0.0 | 0.0 | 8.0 | ||
| Sewage: 24,382,000 m³/year Sludge: 4,267 t/year |
With sludge removal | - | 0.012 | 4.27 | |||||
| Urban environments | Sewage: 15,360,660 m³/year | No sludge removal | - | 0.031 | 0.0 | ||||
| Sewage: 204,077,340 m³/year Sludge: 35,714 t/year |
With sludge removal | - | 0.102 | 3.57 | |||||
| Remote environments or input control | N/A | ||||||||
Category 9c Open Water Dumping
Water consumption in urban areas reached a total amount of 971,000 m³/day in 2005, producing 873,900 m³ sewage/day. By discounting the volume of sewage collected and treated (668,000 m³/day), it was calculated that the amount dumped in open water (mainly rivers and ocean) was of 205,900 m³/day or 75,153,500 m³/year. The same consideration was made in relation to the presence of industrial effluents. Thus, the activity rate in class 1 will be 10% of total sewage volume discharged in open water, and the remaining 90% is assigned to class 2. No information was collected on class 3 (remote environments or input control).
Annual PCDD/PCDF releases for source category 9c (reference year 2005)
| Category | Class | Activity Rate | Annual release (g TEQ/a) | Total | ||||
|---|---|---|---|---|---|---|---|---|
| Air | Water | Land | Product | Residue | ||||
| Open Water Dumping | Mixed omestic and industrial inputs | 7,515,350 m³/year | - | 0.038 | - | - | - | 0.051 |
| Urban environments | 67,638,150 m³/year | - | 0.014 | - | - | - | ||
| Remote environments | N/A | |||||||
Category 9d Composting
Composting is not a relevant way of disposing of waste in Country A, and estimates of amounts of wastes converted to compost are uncertain. About 1% of municipal waste is considered to be converted in compost, that is, around 20,000 t/year. Considering the default value of 30% of water content given in the Toolkit (2005), the total amount of compost produced would be 14,000 t/year (dry basis). Assuming an all organic fraction in compost, annual releases of PCDD/ PCDF are of 1.4 g TEQ/year.
Category 9e Waste Oil Treatment (Non-Thermal)
As there is no emission factor for this type of source, no further attempt was made to quantify PCDD/PCDF releases from this source.
Total Annual Releases from Source Group 9
The total annual releases of PCDD/PCDF from source group 9 in Country A, in the reference year 2005, amount to 24.4 g TEQ/year.
Based upon the results of 2005 baseline inventory, Country A introduced a number of measures to reduce releases of PCDD/PCDF. In relation to source group 9, the main actions taken were:
- To reduce by 50% the hazardous content of wastes deposited on landfills and dumps;
- To introduce a recycling program to reduce the amount of landfilled waste per capita. In 2010 the reduction was of 5%;
- To eliminate mixing of industrial inputs into sewage collection and treatment systems.
The update of the inventory is described below.
Category 9a Landfills and Waste Dumps
The same methodology as in the baseline inventory was employed to estimate releases generated by organic decomposition of municipal solid waste. According to the Toolkit 2013, emission factors for category 9a have been revised and the need to estimate the amount of leachate generated by waste decomposition has been eliminated; the emission factors are now based on the amount of solid wastes generated. Also, as a result of measures taken, hazardous wastes contained in domestic wastes reduced by half and there was a 5% reduction on domestic wastes.
The updated values are shown in the table below. The results show a decrease of 6.4 g TEQ/year, as compared with the baseline release estimates.
Annual PCDD/PCDF releases for source category 9a (reference year 2010)
| Category | Class | Activity Rate | Annual release (g TEQ/a) | Total | ||||
|---|---|---|---|---|---|---|---|---|
| Air | Water | Land | Product | Residue | ||||
| Landfills and waste dumps | Hazardous wastes | 45,530 t/year | - | 0.2 | - | - | NA | 8.5 |
| Mixed wastes | - | - | - | - | ||||
| Domestic wastes | 1,643,637 t/year | - | 0.08 | - | - | 8.2 | ||
Category 9b Sewage and Sewage Treatment
The data from the National Statistics Department show that the sewage volume decreased by 10% due to the elimination of mixed industrial and domestic effluents in relation to 2005. The type of disposal and treatment remained the same as in 2005. Then the volume of sewage collected and treated was of 601,200 m³/day (219,438,000 m³/year). The amount of sludge generated in several types of treatment processes in use in Country A was thus similarly estimated as in 2005.
However, based on the measures included in the National Implementation Plan (NIP) of Country A, there is no mixing of industrial inputs with chlorine relevance. All sewage collected can be classified as class 2, 93% being treated in systems with sludge removal and 7% in systems without sludge removal.
No statistics were available to calculate the activity rates for remote environments or with input control, and they were not included in the inventory.
The total annual releases for 2010 show a reduction of 7.14 g TEQ/year as compared with the baseline situation.
Annual PCDD/PCDF releases for source category 9b (reference year 2010)
| Category | Class | Activity Rate | Condition | Annual release (g TEQ/a) | Total | ||||
|---|---|---|---|---|---|---|---|---|---|
| Air | Water | Land | Product | Residue | |||||
| Sewage and sewage treatment | Mixed domestic and specific industrial inputs | 0.0 | No sludge removal | - | 0.0 | 0.0 | 0.7 | ||
| 0.0 | With sludge removal | - | 0.0 | 0.0 | |||||
| Urban and industrial inputs | Sewage: 13,824,594 m³/year | No sludge removal | - | 0.01 | 0.0 | ||||
| Sewage: 183,669,606 m³/year Sludge: 32,142 t/year |
With sludge removal | - | 0.04 | 0.64 | |||||
| Domestic inputs | N/A | ||||||||
Category 9c Open Water Dumping
Water consumption in urban areas registered a 10% reduction in relation to 2005 consumption, due to the separation of industrial effluents with chlorine relevance from domestic effluents, reaching a volume of 873,900 m³/day, producing a total amount of sewage of 786,510 m³/day. By discounting the volume of sewage collected and treated (601,200 m³/day), the amount dumped in open water (rivers and ocean) was estimated at 185,310 m³/day or 67,638,150 m³/year. This is entirely assigned to class 2. There is no information on class 3 (remote environments or input control). The total annual releases for category 9c in 2010 (0.014 g TEQ/year) are thus lower than 2005 releases (0.051 g TEQ/year).
Category 9d Composting
The situation in 2010 changed due to changes in the Toolkit 2013 emission factors. The amount of wastes converted to compost remained the same and is assigned to class 1 (compost of organic wastes separated from mixed wastes). The release decreased by 50%, with a total of 0.7 g TEQ/year of PCDD/PCDF.
Category 9e – Waste Oil Treatment (Non-Thermal)
No releases are calculated for this source category, similarly as in 2005.
Total Annual Releases on Source Group 9
The total annual releases of PCDD/PCDF from source group 9 in Country A, in the reference year 2010, amounts to 9.9 g TEQ/year, registering thus a decrease of 14.4 g TEQ/year as compared to the baseline.
The update of the inventory for the reference year 2010 was associated with changes in the Toolkit emission factors. Thus, to be able to calculate trends in releases over time based on a consistent set of emission factors, the baseline values must be recalculated by using the Toolkit 2013. The revision of the baseline inventory enabled the detection of a decreasing trend in releases from 2004 to 2010.
Category 9a Landfills and Waste Dumps
Annual PCDD/PCDF releases for source category 9a (revised for the reference year 2005)
| Category | Class | Activity Rate | Annual release (g TEQ/a) | Total | ||||
|---|---|---|---|---|---|---|---|---|
| Air | Water | Land | Product | Residue | ||||
| Landfills and waste dumps | Hazardous wastes | 91,060 t/year solid waste | - | 0.5 | - | - | NA | 9.2 |
| MiIxed wastes | 0 | - | - | - | ||||
| Domestic wastes | 1,730,144 t/year solid waste | - | 0.1 | - | - | 8.7 | ||
Category 9b Sewage and Sewage Treatment
Annual PCDD/PCDF releases for source category 9b (reference year 2005)
| Category | Class | Activity Rate | Condition | Annual release (g TEQ/a) | Total | ||||
|---|---|---|---|---|---|---|---|---|---|
| Air | Water | Land | Product | Residue | |||||
| Sewage and sewage treatment | Mixed domestic and industrial inputs | N/A | No sludge removal | - | 0.0 | 0.0 | 0.9 | ||
| Sewage: 24,382,000 m³/year Sludge: 4,267 t/year |
With sludge removal | - | 0.024 | 0.85 | |||||
| Urban and industrial inputs | Sewage: 15,360,660 m³/year | No sludge removal | - | 0.015 | 0.0 | ||||
| Sewage: 204,077,340 m³/year Sludge: 35,714 t/year |
With sludge removal | - | 0.04 | 0.7 | |||||
| Domestic inputs | N/A | ||||||||
For categories 9c Open Water Dumping, and 9e Waste Oil Treatment, no changes in emission factors have been made in the revised Toolkit, therefore there is no impact on the calculation of release estimates for these sources. The inventory does not need to be revised in such cases where both the emission factors and the activity rates remain unchanged as compared with the baseline. For category 9d Composting, the releases are revised to account for the changes in emission factors. The revised PCDD/PCDF release estimates amount to 0.7 g TEQ/year.
Comparison of total releases for reference year 2010 to the revised baseline inventory
The total annual releases of PCDD/PCDF from source group 9 in Country A, in the reference year 2010, amounts to 10 g TEQ, and 12 g TEQ in the revised baseline inventory for reference year 2005, registering a reduction of 2 g TEQ, or around 15%. The results show the importance of the revision of baseline inventory, since without this step the conclusion after updating the inventory would have been a reduction of about 13 g TEQ, or around 60%.
