This example shows that when updating the dioxin inventory, examination of the previous inventory is essential in order to identify quickly the approach used, find valuable information sources to estimate activity rates, use consistent expert judgment to fill information gaps, etc. It also shows that, besides changes in the Toolkit through its revision in 2013, new information that becomes available at the country level is equally important in triggering revision of baseline estimates of releases. If this revision is not performed, the results obtained for the different reference years cannot be compared and trends over time cannot calculated.
II. Example of baseline inventory using national waste combustion statistics as a major activity data source
This example illustrates the inventory process in the case where activity data are mainly obtained through national waste combustion statistics (questionnaires are partially used / targeted to obtain detailed information on incineration technologies in place). The example provides information on the baseline inventory process only, and is mainly focused to providing useful guidance on estimating activity rates.
Country X prepared its first inventory of dioxins and furans in 2006 to support the development of the action plan as required by Article 5 of the Convention. Activity data for the different sources of PCDD/PCDF were collected for the reference year 2004 (baseline year). The inventory is developed by applying the Toolkit 2005 methodology and the emission factors specified in that version of the Toolkit. Activity data was obtained from waste incineration national statistics.
According to waste statistics, in 2004 350,000 tons of wastes of more than 50 types were incinerated. Greatest incinerated volumes are communal-domestic wastes, wood wastes without pollution (‘clean’ wood wastes), polluted wood wastes, petrochemical sludge, wastes from paint production, waste petroleum oils, old tires, wastes from chipboard production, wastes from resins production, old sleepers impregnated with creosote, rags polluted with oils, old containers from pesticides, polluted paper and cardboard, liquid spirits, washing waters from chemical production and petroleum products storage, and hospital wastes.
For the quantification of PCDD/PCDF emissions, these major categories of combusted wastes were aggregated into different categories according to the Toolkit classification.
It was thus accounted that 60,000 tons of wastes are ‘Municipal solid wastes’, 50,000 tons ‘Hazardous wastes’, 5,000 tons ‘Medical wastes’, and 70,000 tons ‘Waste wood and waste biomass’. No incineration of sewage sludge, light fraction shredder wastes and animal carcasses was accounted for.
Among these waste types, 10,000 tons of old tyres were combusted in cement kilns; PCDD/PCDF emissions from this category were accounted for in Group 4 – Mineral products. 100000 tons of ‘clean’ wood wastes and 40,000 tons of biomass waste were incinerated in boilers for energy and heat production and accounted in Group 3. 15,000 tons of wastes could not be included into any category and PCDD/PCDF emissions from their incineration were not accounted for.
In addition, statistical data on wastes combusted in private households could not be obtained; an expert assessment of the total amount of such wastes used as an energy source for residential purposes was made, and emissions were accounted in Source Group 3.
The Environmental Protection Agency notifies that there are ten waste incineration plants in the country which mostly burn municipal wastes (or similar) and two plants which incinerate medical wastes. No statistical data could be found on the distribution of wastes according to the technology of combustion and level of abatement. To obtain such detailed data, questionnaires were sent to major waste incineration facilities, communal services and companies which produce the largest amounts of wastes.
It was found that most of the industrial waste and partially medical wastes are incinerated ‘on-site’, by the plant/hospital generating these wastes. As for municipal wastes, these are incinerated at special plants.
Through the analysis of the questionnaires it was found that waste incineration practices include simple types of incineration furnaces, mostly batch-type. It was thus concluded that most of the waste combustion installations are equipped with simple abatement devices (1-stage with afterburners, cyclones, scrubbers), which correspond to Class 2 of the Toolkit. Only a minor part of incineration facilities are equipped with 2-stages abatement systems including bagfilters; this corresponds to Class 3 of the Toolkit. Finally, some facilities do not have abatement at all (Class 1).
There is no special management of residues from waste burning and fly ash: these are collected and landfilled together with other industrial and municipal wastes.
According to these data, baseline estimates of PCDD/PCDF emission from this source group amounted to:
- Air emissions: 54.9 g/TEQ,
- Emissions to residues: 58.6 g/TEQ.