Municipal solid waste (MSW) is defined differently among countries as well as among international agreements. MSW typically includes almost any solid waste generated by households during normal daily life and it also commonly includes wastes produced in industrial, commercial and agricultural activities. Common constituents in MSW include paper and cardboard, plastics, food and kitchen residues, cloth and leather, wood, glass, and metals as well as dirt and rocks and other inert materials. Small quantities of hazardous materials such as batteries, paints, drugs, and some household chemicals also occur in MSW. Nonetheless, most authorities consider MSW as non-hazardous.

MSW incinerators range from batch-fed muffle furnaces to highly sophisticated mass burn systems with grates, heat recovery boilers, and complex air pollution control (APC) systems. In capacity, they range from a few tons per day in small, batch-fed units to more than two thousand tons per day in massive, continuously-fed facilities. A thorough, detailed discussion of more advanced MSW incinerators is given in the BAT&BEP Guidelines.

MSW incinerators release PCDD/PCDF in flue gas, fly ash, bottom ash, wastewater and filter cake from wastewater treatment. For the most advanced incinerators, PCDD/PCDF concentrations per unit mass of these outputs can be ranked as follows: filter cake > fly ash >> bottom ash >> wastewater > flue gas.

Emission Factors

PCDD/PCDF emission factors for the four classes of MSW incinerators are listed in Table II.1.3. Detailed information on the derivation of these emission factors can be found in Annex 9.

Table II.1.3 PCDD/PCDF emission factors for source category 1a Municipal Waste Incinerators

1a	Municipal Waste Incinerators	Emission Factors (µg TEQ/t MSW incinerated)
Classification		Air	Residue
			Fly Ash	Bottom Ash
1	Low technology combustion, no APCS	3,500	ND	75
2	Controlled combustion with minimal APCS	350	500	15
3	Controlled combustion with good APCS	30	200	7
4	High technology combustion, sophisticated APCS	0.5	15	1.5

In addition, PCB emission factors to air have been determined in a measurement campaign in France (Delepine et al. 2011). These are mentioned in Annex 9.

Guidance for Classification of Sources

For the purpose of selecting emission factors, four broadly defined classes of MSW incinerators are as follows:

Class 1 includes MSW incinerators that are simple, batch-fed furnaces with no APC systems and capacities of 500 kg/h or less.
Class 2 includes MSW incinerators that are continuously fed, controlled combustors equipped with minimal APC systems, such as electrostatic precipitators, multi-cyclones and/or simple scrubbers.
Class 3 includes MSW incinerators that are continuously fed, controlled combustors equipped with improved APC systems such as a combination of electrostatic precipitators and multiple scrubbers, a combination of spray-dryers and baghouse, or similar combinations.
Class 4 is limited to state-of-the-art MSW incinerators equipped with sophisticated APC technologies, such as activated carbon adsorption units or SCR DeDiox@ systems that should be capable of ensuring compliance with a strictly enforced regulatory value for air emissions in flue gases that is equivalent to 0.1 ng TEQ/Nm³ at 11% O2).

Activity rates

Activity rates for MSW incineration may be obtained from various sources, such as the following:

• State, provincial, national and/or international agencies that gather centralized statistical information, including MSW generation and treatment;
• State, provincial and national agencies that issue permits to MSW incinerators;
• Owner/operators of MSW incineration facilities (by questionnaires);
• Other release inventories such as the inventory of mercury sources and releases, criteria pollutants and/or greenhouse gases;
• Associations of MSW owner/operators;
• Waste recycling organizations;
• International statistics such as EUROSTAT, OECD, World Bank, etc.

Level of Confidence

Based on the relatively comprehensive data coverage and the level of agreement among the different datasets, the emission factors are assigned a medium confidence level.

Hazardous waste (HW) refers to residues and wastes that are classified as hazardous due to their characteristics or that contain materials regarded as hazardous. For example, hazardous wastes are commonly generated during the manufacture of chemicals, including commercial chemicals, pharmaceuticals, pesticides, etc. In general, all materials that require special precautions and restrictions during handling and use and any consumer goods that are labeled as hazardous and have entered the waste stream are considered hazardous waste. These include solvents and other volatile hydrocarbons, paints and dyes, chemicals including pesticides and other halogenated chemicals, pharmaceutical products, batteries, fuels, oils and other lubricants, as well as goods containing heavy metals. Also, all materials contaminated with these materials such as soaked rags or paper, treated wood, production residues, etc., must be considered hazardous waste.

The term “hazardous waste” as used in the Toolkit does not include medical waste since hazardous and medical wastes have different origins and the technologies for their treatment are different (see source category 1c Medical Waste Incinerators). Typically HW incinerators are special technology incinerators or rotary kiln type furnaces. Special technology incinerators include very low technology grate, or muffle furnaces. Since the classification of hazardous waste is highly dependent on country-specific legislation and on the number of different technologies used for hazardous waste, incineration plants can have many features. A detailed discussion of hazardous waste incineration technologies can be found in the BAT&BEP Guidelines.

Co-combustion in cement kilns is addressed in Group 4 – Mineral Products.

Emission Factors

PCDD/PCDF emission factors for four classes of HW incinerators are listed in Table II.1.4. Detailed information on the derivation of these emission factors can be found in Annex 10.

Table II.1.4 PCDD/PCDF emission factors for source category 1b Hazardous Waste Incinerators

1b	Hazardous Waste Incinerators	Emission Factors (µg TEQ/t HW incinerated)
Classification		Air	Residue (fly ash only)
1	Low technology combustion, no APCS	35,000	9,000
2	Controlled combustion with minimal APCS	350	900
3	Controlled combustion with good APCS	10	450
4	High technology combustion, sophisticated APCS	0.75	30

PCB emission factors to air have been derived in a measurement campaign in France (Delepine et al. 2011). These are mentioned in Annex 10.

Guidance for Classification of Sources

For the purpose of selecting emission factors, four broadly defined classes of HW incinerators are defined as follows:

Class 1 includes very small (< 500 kg/h) and simple furnaces operated in a batch-fed mode without any APC system for stack gases, e.g., muffle ovens, with flue gas volume flow rate of about 17,500 Nm³/t of hazardous waste.
Class 2 includes HW incinerators with controlled combustion and minimal APC systems, with flue gas volume flow rate to 15,000 Nm³/t of hazardous waste.
Class 3 incinerators have further improved combustion efficiencies and more efficient systems resulting in PCDD/PCDF concentrations of about 1 ng TEQ/Nm³ (at 11% O2). Also, the specific flue gas volume flow rate is reduced to 10,000 Nm³/t HW.
Class 4 is limited to highly sophisticated hazardous waste incineration plants that are capable of complying with a regulatory value of 0.1 ng TEQ/Nm³ (at 11% O2), such as legislated in the in European Union. It represents the current state-of-the-art in HW incineration and APC technology with stack gas flow rates of some 7,500 Nm³/t HW.

Activity rates

Activity rates for HW incineration may be obtained from various sources, such as the following:

• State, provincial, national and/or international agencies that gather centralized statistical information, including hazardous waste generation and treatment;
• State, provincial and national agencies that issue permits to HW incinerators;
• Owner/operators of HW incineration facilities (by questionnaires);
• Other release inventories such as the inventory of mercury sources and releases, criteria pollutants and/or greenhouse gases;
• Associations of HW owner/operators;
• International statistics such as EUROSTAT, OECD, World Bank, etc.

Level of Confidence

The default emission factors are based on a certain number of assumptions detailed in Annex 10. In addition, data are lacking for bottom ash concentrations. The emission factors are thus assigned a low confidence level.

Medical waste (MW) is considered to be every waste generated from medical activities regardless if these activities take place in a hospital or are performed by a medical doctor, dentist or any other healthcare facility or provider. In many cases, waste generated during these activities contains infectious materials, human secretions, blood, pharmaceuticals and packaging materials and/or tools used during or for the medical treatment of people or animals. To destroy viruses, bacteria, and pathogens this waste is often thermally treated (by incineration or pyrolysis). Further, due to its origin and its composition, medical waste can contain toxic chemicals, e.g., heavy metals or precursors, high concentrations of organic (polyvinyl chloride and certain pharmaceuticals) and inorganic (saline solution and body fluids) chlorine that may alter combustion characteristics, and absent proper technology may enhance PCDD/PCDF formation.

MW is a waste that requires special surveillance and incineration of all wastes generated within a hospital has been regarded as an efficient way to dispose of these wastes. However, it has also been shown that incineration of medical waste in small and poorly controlled incinerators is a major source of PCDD/PCDF.

Typically, medical waste is incinerated locally at the hospital or any other medical facility in small furnaces in a batch-type mode. In many cases, larger and centralized medical waste incineration facilities are operated only for eight hours a day and five days a week. Large and continuously operated medical waste incinerators are rare and mostly found in developed regions and countries. Also, waste heat recovery boilers are rare. For a more detailed discussion of medical waste incinerators refer to the BAT&BEP Guidelines.

Emission Factors

PCDD/PCDF emission factors for four classes of MW incinerators are listed in Table II.1.5. Detailed information on how these emission factors have been derived can be found in Annex 11.

Table II.1.5 PCDD/PCDF emission factors for source category 1c Medical Waste Incinerators

1c	Medical Waste Incinerators	Emission Factors (µg TEQ/t MW incinerated)
Classification		Air	Residue
1	Uncontrolled batch type combustion, no APCS	40,000	200*
2	Controlled, batch type combustion, no or minimal APCS	3,000	20*
3	Controlled, batch type combustion, good APCS	525	920**
4	High technology, continuous, controlled combustion, sophisticated APCS	1	150**

* Refers only to bottom ash left in the combustion chamber.
** Refers to combined bottom and fly ashes.

Guidance for Classification of Sources

For selection of the most appropriate emission factors, the range of MW incineration technologies is divided into four classes:

Class 1 includes very small and simple, small box type incinerators operated intermittently (in which waste loads are ignited and left) with no secondary combustion chamber, no temperature controls and no air pollution control equipment.
Class 2 applies to all medical waste incinerators with controlled combustion and an afterburner, but still operated in a batch type mode.
Class 3 includes controlled batch-type plants, with good APC systems in place, e.g., ESPs or preferably baghouse filters.
Class 4 includes highly sophisticated medical waste incineration plants that are capable of complying with an air emission 0.1 ng TEQ/Nm³ (at 11% O2). Whether these plants are continuous or batch type operations is not relevant when they are preheated with oil or natural gas to achieve a furnace operating temperature of usually well above 900°C or higher before medical waste is introduced into the furnace.

Activity rates

Activity rates for MW incineration may be obtained from various sources, such as the following:

• Ministry of health;
• State, provincial, national and/or international agencies that gather centralized statistical information, including medical waste generation and treatment;
• State, provincial and national agencies that issue permits to MW incinerators;
• Hospitals and other healthcare facilities with on-site MW incinerators (by questionnaires);
• Owner/operators of commercial MW incineration facilities (by questionnaires);
• Other release inventories such as the inventory of mercury sources and releases, criteria pollutants and/or greenhouse gases;
• Associations of MW incinerator owner/operators;
• International statistics such as EUROSTAT, OECD, World Bank, etc.

Level of Confidence

For well controlled processes such as those described in class 3 and 4, emission factors are assigned a medium confidence level. For class 2, results for bottom ash from a medical waste incinerator in Thailand were extremely high, showing a large variation from the levels calculated using the corresponding emission factor. For class 1 and 2, where the processes are less controlled, emission factors are thus assigned a low confidence level.

Light-fraction shredder waste (LFSW, also sometimes referred to as shredder “fluff” or light weight aggregate) describes the light fraction derived from shredding large items such as end-of-life vehicles, white goods, bulky containers, etc. that are shredded in order to reduce the volume as well as enable the separation of recoverable materials such as metals. Typical separation mechanisms include screening, sifting, and fractionation processes, in which weight differences between the materials or the magnetic properties of ferrous metals allow the shredder aggregate to be fractionated into ferrous metals, non-ferrous metals, glass, other heavy inerts, and light-weight fractions. In some cases the light fraction has little use and may be combusted for disposal.

Emission Factors

PCDD/PCDF emission factors for three classes of LFSW incinerators are listed in Table II.1.6. Detailed information on how these emission factors have been derived can be found in Annex 12.

Table II.1.6 PCDD/PCDF emission factors for source category 1d Light-Fraction Shredder Waste Incinerators

1d	Light-Fraction Shredder Incinerators	Emission Factors µg TEQ/t LFSW incinerated
Classification		Air	Residue
1	Uncontrolled batch type combustion, no APCS	1,000	ND
2	Controlled, batch type combustion, no or minimal APCS	50	ND
3	High technology, continuous, controlled combustion, sophisticated APCS	1	150

Guidance for Classification of Sources

For selection of the most appropriate emission factors, the range of LFSW incineration technologies is divided into three classes:

Class 1 includes very simple stationary grate furnaces with no combustion controls and no APC equipment. Batch type furnaces without any APC also fall into class 1.
Class 2 includes all other furnaces with some kind of combustion control technology such as under and/or over fire air, stoker controls, fluidized beds, etc. including the facilities with some kind of APC system such as an ESP, baghouse or wet scrubber for dust removal. Class 2 also applies to LFSW incinerators with controlled combustion and adequate APC equipment, which, however, are still operated in a batch type mode.
Class 3 includes highly sophisticated incineration plants that are capable of achieving a regulatory value for air emissions equivalent to 0.1 ng TEQ/Nm³ (at 11% O2).

Activity rates

Activity rates for LFSW incineration are most likely to be available from sources such as the following: following:

• State, provincial, national and/or international agencies that gather centralized statistical information, including waste generation and treatment;
• State, provincial and national agencies that issue permits to LFSW incinerators;
• Owner/operators of LFSW incineration facilities (by questionnaires);
• Associations of LFSW owner/operators;
• Waste recycling organizations;
• Other release inventories such as the inventory of mercury, criteria pollutants and/or greenhouse gases;
• International statistics such as EUROSTAT, OECD, World Bank, etc.

Level of Confidence

Based on the geographical coverage of emission data used for deriving emission factors for this category, class 2 and 3 emission factors are assigned a medium level of confidence. No accurate data are available for class 1, in which case the emission factor is assigned a low confidence level.

Sewage sludge is produced from all wastewater treatment processes regardless of the wastewater’s origin (e.g., wastewater from municipal, agricultural or industrial activities). When untreated, such wastewater always contains solids, which are normally removed as sludge during the treatment process. Since PCDD/PCDF are almost insoluble in water, the majority of the PCDD/PCDD adsorb to the solids present in the wastewater. These solids along with the adsorbed PCDD/PCDF can be removed by filtration or flocculation, so that the PCDD/PCDF are collected in the wastewater treatment sludge. This sludge can be disposed of in a variety of ways, including combustion in dedicated incinerators. A detailed discussion of sewage sludge incineration technologies is presented in the BAT&BEP Guidelines.

Disposal of sewage sludge in landfills is addressed in Group 9 – Disposal/Landfill; combustion with energy recovery, in Group 7 – Production and Use of Chemicals and Consumer Goods; co-combustion in boilers and fossil fuel power plants, in Group 3 – Power Generation and Heating; and co-combustion in cement kilns, in Group 4 – Mineral Products.

Emission Factors

PCDD/PCDF emission factors for three classes of sewage sludge incinerators are listed in Table II.1.7. Detailed information on the derivation of these emission factors can be found in Annex 13.

Table II.1.7 PCDD/PCDF emission factors for source category 1e Sewage Sludge Incinerators

1e	Sewage Sludge Incinerators	Emission Factors (µg TEQ/t sewage sludge)
Classification		Air	Residue
1	Older furnaces, batch type operation, no or very little APCS	50	23
2	Updated, continuously operated and controlled facilities, some APCS	4	0.5
3	Modern state-of-the-art facilities, continuous, controlled operation, full APCS	0.4	0.5

PCB emission factors to air have been derived in a measurement campaign in France (Delepine et al. 2011). These are presented in Annex 13.

Guidance for Classification of Sources

For selection of the most appropriate emission factors, the range of sewages sludge incineration technologies is divided into three classes:

Class 1 includes older furnaces with batch type operation and no or minimal APC system. Incinerators in this class have a flue gas volume flow rate of about 12,500 Nm³/t of sewage sludge burned.
Class 2 includes updated, controlled combustion, continuous–feed incinerators equipped with APC systems.
Class 3 includes modern state-of-the-art facilities, continuous-feed fluidized bed incinerators with optimized APC systems capable of consistently meeting the emission limits equivalent to 0.1 ng TEQ/Nm³ (at 11% O2).

Activity rates

Activity rates for sewage sludge incineration may be available from:

• State, provincial, national and/or international agencies that gather centralized statistical information, including sewage sludge generation and treatment;
• State, provincial and national agencies that issue permits to sewage sludge incinerators;
• Owner/operators of sewage sludge incineration facilities (by questionnaires);
• Sewage sludge (biosolids) recycling organizations;
• Other release inventories such as the inventory of mercury, criteria pollutants and/or greenhouse gases;
• Pollution Release and Transport Registers (PRTR);
• International statistics such as EUROSTAT, OECD, World Bank etc.

Level of Confidence

Based on the consistency among the data sets used to derive the emission factors, these are provided with medium confidence.

Contaminated wood and other contaminated biomass can result from many anthropogenic activities, especially wood processing industries ( e.g., building materials, furniture, packing materials, toys, ship building, general construction, etc.) as well as construction and demolition debris. Such wood/biomass waste may contain paints, coatings, pesticides, preservatives, anti-fouling agents, and many other potentially problematic materials. These materials, when incinerated together with the biomass, can enhance the formation of PCDD/PCDF during combustion.

Biomass with a high content of chlorine (organic or inorganic) or heavy metals such as copper, lead, tin, or cadmium typically result in higher PCDD/PCDF emissions than the burning of virgin biomass. Combustion of clean biomass for generation of steam/heat is addressed in Group 3 – Power Generation and Heating, and open burning of either “clean” biomass or contaminated biomass is addressed in Group 6 – Open Burning Processes.

Emission Factors

PCDD/PCDF emission factors for three classes of waste wood and waste biomass incinerators are listed in Table II.1.8. Detailed information on the derivation of these emission factors can be found in Annex 14.

Table II.1.8 PCDD/PCDF emission factors for source category 1f Waste Wood and Waste Biomass Incinerators

1f	Waste Wood and Waste Biomass Incinerators	Emission Factors (µg TEQ/t biomass burned)
Classification		Air	Residue (fly ash only)
1	Older furnaces, batch type operation, no or very little APCS	100	1,000
2	Updated, continuously operated and controlled facilities, some APCS	10	10
3	Modern state-of-the-art facilities, continuous, controlled operation, full APCS	1	0.2

Guidance for Classification of Sources

For selection of the most appropriate emission factors, the range of waste wood and waste biomass incineration technologies is divided into three classes:

Class 1 includes older, batch-fed furnaces with no APC system.
Class 2 includes updated, controlled, continuously-fed facilities that are equipped with some APC system.
Class 3 includes modern, continuously-fed and controlled, state-of-the-art facilities, equipped with full APC systems capable of meeting emission limits equivalent to 0.1 ng TEQ/Nm³ (at 11% O2).

Activity rates

• Activity rates for waste wood/biomass incineration may be available from:
• State, provincial, national and/or international agencies that gather centralized statistical information;
• National energy balance;
• State, provincial and national agencies that issue permits to waste wood/biomass incinerators;
• Owner/operators of waste wood/biomass incineration facilities (by questionnaires);
• Other release inventories such as the inventory of mercury, criteria pollutants and/or greenhouse gases;
• Pollution Release and Transport Registers (PRTR);
• International statistics such as EUROSTAT, OECD, World Bank etc.

Level of Confidence

The default emission factors for all three classes were determined based on reported concentrations from a number of studies in Europe and North America. Measured data for bottom ash could not be obtained; consequently the default emission factors for residue only consider fly ash. The data presented in these different studies are in agreement, and the emission factors are assigned a medium confidence level.

Animal carcasses accumulate in quantities sufficient to require large-scale disposal as a result of disease outbreaks in beef and dairy herds, intensive poultry- and hog-raising facilities, veterinary hospitals and practices, etc. The incineration of animal carcasses to reduce public exposure to zoonotic disease is often carried out in simple, low technology, poorly controlled furnaces. As a result, incomplete combustion is the norm rather than the exception. Thus, it is virtually impossible to describe a typical animal carcass-burning furnace. These furnaces are often not designed to guarantee well-controlled combustion conditions nor a high removal efficiency of particulate matter to reduce PCDD/PCDF air emissions.

Destruction of animal carcasses via open burning is addressed in Group 6 – Open Burning Processes.

Emission Factors

PCDD/PCDF emission factors for three classes of animal carcass incinerators are listed in Table II.1.9. Detailed information on how these emission factors have been derived can be found in Annex 15.

Table II.1.9 PCDD/PCDF emission factors for source category 1g Destruction of Animal Carcasses

1g	Destruction of Animal Carcasses	Emission Factors (µg TEQ/t animal carcasses incinerated)
Classification		Air	Residue
1	Older furnaces, batch type operation, no or very little APCS	500	ND
2	Updated, continuously operated and controlled facilities, some APCS	50	ND
3	Modern state-of-the-art facilities, continuous, controlled operation, full APCS	5	ND

Guidance for Classification of Sources

For selection of the most appropriate emission factors, the range of animal carcass incineration technologies is divided into three classes:

Class 1 includes older, batch-fed furnaces with no APC systems.
Class 2 includes updated, continuously-fed and controlled facilities that are equipped with some APC systems.
Class 3 includes modern state-of-the-art, continuously-fed and controlled facilities with full APC systems capable of meeting emission limits equivalent to 0.1 ng TEQ/Nm³ (at 11% O2).

Activity rates

Activity rates for animal carcass incineration may be available from:

• Ministry of agriculture;
• State, provincial, national and/or international agencies that gather centralized statistical information, including large-scale disease outbreaks, such as bird flu, swine flu, bovine encephalopathy, etc., and the associated generation and treatment of animal carcasses;
• State, provincial and national agencies that issue permits to animal carcass incinerators;
• Owner/operators of animal carcass incineration facilities (by questionnaires);
• Other release inventories such as the inventory of criteria pollutants and/or greenhouse gases;
• Pollution Release and Transport Registers (PRTR);
• International statistics such as EUROSTAT, OECD, World Bank etc.

Level of Confidence

No data were found for assigning default emission factors for residues. Based on the scope and agreement of existing air emission data sets for classes 1, 2 and 3, the emission factors are assigned a medium confidence level.