Greenhouse Gas Emissions from Municipal Solid Waste Management …
139
5.4 GHG Emissions from Incineration and Thermal
Treatments
Incineration or thermal treatment unit consists of a fuel chamber where fossil fuel
such as natural gas/oil is used only for the startup and shutdown of the operations.
Besides, it is composed of a combustion chamber for transformation of waste into ash
and flue gas. The combustion chamber is equipped with an airflow passage, which
provides oxygen for combustion. The thermal energy generated from the combustion
of waste is transferred to steam in the boiler segment through superheater tubes, which
is further used in electricity generation and heating. The hot flue gas is then passed
through flue gas purification system (facilitated with water scrubber) for cleaning and
lowering of temperature before being emitted to the atmosphere. The emitted gas
consists of CO 2 , N 2 O, NO x , NH 3 , and organic C. Methane generation during waste
incineration process is minimum and only arises in exceptional cases (from remain
over waste in waste bunker), therefore quantitatively it is not regarded as climate
relevant. In incineration unit, CO 2 constitutes the main climate-relevant emission.
Moreover, the residues of the process include ash and flue gas purification residues.
However, incineration is still not an ideal technology for municipal solid waste in
many developing nations due to high proportion of food waste and moisture content.
In Germany, incineration of 1 t of MSW was generally associated with the release
of nearly 0.7–1.2 t of CO 2 [93]. Bogner et al. [5] estimated the release of GHG
from waste incineration approximately 40 Mt CO 2 e year
−1 . The CO 2 emission from
incineration unit in European Union was reported as 9 Mt CO 2 e year
−1 [20].
5.5 GHG Emissions from Landfill
Landfills are the significant contributors to anthropogenic climate change and one
of the primary sources of global GHG emissions specially CH 4 , accounting for
1–2% of total emissions [101]. The yet another large source of releases of CH 4
and N 2 O from the waste sector is leachates from landfill sites [101]. The landfill
GHG emissions are mainly influenced by landfill volume, age of the disposed waste,
temperature, and moisture content [101]. In addition, fates of the carbon in the waste
including carbon sequestered in landfills, in CO 2 from collection, decomposition,
combustion and oxidation as well as in CH 4 emitted to the atmosphere, are the major
determinants of GHG productions from landfills [101]. Therefore, different stages
of MSW management also influence the emissions of GHGs from landfill sites [91].
Bogner et al. [5] reported that landfill CH 4 emission in Europe, the USA, and South
Africa in the ranged between 0.1 and 1.0 t CH 4 ha
−1 day
−1 . Since 2009, British
landfill greenhouse gas emissions have declined. Tiseo [86] found ~50% reduction
in GHG emissions from 2009 (29 million metric tonne (MMt) CO 2 e year
−1 ) to
2018 (14.1 MMt CO 2 e year
−1 ) in the UK with the lowest emission recorded in
year 2016 (13.9 MMt CO 2 e year
−1 ). In a study conducted by [33] on landfills in
139
5.4 GHG Emissions from Incineration and Thermal
Treatments
Incineration or thermal treatment unit consists of a fuel chamber where fossil fuel
such as natural gas/oil is used only for the startup and shutdown of the operations.
Besides, it is composed of a combustion chamber for transformation of waste into ash
and flue gas. The combustion chamber is equipped with an airflow passage, which
provides oxygen for combustion. The thermal energy generated from the combustion
of waste is transferred to steam in the boiler segment through superheater tubes, which
is further used in electricity generation and heating. The hot flue gas is then passed
through flue gas purification system (facilitated with water scrubber) for cleaning and
lowering of temperature before being emitted to the atmosphere. The emitted gas
consists of CO 2 , N 2 O, NO x , NH 3 , and organic C. Methane generation during waste
incineration process is minimum and only arises in exceptional cases (from remain
over waste in waste bunker), therefore quantitatively it is not regarded as climate
relevant. In incineration unit, CO 2 constitutes the main climate-relevant emission.
Moreover, the residues of the process include ash and flue gas purification residues.
However, incineration is still not an ideal technology for municipal solid waste in
many developing nations due to high proportion of food waste and moisture content.
In Germany, incineration of 1 t of MSW was generally associated with the release
of nearly 0.7–1.2 t of CO 2 [93]. Bogner et al. [5] estimated the release of GHG
from waste incineration approximately 40 Mt CO 2 e year
−1 . The CO 2 emission from
incineration unit in European Union was reported as 9 Mt CO 2 e year
−1 [20].
5.5 GHG Emissions from Landfill
Landfills are the significant contributors to anthropogenic climate change and one
of the primary sources of global GHG emissions specially CH 4 , accounting for
1–2% of total emissions [101]. The yet another large source of releases of CH 4
and N 2 O from the waste sector is leachates from landfill sites [101]. The landfill
GHG emissions are mainly influenced by landfill volume, age of the disposed waste,
temperature, and moisture content [101]. In addition, fates of the carbon in the waste
including carbon sequestered in landfills, in CO 2 from collection, decomposition,
combustion and oxidation as well as in CH 4 emitted to the atmosphere, are the major
determinants of GHG productions from landfills [101]. Therefore, different stages
of MSW management also influence the emissions of GHGs from landfill sites [91].
Bogner et al. [5] reported that landfill CH 4 emission in Europe, the USA, and South
Africa in the ranged between 0.1 and 1.0 t CH 4 ha
−1 day
−1 . Since 2009, British
landfill greenhouse gas emissions have declined. Tiseo [86] found ~50% reduction
in GHG emissions from 2009 (29 million metric tonne (MMt) CO 2 e year
−1 ) to
2018 (14.1 MMt CO 2 e year
−1 ) in the UK with the lowest emission recorded in
year 2016 (13.9 MMt CO 2 e year
−1 ). In a study conducted by [33] on landfills in