Greenhouse Gas Emissions from Municipal Solid Waste Management …
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4.2.3 Scenario 3
Composting and incineration units are facilitated with scenario 2, which carries out
segregation of wastes into inorganic and organic followed by aerobic digestion of
biodegradable fraction and recovery of energy from nonbiodegradable. The outputs of
the scenario are GHGs, flue gas, compost, and residues from incinerator (Fig. 6). The
scenario minimizes the waste generation to landfill and GHG emissions compared
with scenario 2.
4.2.4 Scenario 4
Scenario 4 supports the material recycling of waste along with composting and
incineration. Material recycling unit reduces the amount of the wastes to a significant level through the recovery of reusable plastics, glass, and metals. Recovery of
recycling materials followed by composting of biodegradable waste and incineration
of remaining waste leads to disposal of the relatively less fraction of MSW (compost
and residues from incineration) at the landfill (Fig. 6). In this case, emitted CH 4 is
harnessed for energy recovery and thus reduces landfill GHG emissions.
4.2.5 Scenario 5
This is the progressive scenario widely practiced in developed countries and in some
cities of developing countries to manage MSW. The scenario is the combination of
previous four scenarios where after collection, transportation and recycling of materials, equal proportions of biodegradable waste are subjected to anaerobic digestion
and composting followed by incineration and waste disposal at landfill sites (Fig. 6).
Intermediate treatment processes from collection to disposal site reduce the GHG
emissions and landfill waste to a great extent. Landfills are further inculcated with
more advanced system of methane collection and energy generation units.
4.3 Life Cycle Inventories (LCI)
System boundaries are further divided into foreground and background systems [5].
Foreground system is allied to the generation of useful products such as electricity
and compost along with simultaneous emissions to air (e.g. GHG emissions), water
and soil during material recycling, composting, anaerobic digestion, and disposal at
landfill. Background system incorporates the utilization of resources (MSW, energy,
storage containers, and vehicles) to the foreground system [5]. These inputs and
outputs are quantified and qualified during LCI of the various processes involved
in MSW management. Collection of MSW can either be in mixed or segregated
forms. However, wastes in segregated form from point source are highly encouraged
135
4.2.3 Scenario 3
Composting and incineration units are facilitated with scenario 2, which carries out
segregation of wastes into inorganic and organic followed by aerobic digestion of
biodegradable fraction and recovery of energy from nonbiodegradable. The outputs of
the scenario are GHGs, flue gas, compost, and residues from incinerator (Fig. 6). The
scenario minimizes the waste generation to landfill and GHG emissions compared
with scenario 2.
4.2.4 Scenario 4
Scenario 4 supports the material recycling of waste along with composting and
incineration. Material recycling unit reduces the amount of the wastes to a significant level through the recovery of reusable plastics, glass, and metals. Recovery of
recycling materials followed by composting of biodegradable waste and incineration
of remaining waste leads to disposal of the relatively less fraction of MSW (compost
and residues from incineration) at the landfill (Fig. 6). In this case, emitted CH 4 is
harnessed for energy recovery and thus reduces landfill GHG emissions.
4.2.5 Scenario 5
This is the progressive scenario widely practiced in developed countries and in some
cities of developing countries to manage MSW. The scenario is the combination of
previous four scenarios where after collection, transportation and recycling of materials, equal proportions of biodegradable waste are subjected to anaerobic digestion
and composting followed by incineration and waste disposal at landfill sites (Fig. 6).
Intermediate treatment processes from collection to disposal site reduce the GHG
emissions and landfill waste to a great extent. Landfills are further inculcated with
more advanced system of methane collection and energy generation units.
4.3 Life Cycle Inventories (LCI)
System boundaries are further divided into foreground and background systems [5].
Foreground system is allied to the generation of useful products such as electricity
and compost along with simultaneous emissions to air (e.g. GHG emissions), water
and soil during material recycling, composting, anaerobic digestion, and disposal at
landfill. Background system incorporates the utilization of resources (MSW, energy,
storage containers, and vehicles) to the foreground system [5]. These inputs and
outputs are quantified and qualified during LCI of the various processes involved
in MSW management. Collection of MSW can either be in mixed or segregated
forms. However, wastes in segregated form from point source are highly encouraged