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M. Gautam and M. Agrawal
5.2 GHG Emissions from Waste Segregation and Material
Recycling Facilities
Waste segregation and recycling replace the raw materials in production, reduce the
cost incurred and energy consumption in production processes, and minimize the
GHG emissions during further management processes [5]. The MSW is maximally
contributed by organic wastes such as domestic and agricultural wastes, and recyclable materials as stated previously [34]. Organic wastes have high proportion of
moisture content whose treatments consume more energy and thus there are more
gaseous emissions. Similarly, in the process through recovery of recyclable materials such as glass, metals, and plastic, quality cascading occurs in many countries at
large scale, which is energy consuming [96]. Nonetheless, most developed countries
and some developing nations have implemented comprehensive recycling programs
for recycling of materials in order to reduce the burden on MSW management. All
these lead to indirect energy conservation and great reduction in GHG emissions.
[81] thoroughly addressed the GHG emissions’ benefits from recycling across the
European Union (EU). Pimenteira et al. [69] quantified GHG emission reductions
from recycling in Brazil. At Beijing in China, total GHG emanations from incineration were reduced by 0.0251 t CO 2 e after sorting and recycling of MSW at material
recycling facility [96].
5.3 GHG Emissions from Composting and Anaerobic
Digestion
Several developed and developing nations practice anaerobic digestion and
composting of mixed biodegradable waste fractions (kitchen, garden and agricultural wastes, etc.). Generally, composting is applicable to dried waste, while anaerobic digestion is more suited for wet waste [5]. Composting decomposes waste into
CO 2 , water, and compost with high humic acid content, whereas anaerobic digestion
of waste in the absence of air leads to CH 4 generation. Composting is relatively
cost-effective and sustainable approach in managing MSW in developing countries,
and yields compost. Depending on compost quality and properties of soil, there are
several probable applications for MSW compost in agriculture and horticulture to
stabilize and improve soil quality [13]. Xin et al. [96] reported that compost is the
fraction of MSW, which emits least GHGs and further reported that the GHG emissions t
−1 of waste composting is only 0.177 t CO 2 e in China. A study conducted by
[61] in Queensway, UK found that GHG emissions from normal composting release
470 kg CO 2 e t
−1 of waste, while solid anaerobic digestion batch with inoculum and
postcomposting reduce the generation to 382 kg CO 2 e t
−1 of waste. Kristanto and
Koven [54] reported that GHG emissions from anaerobic digestion and composting
resulted in net emissions of GHG of 40 and 340 t CO 2 e day
−1 in Depok, Indonesia.
M. Gautam and M. Agrawal
5.2 GHG Emissions from Waste Segregation and Material
Recycling Facilities
Waste segregation and recycling replace the raw materials in production, reduce the
cost incurred and energy consumption in production processes, and minimize the
GHG emissions during further management processes [5]. The MSW is maximally
contributed by organic wastes such as domestic and agricultural wastes, and recyclable materials as stated previously [34]. Organic wastes have high proportion of
moisture content whose treatments consume more energy and thus there are more
gaseous emissions. Similarly, in the process through recovery of recyclable materials such as glass, metals, and plastic, quality cascading occurs in many countries at
large scale, which is energy consuming [96]. Nonetheless, most developed countries
and some developing nations have implemented comprehensive recycling programs
for recycling of materials in order to reduce the burden on MSW management. All
these lead to indirect energy conservation and great reduction in GHG emissions.
[81] thoroughly addressed the GHG emissions’ benefits from recycling across the
European Union (EU). Pimenteira et al. [69] quantified GHG emission reductions
from recycling in Brazil. At Beijing in China, total GHG emanations from incineration were reduced by 0.0251 t CO 2 e after sorting and recycling of MSW at material
recycling facility [96].
5.3 GHG Emissions from Composting and Anaerobic
Digestion
Several developed and developing nations practice anaerobic digestion and
composting of mixed biodegradable waste fractions (kitchen, garden and agricultural wastes, etc.). Generally, composting is applicable to dried waste, while anaerobic digestion is more suited for wet waste [5]. Composting decomposes waste into
CO 2 , water, and compost with high humic acid content, whereas anaerobic digestion
of waste in the absence of air leads to CH 4 generation. Composting is relatively
cost-effective and sustainable approach in managing MSW in developing countries,
and yields compost. Depending on compost quality and properties of soil, there are
several probable applications for MSW compost in agriculture and horticulture to
stabilize and improve soil quality [13]. Xin et al. [96] reported that compost is the
fraction of MSW, which emits least GHGs and further reported that the GHG emissions t
−1 of waste composting is only 0.177 t CO 2 e in China. A study conducted by
[61] in Queensway, UK found that GHG emissions from normal composting release
470 kg CO 2 e t
−1 of waste, while solid anaerobic digestion batch with inoculum and
postcomposting reduce the generation to 382 kg CO 2 e t
−1 of waste. Kristanto and
Koven [54] reported that GHG emissions from anaerobic digestion and composting
resulted in net emissions of GHG of 40 and 340 t CO 2 e day
−1 in Depok, Indonesia.