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Table 2 Assumptions used in MFA and LCA

From: Material flow analysis and life cycle assessment of solid waste management in urban green areas, Thailand

Assumption

Ref.

Goal and scope

 

- Environmental impacts from upstream life cycle stages before the SW collection were excluded

- Environmental impacts of the infrastructures, capital goods, and wastewater treatment from the treatment plants were also excluded

- The collection and the source separation assumed to have no material and energy consumption

[3, 8, 23]

LCI

MFA

Considered transfer coefficients are recycling process (25.5%-plastic,11%-paper, 0%-glass, 16.5%-aluminum), 35%-composting process, and 17%-incineration process

[24, 27, 28]

  

- Emissions of biogenic CO2 were assumed to be neutral

[27, 29]

 

Landfilling with gas recovery

- The efficiency of the landfilling system with gas recovery is 50%

[27, 29]

 

Recycling system

- Secondary products produced from the recycling process replace the production of alternative products. The potential avoidance of primary products (90%-plastic, 95%-glass, 90%-paper, 75%-aluminum)

[30, 31]

 

Composting process

- Compost produced from the composting process replaces the chemical fertilizers in S4. The potential avoidance of chemical fertilizer usage is 7.1 kg N, 4.1 kg P2O5, 5.4 kg K2O t− 1 of compost.

[30, 31]

 

Incineration process

- The electricity recovering efficiency at the incineration plant for S2 and S3 is 8% and for S4 20%

- Electricity produced from incineration displaces an equivalent amount of electricity generated

 
 

Transportation

- Transport distances

50 km (to landfill)

10 km (to composting plant)

100 km (to incineration plant)

50 km (to recyclable waste collection plant)

- the process “Transport, municipal waste collection, 21 t lorry and freight, lorry” for waste transportation to the landfill site, composting plant, and incineration plant

- the process “Transport, freight, lorry, unspecified” was selected for the transportation of recyclable waste to the treatment facility