Municipal solid waste landfill age and refuse-derived fuel

Area of Science:

• Environmental Science
• Waste Management
• Material Science

Background:

• Taiwan faces challenges in securing new landfill sites.
• Closed landfills contain municipal solid waste (MSW) with significant combustible content and calorific value (CV).
• Repurposing closed landfills as 'municipal mines' can extend their lifespan and promote environmental sustainability.

Purpose of the Study:

• To investigate the characteristics of MSW from landfills of varying landfill ages (LAs).
• To analyze the manufacturing conditions and combustion behavior of refuse-derived fuel (RDF) produced from this MSW.
• To determine optimal parameters for RDF production to maximize its fuel potential.

Main Methods:

• MSW was collected from closed landfills of different LAs.
• Combustibles were transformed into RDF through pretreatment and squeeze forming.
• Characteristics of MSW, RDF manufacturing conditions, and RDF firing behavior were analyzed.
• Fixed carbon initiation temperatures and calorific values were measured.

Main Results:

• The proportion of combustibles in MSW decreases as LA increases; incombustible materials and soil increase correspondingly.
• Landfill age (LA) is negatively correlated with the calorific value (CV) of MSW.
• MSW from a 10-year LA still shows high potential as fuel material.
• Fixed carbon initiation temperatures decreased with increasing LA (1-year: 259°C, 5-year: 256°C, 10-year: 245°C).
• RDF's CV and flame temperature increased with squeeze temperature (ST) up to 120°C, then decreased at 130°C.

Conclusions:

• MSW from older landfills has reduced combustible content but remains a viable fuel source.
• Optimal RDF production involves specific squeeze pressure (41.65 ± 8.24 kg cm⁻²), ST (110°C), and combustible size (10-20 mm).
• This approach supports sustainable waste management by transforming landfill waste into valuable RDF.