Nusa Dua, Bali, Indonesia

1

• Part 2
• LFG Generation

2
LFG Generation

• Factors that affect LFG generation
• Waste Management and Processing Variables
• Baling of waste
• Shredding and crushing
• Design
• Landfill dimensions (area and depth)
• Gas containment (liner and cover)
• Gas extraction system

3
LFG Generation

• Factors continued
• Landfill Operations
• Day-to-day refuse handling
• Degree of compaction or segregation
• Cover characteristics
• Degree of material breakdown
• Liquid Addition
• Managed (liquid additions and leachate
  recirculation)
• Natural (precipitation and groundwater
  infiltration)
• Post-closure changes (infiltration and leachate
  movement)

4
LFG Generation

• Factors continued
• Waste Composition
• Organic content ()
• Proportion of organics (food, paper, and wood)
• Rate of decomposition
• Biological Factors
• Moisture (quality, seasonal, and movement)
• Nutrients (availability and movement)
• Bacteria (location, density, and mobility)
• pH
• Temperature

5
LFG Generation

• Factors continued
• It is difficult to predict the rate, extent, and
  timing
• of LFG generation. Some of the uncertainties
• include
• Waste placement (history, location, and
  composition)
• Moisture content (significant effect on LFG
  production)
• Biological parameters (nutrients, temperature,
  and pH)
• LFG collection efficiencies

6
LFG Generation
7
LFG Generation

• Steps for assessing LFG generation potential
• STEP ONE
• LFG Modelling exponential decay model typically
  used to
• Determine size of LFG collection systems
• Estimate gaseous emissions to the environment
• Evaluate the benefits of LFG utilization
• Example Landfill Gas Emissions Model a.k.a.
  LandGEM
• developed by US EPA
• Automated tool for estimating emission rates for
  total LFG, methane, carbon dioxide, etc. from
  municipal solid waste (MSW) landfills
• Available for free download from US EPAs
  Technology Transfer Network website at
  www.epa.gov/ttn/catc/products.html

8
LFG Generation

• Typical LFG Modelling Input
• Year landfill opened
• Landfill closure year
• Waste design capacity
• Waste acceptance rate
• k value methane generation rate (default 0.05)
  
• Lo value potential methane generation capacity
  (default 170 m3 CH4/tonne of MSW)
• Methane content (default 50)

9
LFG Generation

• Typical LFG Modelling Output

10
LFG Generation

• STEP TWO
• LFG Extraction Testing
• involves installing one or
• more extraction wells and
• monitoring probes in the
• refuse. Used to measure
• Gas pressure
• Gas composition distribution
• Zone of influence
• Extent of air intrusion

11
LFG Generation

• Typical LFG Extraction Test Set-Up

12
LFG Generation

• Typical LFG Extraction Test Layout