Lesson 12: MSW Landfills

Introduction

Read:

• Text: Chapter 8, pp. 102-123
• Review: RCRA - Introduction to Municipal Solid Waste Disposal Facility Criteria (EPA Document, PDF file)
  • **be sure to read all bold headings and a few sentences under each to get a sense of what they address

Operation: spread refuse in thin layer, compact it, place daily cover (soil, ADC, geonet, tarp, etc.) over waste at end of day

Compaction of Placed Waste  (Note: New Construction)	Compaction of Daily Cover

 

Equipment Used to Apply Foam as Daily Cover Material

 

Older Landfill(Note Covered Waste Cells  and Recently Placed Waste at Right)

• Moisture
  • Dry LF - keep waste dry to limit biological activity
  • Wet LF - leachate recirculation used to moisten waste, bioreactor
• Use
  • Municipal (sanitary)
  • Hazardous
  • Controlled LF - co-disposal
• Configuration
  • Above ground LF - catch pan design - 3:1 or 4:1 slope
  • Under ground LF - valley or depression used
• Special LF
  • Conventional
  • LF for milled (shredded) SW (35% greater in place density, daily cover not required)
  • Bale fills - waste compacted and baled prior to placement
  • ”Mono-fill” LF - specialized cells - aesbestos, incinerator ash, anaerobic decomp of yard waste

• Excavation method - ground water table (GWT) is distant from surface
  • Trenches are excavated,L=100-400ft, W=15-25ft, D=10-15ft
  • SW is dumped into trenches
  • Tractors/compactors spread & compact refuse by pushing it up the working face - multiple passes are made to maximize compaction
  • Soil cover is placed on refuse, obtained from excavation
• Above ground method - used when excavation method is not feasible
  • SW is unloaded and spread in long narrow strips (15-30in thick)
  • Placement in strips is repeated multiple times until a predetermined cell thickness is reached (usually 5-20 ft)
  • Cover soil is applied (6-12in) at end of day (geotextiles, foams, ground tires, compost, and other materials are often used)
  • Embankment (working face) slope - 3:1 or 4:1
• Canyon/depression method
  • Similar operational technique to Above Ground Method
  • Used in areas where depressions (natural or artificial) exist, (canyons, valleys, ravines, borrow pits)

• Leachate recirculation system (LRS)used to enhance biological activity
  • Accelerate Lf stabilization
  • Accelerate decomposition of organic SW
  • In-situ storage and treatment facilities for leachate
  • Increase biogass production
  • Reduce liability, care, and post-closure costs
  • Attenuation capacity against toxicity

Vertical Wells for Leachate Introduction	Lysimeter at Delaware Solid Waste   Authority Note: Leachate Wells

• Co-disposal with sewage sludge
  • Moisture
  • Micro-organisms
  • Buffering capacity
  • Nutrients
• Gas recovery systems - energy recovery

• Large enough to accomodate the SW needs of the area it serves (lifetime, 10 yrs)
• Compatible with the local SW management programs
• Site must protect public health, safety, welfare, & environment
• Minimize adverse impacts on surrounding area
• Minimeze adverse impacts on property value
• Minimize impacts on traffic flow
• Minimize potential for fire, spill, accidents
• Outside the 100 year flood plain
• Far from airports (birds) - 10,000’ from jet ports, 5,000’ from other airports
• Provide emergency response plan including notification, evacuation, & containment procedures

Factors Affecting site selection

• Land availability
• Haul distance
• Impact on SW management program
• Soil conditions and topography
• Geological conditions - no LF within 200’ of fault or unstable area, seismic activity
• Hydrologic conditions (surface and ground water) ----- leachate concerns
• Climatic conditions (rainfall and wind)
• Environmental and ecological conditions
• Public input and concerns - NIMBY, NIMTOO
• Potential use after closure

• leachate -
• LCRS (LCS) -
• LRS
• GCS -
• lifts -
• cells -
• cover -
• cap -