Landfills: An Overview David T. Brown Dept. of Tourism and Environment Brock University St. Catharines, Ontario L2S 3A1 References: O’Leary, Philip & Patrick Walsh. Landfill Course. Waste Age, January 2002 – Janu ary 2003 . TREN 3P14: Sustainable Integrated Waste Management
Landfills: An Overview. TREN 3P14: Sustainable Integrated Waste Management. David T. Brown Dept. of Tourism and Environment Brock University St. Catharines, Ontario L2S 3A1 References: O’Leary, Philip & Patrick Walsh. Landfill Course. Waste Age, January 2002 – January 2003. Landfill. - PowerPoint PPT Presentation
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Landfills: An Overview
David T. BrownDept. of Tourism and EnvironmentBrock UniversitySt. Catharines, Ontario L2S 3A1
References: O’Leary, Philip & Patrick Walsh. Landfill Course. Waste Age, January 2002 – January 2003.
TREN 3P14: Sustainable Integrated Waste Management
• typical landfill consists of several cells in which the waste is systematically placed
• Landfill base usually consists of a liner (clay or synthetic) that minimizes the leakage of liquid waste materials and leachate into groundwater system
• Wastes covered daily with soil, geomembranes, or other cover materials to prevent lightweight wastes, dust, and odors from escaping and to discourage vermin
Photo: Bung-orn Thirapoj
Weigh Station
Photo: David T. Brown
Weigh Scale operator
Photo: David T. Brown
Truck on weigh scale at entry
Load cell to weigh truckPhoto: David T. Brown
Photo: David T. Brown
Landfill liner detail
Synthetic linerPhoto: David T. Brown
Sanitary Landfill
• Modern landfills are sophisticated facilities that require millions of dollars to build
• Services provided often valued at millions of dollars per year
Sanitary Landfill
• Typical landfill operates between 10 and 20 years
• During this period, waste in the landfill undergoes complicated decomposition processes
Sanitary Landfill
• Decomposition results in the release of:– liquids (leachate)
must be contained in the landfill and treated prior to release
– gases must be managed as they escape through the landfill cover, or are collected for burning or storage
Lined landfill section
Liner
Ponded water
Sand cover to protect and retain plastic liner
Photo: David T. Brown
Leachate retention pond
Culvert
Photo: David T. Brown
Access well in new section
Liner
Access well
Photo: David T. Brown
Sanitary Landfill
Various options available to landfill operators regarding:
• Preparation of waste before it arrives at the landfill
• Compaction procedures for waste
• Alternatives for managing leachate and gas
Technological innovations
Recent technological innovations include:• improved groundwater monitoring and leachate
collection systems• Improved gas monitoring and collection systems
– meet air pollution control standards– facilitate energy recovery
• installation of geosynthetic covers • introduction of large waste compaction equipment• Development of alternative cover materials installed
Slope Stability• earthquake activity can also potentially
cause slope failure at a large landfill• also an issue at landfills that receive
specialized wastee.g. if wastes contain significant amounts of water, slope stability decreases
Safety Considerations
Worker SafetyMaterials in landfills may be hazardous.
Workers need protection from:
• Sharp, hazardous, infectious or pathogenic wastes• Dust and particulates• Noise and hazards from vehicles and equipment• Fire and explosion• Vermin• Volatile substances, odours• Extreme weather, wind, high and low temperatures• Construction accidents
Photo: Bung-orn Thirapoj
Decomposition in landfills
• The decomposition process is a principal driving force in the development, operation and closure of a landfill
• MSW contains organic material that naturally decomposes when landfilled
Decomposition in landfills
Two phases:
• Aerobic (oxygen present)
• Anaerobic (stages 1 and 2) (little or no oxygen present)
Photo: Bung-orn Thirapoj
Organic refuse
Photo: David T. Brown
Photo: Bung-orn Thirapoj
Decomposition in landfillsBoth aerobic and anaerobic phases have byproducts:
Aerobic phase: • carbon dioxide • contaminated water that flows toward the base of
the landfill
Anaerobic phase: • methane • carbon dioxide• liquid byproducts with various contaminants
• decomposition process continues for many years
• trace quantities of materials which may impact the environment are contained in both landfill gas and leachate (e.g., metals in leachate; VOCs, greenhouse gases)
• trace materials are generated until the landfill becomes completely stabilized (between 300 and 1,000 years)