Types of U.S. solid waste
Municipal urban solid waste
•
Solid waste/person/day: ~5 lbs
•
By economic sector (%):
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demolition (building materials) 40%,
•
residential 30,
•
commercial 20,
•
industrial 2,
•
misc 8%.
Types of Municipal solid waste
•
•
paper (38%)
•
building, rubber, textiles (15%),
•
plastic (8%),
•
glass (7%),
•
yard clippings (18%),
•
food (7%).
Methods of disposal
1) Isolation by
• sealing (e.g. landfills),
• burial (deep wells- liquid waste),
• geologic repository (solid nuclear waste).
• 2) Attenuation by
• dilution (e.g. add water)
• or spreading thin (farm waste).
• 3) Recycling
Landfills
Waste Groups
• Group I. Toxic liquids, solids, fertilizers, pesticides, heavy metals, brines, toxic
chemicals.
• Group II. Household and commercial garbage
• Group III. Non-soluble solid waste: concrete, glass, rubber etc.
Classes of landfills
•
Class I: totally impermeable to and away from groundwater. Takes Group I waste.
•
Class II: near groundwater but sealed. Takes Group II waste.
•
Class III. No protection from groundwater. Takes Group III waste only.
From dumps to landfills
•
Bottom of landfill lined w/ plastic or clay
•
Each days trash compacted by tractors and isolated with 6” clay soil cover.
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Pile consists of “cells” of daily trash.
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Landfill covered with 20” clay.
•
Leachate tank- collects liquid from pile and recycles or stores.
Ocean dumping
•
Ocean dumping common prior to 1991 Ocean dumping act.
•
Sludge in coastal waters:
•
Organic pollutants
•
Heavy metals
•
Pesticides and fertilizers
Nuclear waste
•
High level radiation from spent fuel.
•
Alpha, beta and gamma radiation.
•
Need long term isolation (10,000 yrs).
•
Geological repository (Yucca Mt, Nevada ).
•
Will be operative 2010 ? (currently in water filled pools).
•
Stored 300 below ground, but above water table in pyroclastic volcanic rock.
end