Definition
A fairly impermeable seal, usually composed of clay-type soil or a combination of clay soil and synthetic liner, which is placed over a landfill during closure. The cap serves to minimize leachate volume during biodegradation of the waste by keeping precipitation from percolating through the landfill. The cap also keeps odors down and animal scavengers from gathering.
See also:
Hazardous Waste
A subset of solid wastes that pose substantial or potential threats to public health or the environment and meet any of the following criteria: -is specifically listed as a hazardous waste by EPA; - exhibits one or more of the characteristics of hazardous wastes (ignitability, corrosiveness, reactivity, and/or toxicity); - is generated by the treatment of hazardous waste; or is contained in a hazardous waste.
Solid Waste
As defined under RCRA, any solid, semi-solid, liquid, or contained gaseous materials discarded from industrial, commercial, mining, or agricultural operations, and from community activities. Solid waste includes garbage, construction debris, commercial refuse, sludge from water supply or waste treatment plants, or air pollution control facilities, and other discarded materials.