Modern sanitary landfills are carefully engineered structures designed to isolate garbage from nearby water, soil, wildlife, and people.

Today's landfills are designed to stay dry inside, except for liquids that ooze from some garbage, and rainwater that trickles through. As water trickles through a landfill, it dissolves chemicals and other particles, creating a liquid called "leachate." If a landfill isn't lined with clay or plastic and equipped with collection pipes, the leachate can leak out and pollute nearby ground water, wetlands, rivers, and lakes. It couuld even end up in your tap water at home.

Landfills are also nearly airless. Without the oxygen and water needed to break down organic materials, all garbage decays very slowly in a landfill. This means our garbage will probably be around for a very long time.

Features of a modern landfill include:

• clay and plastic liners protect ground water from leachate (the liquid formed when water trickles through a landfill, dissolving chemicals and other particles in it)
  
• collection pipes for leachate
  
• gravel or sand layer
  
• collection pipes for methane (gas given off by slow decay)
  
• cell
  
• bulldozers and compactors
  
• soil cover (keeps out pests, reduces odors, keeps trash from blowing away)
  
• clay or plastic cap
  
• soil layer
  
• landscaping
  
• surface drainage system
  

It's only in the last few years that new landfills have been required to use systems like this for containing leachate. Many older landfills, including Fresh Kills, are still leaking.

Profile: Hazel Johnson and the People for Community Recovery