Environmental Engineering Reference
In-Depth Information
Figure 4.2
Operational (469) and candidate (520) landfi ll gas energy projects in the United States as
of December 2008. (Landfi ll Methane Outreach Program)
percent in landfi ll air. The economic benefi t is clear. For example, at the
world's largest landfi ll in New York City, enough methane is recovered
to satisfy the energy needs of 12,000 households.
Closing a Landfi ll
The size of a landfi ll cannot be increased indefi nitely. At some point, the
fi nal covering of dirt will occur, and a new means of getting rid of the
city's garbage must be found. For many municipalities the solution is to
give it to someone else for disposal. The amount of garbage moved across
state lines for immoral purposes is almost unbelievable (fi gure 4.3).
Many of the eighteen-wheelers on interstate highways are carrying
garbage to far-away places.
