Botkin Environmental Science Earth as Living Planet 8th txtbk

536 CHAPTER 23 Materials Management
Monitoring well
above water table
Monitoring well
below water table
Solid waste
Sand layer
Compacted clay cap
Compacted
clay liner
Plastic liner
Water table
Leachate
collection pipe
Groundwater flow
(a)
FIGURE 23.14 (a) Idealized diagram of a solid-waste facility
(sanitary landfill) illustrating multiple-barrier design, monitoring
system, and leachate collection system. (b) Rock Creek landfill
under construction in Calaveras County, California. This municipal
solid-waste landfill is underlain by a compacted clay liner,
exposed in the center left portion of the photograph. The darker
slopes, covered with gravel piles, overlie the compacted clay
layer. These form a vapor barrier designed to keep moisture in
the clay so it won’t crack. Trenches at the bottom of the landfill
are lined with plastic and are part of the leachate collection system
for the landfill. The landfill is also equipped with a system to
monitor the water below the leachate collection system.
(b)
Landfills must have liners.
Landfills must have a leachate collection system.
Landfill operators must monitor groundwater for many
specified toxic chemicals.
Landfill operators must meet financial assurance criteria
to ensure that monitoring continues for 30 years after
the landfill is closed.
EPA approval of a state’s landfill program allows
greater flexibility:
Groundwater monitoring may be suspended if the
landfill operator can demonstrate that hazardous constituents
are not migrating from the landfill.
Alternative types of daily cover over the waste may be used.
Alternative groundwater-protection standards are
allowed.
Alternative schedules for documentation of groundwater
monitoring are allowed.
Under certain circumstances, landfills in wetlands and
fault zones are allowed.
Alternative financial assurance mechanisms are allowed.
Given the added flexibility, it appears advantageous for
states to develop EPA-approved waste-management plans.
Reducing the Waste
that Ends Up in a Landfill
Most of the municipal solid waste we generate is from our
homes, and over 50% of it could be diverted from the landfill
by the 3 R’s of waste management: reduce, reuse, and
recycle. Diversion may eventually be increased to as much
as 85% through improved waste management. In other
words, the life of the landfill can be extended by keeping
more waste out of the landfill through conservation and
recycling, or by turning waste, even waste that is presently
buried, into a source of clean energy. The latter involves
first removing materials that can be recycled, then linking
noncombustion thermal or biochemical processes with the