1. A typical landfill contains layers that protect the environment from waste, including a cover of native vegetation, topsoil, and protective soil to prevent erosion. 2. Below this is a composite cap system with a drainage layer to remove excess water and a plastic geomembrane to prevent water and gas from entering or leaving the landfill. 3. At the base is a liner system with a plastic geomembrane and compacted clay layers to block leachate, along with a leachate collection system of pipes and pumps to safely remove contaminated liquid from the landfill.

1. Typical Anatomy
of a Landfill
Protective Cover
COVER VEGETATION
1
As portions of the landfill are completed,
native grasses and shrubs are planted
and the areas are maintained as open
spaces. The vegetation is visually pleasing
and prevents erosion of the underlying 1
soils.
2 Top Soil
Helps to support and maintain the growth
Leachate
2
of vegetation by retaining moisture and
Collection System
providing nutrients.
Leachate is a liquid that has filtered
through the landfill. It consists primarily of
3 PROTECTIVE COVER SOIL
precipitation with a small amount coming
Protects the landfill cap system and
from the natural decomposition of the
provides additional moisture retention to
waste. The leachate collection system col-
help support the cover vegetation.
3 lects the leachate so that it can be removed
from the landfill and properly treated or dis-
4 posed of. The leachate collection system has
the following components:
Composite Cap System
4 Drainage Layer 9 Leachate Collection Layer
5
A layer of sand or gravel or a thick plastic
A layer of sand or gravel or a thick plastic
mesh called a geonet drains excess precipi-
mesh called a geonet collects leachate and
tation from the protective cover soil to
allows it to drain by gravity to the leachate
enhance stability and help prevent infiltra- 6
collection pipe system.
tion of water through the landfill cap
system. A geotextile fabric, similar in
appearance to felt, may be located on top 10 Filter Geotextile
of the drainage layer to provide separation A geotextile fabric, similar in appearance
of solid particles from liquid. This prevents to felt, may be located on top of the
clogging of the drainage layer. leachate collection pipe system to provide
7
separation of solid particles from liquid. This
5 prevents clogging of the pipe system.
Geomembrane
A thick plastic layer forms a cap that
11 Leachate Collection
prevents excess precipitation from entering
Pipe System
the landfill and forming leachate. This
8
Perforated pipes, surrounded by a bed of
layer also helps to prevent the escape of
gravel, transport collected leachate to
landfill gas, thereby reducing odors.
specially designed low points called sumps.
Pumps, located within the sumps, automati-
cally remove the leachate from the landfill
6 Compacted Clay
and transport it to the leachate management
7
Is placed over the waste to form a cap
facilities for treatment or another proper
when the landfill reaches the permitted
method of disposal.
height. This layer prevents excess precipi-
tation from entering the landfill and
forming leachate and helps to prevent
8
the escape of landfill gas, thereby
Composite Liner System
reducing odors.
12 Geomembrane
A thick plastic layer forms a liner that pre-
Working Landfill vents leachate from leaving the landfill and
entering the environment. This geomem-
9
7 brane is typically constructed of a special
Daily Cover
type of plastic called high-density polyeth-
At the end of each working period, waste
ylene or HDPE. HDPE is tough, impermeable
is covered with six to twelve inches 10
and extremely resistant to attack by the
of soil or other approved material. Daily
compounds that might be in the leachate.
cover reduces odors, keeps litter from
This layer also helps to prevent the escape
scattering and helps deter scavengers.
of landfill gas.
8 Waste
13 Compacted Clay
As waste arrives, it is compacted in layers
within a small area to reduce the volume Is located directly below the geomembrane
consumed within the landfill. This practice and forms an additional barrier to prevent
also helps to reduce odors, keeps litter leachate from leaving the landfill and enter-
11
from scattering and deters scavengers. ing the environment. This layer also helps to
prevent the escape of landfill gas.
14 Prepared Subgrade
12 The native soils beneath the landfill are
Please Note: This illustration
prepared as needed prior to beginning landfill
depicts a cross section of the standard
construction.
environmental protection technologies
of modern landfills. While the tech-
nologies used in most landfills are
similar, the exact sequence and type
13
of materials may differ from site to site
depending on design, location, climate
and underlying geology.
14
(Not to scale)
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