294 11 The Disposal of Municipal Solid Wastes
landfill (C); leachate collection system (D); ground
water protection base (E); monitoring liner system (F);
secondary protection base (G). The details of the vari-
ous parts of a landfill are in Parts A to G of Fig. 11.5.
The aspects of landfills and their ancillary activities
dealing with ground water, surface water, and methane
gas monitoring are discussed in Fig. 11.8 (Anonymous
2010i).
(A) Protective Cover- Grass and flower cover
As portions of the landfill are completed, they
are planted over with native grass and shrubs,
no trees whose roots will penetrate deep are
included. The vegetation is aesthetically
pleasing and helps prevent erosion. It will
resemble an open space with rolling hills of
wild flowers. - Top soil
This provides the root system with support
and nutrients for the vegetation growing on
the erstwhile landfill. - Soil, sand, and gravel
This protects the liner system from direct rain
and borrowing animals and provides addi-
tional moisture retention to help support the
plant on the top soil.
(B) Moisture Barrier Cap - Filtering system
A fabric composed of felt-like plastic acts as a
filtration system. The geotext prevents the
overlying soil and small particles from clog-
ging the underlying drainage system. High
density polyethylene geo net is a heavy plastic
with large mesh-like openings. The geo
net allows liquid to flow away from the land-
fill and helps prevent the infiltration of rain
water. - Plastic shield
High density polyethylene liner shields the
landfill from liquid penetration. - Clay shield
When the landfill reaches its permitted height,
a minimum of 18 in. layer of re-compacted
clay is placed over the garbage. This liner is
another system which provides an excellent
Fig. 11.7 Vertical section of a generalized landfill (From http://
tontitown.wm.com/documents/tontitown_landfill_anatomy.pdf.
With the kind permission of Waste Management Inc., Texas,
Houston)