TM 5-814-7
The structure should be designed to prevent all rainfall
dated by compactors to minimize settlement.
from entering the cell until final cover is completed; then
(1) Support equipment for a secure landfill
it is dismantled and erected over the next cell. Another
may include a road grader, water truck, pickup trucks
alternative to operations during extremely wet weather is
and vacuum trucks. The road grader can be used to
to containerize or store wastes until the rainfall season is
maintain dirt and gravel roads on the site, to grade the
over. As areas of the secure landfill are filled to final
soil cover, and to maintain any unlined drainage
grade, a final soil cover is installed in accordance with
channels surrounding the fill. Water trucks range from
the facility's operation plan. Figure 5-2 illustrates a
converted tank trucks to highly specialized, heavy
typical landfill operations plan.
vehicles that are generally used in road construction
d. The major design elements of hazardous
operations. They are used at the landfill for construction,
to control dust, and if necessary, fight fires.
wastes landfills, discussed in detail in chapter 6, are:
(2) In accordance with 40 CFR 264.32, all
Double liners
facilities must be equipped with communication or alarm
A leak detection system between the liners
systems, fire control equipment, spill control equipment,
A leachate collection and removal system
and decontamination equipment (unless an exemption is
above the liner
obtained from the EPA Regional Administrator [RA]).
Run-on and run-off control systems
Paragraph 7-1 describes procedures and equipment
A final cover to minimize infiltration of
required for facility contingency plans.
precipitation into the closed landfill
(3) All equipment used to unload and
(1) The base liner system is designed and
place wastes must be decontaminated before being
constructed to prevent migration of wastes during the
taken out of the disposal operation and staging area.
active life of the disposal unit into the liner, and out of the
Incoming vehicles not used in the unloading operation
landfill into subsurface soil, ground-water or surface
should be restricted to staging areas, or clean soil areas
water. A leak detection system between the double
within the landfill.
liners enables the detection and removal of any seepage,
and evaluation of liner performance.
(2) Located above the double liners is the
5-3. Surface Impoundments
leachate collection and removal system, which consists
a. Wastes
suitable
for
impoundments.
of slotted drainage pipes designed to collect leachate
Surface impoundments are used for the evaporation and
that flows under the influence of gravity to low points
treatment of bulk aqueous wastes. Typical DA wastes
within the landfill. The leachate collection and removal
which
would
be
considered
appropriate
for
system must be designed and operated to ensure that
impoundments include waste acids and rinse water with
the depth of leachate over the liner does not exceed 1
traces of propellant. Reactive wastes must not be
foot.
placed in a surface impoundment unless they are made
e. Closure. Closure of a landfill is achieved by
nonreactive and defined in 40 CFR 261.23. Since mixing
installing a final cover which has a permeability less than
of wastes is inherent in a surface impoundment,
or equal to that of the bottom liner. The cover should be
incompatible wastes should not be placed in the same
capable of (1) minimizing infiltration of liquids, (2)
impoundment. The potential dangers from the mixing of
functioning with minimum maintenance, (3) promoting
incompatible wastes include extreme heat, fire,
drainage and minimizing erosion of cover, and (4)
explosion, violent reaction, production of toxic mists,
accommodating settling and subsidence.
fumes, dusts, or gases, and damage to the structural
f.
Equipment needs. Secure landfills require
integrity of the surface impoundment.
Clearly the
equipment for (1) handling wastes and cover material,
potential inpacts on human health or the environment
(2) performing support functions, (3) spill and fire control,
which could result from such conditions must be avoided.
and (4) decontamination. For waste handling, a forklift
b. Disposal
constraints.
Surface
and a front-end loader are typically used to unload and
impoundments should be located in a hydrogeologic
place containers and solid materials in assigned active
setting that limits vertical and horizontal hydraulic
waste lifts. Dozers and self-loading scrapers are used to
continuity with ground-water. Surface impoundments
spread and compact cover material. For grading final
should be sited and designed with maximum protection
surfaces, the crawler dozer is effective; it can
of groundwater provided by liners, and low-permeability
economically doze earth over distances up to 300 feet.
underlying soils. The hydraulic head formed in the
Scrapers can haul cover material economically over
impoundment provides for a high potential for liquid
relatively long distances (more than 1, 000 feet). Since
seepage and subsurface migration. The precautions
construction equipment is heavy when loaded,
concerning location of landfills in karst terrain or seismic
precautions must be taken in placing initial lifts of wastes
zones 3 and 4 also pertain to surface impoundments
over the base liner. Subsequent lifts of bulk wastes and
(see para 5-2b(2)).
soil cover should be consoli-
5-4
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