A landfill, also known
as a dump, is a site
for the disposal of
waste materials by
burial and is the
oldest form of waste
have been the most
common methods of
disposal and remain
so in many places
around the world.
When constructing a landfill:
• an area is filled in a single, well-defined "cell"
• and a rubberized HDPE or clay landfill liner is put in place
• this is to prevent contamination by leachates migrating downward through
the underlying geological formation.
Leachate is liquid generated from rainfall and the natural decomposition of waste
that is filtered through the landfill to a leachate collection system. The leachate
collection system's job is to direct the leachate to collection sumps so it can be
properly removed from the landfill.
The leachate collection system is designed with a minimum 2 percent slope to drain
to collection sumps. A leachate collection sump consists of an HDPE riser and
submersible pump. Leachate drains to the leachate collection system, and the
leachate is then piped to an onsite leachate storage tank. The leachate is transported
to an approved offsite wastewater treatment plant for disposal.
• When the growth of a landfill is at its maximum capacity, landfill covers are installed.
• Geosynthetic material keeps the waste from being exposed to the outside elements.
• The accumulation and treatment of leachate can be reduced dramatically when the
outside elements are kept from contacting the waste.
• Once covered, gases are directed to a flare and/or vents.
• This reduction of leachate and treatment is a definite cost savings
o All landfills will eventually fail and leak leachate into ground and surface water.
o Plastics are not inert.
o State-of-the-art plastic (HDPE) landfill liners (1/10 inch or 100 mils thick) and plastic pipes allow chemicals
and gases to pass through their membranes, become brittle, swell, and breakdown.
• Not only will household chemicals, such as moth balls, degrade HDPE, but much more benign
things can cause it to develop stress cracks, such as, margarine, vinegar, ethyl alcohol (booze),
shoe polish, peppermint oil, to name a few.
they clog up from silt or mud;
they can clog up because of growth of microorganisms in the pipes;
they can clog up because of a chemical reaction leading to the
precipitation of minerals in the pipes; or
the pipes become weakened by chemical attack (acids, solvents,
oxidizing agents, or corrosion) and may then be crushed by the tons of
garbage piled on them.
Problems with Covers
Erosion by natural weathering (rain, hail, snow, freeze-thaw cycles, and
Vegetation, such as shrubs and trees that continually compete with
grasses for available space, sending down roots that will relentlessly
seek to penetrate the cover;
Burrowing or soil- dwelling mammals (woodchucks, mice, moles,
voles), reptiles (snakes, tortoises), insects (ants, beetles), and worms
will present constant threats to the integrity of the cover;
Sunlight (if any of these other natural agents should succeed in
uncovering a portion of the umbrella) will dry out clay (permitting cracks
to develop), or destroy membrane liners through the action of ultraviolet
Subsidence--an uneven cave-in of the cap caused by settling of wastes
or organic decay of wastes, or by loss of liquids from landfilled drums-can result in cracks in clay or tears in membrane liners, or result in
ponding on the surface, which can make a clay cap mushy or can
subject the cap to freeze-thaw pressures;
Rubber tires, which "float" upward in a landfill; and
Human activities of many kinds.
Gasses found in landfills:
The gasses that are produced in landfills are due to the anaerobic
digestion by microbes on any organic matter.
The typical constituents of gases produced by a municipal solid
Percent (dry volume basis)*
Methane : It is often flammable and sometimes even explosive.
Carbon Dioxide: Non harmful to the environment
Nitrogen: Non harmful to the environment
• Ammonia: Ammonia in air is an irritant and causes burning of the
eyes, nose, throat and lungs.
Leading Importers of Waste
Leading Exporters of Waste
In making bacterial plastics, biotechnologists introduce bacterial
genes into plants. These genes code for the enzymes to make
bacterial plastics. The plants are grown and harvested, and the
plastics are extracted from the plant material.
Bioplastics have the advantage of being produced from renewable
resources (bacteria, plants) rather than nonrenewable resources
(oil, natural gas). Furthermore, bioplastics are biodegradable -they can break down in the environment.
A bioreactor landfill operates to rapidly transform and degrade
organic waste. The increase in waste degradation and stabilization
is accomplished through the addition of liquid and air to enhance
microbial processes. By efficiently designing and operating a
landfill, the life of a landfill can be extended by as much as 20
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LANDFILLS: Hazardous to the Environment. Zero Waste
America. 2009. Web. 21 Nov. 2009.
“The Basics of Landfills.” Action Center. 2003. Web.
21 Nov. 2009
CRS Report for Congress. 2007. Print. 21 Nov. 2009.
Bioreactor.org. 2009. Web. 21 Nov. 2009.
“How plastics work.” How Stuff Works. 2009. Web. 21