HDPE Aids Methane Recovery Project
Idaho landfill uses pipeline grid to capture methane and convert to energy to serve 24,000 homes
Drive down any Idaho highway and you’re sure to be
amazed. With a landscape that ranges from sub-alpine to
desert, lakes and waterfalls to canyons and fertal farms,
Idaho is a study in geographic diversity. It is evident to the
observer that the people of Idaho have a lot to be proud
of, and that they are taking care of their piece of America.
They even design their landfills to be aesthetically pleasing
and are now taking it a step further by insuring they don’t
pollute the environment.
Methane gas created by decomposing garbage has a
negative reputation with all those concerned about the
environment. Municipal solid waste landfills are the largest
human-generated source of methane emissions in the United
States. Methane is a very potent greenhouse gas that is a
key contributor to global warming. The gas is created when
waste in a landfill decomposes. It is about 50 percent methane, also known as natural gas, and
45 percent carbon dioxide. Increasingly, the gas is being seen as a positive byproduct for landfill
managers. Instead of allowing landfill gas to escape into the air, or burning it off, the gas can be
captured, converted, and used as an energy source.
The Solid Waste Management Department of Ada County, located just north of Boise, Idaho,
is doing just that. They are using a pipeline grid made of polyethylene pipe to gather methane that
will soon be providing energy to 24,000 homes in the area.
“The landfill serves about 300,000 people which is the largest population base in the state,”
said Rene Phillips, health protection officer in charge of daily operations. “The main goal of the
project is to take a negative by-product and turn it into a positive resource for both the planet and
the citizens of Ada County.”
The landfill is one of 335 methane conversion plants operational in the U. S. with 500 more
listed as candidates for the U.S. Environmental Protection Agency Landfill Methane Outreach
Program (LMOP). LMOP is a voluntary assistance program that helps to reduce methane emissions
from landfills by encouraging the recovery and use of landfill gas as an energy resource.
The LMOP forms partnerships with landfill owners, utilities and power marketers to overcome
barriers to project development. It helps them assess project feasibility, find financing, and market
the benefits of project development to the community. EPA launched the LMOP to encourage
productive use of this resource as part of the United States’ commitment to reduce greenhouse
gas emissions under the United Nations Framework Convention on Climate Change.
Using the gas helps to reduce odors and other hazards associated with landfill gas emissions,
and it helps prevent methane from migrating into the atmosphere and contributing to local
smog and global warming.
 GREEN ENGINEERING
The methane recovery system is composed of 40,000 feet
of polyethylene pipe (PE) that is being installed as the landfill
is created. Horizontal ditches are placed 100 feet apart, lined
with fabric and bedded with two inches of drain rock. The PE
is fused together and perforated to allow the infiltration of gas.
PE was chosen because it is resistant to the chemicals found in
landfills and is expected to last for more than the 100 years that
the landfill is expected to produce methane.
With every 20 feet of refuge, a new pipeline grid is fused together
and laid out and another 20 feet of refuge piled on top. The
gas in the landfill seeks the path of least resistance and enters the
pipe through the perforation holes. The gas is then suctioned out
and transported to generators to be converted to electricity.
One of the most appealing aspects of the project is that
once completed, the landfill will blend into the landscape of southern Idaho. The refuge hills may
climb as high as 80 feet. They are then capped with a layer of dirt and planted with native vegetation.
In the end, the landfill will look just like the surrounding terrain.
“Idaho is concerned about the environment,” said Brian Shields of High Country Fusion (HCFC)
based in Fairfield Idaho. HCFC supplied the pipe for the landfill along with the McElroy fusion
equipment. The fusion equipment is used to join the pipe lengths together without the aid of mechanical
joints. HCFC got its start 12 years ago by converting conventional pipeline projects to polyethylene
pipe. They are experts in the process of McElroy butt fusion and are also a polyethylene
fittings manufacturer. They specialize in design assistance as well as providing everything needed
for a polyethylene project. “The state is very concerned with environmental issues and projects like
this demonstrate how the state is taking advantage of new technologies like polyethylene pipe in
their engineering efforts.”
Shields has been involved with several environmental projects in the region that are making use of
polyethylene pipelines to transport everything from harmful chemicals, to water and sewer and now
methane gas. “It is estimated that this pipeline system will capture roughly 75 to 90 percent of the
methane emitted from the landfill,” said Shields.  “All landfills
generate methane, it just makes sense to use the gas for the
beneficial purpose of energy generation rather than emitting it
to the atmosphere. Polyethylene has environmental benefits that
are unparalleled by any other piping material. It is by far the
best piping technology available and I’m just glad that the state
of Idaho understands this.”
For more information, contact
McElroy PR and Marketing Department
Tyler Henning, public relations specialist
Phone: (918) 831-9286
E-mail: thenning@mcelroy.com |
