Geosynthetics August/September 2019 - 17

Case Study

A minitube blanket for
landfill gas collection
and containment
By Stephan Fourmont, Pascal Saunier and Toraj Ghofrani

andfill gas (LFG) is produced during the decomposition of putrescible material in landfills. Often referred to as biogas, LFG is a
source of odors and fugitive greenhouse gas (GHG) emissions. LFG is
typically 40%-60% methane, which is 25 times more potent to affect
climate change than carbon dioxide (U.S. Environmental Protection
Agency 2013). LFG must be removed from the landfill to reduce or
eliminate odors, to limit the migration of methane to the atmosphere
and to comply with regulatory requirements.
The management of LFG at landfills is an important, and often costly,
operational aspect of a well-run landfill. The need to install a gas collection and control system (GCCS) is dependent on the amount and type of
waste accepted. Typically, LFG is controlled by an active vacuum blower
system, which extracts LFG through a network of horizontal collectors
embedded in rock-filled trenches inside the waste. The collected LFG is
typically sent to a destruction device, such as a flare, where it is combusted,
and the methane is converted to carbon dioxide. Because of the energy
potential of the methane gas, landfill gas-to-energy (LFGTE) projects
have been developed to capitalize on renewable sources of green fuel. In
general, LFGTE projects use the LFG to fuel specially designed turbines,
reciprocating engines or boilers. LFGTE projects can have design lives in
excess of 20 years and range in size from a few kilowatts to 10 megawatts
or more. Also, LFG can be processed into a compressed or natural gas for
home heating or vehicle use, respectively.
The success of an LFGTE project is directly related to the performance
of the GCCS. Traditional methods of LFG collection can be time-consuming and expensive to install, and installation sometimes can be delayed
due to seasonal and budgetary issues. This paper presents the significant
advantages of using a tubular drainage geocomposite for LFG collection
as compared with traditional horizontal LFG collectors (Figure 1).

PROJECT HIGHLIGHTS
CEDAR HILLS
REGIONAL LANDFILL
OWNER

King County Solid
Waste Division
LOCATION

Maple Valley, Wash.
GENERAL CONTRACTOR

King County Solid Waste
Division (in-house)
DESIGN ENGINEER

Toraj Ghofrani, P.E.
GEOSYNTHETIC PRODUCT

DRAINTUBE 500P LFG4 D25
GEOSYNTHETIC MANUFACTURER

AFITEX-Texel

Stephan Fourmont is business
development manager-east with
AFITEX-Texel Geosynthetics Inc. in
Montreal, Que., Canada.
Pascal Saunier is business development
manager-North America with AFITEXTexel Geosynthetics Inc. in Vancouver,
B.C., Canada.
Toraj Ghofrani is engineer III with the
King County Solid Waste Division in
Maple Valley, Wash.
All photographs courtesy of AFITEX-Texel Geosynthetics Inc.

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Geosynthetics August/September 2019

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