| Landfill Gas Venting
(LFG)
Landfill gas (LFG) pressure underneath a lined
cover system can significantly reduce the effective normal stress
on the liner, which can affect cover soil stability. Large-scale
landfill cover slope failures have been recorded over the past decade
to be directly attributed by an inadequate LFG venting layer. According
to recent research, based on intrinsic permeability theory, into
gas transmission rates, the rate of LFG transmissivity is ten times
lower than the hydraulic transmissivity in any porous media. In
the past, however, this relationship was believed to be inverse,
i.e. the air transmissivity was believed to be 100 times greater
than the hydraulic transmissivity. The resulting miscalculations
significantly under design the required transmissivity of the LFG
venting layer, which in turn may cause landfill cover slope failures.
This reveals the great need for a high flow geocomposite layer for
gas venting design.
TENAX TENDRAIN and TENAX TDP geocomposite have at least 2-3 times
the transmissivity of conventional bi-planar geocomposites, whether
fluid or gas transmissivity. This high performance geocomposites
allow for greater compatibility when variances occur that generate
higher amounts of gas, necessary to prevent pore pressure build-up,
and ensure cover soil stability. This allows for wide levels of
gas venting to occur preventing pore pressure build-up and ensuring
cover soil stability.
TENAX TN and TENAX TNT geocomposites are conventional drainage geosynthetics
and are suggested for low critical design situations.
|
Landfill Gas Venting (LFG) 
geo@tenax.net