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.

Products

TENAX TENDRAIN geocomposite

TENAX TDP geocomposite (geotextile + cuspated geonet)

TENAX TN geocomposite (geonet + geotextile)

TENAX TNT geocomposite (geonet + geotextiles)