Geosynthetics are most commonly used in solid waste landfills to protect surface water and groundwater due to their multiple functions, excellent hydraulic properties, ease of installation, and cost saving. Geosynthetic used in landfill include non-woven geotextile, woven geotextile, geogrid, geomembrane, geocells, geosynthetic clay liner (GCL), geonet, geocomposite, etc, and each geosynthetic type serves as specific functions. The functions that geosynthetic system can serve in landfill are separation, drainage, filtration, hydraulic barrier, gas barrier, and protection . Below summarizes geosynthetic types and their functions, and Figure illustrates their use in landfills. Geomembrane, GCL, geopipe, and geotextile are more commonly used geosynthetic materials in landfill applications while geonet, geocomposite, and geogrid are used a lesser extent.

Sepration: Placed between two different materials to maintain or improve the integrity and functioning of both materials

Reinforcement: Provied tensile strength in materials that lacks sufficient tensile capacity

Filtration: Allows water or gas flow across it while rentaining the fine particles on its upstream side

Drainage: Transmits flow within the plane of their structure

hydraulic/Gas Barrier: Relatively impervious material to contain liquids or gasses

Protection: Provides a cushion above/below to prevent damage by punctures during placement of overlying materials

Sepration: Non-woven geoteextile; woven geotextile; geocells; geocomposite

Reinforcement: Woven geotextile;geogrids; geocells; geocomposite

Filtration: Non-woven geotextile; woven geotextile; geocomposite

Drainage: Non-woven geotextile; geopipe; geocomposite; geonet

Hydraulic/Gas Barrier: Non-woven geotextile; geomembrane; geosynthetic clay liner; geocomposite; geonet

Protection: Non-woven geotextile; geosynthetic clay liner; geocomposite