Landfill Engineering

Geosynthetics in waste containment systems Geosynthetics form an integral part of a modern waste containment system, providing value engineered solutions within a complex and demanding environment. Modern landfills are engineered to fit with the nature and scale of the surrounding environment and should be inherently stable. The final landform, including the gradients and drainage of a site should be designed at the outset, taking into account pre-existing conditions, landscaping and pollution control requirements, and the necessity for reclamation post use. The design of a landfill is complex...

Landfill site TUBEX sapling protection See www.tubex.com Cover soil Capping geomembrane Regulating layer Leachate drainage stone Protection geotextile See page 7 Mineral liner Erosion control See page 14 Capping drainage and membrane protection See page 13 Filter geotextile See page 8 Primary geomembrane

Basal Membrane protection The environment within the containment system can be extreme, with elevated temperatures, chemically aggressive leachate and large loadings. It is therefore imperative that the geosynthetics incorporated within the design have been manufactured to the highest possible standards. Load The area at the base of a landfill cell is arguably the most critical in its’ overall design. The base is subjected to the greatest surcharge loading, where hazardous leachate collects and the most inaccessible once filled and therefore the most challenging location to rectify any potential...

Filtration within the landfill cell Leachate collection systems It is imperative that the installed granular gas venting layers remain effective and free from clogging. A properly specified geotextile can provide an effective separation layer preventing the migration of fumes into the stone whilst maintaining adequate filter properties for leachate or gas. Double composite liners with leachate collection systems are accepted as ‘state of the art’ within both municipal and hazardous landfills. A double-lined composite system provides significantly increased environmental safety in that any failure...

Side-slope drainage & membrane protection The design requirements of a cell side slope are principally that the impermeable membrane must be protected from mechanical damage and that leachate must be conveyed to a collection system for treatment or disposal. In some instances, site conditions may give rise to the need for pore-water pressure relief beneath the lining system. Terram SD Robust Geocomposite drains provide the combined functionality of membrane protection and integral drainage, they are used beneath liners to relieve pore water pressure and above liners to collect and convey leachate....

The function of a landfill cap is to seal the landfill cell and separate the waste from the surrounding environment, to prevent the entry of precipitation, and the escape of gas, odour and other contaminants. The design of a cap can be multifaceted requiring careful consideration of factors such as size, shape and gradient to ensure performance. Over time, as the waste in the cell decomposes, settlement may well be experienced thereby modifying the original parameters. The design must therefore be capable of accommodating these changes without detriment to performance. Cell design will vary and...

Erosion Control on landfill caps TERRAM Geocells are three-dimensional blankets of interconnected cells which are placed on slopes, secured in position using pins, or anchor beams and filled with friable topsoil. Controlling erosion on landfill caps Once installed, a TERRAM Geocell provides immediate stability by confining the fill and greatly improves resistance to wind and run-off. With a topsoil fill, the stability is further enhanced as vegetation becomes established and a geocell can be used to establish vegetation on slopes where establishing cover would otherwise have been a problem. The...

Product pages Robust Geotextiles Nonwoven geotextiles manufactuered from UV stabilised, high tenacity, virgin polypropylene fibres that have been mechanically entangled to provide high puncture resistance and tensile strength, high loft and excellent abrasion and lateral stiffness characteristics. The high puncture resistance and stiffness provides an optimised cushioning effect preventing sharp drainage stones from straining the geomembrane at the base of a landfill. The rolled geotextile is easy to place and has high friction characteristics especially against roughened geomembranes. The high...

TERRAM Standard Geotextiles TERRAM geocomposite robust geotextile combined with in plane drainage strips bonded to it at intervals across the width. TERRAM Standard Geotextiles enhance the performance and design life of granular layers by providing the filtration and separation functions. Typical uses for TERRAM Standard Geotextiles include ground stabilisation (between the sub-base and subgrade) and around drainage materials. The robust geotextile is manufactured from UV stabilised, high tenacity virgin polypropylene fibres, has been mechanically entangled to provide high puncture resistance...

TERRAM Geocomposites TERRAM Geocell erosion control TERRAM Geocomposite Drains are manufactured by bonding together geotextiles, membranes and nets in different combinations to create easier-to-install replacements for conventional granular layers. TERRAM Geocell is a relatively shallow cellular confinement system which is used to combat erosion on slopes up to 1:1. The geotextile provides the filter function so this allows liquids and gases to pass into the net core but prevents soil particles from washing into and clogging the core. The net collects the liquids and gases which can then be conveyed...

TERRAM Geonet TERRAM geonets are extruded twin layer lattices made from virgin grade UV stabilised polypropylene. When placed between two relatively flat surfaces they act as a spacer allowing liquids or gas to pass in the plane of the net. They are used in landfills for leak detection where a double lined system is used at the base of a landfill. TERRAM geonets are highly robust and incompressible and able to withstand the high loads imposed by typical waste loads at the base of the landfill cell. The geonets are placed between the primary and secondary geomembranes on the base and side slopes...