Landfill Project at Tirupati – Case Study

For a landfill in Tirupati, Andhra Pradesh, Ocean Non Wovens supplied Ocean HDPE Liner 1.5 mm and Ocean Geotextile 200 gsm, covering 10420 Sqm. The liner forms the barrier that keeps leachate out of the soil and groundwater; the geotextile protects it from damage.

Product – Ocean HDPE Liner 1.5 mm thickness & Ocean Geotextile 200 gsm

Quantity – 10420 Sqm

Location – Tirupati

Problem

Many items that end up in landfills contain toxins. Discarded electronics such as computers, batteries and televisions contain arsenic, acids, lead and other substances. As rainwater percolates through the waste, it picks these up and forms leachate, which can seep into groundwater and soil and contaminate them for years.

Solid waste reaching a landfill comes from homes, workplaces, hospitals, farms, industry and oil refineries. A landfill that is poorly designed or maintained becomes a source of air, land and water pollution. Decomposing waste also produces gases such as methane, which can cause landfill fires and contributes to climate change.

Tirupati’s growth and rising population brought ever larger volumes of waste to its landfill. To prevent further environmental damage, the landfill’s lining system had to be re-evaluated.

Solution

Geomembranes, which act as barriers to liquid and gas, are now a standard part of landfill engineering because of stricter requirements for groundwater and environmental protection. The most widely used landfill geomembranes are high-density polyethylene (HDPE). In India, the Solid Waste Management Rules, 2016 and CPCB guidance call for a composite base liner in sanitary landfills that includes an HDPE geomembrane of at least 1.5 mm thickness, which is the grade used at Tirupati.

A geomembrane needs protection from mechanical damage. Sharp stones, an uneven subgrade or the cover material placed on top can puncture it. Protection layers are usually needle-punched non woven geotextiles, often polypropylene (PP), or composites of the same. At Tirupati, Ocean Geotextile 200 gsm served this cushioning role. Heavier geotextiles are used where the material in contact with the liner is coarse or angular.

On some landfills, a geosynthetic clay liner (GCL) can replace imported natural sealing clay, saving the owner money and reducing the environmental cost of quarrying and transport. GCLs can also be supplied with a polyethylene coating, which adds containment, reduces problems with drying out and root penetration, and protects the bentonite against ion exchange with some soils.

HDPE liner panels are joined on site by hot-wedge welding, with extrusion welding for details and repairs. Seams are tested, by air pressure for dual-track welds and by destructive peel and shear tests on samples, before the liner is covered.

See more landfill and containment projects in our case studies.