Landfill Project at Jharkhand – Case Study

Ocean Global supplied, installed and joined 29629.85 sqm of 1.5mm thick HDPE geomembrane on the base and slopes of a municipal landfill in Jharkhand. The liner is the main barrier that keeps leachate from the waste out of the soil and groundwater.

• Product: Geomembrane, 1.5mm HDPE – 29629.85 sqm
• Scope: Delivery, installation and joining (welding) on base and slopes
• Project Holder Name: Municipals Corporation of Jharkhand

Problem

Cities across India have long lacked proper waste disposal. Household waste is collected, but much of it is dumped untreated at sites outside town, which grow higher every year. The dumpsite this project addresses was receiving more than 600 tonnes of garbage a day, creating environmental and health hazards for people living nearby.

An unlined dump pollutes in two ways. Rainwater percolating through decomposing waste becomes leachate, a strong, contaminated liquid that seeps into groundwater. The waste also generates landfill gas, mostly methane and carbon dioxide; if the gas is not collected and vented, methane can reach its explosive range of about 5–15 percent in air, which is why uncontrolled dumps catch fire and smoulder.

Solution

An engineered landfill contains the waste within a lined cell, collects leachate for treatment and manages gas. The project will reduce waste pollution, protect water and soil, and reclaim a large part of the dumping site for scientific solid waste management.

How a landfill liner system is built

A landfill base typically has several layers, from the bottom up:

• Prepared subgrade
• A compacted clay liner or geosynthetic clay liner (GCL)
• The HDPE geomembrane, which together with the clay layer forms a composite liner
• A protective non-woven geotextile cushion
• A leachate drainage layer of gravel or geonet geocomposite, draining to collection pipes

The composite liner is the primary barrier to leachate reaching surface water or groundwater. India’s Solid Waste Management Rules, 2016 require an HDPE geomembrane of at least 1.5 mm in sanitary landfill liners, which matches the thickness used here.

Why HDPE

HDPE geomembrane has very low permeability, strong resistance to the acids, salts and organic compounds in leachate, good stress-crack resistance, carbon black for UV protection, and remains flexible at low temperatures. It is the most widely used lining material for landfills, biogas digesters, sludge and sewage lagoons and manure ponds. Sheets come smooth or textured: textured sheet gives more friction against soil and geotextile, so it is normally used on landfill slopes to stop cover layers sliding, with smooth sheet on the flat base.

Seams are joined by dual-track fusion welding, with extrusion welding for patches and details, and tested by air pressure and vacuum box so the liner is continuous.