Advanced Leachate Drainage Infrastructure with Ocean Drainage Geocomposite 5.5 MM in Odisha Landfill Project

At a landfill project in Odisha, Ocean Non Wovens supplied and installed Ocean Drainage Geocomposite 5.5 MM across 6700 SQM. The geocomposite forms part of the leachate drainage layer, carrying leachate off the liner so that liquid does not pond and build pressure on the geomembrane below.

Project overview

• Project Type: Landfill Infrastructure Project
• Location: Odisha
• Product Used: Ocean Drainage Geocomposite 5.5 MM
• Quantity: 6700 SQM
• Scope: Supply & Installation
• Application Area: Leachate drainage and landfill containment support

The drainage layer had to keep carrying liquid under continuous waste loading while protecting the containment layers around it.

Why landfill drainage matters

Landfill design in India has moved from simple soil barriers towards engineered containment, as waste management rules have tightened. India’s Solid Waste Management Rules, 2016 require sanitary landfills to have a liner system and leachate collection. A modern base liner combines geomembranes, geotextiles, geosynthetic clay liners and a drainage layer, and each depends on the others.

Leachate forms when rainwater percolates through waste and picks up dissolved and suspended contaminants, including heavy metals, organic compounds and ammonia. If it is not drained, it collects on the liner. The leakage rate through any defect in a geomembrane rises with the head of liquid above it, so a liner with standing leachate on it leaks more than the same liner kept nearly dry. Ponded leachate also adds pressure on seams, can reduce stability on side slopes, and makes compliance harder to demonstrate. Design practice therefore aims to keep the leachate head on the liner low; US EPA Subtitle D, for example, sets a limit of 30 cm.

What a drainage geocomposite is

A drainage geocomposite is a polymer drainage core, typically an HDPE geonet, with a non-woven geotextile bonded to one or both faces. The core provides open flow channels in the plane of the sheet. The geotextile acts as a filter, keeping soil and waste fines out of the core so the channels stay open. The 5.5 MM figure refers to product thickness. Ocean’s range is on the drainage geocomposites page.

Compared with a traditional gravel drainage layer, a geocomposite is thin, light and delivered in rolls. That cuts the haulage and placement of drainage aggregate, takes up less airspace in the cell, and makes large areas quicker to cover.

What the geocomposite does on this site

• Drains leachate: the core carries leachate across the containment system towards the collection pipework.
• Limits head on the liner: fast drainage keeps pressure from building above the geomembrane.
• Filters: the geotextile keeps soil out of the core so flow capacity is maintained.
• Reduces material and time: rolls replace a thick aggregate layer, with less transport and faster coverage.

How a drainage geocomposite is specified

The key property is in-plane flow capacity, or transmissivity, measured to ASTM D4716 under a normal load and hydraulic gradient chosen to represent the site. Because waste loading compresses the core and the geotextile can intrude into the channels over time, designers apply reduction factors for creep, intrusion, chemical clogging and biological clogging to the short-term test value; GRI-GC8 sets out this method. Leachate encourages biological growth, so the geotextile filter has to be chosen to resist clogging in leachate conditions, not just to retain soil.

Site challenges and installation

Uneven subgrade affects how well the drainage layer contacts the layers around it, so grading and surface preparation came first. The core has to be protected from crushing during handling, since a deformed core carries less flow. Overlaps need care: a poorly made overlap can break the flow path. The installation sequence was:

1. Surface grading and inspection
2. Removal of sharp protrusions
3. Controlled roll placement
4. Overlap management
5. Protection during material handling
6. Inspection of drainage continuity

Construction traffic is the main cause of installation damage. Heavy equipment running over an exposed geocomposite can deform the core and reduce transmissivity, so plant is kept off the sheet until an adequate cover layer is in place, and site supervision continues through placement and covering. In typical practice, adjacent geonet cores are tied together at the overlaps and the upper geotextile is overlapped or sewn so that cover soil cannot get into the core.

Ocean geocomposite is also supplied for industrial plants in Odisha: 2,000 sq m went to the BCGCL coal gasification project at Jharsuguda for the plant’s drainage works.

Leachate layers are sized on flow at the design load. Our article on sizing a drainage geocomposite works through transmissivity, long-term reduction factors and the comparison with a granular layer.

Long-term performance

A landfill drainage layer is expected to work for decades, through the operating life of the cell and into post-closure. Its performance over that time depends on compression and creep resistance of the core, a stable filter, chemical and biological resistance in leachate, continuity at overlaps, and the quality of installation. A drainage layer that keeps working avoids the remediation costs that follow from ponded leachate and an overstressed liner.

Ocean Non Wovens manufactures and supplies geosynthetics for landfill, infrastructure, environmental, industrial, irrigation and water management projects across India, with manufacturing, supply and project support for leachate collection, geomembrane containment, cushion protection, reinforcement and slope stabilization.