Landfill Drainage

Final Capping, Pozidrain, Gypsum Landfill, Co. Cavan, Ireland

Project Information

Client:Gyproc
Contractor:Wills Bros / PAGeoContracting
Consultant:RPS
Product:Pozidrain 7S250/NW8
Pozidrain 4S250D/NW8
Quantity65,000m2
Benefits:- Cost savings resulting from the use of Pozidrain with one geotextile
- Rapid installation
- Demonstrated drainage performance


Project Description

Gyproc, part of the Saint-Gobain Group, is Ireland’s largest producer of plaster and plasterboard. Manufacturing in Kingscourt, Co. Cavan, waste from the plasterboard manufacturing process was disposed of in landfill over a number of decades in line with the facility’s Industrial Emissions Licence. Landfilling at the site ceased in 2009, and a permanent capping system was required in order to provide safe containment of this waste.

The Challenge

The landfill closure project involved the re-profiling of the existing landfill in order to create regularised slopes of up to 1:2.5 (21.8°) and the installation of a permanent capping system over an area of approximately 6.5 hectares. At the time of cessation of filling operations, the overall composition of the waste was estimated to be 95% plasterboard and 5% gypsum residue. The waste was considered to be hazardous and would be soft in places underfoot. The proposed capping system comprised a number of elements: a 200 mm blinding/regulation layer, a gas collection geocomposite, a geomembrane liner, a subsurface water geocomposite and finally a 1m topsoil/subsoil layer. The geocomposites needed to be carefully selected to address the build up of flammable gas underneath the liner and to ensure adequate subsurface drainage whilst also being stable on the steep slopes.

The Solution

Working with consulting engineer RPS, ABG approached the selection of a suitable drainage geocomposite from first principles. This involved establishing the permeability of the cover soil in relation to the infiltration rate, and calculating
the required in-plane flow of the geocomposite when tested with soft foam platens as per EN ISO 12958. Appropriate reduction factors and a global factor of safety were applied to establish that Pozidrain 4S250D/NW8 geocomposite would provide adequate drainage to ensure stability on the steep slopes.

Pozidrain utilises an impermeable cuspated core conferring a unique benefit that brings economic savings to projects that have a combination of steep (>12°) and shallow (<12°) slopes. Where the slope is <12° Pozidrain can be used with
one geotextile. ABG was therefore able to offer Pozidrain 7S250/NW8 drainage geocomposite with one geotextile as a value-engineered solution for the flatter areas of the capping. Flow capacity is dependent upon gradient, and Pozidrain 7S250/NW8 also provided higher in-plane flow capacity to cater for the lower gradient on these flatter areas.

ABG Pozidrain Drainage Geocomposite for landfill capping applications

ABG Pozidrain Drainage Geocomposite

Pozidrain is stable on steep slopes of up to 1:2.5 (21.8%) Pozidrain is stable on steep slopes of up to 1:2.5 (21.8%)
Pozidrain landfill capping drainageLong, wide rolls enabled fast installation
Landfill cappingA combination of Pozidrain with one geotextile for the flatter areas and two geotextiles for the steeper areas of the landfill capping provided significant cost savings
Landfill capping project in Ireland using ABG Pozidrain geocomopsite

The ABG Service

ABG assisted with subsurface drainage calculations and facilitated site-specific shear box testing to establish the suitability of the geocomposites.

Contact ABG today to discuss your landfill project specific requirements and discover how ABG past experience and innovative products can help on your project.

Pozidrain

Pozidrain drainage geocomposite is a wide-width preformed drainage and gas venting solution, providing a sustainable, environmental alternative to traditional filter stone drainage layers. Used extensively for landfill and contaminated land drainage on slopes and basal areas to remove water, liquids and gas quickly & efficiently.

more...

Pozidrain Drainage geocomposite for landfill drainage and capping from ABG Geosynthetics
 

Products

Pozidrain

Pozidrain drainage geocomposite is a wide-width preformed drainage and gas venting solution, providing a sustainable, environmental alternative to traditional filter stone drainage layers. Used extensively for landfill and contaminated land drainage on slopes and basal areas to remove water, liquids and gas quickly & efficiently.

more...

Pozidrain Drainage geocomposite for landfill drainage and capping from ABG Geosynthetics
 

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