Extra volume in waste containment

In the construction of waste containments there is an economic advantage of using geosynthetics products.
As seen in the first picture if you use traditional clay and gravel layers in the landfill you can have about 5000 m3 of volume.

But as seen in the second picture if geosynthetics materials are used in the waste disposal area a gain of extra volume will be about 300 m3 with an increase of about 6% in the same area.