Top sealing off Langøya
As part of the completion of the rehabilitation of the northern break in Langøya top sealing of smaller areas will be carried out almost annually until everything is top sealed.
The top seal functions as a "lid", and is designed to fulfill a number of requirements in the permit and the general requirements for all landfills in Norway. The function of the top seal is to ensure that large amounts of water from precipitation and snowmelt cannot penetrate into the filled area.
On Langøya the top seal is built up of a dense membrane consisting of natural dry crust clay followed by a protective layer of limestone. The clay forms the tight layer between the fill and the surroundings above, and has the function of preventing water from penetrating.
The protective layer of limestone helps to preserve the properties of the clay for years to come, by protecting it from frost and drying out. Between the clay and the limestone is placed a fiber cloth, which is often white. The fiber cloth contributes to the clay maintaining its properties in the early phase, until the stone is laid on.
On top of the limestone, a thin growth layer of local soil is placed in the area to further develop the natural fauna on the island.
