Ecklak Landfill Sealing System

Situation

The Ecklak landfill site, in the district of Steinburg, Schleswig-Holstein, was fitted with a temporary sealing system in 1999/2000. This system consisted of a 1.5 mm thick, welded HDPE sealing membrane, a claw mat laid on top and an approx. 10 cm thick substrate soil layer which included grass seed. This temporary sealing was to be replaced by a permanent surface sealing system across an area of 4.2 ha, with embankment gradients ranging from 1:15 to 1:3. In Schleswig-Holstein, a high-quality LAGA-approved geosynthetic clay liner (GTD) was used, for the first time, for this purpose.face.

Solution

In preparation, the temporary surface covering was partially removed or integrated into the new system. For the overlay, the topsoil of the existing substrate layer was milled away. In addition, the HDPE membrane was perforated to allow surface water resulting from weather conditions during the construction phase to drain away. This ensured the proper installation of the base layer for the GTD. The mineral base layer, 10 cm thick, was laid by a tractor and subsequently statically compacted using a smooth-surface roller. The GTD was then laid on top of the base layer as a sealing element. The GTD, which has LAGA suitability assessment for landfill classes I and II, was installed by unrolling it using a laying beam. A drainage mat was installed on top of the KDB as the lower drainage layer element, followed by a 15 cm thick mineral drainage layer.

Advantages

During installation, it proved particularly advantageous that the 5.10 m wide GTD is supplied by the factory on a steel pipe. This made unrolling via the laying crossbar particularly easy, and the width of the roll also ensured an optimised number of overlaps. Furthermore, the sand-textured surface coating of the GTD enables a high  installation rate even in wet weather and on slopes.