Seal

In order to recover this public space, the following different steps were taken.

1 - Preparing the land: Once over a million cubic metres had been removed, the first step was to stop it moving. Gigantic steps were integrated into the hillside - in the future they will form part of a leisure area.

Some areas were even carefully cleaned by hand. This was the case with the rocks, home to varied flora and fauna such as lichen, moss, lizards etc.

2 - Sealing the landfill: Different layers of different materials guarantee correct waste draining and waterproofing from rain. On top there is a layer of grass to cover the old landfill. The distribution fits in perfectly with the area and allows better plant growth.

3 - Runoff and gas treatment: Even though the waste is not visible, it is still there. This should not be forgotten. A large amount of tubes have been installed under the landfill to capture all the runoff, which might be contaminated after contact with waste. This liquid is pumped to a pre-treatment plant.

Waste decomposition also produces biogas, which needs to get out. Vertical wells up to 7 metres deep capture this gas, which is taken through a 20km long network of pipes and burnt at the chimneys. Soon it will be taken to a cogeneration plant to produce electricity. In a few years' time, waste will stop producing gas.

4 - Replanting: Once the landfill was sealed, the whole area was covered with different kinds of grass.

The surface area with waste underneath has been sealed off to the public for fifteen years, when the waste will stop producing gas and then the area will be incorporated into the rest of the park.