Case Study Description

The Châtillon Landfill site is situated in a former gravel pit. The landfill stores mixed waste and slag/ash from the local incinerator plant. The sealing system of clay needed replacing with a bituminous lining system so WALO was commissioned to undertake the works.

As it is impermeable to leachate and methane, WALO’s Dense Asphaltic Concrete (DAC) was an ideal choice for complete containment of the landfill waste brought to Châtillon. WALO constructed cells at the site using DAC formulated in the company’s Zurich laboratory to a design mix unique to the project.

In addition to replacing the lining, the client was looking to benefit financially by increasing the void size available at the site. As WALO specializes in applying DAC to steep slopes using highly advanced laying and compaction techniques, it was possible to construct very steep slopes at Châtillon, thus increasing the void available. As well as being very strong and flexible, WALO’s DAC can be applied in thin layers (here just 70mm), further increasing the size of the void available. Numerous cells at Châtillon have been constructed by WALO in the last two decades. Working at the site, WALO discovered that there is a significant advantage in being able to join each successive cell together, forming one homogeneous, perfectly sealed landfill. The separation of the different compartments within the landfill is done by intercell bunds made of DAC, that the locals call ‘Toblerone’ – owing to their shape!