Landfill sites - Design

Since the mid-1970s, regulations have focused on waste disposal methods, in order to control their environmental impact. Containment sites have evolved from "landfills" to "technical landfill centers". Since the early 1990s, major technical provisions have been introduced for both the design and operation of new "waste storage centers". After an initial article where we set out the economic, social and environmental context in which they operate, we focus here on the first aspect of these technical provisions, i.e. the siting and engineering of landfills. The following article gives a more detailed description of how they work.

When choosing a site for a landfill facility, you need to be aware of a whole range of data to prevent any exchange with the surrounding environment (water, soil, atmosphere). These include geology, hydrogeology and topography, as well as the urban environment and other economic factors. These data are used not only to select the site and define the initial works to be carried out, but also to determine the operating methods and management after the end of the operation (post-operation). In particular, the qualification of soils by means of "in situ" and laboratory investigations guides the choice of construction of the passive barrier, its reinforcement if required, and its reworking if necessary.

The design of the landfill itself is therefore determined first and foremost by its location, but also by the category of waste accepted (classes I, II and III). The leachate drainage sealing system and the final cover of the site are designed to ensure safety. Their design features include the geometry of the subgrade, the size of the drainage layer and the choice of materials. The landfill cover isolates the waste from the outside environment, both to control water infiltration and to prevent biogas emissions. It can be semi-permeable or impermeable.