Safety and stability according to Landfill Directive
The Landfill Directive serves as the legal basis for German landfill construction. It is decisive for the construction, operation, decommissioning/closure and aftercare of landfills and also regulates the use of landfill construction materials. It applies to carriers and operators/owners of landfills and long-term storage facilities, producers and owners of waste and operators of facilities for the production of substitute landfill construction materials.

Multi-barrier principle of landfill sites
The Landfill Directive regulates, among other things, the following requirements:
- Geological barrier: Serves to prevent the spread of pollutants in liquid or gaseous form.
- Location in relation to groundwater: Minimum requirement is a distance of at least 1 m between the highest expected groundwater level and the upper edge of the geological barrier.
- Hydraulic barrier: The potential gradient of the groundwater flow direction is considered as an additional possible barrier.
- Landfill base sealing: Installation on the lateral embankment surfaces as well as on the landfill level; it is a combination of mineral sealing layers and/or plastic sealing sheets stratified on top of it, to which an appropriate protective layer is applied to protect against damage.
- Drainage system: Water and leachate accumulate in the landfill, which are collected and discharged in a controlled manner.
- Stability of the landfill body: The stability of the landfill can be increased by solidifying the waste, e.g. with lime or cement.
- Landfill surface sealing: The system consists of several layers such as the recultivation layer, the drainage layer or drainage system, a mineral sealing layer, possibly a gas drainage layer and a levelling layer.
- Controlled degassing: If relevant quantities of gas concentrations occur, gas drains and landfill gas handling, discharge and treatment equipment must be installed.
- Controlled water and leachate collection.