This depends very much on how the site is operated - but could be centuries.
Landfill aftercare is required for as long as there is a need to manage emissions from the site to prevent harm to human health and the environment (HHE). During this time outputs from the site need to be released in a controlled & acceptable way. Ideally, the need for aftercare should not be passed on to the next generation.
End of Aftercare
The residues remaining in the landfill should pose no threat to human health or the environment, and should not compromise the future use of groundwater or other resources, under the conditions of:
- No active management
- Partial or full failure of all engineered containment
- Attainment of hydraulic equilibrium
Barriers to a short aftercare period
1) Landfill gas from degradation of wastes