It is necessary to monitor landfills even after they are closed to ensure that they do not pose ongoing risks to human health and the environment. Closed landfills can still produce contaminants such as leachate (liquid that drains from waste) and landfill gas (including methane), which can escape and pollute surrounding groundwater, surface water, and air if not properly contained. Monitoring helps detect these issues early and ensures that the landfill's containment systems, such as the final cover, leachate collection, and gas monitoring systems, remain effective over time. Additionally, maintenance prevents soil erosion and exposure of buried waste, and supports the integrity of the landfill site, potentially allowing for safe future land use. The monitoring period often extends for decades after closure, with some regulatory requirements mandating 20-30 years or more of post-closure care.
Key Reasons for Post-Closure Monitoring
- Detect and control leachate and landfill gas emissions to prevent environmental contamination
- Maintain the integrity of the landfill cover to avoid erosion and exposure of waste
- Monitor groundwater and surface water quality to protect water resources
- Ensure public safety and prevent nuisance to nearby residents
- Comply with environmental regulations requiring long-term oversight
- Assess site stability and manage potential long-term liabilities
- Facilitate potential future reuse or redevelopment of the landfill site in a safe manner
Thus, post-closure monitoring is critical to managing the long-term environmental impact and ensuring ongoing protection of public health.
