PFAS in landfill leachate

Why are PFAS important in landfill leachate?

PFAS (per- and polyfluoroalkyl substances) are playing an increasingly important role in landfill leachate. Due to their high chemical stability, persistence and mobility, they can be washed out of landfill sites and contaminate groundwater, surface water and soil over long periods of time.  

Landfills often act as long-term sources of emissions, as PFAS are hardly degraded in waste and continuously migrate into the leachate. Many PFAS are suspected of causing damage to health and the environment and therefore pose a particular challenge for environmental monitoring and remediation.

How does PFAS get into landfill leachate?

PFAS can enter landfills in various ways, including:

• Industrial and production waste containing PFAS,
• Contaminated soil and construction waste materials,
• Firefighting foams (AFFF) used in firefighting operations,
• Historically contaminated waste streams, e.g. from wastewater treatment.  

When precipitation water infiltrates the landfill, PFAS are dissolved from the landfill body due to their high water solubility and transported further with the leachate. The very stable carbon-fluorine bond prevents natural degradation, meaning that PFAS can remain in the environment for decades. Individual compounds can also accumulate in organisms and thus enter the food chain.

Challenges in treating landfill leachate

Conventional methods for treating landfill leachate or municipal wastewater are generally not designed to remove PFAS. Biological treatment stages have little effect, as PFAS are not biodegradable or only biodegradable to a very limited extent.

This poses considerable technical and regulatory challenges for landfill operators:  

• long-term monitoring obligations,
• increasing requirements for effluent quality,
• need for specialised treatment processes, e.g. activated carbon, ion exchange or membrane-based systems.

Landfill leachate is therefore one of the most demanding applications in PFAS water treatment.

Here you can find our PFAS removal solutions.