Greg Johnson
PFAS are known as âforever chemicalsâ because of their persistence in the environment. The U.S. EPA is actively developing new regulations to address PFAS compounds found in landfill leachate and elsewhere. The agency has announced plans to revise the Effluent Limitation Guidelines (ELGs) for leachate discharge. This decision follows a 2021 study of 200 landfills, which detected PFAS in 95 percent of leachate samples tested and identified 63 different PFAS compounds. The EPA concluded that new effluent guidelines are warranted for landfills that discharge leachate.
Landfills do not generate PFAS; they receive PFAS-laden waste from consumer and industrial products. Treatment technologies under consideration include activated carbon, ion exchange, foam fractionation, physical destruction methods, and reverse osmosis. The EPA has not yet published a final rule or timeline for implementation. Industry stakeholders such as WM, Republic Services, and SWANA are actively engaged in discussions with the EPA. Additional actions could include classifying PFAS as hazardous substances, which would significantly impact landfill liability and cleanup requirements. Being considered equivalent to other hazardous substances could be very disruptive for landfill operations.
There are approximately 7,000 drinking water systems in the U.S. where PFAS fluorinated polymers have been detected, many at levels exceeding the limits the EPA plans to regulate. These chemical polymers have been produced for decades, do not decompose, and have migrated throughout the environment. PFAS can now be found everywhere, including rainwater. While PFAS are suspected to pose health risks, more research is needed to determine the specific hazards. PFAS include hundreds of fluorinated chemicals that have been used in consumer products. These chemicals persist because of the extremely strong carbonâfluorine covalent bond. Since PFAS have spread throughout the environment and are appearing in drinking water, efforts to regulate their discharge in effluents will intensify to prevent contamination of water supplies.
Addressing PFAS
Polyfluoroalkyl substances (PFAS) are being addressed by environmental agencies worldwide. Although the widespread presence of PFAS in the environment has been known for years, it has only recently received significant attention. While thousands of academic studies have focused on greenhouse gases, relatively little research has evaluated the potential dangers PFAS pose to human health. PFAS are suspected to cause cancer and other health issues, but this has not been fully studied. Safe threshold levels for PFAS remain undefined, and it is unclear which of the hundreds of PFAS compounds present the greatest risk.
Landfills will likely need to prepare for these changes by installing or upgrading leachate treatment systems to remove PFAS before discharge. Treatment systems are costly, especially for smaller or rural landfills. Landfills may face increased liability if PFAS are designated as hazardous substances, which could trigger cleanup obligations. The new ELGs will require landfills to meet stricter discharge standards, and not all landfills are permitted to receive hazardous waste.
The challenge for landfills is twofold: they are not wastewater treatment experts, and there are lots of PFAS removal technologies with many of them being experimental. How should a landfill operator decide on the best option for their leachate? Available treatment technologies fall into three main categories:
- Adsorption
- Granular Activated Carbon (GAC)
- Foam Fractionation
- Ion Exchange Resins
- Oxidation and Destruction
- Electrochemical Oxidation
- Plasma Treatment
- Photocatalysis and UV-based processes
- Incineration (>1,100°C)
- Membrane Separation
- Conventional Spiral Reverse Osmosis (RO)
- Advanced RO Membrane Systems (VSEP)
In addition to there being many dissimilar technologies vying for adoption, each one will have advantages and disadvantages. These need to be compared with a complex matrix, including removal efficiency, cost, scalability, residual management, and technology maturity.
Granular Activated Carbon (GAC)
Mature technology with low capital cost that is effective for long-chain PFAS (like PFOA, PFOS). But this may not be effective for short chain PFAS chemicals, and it will require frequent replacement of the media. Disposal of the spent carbon needs to be accounted for.
Ion Exchange Resins
Has higher capacity and selectivity than GAC. Works well for both long- and short-chain PFAS. Will require replacement and/or cleaning of the resin media. Spent resin and cleaning solutions disposal should be considered. Low capital cost, but significant operating costs
Foam Fractionation
Uses air bubbles introduced into the water where the PFAS adsorbs to the air-water interface. The bubbles rise collecting PFAS and create a foam at the top that is skimmed off. Works well for long chain PFAS that are hydrophobic. It is not as effective on short chain PFAS which are less hydrophobic. It is not a stand-alone treatment because residual PFAS will remain in the treated water and the foam concentrate will need a destruction method.
Electrochemical Oxidation
Breaks down PFAS into smaller, less harmful compounds. Removal efficiency may vary depending on the type of PFAS and 100 percent removal may not be possible
Plasma Treatment
Uses high-energy plasma to destroy PFAS. Not widely deployed. Only economical for small volumes due to power required.
Photocatalysis & UV-based processes
Limited effectiveness unless combined with other methods.
Incineration (>1,100°C)
Used for PFAS-containing solids or concentrates. Must ensure complete destruction to avoid harmful byproducts. Not economical for large flow rates
Conventional Spiral Reverse Osmosis (RO)
Highly effective for PFAS removal from water. Produces a concentrated brine that needs further treatment. If used for landfill leachate, this membrane type would require significant pretreatment with added complexity and would recover relatively low volume of treated water from the leachate compared to advanced RO membrane systems.
Advanced RO Membrane Systems
There are several RO membrane systems with special designs to increase the water recovery rate. These will have higher capital costs but can achieve nearly 100 percent removal of PFAS chemicals. Each will generate a concentrate brine stream that would need disposal. These advanced membrane systems include some that modify the conventional spiral design by reversing the feed flow or closing the discharge periodically. These will still require pretreatment and recovery rates that are better but still limited. Another type uses parallel circular membranes in a design that creates large turbulence as a way of scouring the membrane to keep it clean. The third type is the VSEP RO membrane which employs torsional oscillation of the membrane where it moves back and forth 50 times per second. This generates very high shear at the membrane surface which disrupts concentration polarization and removes any solubility limit allowing for the highest recovery rates.
Investigating Your Options
Industry data and research on PFAS removal performance for each technology has been evaluated. Ranking scores have been given with 1 being poor and 5 being excellent. Figure 1, shows the comparison. This is based on the effectiveness for removal of both long-chain and short-chain PFAS and based on the practical application of the technology to landfill leachate treatment systems. Adsorption methods may have limited removal capabilities and are not widely used to treat landfill leachate. Evaporation has been used for a long time to treat landfill leachate. It is effective and can make a very small volume of sludge containing the PFAS materials, but operating costs are high.
The VSEP advanced RO system has been installed at more than 25 landfill projects since 1987 and is a proven method for treating leachate. During recent testing with a VSEP system, eight PFAS chemicals were tested. Four were measured as non-detect after two passes with RO membranes. The other four measured <5 part per trillion, well below the limits being considered by the EPA. The benefit of using membranes is that it not only removes PFAS chemicals, but will remove all other pollutants such as ammonia, heavy metals, and organics.
The coming regulations will be challenging for landfill operators. The EPA will be considering this and there likely could be grants available to help with construction costs of treatment plants. While the rule may be a few years away from becoming final, it would be wise for landfill operators to begin looking at their options and investigate what may be right for them.
Greg Johnson has been the CEO of New Logic Research since 2000. New Logic Research has been a trusted provider of water treatment solutions for landfill industry since 1987. To explore methods for cleaner landfill operations, visit or visit .