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Comparing PFAS treatment options for leachate

With numerous options available for PFAS treatment, it can be overwhelming to navigate. However, when it comes to effectively addressing complex waste streams like leachate, foam fractionation stands out as an exceptional choice.

Regulation in the United States (US)

The US Environmental Protection Agency has been actively intensifying its efforts to combat per- and polyfluoroalkyl substances (PFAS) since the release of the PFAS Strategic Roadmap in 2021. One of their recent initiatives, announced in March 2023, involves proposing nationally enforceable limits for six PFAS compounds that are commonly found in drinking water.

Anticipated to be implemented by the end of 2023, this regulation will require various industries, including landfill operators and those involved in leachate management, to proactively prepare for compliance well in advance.

PFAS, often referred to as “forever chemicals,” pose an ongoing challenge for remediation efforts, which have garnered significant attention from governments worldwide. As the efficacy of different treatment methods comes under scrutiny, it’s important to evaluate their effectiveness.

Granular activated carbon absorption

Granular activated carbon (GAC) is a widely used treatment approach that employs a highly porous substance to adsorb PFAS through its surface. This method does have certain drawbacks with one limitation being its reduced efficacy when dealing with short-chain PFAS compounds. Additionally, the surface of the GAC can become fouled by other co-contaminants present in complex water sources. As a result, there is less removal of PFAS, necessitating more frequent replacement and disposal of the carbon material. This incurs additional costs and there are environmental implications associated with disposal. Typically, PFAS-laden activated carbon is disposed of in landfills, although it can be regenerated. However, the disposal of the PFAS that is removed during the regeneration of GAC also needs to be taken into consideration.

Ion exchange resins

Ion exchange resins work by exchanging ions in the liquid phase with ions attached to functional groups on the surface of the resin. Although ion exchange resins are more costly compared to GAC, they generally exhibit faster adsorption of PFAS and possess a higher capacity for PFAS removal onto the resin. They can also remove both short and long chain PFAS molecules. Similar to GAC, with the complexities of leachate they encounter fouling issues that significantly reduce their ability to remove PFAS. Typically, PFAS resins are not regenerated due to requiring highly hazardous solvents, leading to similar disposal problems as GAC.

Reverse osmosis

Reverse osmosis (RO) entails using a semi-permeable membrane to separate contaminants from water. Unlike the previous treatment methods mentioned, it doesn’t necessarily need a high surface area for a high PFAS load and has demonstrated highly effective concentration of PFAS. However, it does demand significant energy inputs, resulting in increased operational costs. Additionally, the concentrate stream generated in RO treatment can range from 10-20% of influent flow, containing concentrated PFAS. This concentrated stream necessitates further treatment or disposal.

Foam fractionation

Foam fractionation is a straightforward and scalable technology that exhibits a remarkable capacity for removing PFAS. This efficient process has minimal energy requirements and generates a low waste stream. It produces a low volume of foam concentrate, which is easier to manage, thereby reducing environmental impacts. Additionally, foam fractionation can be integrated with other methods, such as reverse osmosis, to create a comprehensive treatment system.

Known for its cost-effectiveness and low energy demands, foam fractionation serves as the core technology in the proprietary Low Energy Evaporative Fractionation (LEEF) System® developed by the Water & Carbon Group. This technology offers several advantages for PFAS treatment:

  • Direct PFAS removal from heavily contaminated leachate
  • Substantial flexibility to allow for customization
  • Minimal concentrated waste stream
  • Pre-treatment is typically not required
  • Modular and scalable
  • Low energy demand
  • No consumables
  • Removes up to 100% of targeted PFAS compounds

The effectiveness of the LEEF System® has been proven in challenging scenarios involving highly contaminated leachates. Notably, successful demonstrations in Tennessee, Virginia, Alabama, and Vermont have showcased its capability to reduce PFAS concentrations to levels below the analytical limit of detection.

To arrange an onsite demonstration of the LEEF System® for your site contact us today.

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