Remove PFAS

PFAS removal is a case-by-case approach. PFAS (per- and polyfluorinated alkyl substances) are a group of chemicals that are used in many industrial and consumer products, such as non-stick pans, outdoor textiles, fire-fighting foams and coatings, but also in particular as an additive for formulations in electroplating, e.g. in the ChromVI process. Known subgroups are PFT and PFC, known individual substances are the now banned PFOS, PFOA and the newer substitutes H4PFOS and 6:2-fluorotelomer sulfonic acid (6:2-FTS). They are persistent in the environment and can accumulate in the human body, where they can cause health problems such as cancer, thyroid disorders, immune system weakness and reproductive disorders. PFAS can enter groundwater or industrial wastewater if they leach out of contaminated sites or products, sometimes over decades. Operators of industrial plants are also often unaware that PFOS were used in the formulations – even in the past – if they were not listed in the safety data sheet due to subordinate concentrations.

From 2026, there will be limit values for PFAS in drinking water and PFAS are also included in the current drafts for the future industry-relevant wastewater monitoring values in the Wastewater Ordinance. See also: The development of various PFAS limit values and monitoring values in wastewater.

There are various methods that can be used to remove PFAS, depending on the concentration, type and composition of the PFAS, the volume of water and the type of water (drinking water, wastewater, groundwater). Each variant is considered on a case-by-case basis and is sampled in advance in the laboratory to identify the appropriate removal method. There is research into the complete mineralization of PFAS, but these processes are currently not economically viable or sufficiently researched.

Typical processes for disposable loading with subsequent thermal utilization of the filter materials to remove PFAS are

  • Activated carbon

This method uses the adsorption properties of activated carbon to bind PFAS from the water. Activated carbon is a porous material made from plant sources and has a large surface area that can attract many molecules. Activated charcoal filters must be replaced regularly to maintain their effectiveness. This method is relatively inexpensive and easy to install, but cannot remove all PFAS types and generates a waste stream that must be disposed of. When designing activated carbon filtration, in addition to the selection of the specific activated carbon, other parameters must also be taken into account that rule out the process in some applications.

This method uses the ion exchange capacity of synthetic resins to remove PFAS from the water. Ion exchange resins are solid particles that contain positively or negatively charged groups that can bind or release ions in the water. In the PFAS removal application, however, the mechanism of action is not the functional group as known from other applications. The ion exchangers are individual applications in each case, as no process-safe regeneration can be carried out, i.e. bound PFAS are not eluted in such a way that the ion exchanger can be returned to a safe initial state. This method is more expensive than activated carbon filtration, but can remove more PFAS types and generates a lower waste stream due to the often higher capacity.

A combination of both techniques is also frequently used.

In addition to the PFAS distance, other monitoring parameters must often also be complied with, e.g. the monitoring values for heavy metals, especially in the case of an old industrial site. This is regularly ensured by a conventional selective exchanger.

Do you have further questions about PFAS removal? Please feel free to contact us.