PFAS – in Water

Nowadays, those extremely robust fluorine containing substances are found in grounds and sediments, in surface water and in groundwater, but also in flora and fauna and even in blood. These vast contaminations in grounds and waters are often caused by commercial or industrial processes, aqueous film forming fire extinguishing foams or hazardous waste. PFAS also end up in the water circulation via leakage water from landfills, through sewage sludge from water treatment or by means of industrial wastewater. This way they get into the human organism, possibly with health threatening impact if highly concentrated.

Due to their persistence, PFAS will remain in the environment for a long time, they will continue to spread and will be found in various media. For some chemical bonds, regulations do exist already with further legal requirements regarding defined parameters to follow within the following years.

For this reason, municipal providers as well as communities will increasingly be forced to deal with PFAS in drinking water, surface water, ground water, leakage water, sewage sludge and in other waste streams, requiring additional extraction methods for these media.

Choosing the appropriate treatment technique for PFAS is dependent on various location-specific criteria. There are multiple methods of reducing or completely eliminating PFAS bonds. These techniques include:

• Ion-exchange resins (IX) (combined with destructive methods to treat regen­er­a­tion fluids)

• Elec­tro­chem­i­cal treatment

• UV reductive treatment

• Reverse osmosis (RO)

Granulated activated carbon (GAC)

This method is the most widespread treatment of PFAS in water: some PFAS like PFOA and PFOS adsorb at the active carbon‘s surface and thus can be extracted from the water. CDM Smith is an expert in this method – we not only support you with the application of GAC but also with the treatment and disposal of used GAC. While GAC is partic­u­larly used for long-chained PFAS, this method is less effective with short-chained PFAS bonds.

Anion Exchange (AIX)

This method uses synthetic resins, produced from polymers with charged groups. These resins retain the hazardous substances and thus purify the water, while their performance can be manipulated by various parameters. AIX just like GAC has been implemented success­fully at numerous project locations with research findings verifying that AIX is also suitable to treat short-chained PFAS.

Diaphragm Technology

Despite this technology not being as common as GAC or AIX, it also has been evaluated as to how effectively PFAS can be treated this way. Reverse osmosis (RO) is applied in industrial processes as well as in drinking water treatment. RO operates with a two-chamber system. PFAS cont­a­m­i­nated water is forced from the first chamber through a membrane into the second chamber with the PFAS concentrate remaining in the first chamber. The nano-filtration or rather low-pressure reverse osmosis (LPRO) is also a proven treatment for successful elimination of PFAS, including short-chained bonds.