The new Directive (EU) 2024/3019 intensifies regulatory pressure on PFAS in water
Celia Ibáñez
The recent Directive (EU) 2024/3019 of the European Parliament and of the Council, concerning the treatment of urban wastewater, strengthens the European regulatory framework on emerging contaminants and sets more demanding obligations for the removal of substances such as PFAS (per- and polyfluoroalkyl substances) in sanitation and water treatment systems. This directive, which updates and repeals the previous 1991 regulation, makes clear that the water industry needs effective, scalable, and economically viable technological solutions to address these contaminants. In this context, the results obtained by SIGMADAF‘s R&D department in PFAS removal trials take on relevance.
What are PFAS and why are they a problem?
PFAS are a family of synthetic compounds used for decades in industrial and consumer products: firefighting foams, food packaging, waterproof textiles, and cookware, among others. Their high chemical and thermal stability, low biodegradability, and capacity for bioaccumulation make them persistent contaminants both in the environment and in the human body. Drinking water is the primary route of human exposure to PFAS, and their presence is detected even at concentrations of just a few ng/L.
The most detected PFAS in the environment are perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS), although the family includes short- and long-chain compounds with different behaviour under conventional treatments.
The treatment challenge: why are conventional methods not enough?
Laboratory-scale coagulation and flocculation testing used to assess PFAS removal performance in industrial wastewater treatment processes.
Advanced PFAS removal technologies — granular activated carbon, ion exchange, high-density membranes, or advanced redox processes — show strong technical potential, but their operating and capital costs make them unviable in many industrial contexts. Hence the need to optimise conventional physicochemical processes, particularly coagulation-flocculation, to maximise their efficiency against these microcontaminants.
Coagulation-flocculation is already the benchmark process in water treatment for its effectiveness in removing colloids, suspended solids, and dissolved organic matter, and for its low cost. PFAS adsorbs onto the coagulant-organic matter complexes during the process, being removed along with the solids in the resulting flocs. These low-density floats are particularly well suited for separation by dissolved air flotation (DAF).
The key to maximising PFAS removal lies in coagulation assisted with specialised additives: modified polymers with medium-to-high charge density, specifically formulated to promote the formation of stable complexes with the anionic groups of PFAS. Dosing must be precise: overdosing or underdosing can reverse the process and return PFAS to the aqueous phase.
Success case: soil washing wastewater in civil engineering works
The SIGMALAB laboratory, part of SIGMADAF‘s R&D department, carried out physicochemical treatment trials on an effluent from a contaminated soil washing process at a civil engineering site. The objective: to assess the feasibility of an assisted coagulation-flocculation system for the removal of a panel of 17 PFAS microcontaminants and fluorotelomers, including PFOS, PFOA, PFHxS, PFHxA, and FTS 6:2 and 8:2 compounds.
Treatment sequence applied
The chemical combination that proved most effective was:
- Ferric chloride (FeCl₃) as the base coagulant
- Special PFAS coagulant (SPEC-1), a high charge-density cationic polymer
- Cationic flocculant (medium-density cationic polyacrylamide)
Reaction times are a critical factor for process efficiency, particularly for the reaction with the special coagulant, with a required contact time of between 15 and 30 minutes in this case. The flocs generated are consistent and low-density, making them optimal for separation by a DAF system.
Industrial-scale dissolved air flotation system developed by SIGMADAF for advanced wastewater and PFAS treatment processes.
Results
The most effective trial achieved an overall removal of 84% of the total sum of PFAS microcontaminants, reducing the total concentration from 3,731 µg/L in the original sample to 0.60 µg/L in the clarified effluent. Long-chain compounds such as PFOS, PFOA, PFHxS, and PFDA showed the highest individual removal rates. Short-chain PFAS (PFBA, PFPeA) showed greater resistance to treatment, in line with existing scientific literature.
The addition of a polishing stage using powdered activated carbon (PAC) or a PFAS-specific adsorbent can raise the overall removal rate to above 95%.
Conclusions
The results demonstrate that coagulation-flocculation assisted with PFAS-specific products, integrated with a DAF system, constitutes a technically and economically viable solution for the treatment of industrial wastewater containing PFAS. This approach is particularly relevant given the growing requirements of Directive (EU) 2024/3019 and the sector’s need for real operational alternatives to address emerging contaminants.
