PFAS are a group of contaminants that have gained increased attention due to their potential to bio-accumulate, their environmental persistence, potential toxicity and, for many of them, high water solubility. They have been found in all environmental compartments, including wildlife and humans. Studies have identified waste water treatment plants as a pathway for PFAS to the environment. PFAS are a growing concern especially in relation to water resources used for the abstraction of drinking water.

Waste water treatment plants (WWTP) are currently not equipped to completely remove PFAS from waste water. PFAS are very resistant to biological treatment, and as a result, can end up in the WWTP effluent or in sewage sludge. Moreover, the very persistent perfluoroalkyl acids (PFAA, such as PFOS and PFOA) appear to be produced during the biological treatment process in the WWTP following the degradation of polyfluoroakyl precursor compounds.

The applicability of advanced (industrial) technologies to remove PFAS from urban waste water, based on physical separation or destruction techniques, is currently being investigated in pilot projects in laboratories. The results indicate that the large scale removal of PFAS in urban WWTP will not be economically nor environmentally viable.

Preventing PFAS from entering WWTP through control-at-source measures is the only way to avoid PFAS from being released to the (aquatic) environment through this pathway. A ban of all non-essential uses might be a first step. However, a coherent regulatory framework with clear instruments covering all persistent, mobile, toxic (PMT) and very persistent, very mobile (vPvM) substances needs to be in place to prevent and limit the emission of these substances to the water cycle.

Read the briefing note here.