PROMISCES developed, tested and demonstrated new technologies and innovations to prevent, monitor and remediate PFAS and iPM(T)s within the soil-sediment-water system under real-life conditions.
Ten targeted methods for a variety of matrices were developed, and a final set of 62 PFAS could be analysed. These matrices include surface water, groundwater and drinking water as well as complex matrices such as landfill leachate, sewage sludge, membrane filtration concentrates, bio-char, plants, sediments, and soils. The development of global PFAS approaches (AOF, TOF, EOF, TOP assay) allows to better define the PFAS spectrum. GC and LC-HRMS methods and data treatment workflows have been implemented allowing prioritization and retrospective identification of relevant substances in the water cycle. Additionally, field implementation demonstrated the efficacy of passive samplers for PFAS monitoring in urban water systems. Results from case studies provided crucial insights into the occurrence and persistence of PFAS in various environments, such as riverbank filtration sites, large river basins, or urban areas.
In silico models (QSPR models, artificial intelligence/machine learning approaches) to predict properties of PFAS (solubility, vapour pressure, Koa, Kow, Kaw, kH and Koc, aquatic toxicity) have been developed and published. Existing in silico models that predict properties (e,g, toxicity, solubility) from the structure of the compound (i.e. QSPR models) for PFAS compounds were improved and new ones were developed. Fate and transport modelling approaches were also developed to simulate PFAS transport in saturated and unsaturated zones, and sorption reactions at the air-water and water-solid interfaces. A generic bank filtration (BF) model has been developed. These models enhanced our ability to assess environmental risk-based exposure of PFAS and iPM(T)s. The development of an innovative large-scale emission model at the catchment scale allowed assessment scenarios such as climate change, accidental spills, and legacy pollution remediation at large river basin scale.
Eight technologies were investigated in PROMISCES, from experimental work to define the operational conditions to field scale application for the removal of PFAS and iPM(T)s.
For soil and groundwater remediation, promising results were achieved. A process for flushing PFAS in high concentrations out of soils using non-Newtonian liquids (foams) was developed. An on-site chemical reduction process for the degradation of PFAS has been designed and tested using DMSO-NaOH or persulfate activation with ferrate (PS+Fe(VI)) for PFAS removal. The upscaling of ultrasonic cavitation treatment shows promise for effective PFAS destruction. Nano Zero-valent iron activation of persulfate (PS+nZVI) was tested for organochlorine remediation. The biological treatment (fungi) showed poor performance in terms of their ability to degrade PFAS.
A sediment treatment pilot was tested and a washing procedure for PFAS mobilisation has been developed. Dredged sediments pyrolysis at 600°C proved effective for PFAS removal in both low- and high-contaminated sediments.
Innovative drinking water treatment (DWT) trains capable of removing iPM(T)s and PFAS from water sources with high organic matter background were investigated by testing the removal capacity of multiple adsorptive media such as ion exchange resins and surface-modified clay at laboratory and pilot-scale.
To reduce the transfer of iPM(T)s and PFAS during water reuse for agricultural irrigation of WWTP effluent with a high share of industrial wastewater, an electro-oxidation process was tested at laboratory and pilot scales to identify optimal operating conditions for removal of target iPM(T) and PFAS. The removal rates for iPMTs are notably greater than those for PFAS, which exhibited comparatively low elimination efficiencies.
Landfill leachate treatment options including pyrolysis, plasma treatment, and membrane filtration to eliminate PFAS emission into water-based CE routes were tested at laboratory scale. Pilot plants for NF/RO treatment of landfill leachate and testing of plasma treatment with PFOA model solutions are advancing towards practical applications. Overall, pyrolysis was found to be more energy efficient than incineration with a higher production of thermal energy, which can be obtained by combustion of syngas and bio-oil, and a lower consumption of electrical energy. Systems using NF had lower electrical energy consumption than systems using RO.
All plasma devices showed high effectiveness in long-chain PFAS degradation (from 40 % to above 90 %). It was also demonstrated that the plasma treatment reduces the toxicity of the leachate, and the leachate spiked with PFAS.
To design the online Decision Support Framework (DSF), available information and expectations from end-users have been collected. A database mapping over 120 000 substances has been developed.
Policy briefs and Recommendations have been written for facilitating decision-making on PFAS management strategies, and supporting the zero pollution ambitions of the EU and circular economy goals. Initiatives such as the CEN Workshop Agreement on "Solutions Strategies" and a MOOC are fostering knowledge exchange and public awareness.
