CIRCULARIS tackles one of today’s most urgent environmental challenges: the persistent contamination of drinking and wastewater with per‑ and polyfluoroalkyl substances (PFAS). These “forever chemicals,” used for decades in countless industrial and consumer products, are highly mobile, resistant to degradation, and toxic even at trace levels. Conventional treatment technologies such as activated carbon and ion‑exchange resins are insufficient, particularly for short‑chain PFAS, and generate significant secondary waste. Responding to the tightening EU Drinking Water Directive (2023/2188), proposed REACH restrictions, and the Zero Pollution Action Plan, CIRCULARIS introduces a new paradigm for PFAS remediation through circular materials, digital design, and scalable water treatment technologies. The project is driven by Austria, upcycling post‑consumer plastic waste—primarily PET—into circular adsorbent materials functionalized with porous frameworks tailored for selective PFAS capture. This approach simultaneously diverts PET from landfills and incineration and produces robust, high‑performance sorbents for water treatment. Crucially, CIRCULARIS embeds digital innovation at its core: the subcontractor Thinktropy will provide a Bayesian optimization and active learning model that uses experimental data to iteratively predict, propose, and refine new adsorbent candidates. This AI‑guided loop reduces trial‑and‑error synthesis, lowers resource consumption, and accelerates the discovery of breakthrough PFAS adsorbents. CIRCULARIS progresses from TRL 2–3 to TRL 5, integrating PET‑based adsorbents into three reactor formats— batch, fixed‑bed, and modular cartridge systems—engineered and validated in Austria by TU Wien, Protovation GmbH, and GIS Aqua. Envites (CZ) will support by confirming the developed solutions under Czech water conditions and translating findings for future regulatory and market uptake in Central Europe. TU Wien will also lead life cycle assessment (LCA) and techno‑economic analysis (TEA) to ensure sustainability and scalability. By merging plastic waste valorization, AI‑guided materials discovery, and practical water treatment technologies, CIRCULARIS delivers a holistic, circular economy solution to one of Europe’s most critical pollution problems. Expected impacts include: (i) breakthrough removal efficiency for PFAS, including short‑chain compounds like TFA; (ii) a digital design workflow that transforms how circular adsorbents are developed; (iii) significant diversion of PET waste into high‑value applications; and (iv) measurable contribution to EU sustainability policies, positioning Austria as a leader in next‑generation water purification technologies, with cross‑border confirmation from the Czech partner to support broader adoption.