Task 1 focuses on profiling biocides from different sampling points selected to be representative of domestic, industrial and hospitalar wastewaters in an urban context. Influent and effluent waters at two wastewater treatment plants (WWTP) - Freixo and Sobreiras - will also be evaluated as well as water prepared for reuse produced by Freixo WWPT. The aim is to create a spatial diagnosis of Porto city in what respects the presence of biocides in waters, pinpointing zones of urban biocide emission, transformation, and accumulation.

Task 2 aims the development and implementation of a catalytic reactor for photo-oxidation of biocides to be applied in the treatment of water effluents consisting on immobilized semiconductor nanomaterials (quantum-dots) that will be activated by visible/ultraviolet light. A class of biocides of particular relevance will be chosen according to the results obtained from T1. The immobilization of the reactor on a solid support will help to prevent contamination and reduce operational costs while maintaining catalytic efficiency. The validation and applicability will be tested using real water samples. The results obtained will be crucial, potentially leading to a patent.

Task 3, the development of a new natural deep eutectic solvent (NADES) with biocide activity will be carried out. The goal is to develop a non-toxic compound suitable to be used in disinfectant formulations, replacing toxic biocides currently in use. Produced compounds will undergo physical-chemical characterization and stability testing. The most promising candidates will then be assessed for their antiseptic properties to select a new biocidal compound for ecotoxicological evaluation.

Task 4 comprise the ecotoxicological characterization of the new NADES with biocidal activity selected in T3, alone and in mixture with a selected biocide of concern. Bioassays with two organisms, the microalgae (Chlorella vulgaris) and the crustacean cladoceran (Daphnia magna), widely used as representative of freshwater primary producers and primary consumers, respectively, will be conducted, following OECD guidelines.

Task 5 focuses on disseminating, exploiting, and communicating the obtained results. A well-structured strategy will guide activities, including a project website, tailored messages to reach various audiences (scientific community, regulatory authorities, and general public), and team participation in relevant International and National conferences. At the end of the project, a workshop will be organized to share results and recommendations with all stakeholders of the sector.

Task 6 will deal with the coordination and management of the project, being planned a kick-off meeting in the 1st month, and ordinary on-line meetings every 6 months between the IR and the leaders of each task.