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Urban wet-weather discharges (combined sewer overflows, CSO and stormwater outlets from separate sewers, SWO) contain various trace contaminants which can pose a threat to receiving waters (Launay et al., 2016; Mutzner et al., 2020; Wicke et al., 2021). Hence, there is a need to identify critical contaminants and to quantify pollutant concentrations in wet-weather discharges to assess effective control strategies. Efforts have been made in the last decade to increase our understanding of the presence, magnitude, and diversity of contaminants in wet-weather discharges (e.g. Gasperi et al., 2014; Launay et al., 2016; Masoner et al., 2019; Mutzner et al., 2020; Rippy et al., 2017). Despite these efforts, the information gained with these monitoring campaigns is still limited, as most contain small, local datasets both in terms of sampled discharge events and spatial coverage. In this study, we use a data-driven statistical analysis of existing measurements collected at more than 60 wet-weather discharge sites to gain insight on the frequency of detection and relative abundance of trace contaminants. This information can be used to inform future monitoring efforts as utilities and regulators work towards building effective management strategies.

Comunicació de congrés presentada a: 16 th International Conference on Environmental Science and Technology, celebrat a l'Illa de Rodes (Grecia), del 4 a 7 de setembre de 2019 This work aims at integrating the last advances in high resolution mass spectrometry (HRMS) and statistical analysis of data to develop and optimize a smart methodology (workflow) for the assessment of the performance of innovative water treatments using different technological approaches based on advanced oxidation processes with UV-254nm: (i) UV/K2S2O8, where oxidation takes place mainly following the initial formation of sulfate radicals, (ii) UV/KHSO5, where oxidation begins with the formation of both sulfate and hydroxyl radicals and (iii) UV/H2O2, when only the formation of hydroxyl radicals takes place initially. Experiments were carried out using secondary effluent from a local wastewater treatment plant. The developed workflow allows the evaluation of the treatments in terms of overall oxidation through the careful study of Van Krevelen diagrams, where all the masses of the HRMS chromatograms are considered. The potential formation of transformation products with sulfur due to the sulfate radicals was also evaluated using statistical tools based on the isotopic pattern and accurate mass. Finally, the behavior of a large number of micropollutants with a wide range of physicochemical properties was studied using suspect screening strategies This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement SMARTWORKFLOW (747698), the Spanish Ministry of Science and Innovation (grant number CTQ2015-69832-C4), and the Economy and Knowledge Department of the Catalan Government (Consolidated Research Group program: ICRATECH - 2017 SGR 1318 and ICRA-ENV - 2017 SGR 01124)

Forward osmosis (FO) is known to be particularly efficient at treating impaired water sources with a high fouling potential. In the context of water reuse FO is being introduced as a robust pre-treatment process, usually as a first barrier prior to a reverse osmosis (RO) step. The commercialisation of FO however hinges on the development higher permeability membranes and a recent breakthrough came with the introduction of thin-film composite (TFC) membranes. While promising state-of-the-art TFC membranes have been successfully fabricated and tested at the pilot-scale, their performance in FO is yet to be determined by comprehensive characterisation under the changed, elevated transmembrane water flux conditions. In this thesis mass transport through novel TFC membranes was initially studied and modelled using two FO-only characterisation methods. Alginate fouling in novel TFC membranes was then examined under different driving forces. L'osmosi directa (OD) és particularment eficaç en tractar aigües residuals amb un alt potencial de contaminació i embrutiment. En el context de la reutilització de l'aigua, la OD s'està introduint com un procés de tractament robust, generalment abans d'una etapa d'osmosi inversa (OI). No obstant això, la comercialització de la OD depèn del desenvolupament de membranes de major permeabilitat. Un avanç recent es va produir amb la introducció de membranes thin-film composite (TFC). Tot i que les membranes de TFC s'han fabricat i provat amb èxit a escala pilot, el seu rendiment en OD encara no s'ha determinat mitjançant una caracterització completa amb condicions de flux d'aigua elevat. En aquesta tesi, el transport de massa a través de les noves membranes de TFC s'ha estudiat i modelatge inicialment utilitzant dos mètodes de caracterització d'OD. També en aquest estudi es va examinar l'embrutiment d'alginat de les noves membranes de TFC sota diferents forces impulsores (pressió osmòtica i pressió hidràulica.

Stormwater is a major driving factor of aquatic ecosystem degradation as well as one of the largest untapped urban freshwater resources. We present results from a long-term, multi-catchment study of urban stormwater pesticides across Australia that addresses this dichotomous identity (threat and resource), as well as dominant spatial and temporal patterns in stormwater pesticide composition. Of the 27 pesticides monitored, only 19 were detected in Australian stormwater, five of which (diuron, MCPA, 2,4-D, simazine, and triclopyr) were found in >50% of samples. Overall, stormwater pesticide concentrations were lower than reported in other countries (including the United States, Canada and Europe), and exceedances of public health and aquatic ecosystem standards were rare (10% of samples). Spatio-temporal patterns were investigated with principal component analysis. Although stormwater pesticide composition was relatively stable across seasons and years, it varied significantly by catchment. Common pesticide associations appear to reflect 1) user application of common registered formulations containing characteristic suites of active ingredients, and 2) pesticide fate properties (e.g., environmental mobility and persistence). Importantly, catchment-specific occurrence patterns provide opportunities for focusing treatment approaches or stormwater harvesting strategies. Refereed/Peer-reviewed

Urban runoff usually contains significant amounts of organic and inorganic colloidal particles. Due to their high surface area and associated surface charges, these colloidal particles become a strong binding site and carriers for many contaminants found in the runoff. This paper presents a study on the physicochemical properties and behaviors of organic colloidal particles found in urban runoff under different simulated pH conditions. Four optical characterization techniques, namely (1) UV spectroscopy; (2) fluorescence spectroscopy; (3) size-exclusion chromatography with UV detector and (4) dynamic light scattering were used to examine and evaluate the colloidal properties and their behaviors. It was found that the colloidal particles under both acidic and alkaline conditions exhibited a distinct bimodal characteristic in particle-size distribution. Parallel interpretation of the four optical characterization results revealed that the influence of pH on the colloidal particles were more prominent at alkaline conditions, where an enormous growth of larger colloidal particles was observed as a result of aggregation and/or dissolution of humics and fulvic-type substances as well as biopolymers and their precursors. Results showed that the colloidal particles behave differently under acidic, neutral and alkaline conditions. This has an important implication on the water quality and immediate water treatment processes are required.