http://hdl.handle.net/10256/9553 2025-09-17T17:16:17Z http://hdl.handle.net/10256/27174 Streamflow Generation Processes and Stream Intermittency in a Mediterranean Basin: Insights From End-Member Mixing Analysis Córdoba-Ariza, Paula Gabriela; Batalla, Ramon J.; Gutiérrez Provecho, Carmen; Sabater, Sergi; Mas-Pla, Josep Climate change, land use, and resource exploitation increasingly threaten river hydrology and water quality, leading to scarcity. Non-perennial or intermittent rivers are vulnerable systems characterised by highly variable flows. While recent research has advanced understanding of their natural variability, integrating the complex effects of multiple human impacts at the basin scale remains challenging. Aiming to improve this understanding and supporting effective management, this study uses end-member mixing analysis (EMMA) to identify streamflow sources in an intermittent Mediterranean river network, based on hydrochemical data from 23 sites over 14 monthly surveys and potentiometric data from six shallow wells. The analysis identifies three main contributors to streamflow: headwater runoff, groundwater baseflow from aquifers and hillslopes and treated wastewater. Their relative contributions varied spatially and seasonally. Upstream of urban areas, headwater runoff dominated (71%), while in the central catchment, groundwater contributed 15%-75%. Downstream of industrial areas, contributions were more balanced: 35% runoff, 27% groundwater and 38% wastewater. Alluvial groundwater was more important in small upstream subbasins in terms of maintaining the connectivity of the streamflow, whereas groundwater contribution from deeper aquifers dominated in lower reaches. EMMA results also highlighted discrepancies with point potentiometric data, emphasising the limitations of local measurements for understanding basin-scale hydrology. Under future climate scenarios, reduced headwater runoff and groundwater storage are expected to lower baseflow, increasing reliance on treated but lower-quality wastewater to sustain streamflow. This highlights the need for long-term monitoring and management, with a focus on protecting baseflow sources and improving wastewater quality to ensure water sustainability 2025-06-23T00:00:00Z http://hdl.handle.net/10256/26991 Evaluation of pharmaceutical removal through a full-scale UASB-CW system in a water-scarce Mediterranean region Castaño-Ortiz, Jose Maria; Alonso, Lucas Leonel; Noutsopoulos, Constantinos; Seintos, Taxiarchis; Sáez, Natalia; Rodríguez-Mozaz, Sara; Buttiglieri, Gianluigi In a world threatened by water scarcity, the use of non-conventional water sources, as reclaimed wastewater, for irrigation purposes is a promising option. Nonetheless, a suitable water treatment strategy must be implemented to reduce the concentration of emerging contaminants such as pharmaceutically active compounds (PhACs). Upflow anaerobic sludge blanket (UASB) technology is characterized by lower sludge production, lower energy demand as well as lower construction and operational costs compared with conventional activated sludge systems. In this work, the efficiency of a UASB system coupled to a constructed wetland (UASB-CW) was evaluated for the removal of pharmaceuticals present in urban wastewater on a Greek Island in a Mediterranean area suffering from water scarcity. Results showed that influent wastewater (IWW) concentrations in summer doubled in fall (238[thin space (1/6-em)]856 ng L−1 and 95[thin space (1/6-em)]057 ng L−1, respectively). The UASB reactor achieved a high removal efficiency for PhACs, particularly for acetaminophen (the most concentrated PhAC in the IWW), with removal rates of 88% in fall and 90% in summer, while exhibiting lower removal rates for other PhACs. The CW, however, decreased the concentration of most pharmaceuticals. The overall removal rate of the system ranged between 64% (summer) and 69% (fall) of the total IWW concentrations. Upon irrigation with reclaimed water, the impacts on the aquatic and terrestrial ecosystems were also considered. Effluent dilution and/or further polishing treatment would be necessary to better eliminate the contaminants and prevent any risk to the environment 2025-07-01T00:00:00Z http://hdl.handle.net/10256/26960 Integration of Specific Aeration Demand (SAD) into Flux-Step Test for Submerged Membrane Bioreactor Galizia Amoraga, Albert; Comas Matas, Joaquim; Rodríguez-Roda Layret, Ignasi; Blandin, Gaetan; Monclús Sales, Hèctor This study proposes a novel methodology to assess fouling that complements the flux-step test (FST) by integrating aeration-step tests (ASTs) to optimise the specific aeration demand (SADm) for ultrafiltration hollow-fibre (UF-HF) submerged membranes in membrane bioreactor (MBR) configurations. Three membranes with distinct manufactur- ing processes non-thermal-induced phase separation (NIPS) and thermal-induced phase separation (TIPS) were evaluated under continuous and intermittent aeration. The AST revealed that the critical SADm has a range of 0.1-0.5 m3·m−2·h−1 for continuous aeration and 0.1-0.2 m3·m−2·h−1 for intermittent aeration. NIPS membranes with homogeneous structures were less prone to fouling under intermittent aeration, while TIPS membranes with a heterogeneous structure exhibited better recovery under continuous aeration, reflecting distinct fouling dynamics. Findings indicate that the FST alone does not fully represent operational conditions, as aeration efficiency is linked to membrane structure and aeration mode. By combining the FST with ASTs, our approach enables tailored fouling control strategies, reducing energy consumption and improving MBR performance. These insights are critical for advancing toward energy-efficient wastewater treatment technologies 2025-04-03T00:00:00Z http://hdl.handle.net/10256/26853 Characterization of scrubber water discharges from ships using comprehensive suspect screening strategies based on GC-APCI-HRMS García-Gómez, Elisa; Gkotsis, Georgios; Nika, Maria Christina; Hassellöv, Ida-Maja; Salo, Kent; Lunde Hermansson, Anna; Ytreberg, Erik; Τhomaidis, Νikolaos S.; Gros Calvo, Meritxell; Petrović, Mira An extended suspect screening approach for the comprehensive chemical characterization of scrubber discharge waters from exhaust gas cleaning systems (EGCSs), used to reduce atmospheric shipping emissions of sulphur oxides, was developed. The suspect screening was based on gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS) and focused on the identification of polycyclic aromatic hydrocarbons (PAHs) and their alkylated derivatives (alkyl-PAHs), which are among the most frequent and potentially toxic organic contaminants detected in these matrices. Although alkyl-PAHs can be even more abundant than parent compounds, information regarding their occurrence in scrubber waters is scarce. For compound identification, an in-house compound database was built, with 26 suspect groups, including 25 parent PAHs and 23 alkyl-PAH homologues. With this approach, 7 PAHs and 12 clusters of alkyl-PAHs were tentatively identified, whose occurrence was finally confirmed by target analysis using GC coupled with tandem mass spectrometry (GC-MS/MS). Finally, a retrospective analysis was performed to identify other relevant (poly)cyclic aromatic compounds (PACs) of potential concern in scrubber waters. According to it, 18 suspect groups were tentatively identified, including biphenyls, dibenzofurans, dibenzothiophenes, and oxygenated PAHs derivatives. All these compounds could be used as relevant markers of scrubber water contamination in heavy traffic marine areas and could be considered as potential stressors when evaluating scrubber water toxicity 2023-12-01T00:00:00Z