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International audience; Environmental pollution monitoring represents a major challenge due to the growing presence of a large and diverse number of potential contaminants. In complement to target analysis, nontarget analysis, via liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS), is increasingly used to provide a more comprehensive characterization of pollution. The challenge associated with this type of analysis is particularly related to the data treatment for substance identification. One of the main limitations is that all data must be manually reviewed, which is tedious and time-consuming. Machine learning algorithms aim to reproduce human behavior, and their capabilities were therefore evaluated to automatically identify substances in suspect screening approaches. After selecting the relevant features produced from LC/HRMS, seven different machine learning models were evaluated for each of the three different databases, which resulted in the selection of logistic regression (LR) and random forest (RF)-based algorithms. An interface was built to rank the identified substances and to assess the performance of the developed models. The LR model provided the best results when retention times were available. The developed LR and RF models were determined complementarily, particularly when no retention times were available. However, limitations were noticed when using a database containing different HRMS technologies.

International audience; Marine sediment disposal is an important economic and environmental issue worldwide. In order to minimize these discharges and optimize resources through a circular economy approach, this study discusses the potential use of fine marine sediments without treatments as a sand substitute in the marine concrete class (XS2, C30/37). The Dreux-Gorisse method was applied to find the concrete formulation containing 10, 20, 30, 40 and 50% sediment by weight. The results show that an XS2 concrete C30/37 with a water to binder ratio of 0.55 could be designed with 10% of sediment replacement content without significantly affecting the concrete properties. However, the optimization of concrete mix design shows that marine concrete (XS2, C30/37) could be designed with 30% of sediment replacement content without significantly affecting the potential durability and the estimated lifetime of the concrete structure.

International audience; The effects of sediment elutriate, prepared from a sediment resuspension simulation process, on the growth of bacterioplankton and of different sized phytoplankton as well as on their grazing by protozooplankton were investigated in Mediterranean coastal ecosystems during spring phytoplankton bloom. In parallel, the response of bacterioplankton, phytoplankton and protozooplankton to sediment elutriate enrichment was assessed in microcosm experiments. Elutriate addition provoked a high enrichment in nutriments of the overlying water, particularly in ammonium, dissolved organic matter but also in trace metal elements and herbicides. Overall, elutriate addition significantly increased the biomass of bacterioplankton and of total phytoplankton, but the phytoplankton size fractions responded differently to elutriate enrichment. The picophytoplankton showed a significant strong enhancement in both growth and production rates, relatively to control, while these rates significantly decreased for nano- and microphytoplankton. Accordingly, the phytoplankton size structure shifted in elutriate microcosm toward a dominance of the picophytoplankton concomitant with a significant reduction in larger size fractions. The elutriate addition caused also a clear shift in the taxonomic composition of protozooplankton, associated with a significant modification of its functional diversity, with the dominance of pico-sized cell consumers (such as aloricate ciliates, heterotrophic nanoflagellates and mixotrophic dinoflagellates) in the detriment of grazers of nano- and microphytoplankton (such as heterotrophic dinoflagellate). The protozooplankton grazing on small prey (bacterioplankton and picophytoplankton) increased, while feeding on nano- and micro-sized phytoplankton decreased after elutriate addition. These results have implication for the carbon transfer pathway, which could change from an herbivorous food web to a microbial food web, influencing so the exportation of biogenic carbon through the other trophic compartments.

International audience; The increase in food needs due to high population growth in Niger has led to the intensification of urban agriculture and the increased use of pesticides. The objective of this study is primarily to assess the polar pesticide contamination (mainly herbi-cides) of the Niger River and its tributary, the Mekrou River, in Niger, using both grab sampling and POCIS (Polar Organic Chemical Integrative Samplers), and then to evaluate the risk to the aquatic environment. Two water sampling campaigns were carried out during the wet and dry seasons. The polar pesticides were analyzed by liquid chromatography coupled with tandem mass spectrometry, which allowed the identification of compounds with concentrations in the grab samples above the WHO guide values and the EU directive: diuron with 2221 ng/L (EU quality guideline: 200 ng/L), atrazine with 742 ng/L (EU quality guideline: 600 ng/L) and acetochlor with 238 ng/L (EU quality guideline: 100 ng/L). The risk assess-ment study indicated that diuron and atrazine present a high risk for the aquatic environment during the wet season. The main source of water contamination is the intensive use of pesticides in urban agriculture near the city of Niamey, and the intensive cotton farming in the Benin. Moreover, the surveys (30 producers interviewed) showed that 70% of the pesticides used are not approved by the Interstate Committee for Drought Control in the Sahel (CILSS) and some are prohibited in Niger. The inventory of pesticides sold in the zone showed that active ingredients used by producers are 48% insecticides, 45% herbicides, and 7% fungicides.

International audience; The degradation of three antibiotics (sulfamethoxazole, trimethoprim, and ofloxacin) and one synthetic hormone (17 α-ethinylestradiol) was investigated in three in-vitro biotransformation models (i.e., pure enzymes, hairy root, and Trichoderma asperellum cultures) for anticipating the relevance of the formation of transformation products (TPs) in constructed wetlands (CWs) bioaugmented with T. asperellum fungus. The identification of TPs was carried out employing high-resolution mass spectrometry, using databases, or by interpreting MS/MS spectra. An enzymatic reaction with β-glucosidase was also used to confirm the presence of glycosyl-conjugates. The results showed synergies in the transformation mechanisms between these three models. Phase II conjugation reactions and overall glycosylation reactions predominated in hairy root cultures, while phase I metabolization reactions (e.g., hydroxylation and N-dealkylation) predominated in T. asperellum cultures. Following their accumulation/degradation kinetic profiles helped in determining the most relevant TPs. Identified TPs contributed to the overall residual antimicrobial activity because phase I metabolites can be more reactive and glucose-conjugated TPs can be transformed back into parent compounds. Similar to other biological treatments, the formation of TPs in CWs is of concern and deserves to be investigated with simple in vitro models to avoid the complexity of field-scale studies. This paper brings new findings on the emerging pollutants metabolic pathways established between T. asperellum and model plants, including extracellular enzymes.

Accurate streamflow forecasting can help minimizing the negative impacts of hydrological events such as floods and droughts. To address this challenge, we explore here artificial neural networks models (ANNs) for streamflow forecasting. These models, which have been proven successful in other fields, may offer improved accuracy and efficiency compared to traditional conceptually-based forecasting approaches.The goal of this study is to compare the performance of a traditional conceptual rainfall-runoff (hydrological) model with an artificial neural network (ANN) model for streamflow forecasting. As a test case, we use the Severn catchment in the United Kingdom. The adopted ANN model has a long short-term memory (LSTM) architecture with two hidden layers, each with 256 neurons. The model is trained on a 25-year dataset from 1988 to 2013 and tested on a 3-year dataset (from 2014 to 2016). It is also validated on a 3-year dataset (from 2017 to 2020, 2019 being a particularly wet year), to assess its performance in extreme hydrological conditions. The study focuses on daily and hourly predictions.To conduct this study, the conceptual hydrological model called Superflex is used as a benchmark. Both models are first evaluated using the Nash-Sutcliffe Efficiency (NSE) score. To enable a fair and accurate comparison, both models share the same inputs (i.e. meteorological forcings: total precipitation, daily maximum and minimum temperatures, daylight duration, mean surface downward short wave radiation flux, and vapor pressure). The ANN model was implemented using the Neuralhydrology library developed by F. Kratzert.In our study, we found that LSTM model is able to provide more accurate one-day forecasts than the hydrological model Superflex. For the daily predictions, the average NSE score using the LSTM model is 0.85 (with an average NSE score of 0.99 for training period, and 0.85 for validation period), which is higher than the NSE score of 0.74 achieved by the Superflex model (with a score of 0.84 for training period).The hourly prediction using NSE with the superflex model had a score of 0.88, with a score of 0.7 during training. The LSTM model had an average NSE score of 0.87, with an average score of 0.99 during training and an average score of 0.85 during validation.These results were obtained without adjusting the hyperparameters and by training the model only on data from the Severn watershed.The ANN model has demonstrated promising results compared to a state-of-the-art conceptual hydrological model in our studies. We will further compare both models using different training dataset periods, and different catchements. These additional tests will provide more information on the capabilities of the LSTM model and help to confirm its effectiveness.

Floods are a major natural hazard in the Mediterranean region, causing deaths and extensive damages. Recent studies have shown that intense rainfall events are becoming more extreme in this region, but paradoxically without leading to an increase in the severity of flood events. Consequently, it is important to understand how flood events are changing to explain this absence of trends in flood magnitude despite increased rainfall extremes. A database of 98 stations in Southern France with an average record of 50 years of daily river discharge data between 1958 and 2021 was considered, together with a high-resolution reanalysis product providing precipitation and simulated soil moisture. Flood events, corresponding to an average occurrence of one event per year (5317 events in total), were extracted and classified into excess rainfall, short rainfall and long rainfall event types. The evolution through time of the flood event characteristics and seasonality were analyzed. Results indicated that, in most basins, floods tend to occur earlier during the year, the mean flood date being on average advanced by one month. This seasonal shift can be attributed to the increased frequency of southern-circulation weather types during spring and summer. An increase in total and extreme event precipitation has been observed, associated with a decrease of antecedent soil moisture before rainfall events, linked to a smaller contribution of base flow during floods. The majority of flood events are associated with excess rainfall on saturated soils, but their relative proportion is decreasing over time with a concurrent increased frequency of short rain floods. Therefore, this study shows that even in the absence of trends, flood properties may change over time and these changes need to be accounted for when analyzing the long-term evolution of flood hazards.

A large CFL algorithm is presented for the explicit, finite volume solution of hyperbolicsystems of conservation laws , with a focus on the shallow water equations. The Riemannproblems used in the flux computation are determined using averaging kernels that extendover several computational cells. The usual Courant-Friedrichs-Lewy stability constraint is replaced with a constraint involving the kernel support size. This makes the method unconditionally stable with respect to the size of the computational cells, allowing the computational mesh to be refined locally to an arbitrary degree without altering solution stability. The practical implementation of the method is detailed for the shallow water equations with topographical source term. Computational examples report applications of the method to the linear advection, Burgers and shallow water equations. In the case of sharp bottom discontinuities, the need for improved, well-balanced discretizations of the geometric source term is acknowledged.

Flood risk is the natural phenomenon that affects the most people in the world, and climate change is likely to increase this trend. Floods, whether in rivers or in urban areas, carry debris that can have a significant impact on hydrodynamics and therefore on risk. Although numerical models are frequently used to anticipate the impacts of floods in order to improve land-use planning and facilitate crisis management, there are few models capable of representing accurately both the flood hydrodynamics and the associated debris transport process. Numerical models, when they exist, are generally based on simplifying assumptions. In this paper, we propose a new operational model that is validated and compared with analytical results, other models and experimental data. The proposed model, implemented in the SW2D software, paves the way for a better representation of debris clogging on hydrodynamics, even with a large number of transported objects.

Données de pluie collectées par l'observatoire urbain d'HSM (Omsev), 2019

Non-target screening (NTS) methods are rapidly gaining in popularity, empowering researchers to search for an ever-increasing number of chemicals. Given this possibility, communicating the confidence of identification in an automated, concise and unambiguous manner is becoming increasingly important. In this study, we compiled several pieces of evidence necessary for communicating NTS identification confidence and developed a machine learning approach for classification of the identifications as reliable and unreliable. The machine learning approach was trained using data generated by four laboratories equipped with different instrumentation. The model discarded substances with insufficient identification evidence efficiently, while revealing the relevance of different parameters for identification. Based on these results, a harmonized IP-based system is proposed. This new NTS-oriented system is compatible with the currently widely used five level system. It increases the precision in reporting and the reproducibility of current approaches via the inclusion of evidence scores, while being suitable for automation., PGF acknowledges his Ramon y Cajal fellowship (RYC2019-027913-I) from the AEI-MICI. ELS is supported by the Luxembourg National Research Fund (FNR) for project A18/BM/12341006.

International audience; Simulated free surface transients in periodic urban layouts have been reported to be self-similar in the space-time domain when averaged on the scale of the building period. Such self-similarity is incompatible with the head loss model formulae used in most porosity-based shallow water models. Verifying it experimentally is thus of salient importance. New dam-break flow laboratory experiments are reported, where two different configurations of idealized periodic buildings layouts are explored. A space-time analysis of the experimental water level fields validates the self-similar character of the flow. Simulating the experiment using the two-dimensional shallow water model also yields self-similar period-averaged flow solutions. Then, the Single Porosity (SP), Integral Porosity (IP) and Dual Integral Porosity (DIP) models are applied. Although all three models behave in a similar fashion when the storage and connectivity porosities are close to each other, the DIP model is the one that upscales best the refined 2D solution.

International audience; The integrated life cycle assessment (LCA), life cycle cost assessment (LCC) and laboratory-based experimental assessment were applied to provide insight for early stage decision-making on the valorization of the dredged sediments. The objective was to find a viable and sustainable solution for the valorization of the dredged sediment in concrete, holding up a certain level of standard concrete performance without compromising in terms of economy and environment. For the sensitivity analysis, parametric life cycle inventories were developed to assess the sensitivity of environmental and economic costs to the rate of sand substitution by sediment, as well as the variations in the concrete components. The workability of fresh concrete and the compressive strength of hardened concrete at 28 days were assigned as the quality indicators to evaluate the influence of sand substitution by sediment on the concrete performance. The compressive strength evaluation in the laboratory demonstrated that a maximum rate of sand substitution in concrete up to 40 % by predominantly sandy sediment could sustain the concrete strength class. However, LCA and LCC negated the rate of sand substitution by sediment higher than 20 %. The integrated environmental, economic, and experimental assessments demonstrated that the substitution of sand by predominantly fine sediment downgrades the strength class of concrete, even in the low rate of incorporation (10 %) and increases the environmental and economic costs. Inferred from the results, the maximum rate of sustainable sand substitution by sediment in concrete could be optimized through a compromise between the expected mechanical strength and workability of the concrete, the economic and environmental impacts of the superplasticiser and the sediment transport. Overall, integrating environmental and economic cost assessments into the laboratory-based assessment of the valorization scenarios would determine the threshold for the sustainable rate of incorporation of sediment in valorization scenarios.

International audience; The present paper focuses on solute transport behaviour in a Model Heterogeneous Porous Medium (MHPM) under different flow rates. We report tracer experiments under stationary hydraulic conditions, with 7 different stationary flow rates spanning two orders of magnitude. Several replicates are carried out on several MHPMs, allowing for a sound statistical assessment of experimental imprecision. The experimental BreakThrough Curves (BTCs) exhibit a dual transport mode in agreement with previously-reported field scale experiments. This dual transport mode is shown to be flow-rate independent under a suitable variable change, with the BTCs superposing in the limit of experimental uncertainty. The experiment is modelled using a classical Multi-Region Advection-Dispersion (MRAD) model with only two mobile regions. We present a flow rate independent reformulation of the MRAD model that that allows both water and solute continuity to be preserved during the calibration process. Assuming a linear dependence of the dispersion and exchange coefficients on the flow rate is shown to yield satisfactory model behaviour. This confirms the linearity of the dispersion coefficient with respect to the flow rate, often suggested in the literature, over a wide range of flow conditions.

A large CFL algorithm is presented for the explicit, finite volume solution of hyperbolic systems of conservation laws. The Riemann problems used in the flux computation are determined using averaging kernels that extend over several computational cells. The usual Courant-Friedrichs-Lewy stability constraint is replaced with a constraint involving the kernel support size. This makes the method unconditionally stable with respect to the size of the computational cells, allowing the computational mesh to be refined locally to an arbitrary degree without altering solution stability. The practical implementation of the method is detailed for the shallow water equations with topographical source term. Computational examples report applications of the method to the linear advection, Burgers and shallow water equations. In the case of sharp bottom discontinuities, the need for improved, well-balanced discretizations of the geometric source term is acknowledged.

In the south of France, the Gardons, at the heart of the Mediterranean hot spot, are subject to the intensification of extreme impacts of climate change (droughts, floods etc.). Stakeholders in this territory base their decision-making on a certain representation of the "health" status of the rivers. In other words, watershed management is based on an adjustment between a perception of the health of the hydro-social cycle (taking care) and the actions implemented to improve it (giving care). To participate in guaranteeing accessible and available water for future generations, this thesis provides keys to understanding these heed-concern dynamics, in order to ensure the proper adjustment of management practices with the state of health of the watercourse. By mobilizing a care ethic of the hydro-social cycle, this thesis invites us to question the epistemological potential of the health analogy applied to watershed management. Inscribed in the continuity of the works carried out in sustainability science, it proposes an original approach imposing a renewal of the researcher's posture. Interdisciplinary, it calls upon the theoretical fields of hydrology, geography, and sociology. Transdisciplinary, it participates in the emergence and interpretation of the points of view of local actors. A survey, conducted between 2020 and 2022, articulates an approach by semi-structured interviews and a questionnaire approach to collect the diversity of these points of view on the health of the Gardons. It seeks to determine the indicators used by each person to express the link between "paying attention" and "taking care". The results of this research work reveal and explain several "spheres of care", characterized by a form of hydro-social adjustment: referring to the indicators used by the local actors, they open a space for dialogue between the different points of view. This thesis thus feeds the reflections around an adaptive and inclusive management of water, integrating experts, planners, and users alike.; Au sud de la France, les Gardons, au cœur du point chaud méditerranéen, sont soumis à l’intensification des impacts extrêmes des changements climatiques (sécheresses, inondations etc.). Les acteurs de ce territoire basent leurs prises de décision sur une certaine représentation de l’état de « santé » des cours d’eau. Autrement dit, la gestion du bassin versant repose sur un ajustement entre une perception de la santé du cycle hydrosocial (faire attention) et les actions mises en œuvre pour l’améliorer (prendre soin). Pour participer à garantir une eau accessible et disponible pour les générations futures, cette thèse apporte des clés de compréhension de ces dynamiques attention-soin, afin de s’assurer du bon ajustement des pratiques de gestion avec l’état de santé des cours d’eau. En mobilisant une éthique du care du cycle hydrosocial, cette thèse invite à questionner le potentiel épistémologique de l’analogie de la santé appliquée à la gestion du bassin versant. Inscrite dans la continuité des travaux menés en science de la durabilité, elle propose une approche originale imposant un renouvellement de la posture du chercheur. Interdisciplinaire, elle interpelle notamment les champs théoriques de l’hydrologie, de la géographie, de la sociologie. Transdisciplinaire, elle participe à l’émergence et à l’interprétation des points de vue d’acteurs locaux. Une enquête située, menée entre 2020 et 2022, articule une approche par entretiens semi-directifs et une approche par questionnaire afin de recueillir la diversité de ces points de vue sur l’état de santé des Gardons. Elle s’attache à déterminer les indicateurs mobilisés par chacun pour exprimer le lien entre le « faire attention » et le « prendre soin ». Les résultats de ce travail de recherche révèlent et explicitent plusieurs « sphères du care », caractérisées par une forme d’ajustement hydrosocial : se référant aux indicateurs utilisés par les acteurs locaux, elles ouvrent un espace de dialogue entre les différents points de vue. Cette thèse nourrit ainsi les réflexions autour d’une gestion adaptative et inclusive de l’eau, intégrant aussi bien experts, gestionnaires et usagers.

International audience; The Nigerien Liptako in southwest Niger has gold mineralisations in Birimian formations (Paleoproterozoic) that have been mined for several decades. The objective of this study was to document the concentrations of arsenic and other toxic trace elements in groundwaters, river waters, suspended particulate matter and sediments and discuss the potential influence of artisanal gold mining on arsenic and trace elements enrichment. For this, forty-three groundwater samples (boreholes and wells) were analysed in mined and unmined areas. Surface waters, suspended particulate matters and sediments were sampled in three rivers at stations upstream and downstream from mining sites. Rock samples extracted from mine galleries were collected for mineralogical and geochemical characterization. In groundwater, arsenic concentrations ranged from 0.018 to 202 µg/L, exceeding drinking water guidelines (10 µg/L) in three artisanal gold mining areas. Manganese exhibited concentrations exceeding the potability limit in 23% of the samples, mainly in the Continental Terminal aquifer. In rivers, arsenic was the element most enriched in suspended particulate matter and sediments, but its concentration in water did not exceed 3 µg/L. Mineralogical analysis of rocks showed traces of arsenic in association with iron oxides, suggesting a release of arsenic in groundwater by desorption. The consumption of these waters rich in arsenic or manganese presents serious risks for health. These data represent the first large-scale investigation of arsenic and trace elements concentrations in groundwaters and surface waters in the Nigerien Liptako, where no or very scarce water quality measurements have been published yet.

International audience; Chaque année, l’activité portuaire nécessite le draguage d’une importante quantité de sédiments marins qui finissent souvent stockés en décharge sous forme de déchets. Ces opérations sont coûteuses et néfastes pour l’environnement. Afin de minimiser ces rejets et d'optimiser les ressources dans une logique d'économie circulaire, cette étude vise à examiner la possibilité de valoriser des sédiments marins bruts sans aucun traitement pour le port de Pérols (PP) et après un pré-traitement par hydrocyclonage pour le port de Camargue (PC), ports situés sur la côte d’Occitanie en France. Cette valorisation consiste à substituer une partie du sable par ces sédiments fins bruts dans la formulation d’un béton ordinaire de classe XS2 C30/37. L’effet de la substitution du sable par 10, 20, 30, 40, 50% des sédiments de PC ou par 10, 15, 20 et 30% des sédiments de PP a été évalué. Les résultats montrent une diminution de la résistance mécanique avec l’augmentation du taux de substitution. Dans le cas des sédiments de PC, le pourcentage de substitution est limité à 40% si un béton de classe XS2 C30/37 est l’objectif. Pour des classes de béton inférieures, C20 à 25 par exemple, une substitution de sable par des sédiments à hauteur de 50% peut être envisagée. Dans le cas des sédiments de PP, La classe de béton maximale obtenue est C20 ou C25. Pour autant, il est possible de valoriser les fines de sédiments de dragages sans traitement coûteux économiquement ou environnementalement au sein de bétons destinés au milieu marin. Cette étude apporte donc des résultats préliminaires nécessaires à la valorisation durable des sédiments à moindre coût et à long terme.

With growing urbanisation and climate change, flooding is likely to become even more frequent and severe. Therefore, it is essential to constantly monitor water level changes at a large scale. Synthetic Aperture Radar (SAR) images are often used for flood mapping as they allow a rather straightforward detection of water bodies, at almost all weather and illumination conditions. As the number of satellite observations and global digital elevation models (DEMs) are becoming more available, this mapping approach is gaining in popularity.In this study, we propose three different approaches to retrieve water level maps based on the combination of satellite and topographic data, hereby referred to as the global Height Above Nearest Drainage (HAND), the local HAND and the local DEM methods.The three approaches are based on the optimization of a threshold applied on the topography (HAND or DEM) data enabling a best fit with the SAR-extracted flood map. The optimized threshold values provide at the same time the normalized water levels (with respect to the drainage network). The water depth map is thus computed from the difference between the water level and the DEM. The global HAND method applies a single optimized threshold to the HAND map, over the entire area of interest. The local HAND method is based on the same concept but optimizes and applies the HAND threshold value locally, using a sliding window. The local DEM thresholding method employs the same principle as the second method but directly on the DEM.We evaluate these methods using hydraulic model simulation results and ground truth data, and we carry out several experiments using various SAR images (Envisat, TerraSAR-X and Sentinel-1) and topographic datasets (SRTM, CopDEM and LiDAR).The best results are obtained while combining a high-resolution image (e.g:TerraSAR-X) with: 1) a high-resolution dataset (e.g: LiDAR DEM), using the local DEM approach, or 2) a coarse-resolution dataset (e.g: Srtm DEM), using the global HAND approach. RMSDs on the derived water depth maps reach respectively 0.52m and 0.93m.

Estimating the impacts of flooding in urban areas is of primary importance when qualifying the exposure of territories. One of the difficulties encountered is that the processes at stake involve fine scales (building scale). Classical hydraulic approaches of urban floods consider buildings as obstructions to water flow, without taking into account the flow exchanges between streets and buildings. However, according to the literature, it seems necessary for characterizing material damage and human exposure in terms of buildings' dangerousness. Regarding the estimation of material damage, it is usual to assume that the water levels inside and outside the buildings are the same. This practice does not take into account the hydrostatic effects of flooding. As flood damage functions are very elastic with respect to water levels, especially in the lower values, relatively small differences in water levels can lead to large differences in the assessment of material damage. For these reasons, not taking into account the flow exchanges between streets and buildings may introduce a bias in the estimation of property damage. We propose to analyse how fine-scale approaches (building,) taking into account flows, can influence the characterization of material damage at a larger scale (district). We use the Richelieu district of the city of Nîmes, in the south of France to illustrate our work, taking as reference the 1988 event. We couple hydraulic and economic models to simulate water depths following i) a classical approach of building treatment and ii) an alternative approach explicitly taking into account street-building flow exchanges. The simulated water depths are then fed to the economic model, allowing us to determine, by comparing scenarios, possible bias and its magnitude. The Preliminary results show significant differences in water levels inside buildings compared to outside. In terms of damage, at the district level, not taking into account street-building flows leads to an overestimation of material damage. These results invite us to carry out complementary analyses at higher levels of resolution, by considering the dynamics of the flows inside the buildings and their repercussion in terms of material damage but also of danger.

International audience; Reclaimed wastewater associated biofilms are made up from diverse class of microbial communities that are continuously exposed to antibiotic residues. The presence of antibiotic resistance bacteria (ARB) and their associated antibiotic resistance genes (ARGs) ensures also a continuous selection pressure on biofilms that could be seen as hotspots for antibiotic resistance dissemination but can also play a role in antibiotic degradation. In this study, the antibiotic degradation and the abundance of four ARGs (qnrS, sul1, blaTEM, ermB), and two mobile genetic elements (MGEs) including IS613 and intl1, were followed in reclaimed wastewater and biofilm samples collected at the beginning and after 2 weeks of six antibiotics exposure (10 µg L−1). Antibiotics were partially degraded and remained above lowest minimum inhibitory concentration (MIC) for environmental samples described in the literature. The most abundant genes detected both in biofilms and reclaimed wastewater were sul1, ermB, and intl1. The relative abundance of these genes in biofilms increased during the 2 weeks of exposure but the highest values were found in control samples (without antibiotics pressure), suggesting that bacterial community composition and diversity are the driven forces for resistance selection and propagation in biofilms, rather than exposure to antibiotics. Planktonic and biofilm bacterial communities were characterized. Planktonic cells are classically defined “as free flowing bacteria in suspension” as opposed to the sessile state (the so-called biofilm): “a structured community of bacterial cells enclosed in a self-produced polymeric matrix and adherent to an inert or living. surface” as stated by Costerton and co-workers (1999).The abundance of some genera known to harbor ARG such as Streptococcus, Exiguobacterium, Acholeplasma, Methylophylaceae and Porphyromonadaceae increased in reclaimed wastewater containing antibiotics. The presence of biofilm lowered the level of these genera in wastewater but, at the opposite, could also serve as a reservoir of these bacteria to re-colonize low-diversity wastewater. It seems that maintaining a high diversity is important to limit the dissemination of antimicrobial resistance among planktonic bacteria. Antibiotics had no influence on the biofilm development monitored with optical coherence tomography (OCT). Further research is needed in order to clarify the role of inter-species communication in biofilm on antibiotic degradation and resistance development and spreading.

Groundwater provides a significant proportion of the water supply of the territories.The monitoring of the reserves and quality of these resources is therefore a major issue,in line with the United Nations Sustainable Development Goals. In relation to theseobjectives, this thesis deals with the characterization of the quality of groundwaterbodies in a territory with a mining past. It aims at developing a methodology toestimate the respective contributions of the natural geochemical background andanthropogenic inputs to the enrichment of metals and metalloids in groundwater,considering simultaneously the heterogeneity of the geology and the combination ofgeological, geomorphological, tectonic and statistical factors. Quality measurementswere carried out to establish the state of arsenic and antimony concentrations in thegroundwater bodies delimited by the Gardon watershed in the Cevennes. Then, amulti-criteria aggregation operator was developed and implemented in order toproduce quantitative and qualitative maps allowing the discrimination of the naturalgeochemical background from the anthropic contributions mainly constituted by thepast mining activity. This mapping made it possible to determine remarkable focilocated in particular on the Cevennes fault and on which particular attention must bepaid in the context of territorial management of the quality of water resources. Aninteractive workshop allowed to evaluate the differences of perception of the actors ofthe territory in front of information on water quality. It highlighted the need to developadapted scientific information restitution supports in order to reach a sharedawareness of groundwater quality issues by the different actors of a territory.; Les eaux souterraines assurent une proportion importante de l’approvisionnement eneau des territoires. La surveillance des réserves et de la qualité de ces ressourcesconstitue donc un enjeu majeur, en lien avec les Objectifs de Développement Durabledes Nations Unies. En rapport avec ces objectifs, la présente thèse traite de lacaractérisation de la qualité des masses d’eau souterraines sur un territoire ayantconnu un passé minier. Elle vise le développement d‘une méthodologie permettant d'estimer les contributions respectives du fond géochimique naturel et des apportsanthropiques, à l’enrichissement en métaux et métalloïdes dans les eaux souterraines,en considérant simultanément l'hétérogénéité de la géologie, et la combinaison defacteurs géologiques, géomorphologiques, tectoniques et statistiques. Des mesures dequalité ont été effectuées pour établir l’état des lieux des concentrations en arsenic eten antimoine dans les masses d'eau souterraines délimitées par le bassin versant duGardon dans les Cévennes. Ensuite, un opérateur d'agrégation multicritères a étédéveloppé et mis en œuvre afin de produire des cartes quantitatives et qualitativespermettant de discriminer le fond géochimique naturel des apports anthropiques.Cette cartographie a permis de déterminer des foyers remarquables situés notammentsur la faille cévenole et sur lesquels une attention particulière de surveillance doit êtreportée dans le cadre de la gestion territoriale de la qualité des ressources en eau. Unatelier interactif a permis d’évaluer les différences de perception des acteurs duterritoire face à des informations sur la qualité des eaux. Il a mis en évidence lanécessité de développer des supports de restitution des informations scientifiquesadaptés afin d’aboutir à une conscience partagée des questions liées à la qualité deseaux souterraines par les différents acteurs d’un territoire.

Hydraulic simulation represents a powerful tool for studying wastewater networks. In order to achieve this target, hydraulic software require a set of parameters such as pipe slopes, roughness, diameters, etc. However, these pieces of information are rarely known for each and every pipe. Moreover, underground networks are frequently expanded, repaired and improved and these changes are not always reported in databases. The task of completing the required data represents the most time-consuming part of model implementation. In this context, we present algorithms that complete missing data required by hydraulic software. We automated this data insertion and transformation in SWMM© format to make it quicker and easier for the user. This automated solution was compared with manually estimated inputs. The simulation results show a coherent hydraulic behaviour.

International audience

International audience; Located in the French Mediterranean region, the French Alternative Energies and Atomic Energy Commission (CEA) Cadarache Centre is subject to significant rainfall events which can lead to groundwater floods with rapid kinetics and high amplitude. This study aims to improve the understanding of the aquifer’s heterogeneity and piezometric responses at the scale of the Cadarache centre (900 ha) in order to better apprehend the groundwater floods. The deployed method consists in: (i) taking an inventory of reliable data; (ii) conducing a preliminary study of the spatial variability of rainfall at the centre scale with the method of double-mass curves and the comparison of the rainfall amounts of the different stations; and (iii) conducting a comprehensive statistical study of piezometric data (graphs of sorted piezometric data for three different flood events, definition of an original clustering method using an automatic feature detection). The results are of two kinds: (i) several clusters were identified; three appeared to be representative of specific areas; (ii) for each specific area, piezometers were linked with different plurikilometric NW–SE and NE–SW lineaments identified by previous bibliographic studies. This extensive study on nearly 80 piezometers has thus allowed to define a method of automatic feature extraction of the sorted groundwater levels, and to establish a clustering of piezometers according to their statistical behaviour. Even if the statistical “black box” method was applied without any prerequisite on the location of the boreholes, it allowed establishing a very relevant relation between sorted water height and geological structure constraining the flows.

International audience

International audience

National audience

International audience; While perfluoroalkyl sulfonic acids (PFSAs) and perfluoroalkyl carboxylic acids (PFCAs) are ubiquitous in aquatic environments, non-targeted methods have recently revealed the presence of numerous unidentified per- and polyfluoroalkyl substances (PFAS). Besides those methods, the total oxidizable precursor (TOP) assay has proved useful to estimate the contribution of unattributed perfluoroalkyl acids precursors (pre-PFAAs). In this study, an optimized extraction method was developed to examine the spatial distribution of 36 targeted PFAS in surface sediments collected at French nationwide scale (n = 43), including neutral, anionic and zwitterionic molecules. In addition, a TOP assay procedure was implemented to estimate the contribution of unattributed pre-PFAAs in these samples. Conversion yields of targeted pre-PFAAs were determined for the first time under realistic conditions and led to differences in oxidation profiles compared to the common spiked ultra-pure water method. PFAS were detected in 86 % of samples and ∑PFAStargeted was in the range

Future climate scenarios for the Mediterranean region indicate a possible decrease in annual precipitation associated with an intensification of extreme rainfall events in the coming years. A major challenge in this region is to evaluate the impacts of changing precipitation patterns on extreme hydrological events such as droughts and floods. For this, it is important to understand the impact of climate change on soil moisture since it is a proxy for agricultural droughts, and the antecedent soil moisture condition plays a key role on runoff generation. This study focuses on 10 sites, located in southern France, with available soil moisture, temperature, and precipitation observations for a 10-year time period. Soil moisture is simulated at each site at the hourly time step using a model of soil water content. The sensitivity of the simulated soil moisture to different changes in precipitation and temperature is evaluated by simulating the soil moisture response to temperature and precipitation scenarios generated using a delta change method for temperature and a stochastic model (the Neyman–Scott rectangular pulse model) for precipitation. Results show that soil moisture is more impacted by changes in precipitation intermittence than precipitation intensity and temperature. Overall, increased temperature and precipitation intensity associated with more intermittent precipitation leads to decreased soil moisture and an increase in the annual number of days with dry soil moisture conditions. In particular, a temperature increase of +4 ∘C combined with a decrease of annual rainfall between 10 % and 20 %, corresponding to the current available climate scenarios for the Mediterranean, lead to a lengthening of the drought period from June to October with an average of +28 d of soil moisture drought per year.

Underground networks, particularly sewerage networks require accurate information for their management. To successfully and smoothly accomplish the required tasks for network expansion, reparation or simulation analysis, operators collect and analyse data coming from multiple sources. The various and heterogeneous sources available often provide different representations for a network. Thus, raising challenges for information exploitation and communication between the different actors managing these networks. In addition, the imperfections related to the sources are numerous and their consideration in the decision making process is mandatory. In this paper, we propose a generic data modelling for the fusion of sewerage networks data. Our meta-model supports imperfection modelling at data-source level as well as at network object position and attribute levels, allowing thus formal fusion operations to be conducted efficiently and reliably. To validate our meta-model, we implemented it using data analysis and reengineering platform called Moose, and we conducted a test on the town of Prades-le-Lez (France). We took into account three data-sources providing information on the node positions of the sewerage network : 1- the official network map as semi-structured source, 2- a high resolution aerial image database and 3- a Google Street View database as unstructured sources. As result, we were able to reliably perform data monitoring and visualization requests on real heterogeneous multi-source data related to a specific sewerage network., International Journal of Information Science and Technology, Vol 6 No 2 (2022)

International audience; The main objective of this study is to investigate how innovative satellite earth observation techniques that allow for the estimation of soil moisture and the mapping of flood extents can help in reducing errors and uncertainties in hydro-meteorological modelling especially in ungauged areas where potentially no or limited runoff records are available. A conceptual hydrological model is loosely coupled with a shallow water model allowing for the simulation of soil moisture and flood extent. Using as forcing of this model rainfall and air temperature time series provided in the globally and freely available ERA5 database it is then possible to carry out long-term simulations of soil moisture, discharge and flood extent. Next, time series of soil moisture and flood extent observations derived from freely available satellite image databases are jointly assimilated into the hydrological model in order to retrieve optimal parameter sets. For this assimilation experiment, we take benefitof recently introduced Particle Filters with tempering that circumvent some of the usual particle filter limitations such as degeneracy and sample impoverishment. As a proof of concept, we set up an identical twin experiment based on synthetically generated observations and we evaluate the performance of the calibrated model

The eLTER H2020 process aims at developing an European ecosystem research infrastructure and at creating long term observations platforms. In this context, we proposed a platform called P3M (Mediterranean Plain, Piedmont and Plateau) located in the Mediterranean basin that is considered as a hot-spot of both biodiversity and climate change. P3M provides an observation system of several contrasted socio-ecosystems representative of the Mediterranean diversity from local to territorial scales.P3M will study the connection between strong hydro-pedo-climatic gradients and biodiversity that are subjected to an increasing variability of hydroclimatic processes, while being strongly connected to anthropic drivers. P3M is structured around a toposequence of four different agro-ecosystems where the natural and cultivated sphere are highly connected : (i) Cevenol medium-size mountains characterized with hillside forest ecosystem and extensive agriculture on the valley bottom, (ii) High-altitude plateau with an agropastoralism-dryland system and a karstic hydrogeology reagent to precipitations that highly influences the quality and quantity of the water ressource on the entire platform, (iii) Cevenol piedmont natural forest and garrigue ecosystems, (iv) Herault watershed hilly plains organized around cultivated plains and mainly viticultural activities. This scientific collaboration will focus on i) analyzing the hydro-eco-sedimentary dynamics in between each ecosystems but also throughout the entire toposequence, ii) identifying the interactions between those dynamics and human activities within the different ecosystems iii) predicting the evolution of mediterranean landscape facing climate change and providing adapting solutions. To face these challenges, a transdisciplinary approach is necessary to better understand the connections between the increasing pressure of human activity, climatic phenomena, biophysic processus and biodiversity. P3M will answer European environmental scientific issues by ensuring the stability, the availability and the European standardisation of abiotic, biotic and social datas on a long term scale but also the reception of foreigners scientists. This platform gathers four OZCAR labelised observation networks (OMERE, Larzac Observatory, OHM-CV, MEDYCCYS) but also includes ANAEE and ICOS sites. Non-academics partners will take part in this project, for example the national and regional park or the local watershed facilities, to integrate the existing data but also to facilitate the transfer of research to local policies.

International audience; The Vistre plain is subject to a hydraulic functioning specific to Mediterranean regimes, notablycharacterized by intense and short episodes of heavy rainfall, and rapid to torrential floodingkinetics. To guard against risks, the public management institutions of the drainage basin havegradually put in place a set of devices consisting of best practices, administrative tools, technicalinfrastructure, vigilance and flood forecasting services, crisis management plans and awarenessprograms. During the 2014 flood episode, these institutions agreed on the fact that many damageswere limited thanks to the works built, since 2007, within the framework of flood prevention plans.However, it is important to question these devices in light of the challenge of requalification that thishighly anthropized river presents. Indeed, the academic sphere as well as the operational sectorhave recently demonstrated a desire to go beyond the diametric opposition between anthropic andecological interests to renew the questioning on socio-ecological interdependencies. This oppositionis challenged, in particular, by the counter-productivity of certain measures aimed at protectingoneself from nature: the artificialization of the functioning of rivers can increase the risk of flooding.These considerations are part of the objectives of the syndicate in charge of managing the Vistre.Since 2002, it has explicitly chosen a policy of revitalization (or renaturation) rather than restoration(or rehabilitation) of the Vistre. We hypothesize that this political choice contributes to the localemergence of a tension between protecting and being protected from nature. This poster willpresent the first results of a survey by semi-directive interviews and questionnaires conducted withstakeholders (inhabitants, associations and institutions), aiming to better understand the evolutionof the perception of socio-ecological interdependencies at work around the revitalization projects inthe Vistre Plain. This understanding, based on the collection of local representations and practices,will shed light on the conditions of conciliation between revitalization and flood protection policies

Although the impact of floodwaters on buildings is determined by a series of physical mechanisms that, when triggered, result in a wide range of physical damage to buildings and monetary losses, existing research on the topic appears polarized. The majority of work focuses either on the physical mechanisms that transform contact with floodwaters into damage, omitting the estimation of economic consequences, or on improving the estimation of direct damage, but neglecting the mechanisms mentioned above.In the work we present here, we seek to reconcile these two approaches to investigate the potential implications of both. We begin by considering the exchange of floodwater through the exterior and interior openings of a building to assess direct material damage and estimate the monetary value of the loss. To do this, we build a building-level simulation model by coupling a hydraulic model and an economic model. Our hydraulic model simulates the flow exchanges and the flood water height between the interior and exterior of the building and between the rooms inside the building. The economic model is based on a decomposition of the building into elementary components (wall material, cladding, insulation, floor, furniture, etc.), identifying the room and the height at which they are located. For each elementary component, the damage is modeled for all combinations of water depth and duration of flooding. We use our coupled model to simulate four different scenarios on exemplary buildings. The first scenario corresponds to the classical methodology, with homogeneous water depths outside and inside the building. The other three represent: i) street-to-building exchanges in an open plan building; ii) street-to-building/interior exchanges with closed openings; and iii) street-to-building/interior exchanges with open openings. Designating the conventional method as the baseline, we adopt a comparative approach based on monetary valuation of flood damage costs to determine the magnitude of bias of each alternative scenario. Given the high elasticity that flood damage functions exhibit for shallow water depths, the magnitude of the bias in the monetary flood cost assessment for properties may be non-negligible.The estimates of monetary costs show heterogeneous results. The magnitude of the bias with respect to the reference situation varies from rather modest to non-negligible. This heterogeneity is related to multiple sources: duration and depth of flooding, condition of openings, location of rooms in relation to the entry of floodwater into the building. These results encourage us to carry out additional analyses with buildings having more varied room layouts, but also to take into account the resistance of materials (partitions and openings in particular). They also seem promising to develop a coupled approach to refine the modeling for the estimation of damages, but also to qualify the danger of buildings in case of structural failure.

Session: One Health next generation wastewater management and reuse: the role of non-target and retrospective analysis, bioassays, and wastewater surveillance; International audience; The path of the contaminant from its discharge in the environment to the complete degradation to inorganic salts, water and carbon dioxide is rather long and complex. Although the state of knowledge on this subject is still insufficient, it has been demonstrated that some transformation products (TPs) may be as harmful as their parent compounds, in addition, they may be much more harmful in an environmental situation, where they occur in mixtures. In this study, two sampling techniques, passive and grab sampling, were compared for qualitative analysis of pharmaceutical TPs in urban WW effluents. Results demonstrated better suitability of passive sampling mainly due to the better quality of MS2 spectrum. The non-target screening revealed the occurrence of 13 TPs in secondary treated effluents (i.e., tramadol N-oxide, N,O-didesmethyltramadol, amisulpride N-oxide, O-desmethylvenlafaxine N-oxide, O-desmethylvenlafaxine, N-desmethylvenlafaxine, venlafaxine N-oxide, gabapentin lactam, O-desmetyltramadol, clarithromycin N-oxide, hydroxyclarithromycin, hydroxycarbazepine, and carbamazepine-10,11-epoxide). Retrospective analysis of the previously acquired data by high-resolution mass spectrometry was used to reveal the fate of thesecompounds during the treatment in constructed wetlands. Among identified compounds, N-oxides and carabamazepine-10,11-epoxide appeared to be the most recalcitrant, alongside amisulpride, gabapentin, and carbamazepine. The results obtained offer insight into the fate of pharmaceutical TPs and may serve as a guideline for the prioritization of contaminants TPs based on their persistence during the treatment and assist in the design of treatment systems.

International audience; Nowadays, data on wastewater networks covering the same geographical territory areavailable from different sources. The fusion of multi-source spatial data provides a new andricher dataset that can serve several purposes such as quality improvement, decision making,or delivery of new services. It has given rise to several research works focused on thevisualization, analysis, and fusion of spatial databases. However, the original data is oftenimperfect: imprecise, uncertain, vague, incomplete, etc. Therefore, it is essential to useformalisms allowing the modeling of imperfections and to propose adapted fusionmechanisms.In this work, we aim to handle data imperfections in a generic way. We first propose acategorization, according to several dimensions, of data imperfections encountered whenfusing multi-source spatial data. We then propose to model these imperfections according tothe formalism of the belief theory. We consider our conducted experiments that allowed us to match nodes and edges in the different cases of data imperfection, as promising.

International audience

International audience; Different groups of organic micropollutants including pharmaceuticals and pesticides have emerged in the environment in the last years, resulting in a rise in environmental and human health risks. In order to face up and evaluate these risks, there is an increasing need to assess their occurrence in the environment. Therefore, many studies in the past couple of decades were focused on the improvements in organic micropollutants’ extraction efficiency from the different environmental matrices, as well as their mass spectrometry detection parameters and acquisition modes. This paper presents different sampling methodologies and high-resolution mass spectrometry-based non-target screening workflows for the identification of pharmaceuticals, pesticides, and their transformation products in different kinds of water (domestic wastewater and river water). Identification confidence was increased including retention time prediction in the workflow. The applied methodology, using a passive sampling technique, allowed for the identification of 85 and 47 contaminants in the wastewater effluent and river water, respectively. Finally, contaminants’ prioritization was performed through semi-quantification in grab samples as a fundamental step for monitoring schemes.

National audience; Les dégâts causés en milieu urbain par les inondations et pluies diluviennes peuvent être catastrophiques. Les outils de modélisation peuvent aider à prédire l'évolution de certains phénomènes et permettent d'esquisser les différents scénarios possibles...

International audience; The toxicity of four herbicides in mixture (alachlor, diuron, des-isopropyl-atrazine and simazine) on the growth and the photosynthesis parameters of two marine diatoms Pseudo-niszchia mannii and Chaetoceros decipiens have been investigated for 9 days in monoculture and co-culture tests. The catalase (CAT) and guaiacol peroxidase (GPX) were also monitored to assess the oxidative stress response. In single-species assays, while both species displayed no affected instantaneous growth rate by herbicides, their physiological responses were different. Chl a content of P. mannii significantly decreased upon herbicide exposure, due probably to pigment destruction or inhibition of their synthesis. This decrease was associated with a reduction in the chlorophyll fluorescence parameters (ABS0/RC, TR0/RC, ET0/RC and DI0/RC). In contrast, C. decipiens maintained an effective photosynthetic performance under herbicide exposure, as Chl a per cell content and the specific energy fluxes per reaction center remained unchanged relative to control values. GPX activity was significantly higher in contaminated P. mannii and C. decipiens monocultures than in controls at early herbicide exposure (1 day), whereas a significant induction of CAT activity occurred later (from day 3 for C. decipiens and at day 9 for P. mannii) in response to herbicides. In control co-culture, P. mannii was eliminated by C. decipiens. As observed in the monoculture, the herbicides did not affect the photosynthetic performance of C. decipiens in co-culture, but significantly reduced its instantaneous growth rate. The oxidative stress response in co-culture has similar trends to that of C. decipiens in monoculture, but the interspecies competition likely resulted in higher CAT activity under herbicide exposure. Results of this study suggest that herbicide toxicity for marine diatoms might be amplified by interspecies interactions in natural communities, which might lead to different physiological and growth responses.

International audience; L'utilisation des informations géographiques s'est considérablement développée avec l'essor des outils informatiques. Dans les entreprises ou les administrations, les systèmes d'information géographique (SIG) permettent la représentation de l'environnement spatial à partir de formes géométriques de base (polygones, vecteurs, maillages...). Les SIG exploitent donc des outils logiciels, des données à traiter, des serveurs informatiques, mais également des savoir-faire techniques. Cet article propose de présenter aux ingénieurs les potentialités offertes par les SIG et les outils informatiques associés. Ainsi, des exemples d'exploitation de SIG sont exposés sur des thématiques variées.

National audience; Faced with the challenges of the 21st century, the ethics of engineering requires the development of skills in collective intelligence and change management. Without pretending to answer all the questions and challenges adressed by ethics training practices, IMT Mines Alès has inaugurated, in 2021, a new Elective Teaching Unit entitled "Transitions and crises, issues at stake". This article aims to report on the pedagogical practices developed and implemented in the framework of this Teaching Unit. It proposes to step back on the impact of the pedagogical resources developed in support of learning. In particular, we address the question of the impact of the pedagogical choices and the role of pedagogical resources on learning. After describing the pedagogical practices used in this Teaching Unit, we detail the survey and evaluation system that enabled us to collect elements of self-evaluation regarding the acquisition of knowledge, know-how and interpersonal skills, as well as critical analyses of the pedagogical practices used. The exploitation of the results of this survey allows us to draw conclusions about the relevance of the pedagogical practices implemented and the pathways for improvement.; Face aux enjeux du 21ème siècle, l’éthique de l’ingénieur passe notamment par le développement de compétences en intelligence collective et en conduite du changement. Sans toutefois vouloir répondre à l’ensemble des questionnements et des défis que posent les pratiques de la formation à l’éthique, IMT Mines Alès a inauguré, en 2021, une nouvelle Unité d’Enseignement Elective (UEE) intitulée : « Transitions et crises, enjeux en jeu ». Cet article a pour objectif de rendre compte des pratiques pédagogiques développées et mises en œuvre dans le cadre de cette UEE et de prendre du recul sur l’impact des ressources pédagogiques développées en support sur les apprentissages. Nous adressons en particulier la question de l’impact des parti-pris pédagogiques et du rôle des ressources pédagogiques mobilisées sur les apprentissages. Après avoir décrit les pratiques pédagogiques déclinées dans cette UEE, nous détaillons le dispositif d’enquête et d’évaluation qui nous a permis de recueillir, auprès des étudiants, d’une part, des éléments d’autoévaluation quant à l’acquisition de savoir, savoir-faire et savoir-être, puis, d’autre part, des analyses critiques des pratiques pédagogiques déclinées. L’exploitation des résultats de ce dispositif nous permet de tirer des conclusions quant à la pertinence des pratiques pédagogiques mises en œuvre et les pistes d’amélioration.

International audience; We present a new multi-OS platform named SW2D-LEMON (SW2D for Shallow Water 2D) developed by the LEMON research team in Montpellier. SW2D-LEMON is a multi-model software focusing on shallow water-based models. It includes an unprecedented collection of upscaled (porosity) models used for shallow water equations and transportreaction processes. Porosity models are obtained by averaging the two-dimensional shallow water equations over large areas containing both a water and a solid phase. The size of a computational cell can be increased by a factor 10 to 50 compared to a 2D shallow water model, with CPU times reduced by 2 to 3 orders of magnitude. Applications include urban flood simulations as well as flows over complex topography. Besides the standard shallow water equations (the default model), several porosity models are included in the platform: (i) Single Porosity, (ii) Dual Integral Porosity, and others are currently under development such as (iii) Depth-dependent Porosity model. Various flow processes (friction, head losses, wind, momentum diffusion, precipitation/infiltration) can be included in a modular way by activating specific execution flags. We recall here the governing equations as well as numerical aspects and present the software features. Several examples are presented to illustrate the potential of SW2D.

International audience; Effective electrochemical degradation of carbamazepine (CBZ) in water was accomplished with minimal energy and chemical requirements, showing that electrochemical Advanced Oxidation Processes (eAOPs) with a Boron-Doped Diamond (BDD) anode are a promising method for the in situ degradation of contaminants of emerging concern (CECs). The influence of several operating parameters (i.e., pH, temperature and initial anolyte and pollutant concentrations) was determined through the Taguchi optimization method. Optimal conditions corresponded to 1 M CBZ, pH 2, 30 °C, 10 mM NaSO and 50 A m−2, resulting in complete CBZ removal in less than 5 min. Complementary scenarios with different ion species, energy sources and current densities further corroborated the suitability of the optimum. Moreover, they revealed that the optimal conditions were driven by the presence of both SO and NO ions in solution. Hence, the optimal degradation results were also attained when replacing HNO by NaNO, which allowed to operate without prior pH adjustments. The contribution of OH and SO radicals was studied through scavenging tests and it was for the first time tentatively ascribed to the Oxygen Evolution Reaction (OER), since the selection of the operating potential influences the type of oxidative species present. Finally, the primary transformation products formed during CBZ degradation under optimal conditions were investigated.

We built 11 lab-scale dual-conduit structures by varying the apertures of the two conduits and we conduct solute transport experiments consisting of step tracing. We investigated how the transport process can be influenced by the following two factors: flow rate and aperture width of both conduits. We found that, as the flow rate increases, the dual-conduit structures more likely presents a breakthrough curve (BTC) with double-peak effect. When the shorter conduit has smaller aperture than the longer conduit, the dual-conduit structure may lead to either single-peaked BTCs or to dual-peaked BTCs with a much lower early peak. When the shorter conduit has larger aperture than the longer conduit, the dual-conduit structure may lead to double-peaked BTCs or to single-peaked BTCs with a bump on the falling limb.We then compared the ability of three different numerical models in fitting the experimental BTCs: Weighted Sum Advection–Dispersion Equation (WSADE), Mobile Immobile Model (MIM), and Dual Region Mobile Immobile Model (DRMIM). MIM does not reproduce the double-peaked or bump-tailed BTCs, but it captures the overall shape of the experimental curves. The WSADE reproduces some of the double-peaked BTCs except the experiment of 4-6, 200 rpm. The DRMIM exhibits better performance than the other two models, and it captures the observed behaviors of all the experimental BTCs: the second peak, the bump, and the tailing. We finally showed that parameter estimation of the DRMIM model can be improved by restricting the contrast between the parameter pairs: um1 and um2, Dm1 and Dm2, k1 and k2, wm1 and wm2.

International audience; Environmental contaminations can sometimes be difficult to measure, particularly in complex matrices such as seawater. This is the case of organotin compounds (OSn) such as the monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT), whose range of polarity is wide. These compounds, mostly coming from antifouling paints used on ship shell, can be found in water and sediments where they are stable and can persist for years. Passive sampling is gaining in interest to offer solutions to monitor these kinds of compounds even in low concentrations. However, due to the diversity of pollutants present in the environment nowadays, it is important to propose solutions that allow a specific sampling. This work aims to highlight the usability of molecularly imprinted polymers (MIPs) in passive sampling for the monitoring of OSn. MIPs were synthetized using three synthesis ways (bulk, suspension, and mini-emulsion processes) and kinetics were realized in order to estimate the retention of OSn by the solid MIP phase. Results highlighted a good retention of OSn with mean retention kinetic constants near 10−5, 10−6 and 10−7 L.ng.s−1 for DBT, TBT and MBT respectively. The synthesis mode showed no impact on retention kinetics, therefore, bulk synthesis is recommended because of its simplicity. If the elimination of OSn from MIPs is to be optimized, the retention of OSn on MIPs has been demonstrated, and is very promising for their use in specific passive samplers.; Les contaminations environnementales peuvent parfois être difficiles à mesurer, en particulier dans des matrices complexes comme l'eau de mer. C'est le cas des composés organostanniques (OSn) tels que le monobutylétain (MBT), le dibutylétain (DBT), et le tributylétain (TBT), dont la gamme de polarité est large. Ces composés, provenant principalement des peintures antisalissures utilisées sur les coques des navires, se retrouvent dans l'eau et les sédiments où ils sont stables et peuvent persister pendant des années. L'échantillonnage passif gagne en intérêt car il offre des solutions pour surveiller ces types de composés, même en faibles concentrations. En raison de la diversité des polluants présents dans l'environnement de nos jours, il est important de proposer des solutions qui permettent un échantillonnage spécifique. Ce travail vise à mettre en évidence l'utilité des polymères à empreintes moléculaires (MIPs) dans l'échantillonnage passif pour le suivi des OSn. Des MIPs ont été synthétisés selon trois voies de synthèse (procédés en vrac, en suspension et en mini-émulsion) et des cinétiques ont été réalisées afin d'estimer la rétention de l'OSn par la phase solide des MIPs. Les résultats ont mis en évidence une bonne rétention des OSn avec des constantes cinétiques de rétention moyennes proches de 10-5, 10-6 et 10-7 L.ng.s-1 pour DBT, TBT et MBT respectivement. Le mode de synthèse n'a montré aucun impact sur la cinétique de rétention, par conséquent, la synthèse en vrac est recommandée en raison de sa simplicité. Si l'élimination des OSn des MIPs doit être optimisée, la rétention des OSn sur les MIPs a été démontrée, et est très prometteuse pour leur utilisation dans des échantillonneurs passifs spécifiques.

International audience; Two semi-passive treatment systems for iron (Fe) and arsenic (As) removal in AMD were installed and monitored in-situ formore than a year. These technologies were designed to treat the As-enriched AMD (≈ 1 g/L Fe(II) and 100 mg/L As(III)) ofthe ancient Carnoulès mine. The treatment was based on biological Fe and As oxidation by indigenous bacteria, and subse-quent immobilization of As by ferric hydroxysulfates. Forced aeration and wood/pozzolana or plastic support were used forbiofilm attachment. The system performance ranged from 86 to 98% for Fe oxidation, 30 to 60% for Fe removal, and 50 to80% for As removal at a hydraulic retention time of 9 h. No significant difference were measured between the two biofilmsupports. The wood/pozzolana support had a shorter delay for performance recovery after interruptions. Iron oxidation rateswere similar to those obtained in the Carnoulès AMD stream and laboratory bioreactor, while As oxidation seemed to beenhanced. The sludge accumulated between 39 and 91 mg/g of As, mainly in the As(V) oxidation state; jarosite and amor-phous ferric hydroxysulfate phases were the main Fe and As scavengers. Challenging environmental conditions during thelong monitoring period confirm the robustness of the treatment units. The data will be useful in designing future full-scaletreatment systems adapted to As-rich AMD.