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International audience Riverine microplastics (MPs), synthetic polymer particles ≤5 mm, are a global environmental problem. Rivers receive MPs from different sources, transport MPs to the oceans, and can also act as sinks for accumulating MPs. The sources and fate of MPs in river catchments are not fully identified and understood. To advance the understanding of the fate of small (25-300 µm) MPs in urban agglomerations, a one-year monitoring in the Seine river (France) was carried out. We analyzed MP concentrations in the water upstream and downstream of the Greater Paris area in four sampling campaigns from July 2022 - July 2023. The monitoring covered seven sites along the Seine river and tributaries and different water flow conditions. Water samples up to one m3 were taken with the help of a novel in-situ pump and cascade filtration system (UFO®, Aalborg University, DK). MPs were extracted with oxidation and density separation and further analyzed via µ-FT-IR spectrometry. Preliminary, we found concentrations of polypropylene (PP) and polyethylene (PE) were most abundant across all samples (~59 % and ~25 %, respectively). In total, we detected 16 different polymer types, including polystyrene (PS), polyvinyl chloride (PVC), polyester (including polyethylene therephtalate, PET), styrene butadiene rubber (SBR), polyamide (PA), and polyurethane (PU). The variety of polymer types is larger downstream (16 polymer types) compared to upstream (9 polymer types). Concentrations range between ~16 4900 # particles/m3 and vary temporarily and spatially along the river catchment, which suggests potentially complex MP transport and fate dynamics. Very likely, parameters such as surface runoff, combined sewer system overflow (CSO), and hydrodynamics influence MP concentrations. To explain the observations and identify influences on the MP levels observed, we apply the field data to hydrodynamic modeling. We strongly recommend more frequent, intense, and continuous MP monitoring in river catchments to understand the local dynamics, identify sources and sinks (hotspots), and strategically develop mitigation measures.

International audience; Large rivers are important components of the global C cycle. While they are facing an overall degradation of their water quality, little remains known about the dynamics of their metabolism. In the present study, we used continuous multi-sensors measurements to assess the temporal variability of gross primary production (GPP) and ecosystem respiration (ER) rates of the anthropized Seine River over an annual cycle. Downstream from the Paris urban area, the Seine River is net heterotrophic at the annual scale (−226 gO2m−2 year−1 or −264 gC m−2 year−1). Yet, it displays a net autotrophy at the daily and seasonal scales during phytoplankton blooms occurring from late winter to early summer. Multivariate analyseswere performed to identify the drivers of river metabolism. Daily GPP is best predicted by chlorophyll a (Chla), water temperature (T), light, and rainfalls, and the coupling of daily GPP and Chla allows for the estimation of the productivity rates of the different phytoplankton communities. ER rates are mainly controlled by T and, to a lesser extent, by Chla. The increase of combined sewer overflows related to storm events during the second half of the year stimulates ER and the net heterotrophy of the river. River metabolism is, thus, controlled at different timescales by factors that are affected by human pressures. Continuous monitoring of river metabolism must, therefore, be pursued to deepen our understanding about theresponses of ecosystem processes to changing human pressures and climate.

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Modélisation de la contamination fécale en Seine : impact des rejets de temps de pluie

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Stringent discharge regulations are encouraging researchers to create innovative and sustainable wastewater treatment solutions. Urine source separation (USS) is among the potent approaches that may reduce nutrient peak loads in the influent wastewater and improve nutrient recovery. A phenomenological model was used to simulate dynamic influent properties and predict the advantages gained from implementing USS in an urban water basin. Several scenarios were investigated assuming different levels of deployment: at the entire city, or specifically in office buildings for men's urine only, or for both men and women employees. The results confirmed that all scenarios of urine source separation offered benefits at the treatment plant in terms of reducing nitrogen influent load. The economic benefits in terms of reducing energy consumption for nitrification and decreasing methanol addition for denitrification were quantified, and results confirmed environmental advantages gained from different USS scenarios. Despite larger advantages gained from a global USS rate in an entire city, implementation of a specific USS in office buildings would remain more feasible from a logistical perspective. A significant benefit in terms of reducing greenhouse gas emissions is demonstrated and this was especially due to the high level of N2O emissions avoided in nitrifying biological aerated filter.

International audience; Performic acid (PFA) is an emerging disinfectant applied for full-scale disinfection of wastewater effluent. While many studies have focused on assessing the microbial water quality during PFA disinfection, studies on the ability of PFA to oxidize organic micropollutants are still scarce. In this study, nontarget screening of wastewater secondary effluent during PFA treatment was performed using liquid chromatography−high-resolution mass spectrometry. A low dose (2 mg/L) of PFA was able to affect the organic matter composition within a short exposure time (10 min). Multivariate analysis as well as suspect screening indicated that PFA oxidation largely reduced the intensities of micropollutants with a tertiary amine moiety and led to the formation of their mono-oxygenated derivatives, N-oxides, a class of transformation products that are known as biologically stable but whose impact on aquatic organisms still needs to be assessed. Mechanistic studies were conducted on selected micropollutants (i.e., lidocaine, amisulpride, tramadol, and clarithromycin). The minimum apparent second-order rate constant of PFA with lidocaine was determined as 7.54 M −1 s −1 at pH 8.0. Lidocaine was mainly converted (∼95%) into its N-oxide via direct oxygen transfer from PFA. Overall results revealed a strong electrophilic reactivity of PFA toward electron-rich moieties (e.g., amines) of micropollutants.

International audience; Since the COVID-19 outbreak has started in late 2019, SARS-CoV-2 has been widely detected in human stools and in urban wastewater. No infectious SARS-CoV-2 particles have been detected in raw wastewater until now, but it has been reported occasionally in human stools. This has raised questions on the fate of SARS-CoV-2 during wastewater treatment and notably in its end-product, wastewater treatment sludge, which is classically valorized by land spreading for agricultural amendment. In the present work, we focused on SARS-CoV-2 stability in wastewater treatment sludge, either during storage (4 °C, room temperature) or thermophilic anaerobic digestion (50 °C). Anaerobic digestion is one of the possible processes for sludge valorization. Experiments were conducted in laboratory pilots; SARS-CoV-2 detection was based on RT-quantitative PCR or RT-digital droplet PCR. In addition to SARS-CoV-2, Bovine Coronavirus (BCoV) particles were used as surrogate virus. The RNA from SARS-CoV-2 particles, inactivated or not, was close to the detection limit but stable in wastewater treatment sludge, over the whole duration of the assays at 4 °C (55 days) and at ambient temperature (∼20 °C, 25 days). By contrast, the RNA levels of BCoV and inactivated SARS-CoV-2 particles decreased rapidly during the thermophilic anaerobic digestion of wastewater treatment sludge lasting for 5 days, with final levels that were close to the detection limit. Although the particles’ infectivity was not assessed, these results suggest that thermophilic anaerobic digestion is a suitable process for sludge sanitation, consistent with previous knowledge on other coronaviruses.

Dysregulations of lipid metabolism in the liver may trigger steatosis progression, leading to potentially severe clinical consequences such as nonalcoholic fatty liver diseases (NAFLDs). Molecular mechanisms underlying liver lipogenesis are very complex and fine-tuned by chromatin dynamics and multiple key transcription factors. Here, we demonstrate that the nuclear factor HMGB1 acts as a strong repressor of liver lipogenesis. Mice with liver-specific Hmgb1 deficiency display exacerbated liver steatosis, while Hmgb1-overexpressing mice exhibited a protection from fatty liver progression when subjected to nutritional stress. Global transcriptome and functional analysis revealed that the deletion of Hmgb1 gene enhances LXRα and PPARγ activity. HMGB1 repression is not mediated through nucleosome landscape reorganization but rather via a preferential DNA occupation in a region carrying genes regulated by LXRα and PPARγ. Together, these findings suggest that hepatocellular HMGB1 protects from liver steatosis development. HMGB1 may constitute a new attractive option to therapeutically target the LXRα-PPARγ axis during NAFLD. Published version This study was supported by grants from INSERM, Paul Sabatier University, the Agence Nationale de la Recherche (ANR-17-CE14-0016, to J.-P.P.), and the Région Occitanie and Association Française d’Etude et de Recherche sur l’Obésité (to J.-P.P.). J.P. was supported by a scholarship from Paul Sabatier University. E.P. was supported by a scholarship from Agence Nationale de la Recherche (ANR-17-CE14-0016). R.P. was supported by a scholarship from Région Midi-Pyrénées-INSERM (no. 15050341). O.B.-S. and L.C.-S. and the proteomic facility were supported, in part, by the Région Occitanie, European funds (Fonds Européens de Développement Régional, FEDER), Toulouse Métropole, and the French Ministry of Research with the Investissement d’Avenir Infrastructures Nationales en Biologie et Santé program (ProFI, Proteomics French Infrastructure project, ANR-10-INBS-08).

International audience

International audience; This work addresses river contamination by biocidal substances up- and downstream a megacity, with the aim of investigating the contribution of the urban discharges, and proposing effective and concerted mitigation solutions. To this end, ten campaigns were conducted in the two main rivers of the Paris conurbation. Eighteen previously prioritized biocides were all quantified at three sampling locations, and several were found at concentrations that may present a risk to the aquatic ecosystem (dichloroisothiazolinone, diuron, benzalkonium C12 and C14, with concentrations up to 42, 75, 1700, and 150 ng/L, respectively). The collected data enabled daily mass loads of biocides to be assessed (from

International audience; The extensive use and mismanagement of plastic causes environmental pollution in air, soil, and water and threatens ecosystem health and functioning. A large part of plastic in the environment is microplastic (MP), small particles ≤5 mm. To advance the understanding of MP pollution in rivers and anthropogenic environments and to provide new insights into the fate of small (25-300 μm) and large (300-5’000 μm) MPs,we investigate MPs in Greater Paris and the Seine river catchment in France. To compare MP concentrations upstream and downstream of Paris we carried out three out of four samplings at seven sites along the Seine river and tributaries in different flow seasons using a novel in-situ pump and cascade filtration system to increase representativity by sampling larger water volumes up to one m3. Preliminary data analysis of samples collected upstream and downstream of Paris indicate increased MP concentrations andhigher polymer type variation downstream compared to upstream. Among others we detected PP (polypropylene), PE (polyethylene), PS (polystyrene), PVC (polyvinyl chloride), Polyester (including PET), SBR (styrene butadiene rubber), PA (polyamide), PU (polyurethane), Acrylic and ABS (acrylonitrile butadiene styrene). The findings confirm the hypotheses that urban agglomerations may contribute to MP concentration in surface waters. This trend needs to be confirmed by final data analysis including all samplesand size fractions and in combination with biogeochemical parameters. Final results are foreseen to be completed in 2022. These studies can help to identify sources and pathways of microplastics in rivers in urban agglomerations and help policy and decision makers to address environmental pollution and mitigation actions.

International audience; While membrane bioreactors (MBR) have been broadly applied to wastewater treatment, membrane ageing studies have focused mainly on: (i) understanding the chemical action of sodium hypochlorite or (ii) monitoring ageing in direct filtration facilities (drinking water, groundwater, etc.). Thus, a comprehensive investigation under full-scale MBR operating conditions is still required. In the present study, polyvinylidene difluoride (PVDF) hollow fibers were sampled from a full-scale MBR in northern Paris during 7 years of operation. In addition, pristine membranes were aged at bench scale by single soaking in hypochlorite solution at a concentration and pH similar to MBR cleaning protocols. Both bench-scale- and full-scale-aged hollow fibers were characterized using similar analytical methods to assess the contributions of chemical action and operating conditions to the ageing process. At bench scale, membranes experienced no changes in mechanical resistance, but intrinsic permeability (i) first increased as a result of the hydrophilic agent oxidation, i.e., polyvinyl pyrrolidone (PVP), increasing porosity with the appearance of small pores (diameter 20 nm), and (ii) then the structure seemed to collapse and permeability decreased as a result. By contrast, membranes aged at full scale experienced a 46% decline in maximum tensile strength probably due to mechanical stress induced by aeration conditions in MBR. Besides, permeability increased for the whole period as a result of a more pronounced oxidation/dislodgement of PVP molecules leading to higher porosity and the appearance of bigger pores (diameter 40 nm). These changes favored irreversible fouling in contrast to bench-scale ageing. Therefore, bench-scale ageing is not completely representative of full-scale ageing and membrane autopsies must be preferred to this end. However, permeability and PVP content measurements may be applied after cleaning as in situ nondestructive tools in full-scale MBR to monitor membrane ageing. Plant operators should be aware that a continuous increase in intrinsic permeability may favor irreversible fouling accumulation demanding more frequent chemical cleanings.

International audience; Phosphorus (P) removal from the domestic wastewater is required to counter the eutrophication in receiving water bodies and is mandated by the regulatory frameworks in several countries with discharge limits within 1-2mgPL−1. Operating at higher sludge retention time (SRT) and higher biomass concentration than the conventional activated sludge process (CASP), membrane bioreactors (MBRs) are able to remove 70–98% phosphorus without addition of coagulant. In full-scale facilities, enhanced biological phosphorus removal (EBPR) is assisted by the addition of metal coagulant to ensure >95% P-removal. MBRs are successfully used for super-large-scale wastewater treatment facilities (capacity >100,000 m3d−1). This paper documents the knowledge of P-removal modeling from lab to full-scale submerged MBRs and assesses the existing mathematical models for P-removal from domestic wastewater. There are still limited studies involving integrated modeling of the MBRs (full/super large-scale), considering the complex interactions among biology, chemical addition, filtration, and fouling. This paper analyses the design configurations and the parameters affecting the biological and chemical P-removal in MBRs to understand the P-removal process sensitivity and their implications for the modeling studies. Furthermore, it thoroughly reviews the applications of bio-kinetic and chemical precipitation models to MBRs for assessing their effectiveness with default stoichiometric and kinetic parameters and the extent to which these parameters have been calibrated/adjusted to simulate the P-removal successfully. It also presents a brief overview and comparison of seven (7) chemical precipitation models, along with a quick comparison of commercially available simulators. In addition to advantages associated with chemical precipitation for P-removal, its role in changing the relative abundance of the microbial community responsible for P-removal and denitrification and the controversial role in fouling mitigation/increase are discussed. Lastly, it encompasses several coagulant dosing control systems and their applications in the pilot to full-scale facilities to save coagulants and optimize the P-removal performance.

International audience

International audience; The presence of SARS-CoV-2 RNA has been extensively reported at the influent of wastewater treatment plants (WWTPs) worldwide, and its monitoring has been proposed as a potential surveillance tool to early alert of epidemic outbreaks. However, the fate of the SARS-CoV-2 RNA in the treatment process of WWTP has not been widely studied yet; therefore, in this study, we aimed to evaluate the efficiency of treatment processes in reducing SARS-CoV-2 RNA levels in wastewater. The treatment process of three WWTPs of the Parisian area in France was monitored on six different weeks over a period of 2 months (from April 14 to June 9, 2021). SARS-CoV-2 RNA copies were detected using digital polymerase chain reaction (dPCR). Investigation on the presence of variants of concern (Del69-70, E484K, and L452R) was also performed. Additionally, SARS-CoV-2 RNA loads in the WWTPs influents were expressed as the viral concentration in per population equivalent (PE) and showed a good correlation with French public health indicators (incidence rate). SARS-CoV-2 RNA loads were notably reduced along the water treatment lines of the three WWTPs studied (2.5-3.4 log reduction). Finally, very low SARS-CoV-2 RNA loads were detected in effluents (non-detected in over half of the samples) which indicated that the potential risk of the release of wastewater effluents to the environment is probably insignificant, in the case of WWTPs enabling an efficient biological removal of nitrogen.

National audience

International audience; A holistic approach to environmental issues highlights the limits reached by the use of sewers to remove human excreta from inhabited spaces. Megacities, in particular, are today exposed to acute and still unknown challenges Given the major global changes faced by wastewater management systems, such a large concentration of population puts the classical sanitation model under stress.Apart from the frequent overloads of centralised wastewater management systems, there is their deep footprint in terms of energy expenditure, greenhouse gas emissions and continuing frequent pollution of aquatic environments. Yet managed separately, these excreta could be used as fertiliser: their agricultural application would represent a move away from the waste remediation model and an opportunity for mutual benefit between urban and agricultural zones, supplying the latter with lasting, local and nonfossil fertilising materials.Focusing on the case of the Paris conurbation, we provide a crosscutting analysis of the current opportunities for implementing source separation systems in a highly concentrated population centre. More specifically, we examine the technical, organisational and economic obstacles and drivers around the production of fertilisers from human excreta, in particular from urine, under good sanitary and agronomic conditions. We show the build-up of evidence about the limits of the current wastewater management system and the need for a paradigm shift. Nonetheless, pilot projects remain difficult to implement (due to political, sociocultural, economic, regulatory and technical obstacles, which are particularly tough in the case of a megacity). Despite this, there has been a recent shift in the dynamics, with projects emerging on the margins of urban planning. A key factor in their success is adaptation to different territorial configurations. Backed by individuals and groups with specific priorities, these projects offer a glimpse of the possibility of devising new sociotechnical systems for managing human waste.; Une approche holistique des questions environnementales met en lumière les limites atteintes par l’utilisation des égouts pour éloigner les excrétats humains des espaces habités. Les mégapoles, en particulier, sont aujourd’hui exposées à des enjeux aigus et encore méconnus. Dans un contexte de changements globaux majeurs auxquels l’assainissement doit faire face, une si grande concentration de population met le modèle classique de l’assainissement sous tension. À la saturation récurrente des systèmes d’assainissement centralisés, s’ajoute une empreinte élevée en matière de dépense énergétique, d’émissions de gaz à effet de serre et souvent de pollution des milieux aquatiques. Pourtant, ces excrétats, gérés séparément, pourraient être utilisés comme matières fertilisantes : leur utilisation agricole permet de sortir d’une logique de dépollution des excrétats et de créer un mutualisme entre territoires urbains et agricoles, ces derniers bénéficiant alors de matières fertilisantes pérennes, locales et non fossiles. À partir du cas de l’agglomération parisienne, nous proposons une analyse transversale des opportunités actuelles de mise en oeuvre de filières de séparation à la source en contexte de grande concentration urbaine. Plus spécifiquement, nous nous intéressons aux freins et leviers techniques, organisationnels, économiques, en vue de la production de fertilisants à partir des excrétats humains et en particulier des urines, dans de bonnes conditions sanitaires et agronomiques. Nous montrons l’accumulation d’éléments de démonstration quant aux limites du système d’assainissement actuel et la nécessité d’un changement de paradigme. Persiste, nonobstant, une difficulté à mettre en place des projets pilotes (freins politiques, socioculturels, économiques, réglementaires et techniques, exacerbés dans le contexte d’une mégapole). Toutefois, une dynamique récente s’observe, avec des projets qui émergent en marge de la fabrique urbaine. Un facteur clé de leur réussite tient à leur adaptation aux différentes configurations territoriales. Portés par des individus et collectifs aux trajectoires spécifiques, ceux-ci laissent entrevoir une capacité à inventer de nouveaux dispositifs sociotechniques de gestion des excrétats humains.

International audience; Biocidal substances are ubiquitous in urban areas; they are used as preservatives in daily products, building materials, and as domestic pesticides. Despite these facts, urban sources of biocides, contrary to agricultural inputs, have been overlooked in terms of environmental risk assessment. The overall objective of this communication is to explore the use of a stochastic approach to assess the impact of biocide urban discharges on the river contamination. Biocide contamination in surface waters up-and downstream the Paris conurbation was investigated. The urban origins of these biocides were explored by targeting wastewater treatment plant and combined sewer overflow discharges from comparable watersheds, and by assessing biocide mass loads (discharged and transiting in the river) using a stochastic approach based on Monte-Carlo simulations. The 18targeted biocides were all quantified, and several were found at concentrations that can present high risk for the aquatic ecosystem. An increase in biocide loads between up-and downstream the Paris conurbation for several molecules and the contribution of urban discharges to biocide loads towards the receiving waters were ascertained. The results illustrate the interest of a stochastic approach to quantify the uncertainty on the determined values from a realistic description of the variability of biocide concentrations.

International audience

The histone demethylase LSD1 is a key chromatin regulator that is often deregulated in cancer. Its ortholog, dLsd1 plays a crucial role in Drosophila oogenesis; however, our knowledge of dLsd1 function is insufficient to explain its role in the ovary. Here, we have performed genome-wide analysis of dLsd1 binding in the ovary, and we document that dLsd1 is preferentially associated to the transcription start site of developmental genes. We uncovered an unanticipated interplay between dLsd1 and the GATA transcription factor Serpent and we report an unexpected role for Serpent in oogenesis. Besides, our transcriptomic data show that reducing dLsd1 levels results in ectopic transposable elements (TE) expression correlated with changes in H3K4me2 and H3K9me2 at TE loci. In addition, our results suggest that dLsd1 is required for Piwi dependent TE silencing. Hence, we propose that dLsd1 plays crucial roles in establishing specific gene expression programs and in repressing transposons during oogenesis.

International audience; Monitoring the removal of organic micropollutants (OMPs) in advanced wastewater treatment facilities requires expensive and time-consuming analytical methods that cannot be installed online. Spectroscopic techniques such as fluorescence excitation/emission spectroscopy were demonstrated to offer the potential for monitoring OMPs removal in conventional wastewater treatment plants or ozonation pilots but their application to activated carbon (AC) adsorption processes was only investigated at lab scale and not in real treatment facilities. In this study, indexes from fluorescence emission/excitation matrices (EEMs) were used to find correlations with the removal of 28 OMPs from a large-scale AC pilot in fluidized bed employed for wastewater advanced treatment, as well as from batch experiments. Differences in OMPs removal could be observed depending on the operational conditions (i.e. pilot or batch experiments, contact time, type of AC) and the physico-chemical properties of the molecules. 7 PARAFAC components were derived from the fluorescence EEMs of 60 samples obtained before and after adsorption. Positive correlations were obtained between the removal of fluorescence indexes and most OMPs, and correlation coefficients were much higher than the ones obtained with UV254, confirming the interesting potential of fluorescence spectroscopy to accurately monitor adsorption performances at the industrial scale. The highest correlation coefficients were obtained for OMPs having the best removals while the ones that were refractory to adsorption, as well as to interactions with DOM, exhibited weak correlations. These results suggest that interactions between OMPs and fluorescing DOM and their subsequent co-adsorption onto AC were at the origin of the correlations found. Lower correlations were also found for the most biodegradable OMPs, which indicated that the occurrence of biological effects could make the monitoring of these compounds more challenging.

Journée technique nano/microplastiques dans l'eau, France Water Team, Toulouse, FRANCE, 19-/01/2021 - 19/01/2021; Cette présentation vise à dresser un état de l'art de la question de la contamination en microplastiques (taille < à 5 mm) en milieu urbain. Dans un premier temps, plusieurs éléments de contexte, quelques généralités sur cette pollution et un rappel des définitions sont donnés. Dans une seconde partie, sont abordés les nombreux points de vigilances quand on parle de microplastiques, à savoir quelles particules sont considérées, quelle gamme de taille, quelle distribution et/ou quelles méthodes sont mises en oeuvre pour leur détection dans les matrices environnementales. La dernière partie présente un état de l'art sur la contamination des eaux urbaines en couvrant d'une part les eaux usées et l'assainissement, et d'autre part les eaux pluviales.

International audience; This paper analyzes the fate of 71 priority and emerging organic contaminants all along the treatment trains of sewage sludge treatment facilities in Paris including dewatering by centrifugation, thermal drying and anaerobic digestion. It aimed at proposing and applying a mass balances calculation methodology to each process and pollutant. This data validation strategy demonstrated the complexity to perform representative inlet/outlet sampling and analysis campaigns at industrial scales regarding organic compounds and to propose options to overcome this issue. Centrifugation and drying processes only implied physical mechanisms as phase separation and water elimination. Hence, correct mass balance were expected observed for organic contaminants if sampling and analysis campaigns were representative. This was the case for hydrophobic and neutral compounds. For the other more hydrophilic and charged compounds, the mass balances were scarcely correct. Thus, the conventional sampling and analytical practices used with sludge should be questioned and adapted to better take into account the high heterogeneity of sludge and the evolution of matrix effect within sludge treatment processes on micropollutant determination. For the biological anaerobic digestion process where degradations can occur and removals can be observed, the mass balances were deeply interpreted for 60 contaminants. This process contributed to the elimination above 70% of 21 detected compounds including 16 pharmaceuticals, 2 phthalates, 2 hormones and 1 perfluorinated compound. Removals of domperidone, propranolol, escitalopram, lidocaine, verapamil and cefoperazone under this condition were reported for the first time.

In order to mitigate negative urbanization effects on urban water management, nature based solutions (NBS) are often recommended. Some of them can also be recommended to improve thermal comfort, inhabitants well-being, their security, ... They can also take part in climate change adaptation strategies. A more systemic evaluation of such solutions is then becoming essential. The hydro-climatic model TEB-Hydro has been developed in order to evaluate urban planning projects, regarding urban water management and thermal comfort, at the City scale. TEB-Hydro model, based on a regular mesh grid, needs to know the water different paths (at the surface, inside the stormwater or combined network, into the ground). An automatic tool (TOHR) has been developed, from urban data banks, to build an oriented graph of the different water flows, that is then projected on TEB-Hydro grid, to provide to the model all the parameters needed for routing calculation. This oriented graph is based on the stormwater, waste water, combined and natural networks. Thus, it allows the reconstruction of a complete network, by taking into account all the different water flows. Nonetheless, this rebuilt network has to be simplified, in order to be adapted to the grid spatial resolution. The reconstruction result, at the Greater Paris scale is globally satisfying. Numerous errors are due to wrong connections, but at a fine scale. The flow path is then a bit longer than in the reality. The larger difficulties are over Paris where the network is a crossroad with numerous meshes. The reconstruction of the separate system is better as it is less meshed than the combined one. And even on the combined system, realistic large drained areas defined at different points on the network are obtained. Then the reconstructed network is available for hydrologic simulations., Afin d'atténuer les effets négatifs de l'urbanisation sur la gestion des eaux urbaines, des solutions basées sur la nature (NBS) sont souvent recommandées. Certaines d'entre elles peuvent également être recommandées pour améliorer le confort thermique, le bien-être des habitants, leur sécurité, ... Elles peuvent également participer aux stratégies d'adaptation au changement climatique. Une évaluation plus systémique de ces solutions devient alors indispensable. Le modèle hydro-climatique TEB-Hydro a été développé afin d'évaluer les projets d'urbanisme, en matière de gestion de l'eau et de confort thermique, à l'échelle de la ville. Le modèle TEB-Hydro, basé sur un maillage régulier, nécessite de connaître les différents parcours de l'eau (en surface, à l'intérieur du réseau d'eaux pluviales ou combiné, dans le sol). Un outil automatique (TOHR) a été développé, à partir de banques de données urbaines, pour construire un graphique orienté des différents flux d'eau, qui est ensuite projeté sur la grille TEB-Hydro, afin de fournir au modèle tous les paramètres nécessaires au calcul des trajets. Ce graphique orienté est basé sur les réseaux d'eaux pluviales, d'eaux usées, combinés et naturels. Il permet ainsi de reconstruire un réseau complet, en prenant en compte tous les différents flux d'eau. Néanmoins, ce réseau reconstruit doit être simplifié, afin de s'adapter à la résolution spatiale de la grille. Le résultat de la reconstruction, à l'échelle du Grand Paris, est globalement satisfaisant. De nombreuses erreurs sont dues à de mauvaises connexions, mais à une échelle fine. Le chemin d'écoulement est alors un peu plus long que dans la réalité. Les plus grandes difficultés se situent sur Paris où le réseau est un carrefour avec de nombreuses mailles. La reconstruction du système séparé est meilleure car il est moins maillé que le système combiné. Et même sur le système combiné, on obtient de grandes zones drainées réalistes définies en différents points du réseau. Le réseau reconstruit est alors disponible pour des simulations hydrologiques.

Introduction Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiological agent of coronavirus disease (COVID-19). People infected with SARS-CoV-2 may exhibit no or mild non-specific symptoms; thus, they may contribute to silent circulation of the virus among humans. Since SARS-CoV-2 RNA can be detected in stool samples, monitoring SARS-CoV-2 RNA in waste water (WW) has been proposed as a complementary tool to investigate virus circulation in human populations. Aim To test if the quantification of SARS-CoV-2 genomes in WW correlates with the number of symptomatic or non-symptomatic carriers. Method We performed a time-course quantitative analysis of SARS-CoV-2 by RT-qPCR in raw WW samples collected from several major WW treatment plants in Greater Paris. The study period was 5 March to 23 April 2020, including the lockdown period in France (from 17 March). Results We showed that the increase of genome units in raw WW accurately followed the increase of human COVID-19 cases observed at the regional level. Of note, the viral genome could be detected before the epidemic grew massively (around 8 March). Equally importantly, a marked decrease in the quantities of genome units was observed concomitantly with the reduction in the number of new COVID-19 cases, 29 days following the lockdown. Conclusion This work suggests that a quantitative monitoring of SARS-CoV-2 genomes in WW could generate important additional information for improved monitoring of SARS-CoV-2 circulation at local or regional levels and emphasises the role of WW-based epidemiology.

International audience; The use of sewers to transport human excreta away from inhabited zones now causes particularly acute problems in megacities. Given the major global changes faced by wastewater management systems, these huge population centres highlight the limitations of the traditional sanitation management model. Apart from the frequent overloads on centralised wastewater management systems, there is their deep footprint in terms of energy expenditure, greenhouse gas emissions and continuing frequent pollution of aquatic environments. Yet managed separately, these excreta could be used as fertiliser: their agricultural application would represent a move away from the waste remediation model and an opportunity for mutual benefit between urban and agricultural zones, supplying the latter with lasting, local and nonfossil fertilising materials. Focusing on the case of the Paris conurbation, we provide a crosscutting analysis of the current opportunities for implementing source separation systems in a highly concentrated population centre. More specifically, we examine the technical, organisational and economic obstacles and drivers around the production of fertilisers from human excreta, in particular from urine, under good sanitary and agronomic conditions. We show the buildup of evidence about the incoherence of the current wastewater management system and the need for a paradigm shift. Nonetheless, pilot projects remain difficult to implement (due to political, sociocultural, economic, regulatory and technical obstacles, which are particularly tough in the case of a megacity). Despite this, there has been a recent shift in the dynamics, with projects emerging on the margins of urban planning. A key factor in their success is adaptation to different territorial configurations. Backed by individuals and groups with specific priorities, these projects offer a glimpse of the possibility of devising new sociotechnical systems for managing human waste.

International audience

Journée Information Eaux, Poitiers, FRANCE, 06-/10/2020 - 08/10/2020; L'élimination des micropolluants dans les eaux résiduaires urbaines représente un défi majeur pour les stations de traitement des eaux usées, qui seront probablement amenées dans le futur à investir dans des traitements avancés. Le choix technologique (procédés d'oxydation, de filtration ou d'adsorption) repose en priorité sur des critères de performances technico-économiques. En raison des pressions environnementales grandissantes, le calcul d'impacts environnementaux devient également primordial pour soutenir une telle décision. L'utilisation de la méthodologie d'Analyse du Cycle de Vie (ACV) (ISO 14040/44, 2006) permet une évaluation holistique des impacts environnementaux, grâce à la perspective cycle de vie et à la prise en compte de plusieurs critères. Dans cette étude, l'ACV est appliquée à deux types de procédés, l'adsorption sur charbon actif dans un lit fluidisé et l'ozonation, ainsi que leur combinaison, testés à l'échelle pilote dans la STEU Seine Centre opérée par le SIAAP en Région parisienne (Mailler et al., 2015 ; Mailler et al., 2016 ; Guillossou et al., 2019 ; Guillossou et al., 2020). Les résultats visent à comprendre les coûts-bénéfices de ces traitements, selon les conditions opératoires, afin d'étayer la prise de décision.

International audience; This study aims to evaluate the ability of an ultraviolet (UV) probe to simultaneously estimatenitrate and nitrite concentrations in the effluent of a post-denitrifying biologically active filter (BAF). Theestimation of these species is complicated due to the great similarity of their UV spectrum and thepresence of other absorbent molecules in the UV range. Yet, it is essential to develop control algorithmswhich would guarantee a water quality that complies with the requirements of the Water FrameworkDirective. The WTW Nitra Vis 705 IQ NI probe was calibrated and validated in the laboratory on a realeffluent having a nitrite concentration ranging from 0 to 3.5 mgN/L. Then, it was placed at the outlet of aBAF of the Seine Centre plant to evaluate its ability to predict the dynamics of nitrite and nitrateconcentrations. Using a multipoint calibration for nitrite and a multi-linear calibration for nitrate, it waspossible to simultaneously and dynamically measure nitrite in the range 0-5 mgN/L with an accuracy of 0.2 mgN/L and nitrate in the range 0-10 mgN/L with an accuracy of 0.3 to 0.4 mgN/L. Nitrous oxide and nitrite concentrations exhibited similar dynamics as a function of the applied BOD to N-NO3–ratio.Nitrous oxide was found to be better correlated with nitrite (R2= 0.72) compared with NO2– +NO3– (R2= 0.52).; Cette étude vise à évaluer la capacité d’une sonde à rayons ultraviolets (UV) à estimer simultanément les teneurs en nitrate et nitrite en sortie d’une unité de biofiltration en postdénitrification. L’estimation de ces deux espèces est compliquée du fait de la très grande similitude de leur spectre UV et de la présence d’autres molécules absorbantes dans l’UV. Celle-ci est pourtant indispensable au développement d’algorithmes de contrôle, seuls à même de garantir un résiduel en nitrite et nitrate conforme aux exigences de la directive cadre sur l’eau. La sonde WTW Nitra Vis 705 IQ NI a été calibrée puis validée en laboratoire sur un effluent réel dans une gamme de 0 à 3,5 mgN/L en nitrite. Elle a ensuite été installée en sortie d’une unité de biofiltration de la station de Seine Centre afin d’évaluer sa capacité à prédire les dynamiques de concentrations en nitrites et nitrates. Le suivi a montré que, moyennant une calibration multipoint pour le nitrite et multilinéaire pour le nitrate, il est possible de mesurer simultanément et dynamiquement le nitrite dans la gamme 0-5 mgN/L avec une précision de 0,2 mgN/L et le nitrate dans la gamme 0-10 mgN/L avec une précision de 0,3 à 0,4 mgN/L. Les mesures en ligne de protoxyde d’azote dissous, effectuées sur site au moyen de sondes ampérométriques, montrent que la dynamique est similaire à celle du nitrite en fonction du ratio DBO/N-NO3– appliqué, et que l’on obtient une meilleure corrélation du protoxyde d’azote avec le nitrite (R2 = 0,72) comparativement à la somme nitrite + nitrate (R2 = 0,52).

National audience; . CONTEXTE Le protoxyde d'azote (N 2 O) est un puissant gaz à effet de serre dont le potentiel de réchauffement est équivalent à 300 fois celui du dioxyde de carbone (CO 2). Il joue également un rôle clé dans la destruction de la couche d'ozone [1]. Principalement d'origine naturelle (sols et hydrosphère), il est également émis par les procédés de traitement des eaux usées lors du traitement biologique de l'azote par nitrification et dénitrification. Actuellement, le facteur d'émission (3,2 g N 2 O/EH/an équivalent à 0,037% de la charge entrante en azote), utilisé pour quantifier les émissions directes des stations d'épuration, provient de données acquises sur une seule installation à boues activées d'Amérique du Nord [2]. Si les données d'émission de N 2 O par les procédés conventionnels à boues activées se sont multipliées ces dernières années, celles des procédés à biomasse fixée, tels que les biofiltres, sont encore très rares. Or, ce procédé de traitement est très répandu en France (130 installations, 20% de la capacité des stations), en particulier dans les grandes agglomérations. Les mesures réalisées sur les biofiltres nitrifiants de la station de Seine Aval (5,5 millions d'EH, Ile de France) indiquent des taux d'émission du N 2 O bien plus élevés : facteur d'émission = 3,6% en période hivernale et 2,0% en période estivale [3]. De plus, ces émissions-si elles étaient comptabilisées-multiplieraient par 4 le bilan carbone de la file biologique de traitement de l'azote à Seine Aval [4]. Un enjeu émergeant dans le traitement des eaux usées est donc de quantifier et maitriser le N 2 O émis afin de réduire l'empreinte environnementale des installations. Cette étude a été réalisée dans le cadre du programme de recherche Mocopée (http://www.mocopee.com/) avec le support financier de l'ANR [projet N2Otrack 2015-2020, ANR-15-CE04-0014]. Son objectif est d'apporter des informations sur les conditions d'apparition du protoxyde d'azote lors du traitement des eaux résiduaires urbaines par nitrification en biofiltration. A cette fin, un modèle représentant le fonctionnement des biofiltres nitrifiants de la station de Seine Aval [5] a été étendu pour y inclure les principales voies biologiques de production de N 2 O [6,7]. Les paramètres du modèle ont été calés sur un jeu de données comprenant deux ans de fonctionnement des biofiltres et incluant deux périodes pour lesquelles les flux de N 2 O ont été mesurés. Sur la base de ces résultats : un facteur d'émission moyen annuel a été proposé, des leviers de réduction des émissions ont été identifiés et un modèle statistique a été établi afin de proposer une nouvelle méthodologie de quantification.

International audience; Les bioréacteurs à membranes se sont largement développés ces dernières années en assainissement des eaux résiduaires urbaines. Malgré les avantages du procédé, le colmatage des membranes engendre des contraintes économiques liées aux coûts énergétiques et au remplacement prématuré des membranes. Différentes stratégies de limitation du colmatage sont mises en place, dont l’aération séquencée des membranes à l’aide de grosses bulles. Cependant, les mécanismes d’action de cette aération et l’hydrodynamique des réacteurs restent relativement méconnus, en particulier à l’échelle industrielle et en présence de boues. Un pilote semi-industriel de filtration membranaire a été conçu et installé sur l’unité de traitement des jus de Seine Aval. Ce pilote a permis d’étudier l’impact de l’aération sur les performances de filtration en couplant une analyse statistique (systèmes d’inférence floue) et une caractérisation de l’hydrodynamique du réacteur (tomographie de résistivité électrique). Des chemins préférentiels de passage des bulles ont été observés à faible débit d’air et forte concentration en matières en suspension à l’aide de la tomographie de résistivité électrique. Ces observations fournissent des éléments d’explication aux résultats de l’arbre de décision flou focalisé sur l’analyse de l’impact du débit d’air sur la dérive journalière de perméabilité. La concentration en matières en suspension des boues et la différence de demande chimique en oxygène entre le surnageant des boues et le perméat s’avèrent être les facteurs les plus impactants pour les conditions opératoires testées. Ils traduisent l’efficacité de l’aération, que ce soit en matière de répartition du champ de bulles et/ou de relargage d’éléments colmatants. Ces résultats invitent à considérer la régulation de l’aération en fonction des propriétés des boues dans les procédés industriels.

Anthropogenic particles (APs) are a very broad category of particles produced directly or indirectly by human activities. Their ingestion by biota is well studied in the marine environment. In contrast, studies on AP ingestion in wild freshwater organisms are scarce despite high contamination levels in some rivers and lakes. In this study, we aimed to evaluate the ingestion of APs and the possible occurrence of APs in the liver and muscle of a freshwater fish, Squalius cephalus, from the Parisian conurbation. After isolation, the particles were analyzed using Raman spectroscopy. In sixty stomachs, eighteen APs were found, half of which were plastics and the other half were dyed particles. Twenty-five percent of sampled individuals had ingested at least one AP. The mean length of the APs was 2.41 mm. No significant difference was found between the sites upstream and downstream of Paris. Additionally, 5% of sampled livers contained one or more APs, which were characterized as microplastics (MPs). No APs were found in the muscle tissue. The majority of APs isolated from stomach contents were fibers, which is similar to the findings of a previous river contamination study. This highlights that fish could be more exposed to fibers than previously thought and that more studies on the impacts of fiber ingestion are required. Despite their low occurrence, MPs are reported, for the first time, in the liver of a wild freshwater fish species. While the pathways and impacts are still unknown, MPs also occur in liver of marine mollusks and fish. Physiological in vitro studies are needed to better evaluate the impacts of such phenomena.

Dans un cadre réglementaire, la qualité d’une eau est souvent évaluée en comparant des concentrations de substances individuelles à des seuils tels que les normes de qualité environnementale. Cette approche, bien que robuste, présente certaines limites. La seule information sur la présence de contaminants ne suffit pas à quantifier l’impact ou le potentiel toxique de ces eaux; l’information reste «individuelle» à l’échelle de substances, pour lesquelles suffisamment de données écotoxicologiques existent, sans permettre d’évaluer l’effet cocktail qui pourrait en résulter. Les bioessais sont des méthodes globales et intégrées qui fournissent des informations sur le potentiel toxique de l’échantillon considéré, voire sur la toxicité spécifique de certains groupes de substances. Notre démarche a donc consisté à suivre le potentiel toxique de différents échantillons d’eaux urbaines (effluent hospitalier, eaux usées à l’exutoire de deux sous-bassins de la ville de Paris, eaux usées en entrée de station d’épuration et eau épurée, déversoirs d’orage) en utilisant trois panels: toxicité générale (huit bioessais sur algues, bactéries, champignons et cellules humaines), génotoxicité (trois bioessais sur bactéries et cellules humaines), perturbation endocrinienne (six bioessais sur cellules humaines). Les résultats montrent que les déversoirs d’orage apportent un excès de toxicité au milieu récepteur. Sur l’ensemble des émissaires, toutes les dimensions de la toxicité ont, à un moment ou un autre, été observées. La comparaison entre entrée et sortie de station d’épuration semblerait indiquer que l’abattement des paramètres physicochimiques ne se retrouve pas pour les indicateurs de la toxicité. Cependant, des études complémentaires sur ce type d’échantillons sont nécessaires pour confirmer ou non cette première tendance.

The Seine River basin (France) is representative of the large urbanised catchments (78,650 km2) located in Northwestern Europe. As such, it is highly impacted by anthropogenic activities and their associated emissions of pollutants such as polycyclic aromatic hydrocarbons (PAHs). These compounds, originating from household heating and road traffic, are responsible for serious environmental issues across the basin. This study aims at establishing and using mass balance analyses of PAHs at the Seine River basin scale as an efficient tool for understanding PAH pathways in the environment. A dual-scale approach (urban vs. rural areas) was used successfully, and mass balances provided useful knowledge on the environmental fate of PAHs. In urban areas, runoff and domestic and industrial discharges contributed similarly to the PAH supply to the sewer system. During the wastewater treatment process, PAHs were mainly eliminated through sludge removal. At the basin scale, substantial amounts of PAHs were quantified in soils, and the limited annual inputs and outputs through atmospheric deposition and soil erosion, respectively, suggest that these compounds have long residence times within the basin. While wastewater and runoff discharges from urban areas account for a substantial part of PAH urban fluxes to the Seine River, soil erosion seems to be the predominant contributor at the basin scale. Overall, the PAH flux at the basin outlet was greater than supplies, suggesting that the Seine River system may currently be undergoing a decontamination phase.

International audience

To tackle water micropollutant pollution, the development of an advanced wastewater treatment is necessary and should be supported by an environmental evaluation to guide decision-makers. Life cycle assessment (LCA) methodology has been applied in the literature for several technologies and highlighted the variability of results (e.g. site-specific conditions) and the limited (eco-)toxicity benefits compared to additional operating impacts. In this study, the LCA of an activated carbon (AC) adsorption process based on a fluidized bed (limiting AC usage) was performed to determine its optimal operating conditions (dosage, use of micro-grain – μGAC or powder – PAC) and environmental benefits compared to the common ozonation process. This study was based on pilot processes installed at the Seine Centre treatment plant (France), using sensitivity analyses to identify the conditions for choosing a technology. For the seven scenarios (fluidized bed with 10 and 20 mg/L, both for PAC and μGAC; ozonation with 0.6 and 0.9 gO3/gDOC; and pre-ozonation combined with μGAC), the operational impacts generated (energy and material use) and the impacts avoided (micropollutant removal) were evaluated for climate change, freshwater ecotoxicity and human toxicity (USEtox characterization factors for micropollutants complemented with literature data). The LCA results showed that the fluidized bed process should preferably be operated with μGAC rather than PAC. The advantage of μGAC adsorption compared to ozonation is negligible but could nevertheless be significant in European countries with a significant share of coal-based electricity (i.e. all countries except Sweden and France). As in most of the previous works, the (eco)toxicity impacts avoided were found to be negligible, but other substances, such as hormones and oxidation by-products, should be further considered and characterized to better represent the treatment performances. The combination of ozonation and μGAC adsorption on a fluidized bed is a promising option to efficiently remove micropollutants, as well as oxidation by-products, while keeping the impacts generated within a reasonable range. This paper presented valuable results to support the eco-design of advanced wastewater treatment (both in terms of operating conditions and targeted substances) but should be complemented with large-scale evaluations (e.g. using consequential LCA) and better impact characterization of micropollutants.

Stormwater and combined sewer overflows (CSO) might represent an important source of macro and microplastics in the environment, but such fluxes are poorly investigated. In order to fill this knowledge gap, macro and microplastic concentrations were investigated (i) in stormwater and grid refusals at the outlet of a runoff water pipe located in Sucy-en-Brie (Paris suburb, France) and (ii) in CSO discharges at the Clichy outfall (Paris suburb, France). Macroplastics were sorted, weighted and classified. To study microplastics during rain events, 500 litres of water were filtered using plankton net with 80 μm mesh size. Microplastics were then extracted using H2O2 30% digestion followed by NaI density separation (d = 1.6 g.cm−3). A microscope and Fourier Transformed Infrared spectroscopy were applied to identify microplastics. Preliminary results from stormwater outlet of Sucy-en-Brie showed that macroplastic mass percentages were in the range of 1.5 to 37.5%. Moreover, 8 main plastic categories were found to contribute to 95% of total macroplastics and were identified as sanitary textiles, plastic bags or films, food packaging, bottles, cigarette buds, garbage bags, and polystyrene fragments. Macroplastic concentrations in stormwater from March to June 2018 ranged from 3 × 10−5 kg/m3 to 1 × 10−4 kg/m3. Three rain events were sampled at Sucy-en-Brie to study the concentration of microplastics. Microplastics with size of 1 to 5 mm during first rain event were analysed. Results indicated that microplastic concentrations were in the range of 4.6 × 10−2 and 9.3 × 10−3 fragments/L, in which polyamide and polyethylene predominated.

International audience; Highlights 17 • 7 commercial µGACs were characterized and tested with real wastewater 18 • A percentage of microporous volume higher than 65% reduced OMPs adsorption 19 • DOM reduced the adsorption of negatively-charged OMPs more than positive ones 20 • OMPs charge, hydrophobicity and minimal projection area influenced their adsorption 21 • The µGACs particle size had an impact on UV254 removal in continuous column tests 22 Graphical abstract 23 2 24 Abstract 25 Most studies dedicated to organic micropollutants (OMPs) removal from wastewater effluents by adsorption 26 onto activated carbon (AC) only consider a few conventional AC properties. The link between OMPs removal 27 and these properties is often missing, which limits the understanding of the adsorption process and the 28 interpretation of the results. The chemical, physical and textural properties of seven newly commercialized 29 micro-grain activated carbons (µGACs) were determined to assess their influence on the removal of 28 OMPs. 30 Conventional batch tests with wastewater effluent showed that a high percentage of microporous volume (> 31 65%) was detrimental for the removal of 10 OMPs, probably due to a higher blockage of micropores by 32 dissolved organic matter (DOM). The removal of 5 OMPs was correlated with µGACs surface chemistry 33 properties (i.e. charge) which were potentially modified by DOM adsorption or inorganic species, thus 34 favoring the adsorption of positively-charge compounds. A combination of OMPs properties including their 35 charge, hydrophobicity and minimal projection area could explain their removal. Correlations were found 36 between the removal of several OMPs and UV254 and dissolved organic carbon, suggesting that DOM and 37 OMPs interacted with each other or followed similar adsorption mechanisms. A decrease in µGACs particle 38 size had a positive impact on UV254 removal under continuous-flow conditions in columns representative of a 39 large-scale pilot due to better expansion. 40

International audience

International audience

National audience; Several advanced treatments such as activated carbon adsorption or ozonation are considered for micropollutants (MPs) removal in wastewater treatment plants (WWTPs). However, little information exists on the overall performances of a WWTP upgraded with those processes and the benefits provided regarding the elimination of multiple families of MPs. In this study, five sampling campaigns were conducted to determine the removal of 48 MPs (mainly pesticides and pharmaceutical residues) in a WWTP followed by a large-scale micro-grain activated carbon pilot with a treatment rate of 10 g/m3. The primary treatment had no effect on MPs (removal < 20%), while the biological treatment eliminated molecules that were sorbed onto sludges or biodegraded (> 60%). Without advanced treatment, the studied WWTP does not allow compliance with Swiss legislation on micropollutants, with reductions significantly lower than the 80% requested (< 50%) for 5 indicator substances If the additional elimination provided by the advanced treatment was not significant (< 10%) for MPs already well removed in the WWTP, activated carbon adsorption significantly reduces their concentration (e.g. decrease by a factor 100 for ibuprofen) and thus limits the impact of the WWTP on the receiving body. The additional elimination provided by the advanced treatment was significant (30-60%) for compounds recalcitrant to conventional treatments and overall removals higher than 60% were obtained for most MPs. A higher dose of activated carbon would be required to achieve higher removal, notably for MPs used in Switzerland as indicator substances. This study also provided the first data on the behavior of several molecules (acetamiprid, estrone, glyphosate, imidacloprid, lorazepam and ofloxacin) along a WWTP with an advanced treatment.; Plusieurs traitements avancés tels que l’adsorption sur charbon actif ou l’ozonation sont proposés pour le traitement des micropolluants (MP) au sein des stations de traitement des eaux usées (STEU). Cependant, peu d’informations existent sur les performances des STEU équipées de tels procédés et les bénéfices apportés au regard de l’élimination de multiples familles de MP. Dans cette étude, cinq campagnes d’échantillonnage ont été réalisées pour déterminer l’abattement de 48 MP (principalement des pesticides et des résidus pharmaceutiques) sur une STEU équipée d’un traitement avancé par adsorption sur charbon actif en micrograin en lit fluidisé avec un taux de traitement de 10 g/m3. Le traitement primaire n’a pas affecté la majorité des MP (abattement < 20 %), tandis que le traitement biologique a éliminé les molécules sorbées sur les boues ou biodégradées (> 60 %). Sans traitement avancé, la STEU étudiée ne permet pas de respecter la législation suisse sur les Mp, avec des abattements nettement inférieurs aux 80 % demandés (< 50 %) pour cinq substances indicatrices. Si l’élimination propre au traitement avancé n’a pas été significative (< 10 %) pour les MP déjà bien traités sur la STEU, l’adsorption sur charbon actif permet de diminuer de manière significative leur concentration (ex. : diminution d’un facteur 100 pour l’ibuprofène) et ainsi de limiter l’impact de la STEU sur le milieu récepteur. L’élimination propre au traitement avancé a été importante (30 à 60 %) pour les composés récalcitrants aux traitements conventionnels et permet d’atteindre des abattements globaux supérieurs à 60 % pour la majorité des MP. Une dose de charbon actif plus élevée serait nécessaire pour obtenir des abattements plus importants, notamment pour les MP utilisés en Suisse comme substances indicatrices. Cette étude a aussi permis de fournir les premières données sur le comportement de plusieurs molécules (acétamipride, estrone, glyphosate, imidaclopride, lorazépam et ofloxacine) le long d’une STEU équipée d’un traitement avancé.

International audience

International audience

International audience; The technical note of 12 August 2016 explains the procedures for the search for micropollutants in treated wastewater and in the raw water of wastewater treatment plants in metropolitan France. This note constitutes a roadmap for the communities covered by its application to encourage the development of action plans contributing to the reduction of emissions of 96 micropollutants. The aim is to promote reduction actions at source in order to limit the flows arriving at wastewater treatment plants. A lever of action that seems natural to communities is the control of emissions from industries in the watersheds under consideration. The article focuses on another source of contribution to pollutant flows that is not necessarily taken into account: domestic wastewater. In the case of the Paris conurbation, heavily urbanized and scarcely industrialized, we highlighted that the contamination of domestic wastewater is predominant compared to industrial wastewater for three families of micropollutants: alkylphenols and phthalates, listed in the technical note, on the one hand, and parabens, emerging micropollutants of interest, on the other hand. Then, the study of the quality of greywater allowed us to identify shower effluent and washing machine effluent as the main source of domestic wastewater contamination and so to identify ways to reduce it. Finally, the decrease of observed concentrations between 2010 and 2015 in the main trunks of the Paris conurbation, allowed us to understand the determinants (regulations and/or consuming practices) of these fluctuations in order to imagine other levers for action by local authorities.; La note technique du 12 août 2016 explique les modalités de la recherche de micropolluants dans les eaux usées traitées et dans les eaux brutes des stations de traitement des eaux usées sur le territoire métropolitain. Cette note constitue une feuille de route pour les collectivités relevant de son application pour favoriser le développement de plans d’actions contribuant à la réduction des émissions de 96 micropolluants. Il s’agit de favoriser des actions de réduction à la source afin de limiter les flux arrivants aux stations de traitement des eaux usées. Un levier d’action qui semble naturel aux collectivités est le contrôle des émissions issues des industries présentes sur les bassins versants considérés. L’article s’intéresse à une autre source d’apport aux flux de polluants qui n’est pas nécessairement prise en compte : les eaux domestiques. Dans le cas de l’agglomération parisienne, densément urbanisée et faiblement industrialisée, nous avons montré que la contamination des eaux usées d’origines domestiques est majoritaire par rapport à la contamination des eaux usées d’origines industrielles pour trois familles de micropolluants : les alkylphénols et les phtalates, relevant de la liste de la note technique, d’une part, et les parabènes, micropolluants émergents d’intérêt, d’autre part. Ensuite, l’étude de la qualité des eaux grises, a permis d’identifier les eaux de douche et de lave-linge comme sources principales d’émission de ces 3 familles de micropolluants dans les eaux usées domestiques et donc d’identifier des pistes de réduction. Enfin la diminution des concentrations observées, entre 2010 et 2015, dans les principaux émissaires de l’agglomération parisienne, a permis de comprendre les déterminants de ces fluctuations (réglementations et/ou pratiques de consommation) afin d’imaginer d’autres leviers d’action pour les collectivités.

Global estimations state that between 0.5 and 12.7 million metric tons of plastic enter the oceans each year. They are, however, associated with great uncertainties due to methodological difficulties to accurately quantify land-based plastic fluxes into the oceans. New studies at basin scale are thus needed for better model calibrations. Here, a modeling approach based on Jambeck’s statistical method and a field approach are compared in order to (i) quantify plastic fluxes in the Seine River and (ii) characterize and constrain uncertainties of both approaches. Despite the simplicity of the statistical approach and rough extrapolations, both methods yield similar results, i.e., between 1,100 and 5,900 t/yr of plastic litter flowing into the Sea of which about 88–128 t/yr are removed by cleaning operations. According to the marine strategy framework directive (2008/56/EC), actions are required to quantify plastic fluxes entering the oceans. Among different methods, a better use of the data from the waste collection should be considered. The development of a national and homogenous platform listing all the collects would be a first step in that direction.