Refine search
Results 31-40 of 859
How can magnetic resonance imaging (MRI) and particulate contrast agents with finely tuned interfacial properties help understanding particle transport in soil.
2012
Michel, E. | Faure, P. | Guillet, P. | Lafolie, Francois | Neveu, S. | Sammartino, Stéphane | Polidori, A.
Influence de pratiques réelles d’utilisations sur les émissions d’un appareil de chauffage domestique au bois
2018
Brandelet, Benoît | Rose, Christophe | Landreau, Julien | Rogaume, Caroline | Druette, Lionel | Rogaume, Yann
L’objectif de cette étude est de mettre en évidence l’influence sur les émissions et les performances d’un appareil de différents paramètres, comme l’humidité du bois, la présence d’écorce ou non, le calibre utilisé ainsi que le mode d’allumage. De nombreux résultats ressortent de cette étude. Tout d’abord, tous ces paramètres influent de manière considérable sur les émissions des appareils, notamment les émissions de particules, et ce, même à régime nominal. La présence d’écorce modifie la composition en carbone total des particules totales et implique l’émission d’un nouveau type de particule : les nano-cristaux. Une humidité élevée induit des niveaux de températures plus faibles. Ainsi, les émissions d’imbrûlés gazeux tels que les Composés Organiques Volatils vont augmenter de manière importante. Les émissions de particules, en quantité et en composition chimique, sont aussi significativement impactées par l’humidité du combustible. Deux modes d’allumage ont aussi été étudiés. Il s’avère qu’un allumage inversé permet de réduire de manière significative la globalité des émissions par rapport à un allumage classique. En effet, seules les émissions de Carbone Elémentaire sont plus importantes avec un allumage inversé. | he aim of this study is to bring to light the influence on firewood emissions and performance of several parameters like the moisture content of the fuel, the presence of bark, the caliber of the fuel but also the ignition mode. Many results emerge from this study. First of all, all these parameters significantly impact the emissions of the firewood at the nominal thermal heat output, especially the particles emissions. The presence of bark modifies the particles composition in total carbon. Moreover, the presence of bark induces the emissions of a new family of particles: the nanocrystal. A high moisture of the fuel led to a lower temperature in the combustion chamber. Then, the emissions of unburned gases, like the Volatile Organic Compounds, will considerably increase. The particles emissions and the composition of those particles were also significantly impacted by the moisture of the fuel. Two ignition modes were also studied. It appears that the top-down ignition against the traditional ignition allowed a significant decrease of all the emissions. Nevertheless, the elemental carbon emissions were more important with a top-down ignition.
Show more [+] Less [-]L’azote, si cher à nos campagnes
2016
Génermont, Sophie, | Cellier, Pierre
L’azote, si cher à nos campagnes
Show more [+] Less [-]Retour d'expérience des filtres d'apatite granulée en taille réelle pour la rétention du phosphore dans les filtres plantés de roseaux | Full scale experience of granulated apatite filters for phosphorous retention in treatment wetlands.
2018
Delgado Gonzalez, L. | Gerbier, C. | Prost Boucle, S. | Troesch, S. | Molle, Pascal
There are 20 full-scale Phosclean® filters for P removal being used together with treatment wetlands (TW) to treat wastewaters of small and medium-size communities, in France. Some of them are in operation for more than five years now, reason why some field experiences are being conducted under the project name of APPROVE (APatite for P Removal and Valorisation: an Evaluation) to assess the current performance and saturation conditions of full-scale filters. This paper will present fieldfeedback results from 4 different wastewater treatment plants (WWTP) with Phosclean® filters. WWTP A (filter A) has been monitored since its commission in 2017 to assess the effluent's pH evolution due to material dissolution in the very first stage of its life span. Three other WWTPs (B, C and D) with hydraulically different Phosclean® filters, in operation since 2012, are also monitored: vertical up-flow (filter B); vertical down-flow (filter C) and horizontal flow (filter D). Assessment of the treatment plants use regulatory surveys since the beginning of plants operations. As treatment plants have not the same capacity, the number of regulatory surveys is heterogeneous and not high enough to have a precise knowledge on saturation levels and retention kinetics. Consequently, additional measurement campaigns have been carried out over two years. Four-day campaigns have been carried out twice per year for each WWTP. In order to evaluate the P retention's performance, 24h-flow proportional samplings at the inlet and outlet of the Phosclean® filter were coupled to spotsamplings at different hydraulic retention times inside the filter to measure retention's kinetic. Online P-PO4 measurements at the outlet of the filter were also conducted to observe possible dynamic within a day. Mayor parameters as pH, conductivity, redox potential, TSS, BOD, COD, N, TP, P-PO4 3- as well as anions and cations were measured for these samples. For filter A, a flowmeter and an online pH probe at the outlet of the filter have been implemented for several months. To determine the nature of phosphate precipitates, SEM and DRX analyses were performed for solid samples taken at different points in the filters. Furthermore, fluorescein-tracer tests were carried out to precisely determine water retention times and possible short-circuiting, as well as dynamic penetrometer measurements to assess potential changes on the material density due to surface precipitation. Results of first campaigns show that P concentration at the outlet of filters C and D respect the maximal regulation limit for total phosphorous disposal after 5 years of operation. This is not the case for filter B, after 4 years of operation, which is over the regulation limit fixed at 2.5mgTP/L. Nevertheless, differences in the regulation limits, inlet P concentrations, hydraulic loads, operation and design, must be taken into consideration to analyze variations of filters performances. The evolution of TP concentrations along time will be presented for all filters according to saturation levels for comparison. Kinetics evolution as a function of saturation conditions will be also presented. Results show that filters B, C and D are at different saturation levels, being filter B the most saturated.
Show more [+] Less [-]Pore scale monitoring of the resting period and oxygenation of filtering media in Vertical Flow Treatment Wetland by X-ray tomography | Suivi de la période de repos de la couche filtrante des filtres plantés de roseaux par tomographie RX
2018
Martinez Carvajal, G. | Oxarango, L. | Molle, Pascal | Forquet, N.
This study aims to enlighten the geometric changes at the pore scale of filtering media of Vertical Flow Treatment Wetlands (VFTW) and their influence on oxygenation during the rest period. A 3-day ex-situ drying of six samples of a VFTW was carried out at controlled temperature, and relative humidity simulating the rest period. Samples (16-cm long) were taken at the end of the feeding period of a filter in the first stage and let dry. Three of the samples were sterilized before drying using gamma rays to differentiate oxygenation without bacterial activity. At 0, 1 and 3 days of drying, X-ray scans of the samples were performed to observe changes in the samples structure. After each scan, the oxygen transport within the sample was studied by measuring vertical oxygen concentration profiles. Although X-ray tomography allows small structure changes to be detected, it is necessary to modify the drying conditions perform a more realistic drying. The complexity of the results of oxygen profiles lead us to suggest the use of CFD tools to understand how oxygenation occurs.
Show more [+] Less [-]Shipping noise in a dynamic sea: a case study of grey seals in the Celtic Sea
2016
Chen, Feng | Shapiro, Georgy, I | Bennett, Kimberley, A | Ingram, Simon, N | Thompson, Dave | Vincent, Cécile | Russell, Debbie, Jf | Embling, Clare | Centre d'Études Biologiques de Chizé - UMR 7372 (CEBC) ; Institut National de la Recherche Agronomique (INRA)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS)
International audience | Shipping noise is a threat to marine wildlife. Grey seals are benthic foragers, and thus experience acoustic noise throughout the water column, which makes them a good model species for a case study of the potential impacts of shipping noise. We used ship track data from the Celtic Sea, seal track data and a coupled ocean-acoustic modelling system to assess the noise exposure of grey seals along their tracks. It was found that the animals experience step changes in sound levels up to ~20dB at a frequency of 125Hz, and ~10dB on average over 10 1000Hz when they dive through the thermocline, particularly during summer. Our results showed large seasonal differences in the noise level experienced by the seals. These results reveal the actual noise exposure by the animals and could help in marine spatial planning. 2
Show more [+] Less [-]Atmospheric phenanthrene pollution modulates carbon allocation in red clover (Trifolium pratense L.)
2011
Desalme, Dorine | Binet, Philippe | Epron, Daniel, D. | Bernard, Nadine | Gilbert, Daniel | Toussaint, Marie-Laure | Plain, Caroline | Chiapusio, Geneviève | Laboratoire Chrono-environnement (UMR 6249) (LCE) ; Centre National de la Recherche Scientifique (CNRS)-Université de Franche-Comté (UFC) ; Université Bourgogne Franche-Comté [COMUE] (UBFC)-Université Bourgogne Franche-Comté [COMUE] (UBFC) | Ecologie et Ecophysiologie Forestières [devient SILVA en 2018] (EEF) ; Institut National de la Recherche Agronomique (INRA)-Université de Lorraine (UL) | Pays de Montbeliard Agglomeration (PMA)
International audience | The influence of atmospheric phenanthrene (PHE) exposure (160 mgm 3) during one month on carbon allocation in clover was investigated by integrative (plant growth analysis) and instantaneous 13CO2 pulse-labelling approaches. PHE exposure diminished plant growth parameters (relative growth rate and net assimilation rate) and disturbed photosynthesis (carbon assimilation rate and chlorophyll content), leading to a 25% decrease in clover biomass. The root-shoot ratio was significantly enhanced (from 0.32 to 0.44). Photosynthates were identically allocated to leaves while less allocated to stems and roots. PHE exposure had a significant overall effect on the 13C partitioning among clover organs as more carbon was retained in leaves at the expense of roots and stems. The findings indicate that PHE decreases root exudation or transfer to symbionts and in leaves, retains carbon in a non-structural form diverting photosynthates away from growth and respiration (emergence of an additional C loss process).
Show more [+] Less [-]Spatial distribution of PAH concentrations and stable isotope signatures (δ13C, δ15N) in mosses from three European areas - Characterization by multivariate analysis
2014
Foan, Louise | Leblond, Sébastien | Thöni, Lotti | Raynaud, Christine | Santamaria, Jesus Miguel | Sebilo, Mathieu | Simon, Valérie | Chimie Agro-Industrielle (CAI) ; Institut National de la Recherche Agronomique (INRA)-Ecole nationale supérieure des ingénieurs en arts chimiques et technologiques (ENSIACET) ; Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)-Université de Toulouse (UT)-Institut National Polytechnique (Toulouse) (Toulouse INP) ; Université de Toulouse (UT)-Université de Toulouse (UT) | Origine, structure et évolution de la biodiversité (OSEB) ; Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS) | FUB - Research Group for Environmental Monitoring (SWITZERLAND) ; FUB - Research Group for Environmental Monitoring (SWITZERLAND) | Laboratorio Integrado de Calidad Ambiental - LICA (Pamplona, Spain) ; Universidad de Navarra [Pamplona] (UNAV) | Biogéochimie et écologie des milieux continentaux (Bioemco) ; École normale supérieure - Paris (ENS-PSL) ; Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Université Pierre et Marie Curie - Paris 6 (UPMC)-AgroParisTech-Centre National de la Recherche Scientifique (CNRS) | France by the Agence de l'Environnement et de la Maitrise de l'Energie (ADEME) ; Spain by the Foundation of the University of Navarra (FUNA) ; CAN Foundation ; Switzerland by the Federal Office for the Environment (FOEN) ;Communaute de Travail des Pyrenees/Communidad de Trabajo de los Pirineos (CTP)
International audience | Polycyclic aromatic hydrocarbon (PAH) concentrations and N, C stable isotope signatures were determined in mosses Hypnum cupressiforme Hedw. from 61 sites of 3 European regions: Île-de-France (France); Navarra (Spain); the Swiss Plateau and Basel area (Switzerland). Total PAH concentrations of 100-700 ng g-1, as well as δ13C values of -32 to -29‰ and δ15N values of -11 to -3‰ were measured. Pearson correlation tests revealed opposite trends between high molecular weight PAH (4-6 aromatic rings) content and δ13C values. Partial Least Square regressions explained the very significant correlations (r > 0.91, p < 0.001) between high molecular weight PAH concentrations by local urban land use (<10 km) and environmental factors such as elevation and pluviometry. Finally, specific correlations between heavy metal and PAH concentrations were attributed to industrial emissions in Switzerland and road traffic emissions in Spain.
Show more [+] Less [-]The relationship between water quality and the microbial virulome and resistome in urban streams in Brazil
2024
Guedes Stehling, Eliana | Rueda Furlan, João Pedro | Lopes, Ralf | Chodkowski, John | Stopnisek, Nejc | Angelino Savazzi, Eduardo | Shade, Ashley | Universidade de São Paulo = University of São Paulo (USP) | Michigan State University [East Lansing] ; Michigan State University System | Slovenia National Laboratory of Health, Environment and Food [Ljubljana, Slovenia] (NLZOH) | Laboratoire d'Ecologie Microbienne - UMR 5557 (LEM) ; Université Claude Bernard Lyon 1 (UCBL) ; Université de Lyon-Université de Lyon-Ecole Nationale Vétérinaire de Lyon (ENVL)-VetAgro Sup - Institut national d'enseignement supérieur et de recherche en alimentation, santé animale, sciences agronomiques et de l'environnement (VAS)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE) | United States National Science Foundation CAREER #1749544
International audience | Urban streams that receive untreated domestic and hospital waste can transmit infectious diseases and spread drug residues, including antimicrobials, which can then increase the selection of antimicrobial-resistant bacteria. Here, water samples were collected from three different urban streams in the state of São Paulo, Brazil, to relate their range of Water Quality Indices (WQIs) to the diversity and composition of aquatic microbial taxa, virulence genes (virulome), and antimicrobial resistance determinants (resistome), all assessed using untargeted metagenome sequencing. There was a predominance of phyla Proteobacteria, Actinobacteria, and Bacteroidetes in all samples, and Pseudomonas was the most abundant detected genus. Virulence genes associated with motility, adherence, and secretion systems were highly abundant and mainly associated with Pseudomonas aeruginosa. Furthermore, some opportunistic pathogenic genera had negative correlations with WQI. Many clinically relevant antimicrobial resistance genes (ARGs) and efflux pump-encoding genes that confer resistance to critically important antimicrobials were detected. The highest relative abundances of ARGs were β-lactams and macrolide-lincosamide-streptogramin. No statistically supported relationship was detected between the abundance of virulome/resistome and collection type/WQI. On the other hand, total solids were a weak predictor of gene abundance patterns. These results provide insights into various microbial outcomes given urban stream quality and point to its ecological complexity. In addition, this study suggests potential consequences for human health as mediated by aquatic microbial communities responding to typical urban outputs.
Show more [+] Less [-]How to assess trace elements bioavailability for benthic organisms in lowly to moderately contaminated coastal sediments?
2019
Rigaud, Sylvain | Garnier, Jean-Marie | Moreau, Xavier | Jong-Moreau, Laetitia De | Mayot, Nicolas | Chaurand, Perrine | Radakovitch, O. | Détection, évaluation, gestion des risques CHROniques et éMErgents (CHROME) / Université de Nîmes (CHROME) ; Université de Nîmes (UNIMES) | Centre européen de recherche et d'enseignement des géosciences de l'environnement (CEREGE) ; Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS) | Institut méditerranéen de biodiversité et d'écologie marine et continentale (IMBE) ; Avignon Université (AU)-Aix Marseille Université (AMU)-Institut de recherche pour le développement [IRD] : UMR237-Centre National de la Recherche Scientifique (CNRS) | Groupement d'intérêt public pour la réhabilitation de l'étang de Berre (GIPREB) ; GIPREB | Laboratoire de recherche sur les transferts des radionucléides dans les écosystèmes aquatiques (IRSN/PSE-ENV/SRTE/LRTA) ; Service de recherche sur les transferts et les effets des radionucléides sur les écosystèmes (IRSN/PSE-ENV/SRTE) ; Institut de Radioprotection et de Sûreté Nucléaire (IRSN)-Institut de Radioprotection et de Sûreté Nucléaire (IRSN) | Research Federation ECCOREV, INSU-CNRS EC2CO-BERTOX, Région Provence-Alpes-Côtes-d'Azur, GIPREB
International audience | The bioavailability of trace elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Zn) in lowly to moderately contaminated coastal sediments from the Berre lagoon, France, was assessed by comparing their potentially bioavailable concentrations and bioaccumulated concentrations in the polychaete Alitta succinea. No linear correlations were observed contrarily to what is generally observed in similar works in areas with highly contaminated sediment. Correlations between trace and major elements (Fe, Ca, S, Mg, P, Al) in Alitta succinea tissues and their distribution in organism tissues show that, in such lowly to moderately contaminated sediments, biological variabilities should be considered. Normalization procedures allow to take into account these variabilities and to identify that sediment contamination is partly involved in the benthic ecosystem degradation of the Berre lagoon. Alitta succinea cannot be used as relevant bioindicator for Zn and Co bioavailability in sediment, since these elements are regulated by this organism.
Show more [+] Less [-]