Photoemission Spectroscopy and Atomic Force Microscopy Investigation of Vapor Phase Co-Deposited Silver/Poly(3-hexylthiophene) Composites

Nanocomposite matrices of silver/poly(3-hexylthiophene) (P3HT) were prepared in ultrahigh vacuum through vapor-phase co-deposition. Change in microstructure, chemical nature and electronic properties with increasing filler (Ag) content were investigated using in-situ XPS and UPS, and ambient AFM. At least two chemical binding states occur between Ag nanoparticles and sulfur in P3HT at the immediate contact layer but no evidence of interaction between Ag and carbon (in P3HT) was found. AFM images reveal a change in Ag nanoparticles size with concentration which modifies the microstructure and the average roughness of the surface. Under co-deposition, P3HT largely retains its conjugated structures, which is evidenced by the similar XPS and UPS spectra to those of P3HT films deposited on other substrates. We demonstrate here that the magnitude of the barrier height for hole injection and the position of the highest occupied band edge (HOB) with respect to the Fermi level of Ag can be controlled and changed by adjusting the metal (Ag) content in the composite. Furthermore, UPS reveals distinct features related to the C 2p (Sigma states) in the 5-12 eV regions, indicating the presence of ordered P3HT which is different from solution processed films.Comment: Scudier and Wei provided equal contributio

Knowledge of obstetric fistula prevention amongst young women in urban and rural Burkina Faso: a cross-sectional study

Obstetric fistula is a sequela of complicated labour, which, if untreated, leaves women handicapped and socially excluded. In Burkina Faso, incidence of obstetric fistula is 6/10,000 cases amongst gynaecological patients, with more patients affected in rural areas. This study aims to evaluate knowledge on obstetric fistula among young women in a health district of Burkina Faso, comparing rural and urban communities. This cross-sectional study employed multi-stage sampling to include 121 women aged 18-20 years residing in urban and rural communities of Boromo health district. Descriptive statistics and multiple logistic regression analysis were used to compare differences between the groups and to identify predictors of observed knowledge levels. Rural women were more likely to be married (p<0.000) and had higher propensity to teenage pregnancy (p=0.006). The survey showed overall poor obstetric fistula awareness (36%). Rural residents were less likely to have adequate preventive knowledge than urban residents [OR=0.35 (95%-CI, 0.16–0.79)]. This effect was only slightly explained by lack of education [OR=0.41 (95%-CI, 0.18–0.93)] and only slightly underestimated due to previous pregnancy [OR=0.27 (95%-CI, 0.09–0.79)]. Media were the most popular source of awareness amongst urban young women in contrast to their rural counterparts (68% vs. 23%). Most rural young women became ‘aware’ through word-of-mouth (68% vs. 14%). All participants agreed that the hospital was safer for emergency obstetric care, but only 11.0% believed they could face pregnancy complications that would require emergency treatment. There is urgent need to increase emphasis on neglected health messages such as the risks of obstetric fistula. In this respect, obstetric fistula prevention programs need to be adapted to local contexts, whether urban or rural, and multi-sectoral efforts need to be exerted to maximise use of other sectoral resources and platforms, including existing routine health services and schools, to ensure sustainability of health literacy efforts

Etude de la faisabilité du traitement des lixiviats de décharge par cultures fixées sur supports fins

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TED [Axe_IRSTEA]TED-EPUREL'étude fait part de la faisabilité du traitement de lixiviat de décharge par filtre à écoulement vertical à recirculation. Elle se focalise sur la problématique de la nitrification de concentrations élevées en NH4

Retours d'expériences in-situ de traçages à la fluorescéine en traitement des eaux usées

National audienceRetours d'expériences in-situ de traçages à la fluorescéine en traitement des eaux usées (filtres plantés de végétaux, bassins types lagunes, sols)

Protocole d'entretien et d'exploitation des sondes électrochimiques. Application aux paramètres azotés dans la ZRV de type "bassin" à Marguerittes (30). Rapport d'étape

[Departement_IRSTEA]Ecotechnologies [TR1_IRSTEA]TEDLes Zones de Rejet Végétalisées ou ZRV sont des espaces aménagés entre la sortie de la station d’épuration et le milieu récepteur de surface : elles reçoivent donc de l’eau usée traitée par la station. Elles peuvent également recevoir les effluents issus du déversoir d’orage en tête de station ou du by-pass après prétraitement, au-delà du débit de référence. L’objectif global des ZRV vise à une atténuation de pression des rejets de la station d’épuration sur les milieux aquatiques récepteurs de surface, et ce tout particulièrement en période d’étiage. Les attentes sont très nombreuses mais difficiles à quantifier ni forcément quantifiables. Le programme dans lequel s’inscrit cette étude s’intéresse aux attentes suivantes : réduction des volumes d’effluents rejetés et réduction des flux de macropolluants (matières carbonées, azote, phosphore, matières en suspension) et de certains micropolluants, réduction des germes témoins de contamination fécale. Afin d’étudier ces objectifs, une métrologie importante et appropriée a été mise en place. Le travail présenté dans ce document a été réalisé dans ce cadre et porte plus particulièrement sur l’évolution de l’azote au sein de la ZRV. Celle-ci est de type « bassin ». Elle est constituée de 2 bassins en série (B1 et B2) d’environ 1 hectare en eau (Zone de rejet végétalisée de Marguerittes (30) Contexte général, Rapport Irstea, Partenariat 2013-2015, décembre 2014). Afin de répondre aux questions concernant la réduction des flux de macropolluants, il est utile de réaliser des bilans-matière, en l’occurrence sur l’azote. Pour cela, il a été choisi d’obtenir l’évolution dynamique des masses d’eau transitant dans la ZRV ainsi qu’une connaissance approfondie des paramètres chimiques. Pour les paramètres azotés, en plus des prélèvements ponctuels fréquents et les campagnes d’échantillonnage pendant 24h, ont été installées, 6 sondes équipées d’électrodes spécifiques pour la mesure des ions ammonium (NH4+) et nitrate (NO3-) en continu sur le site. Ces sondes sont donc des outils complémentaires installés dans l’objectif d’étudier la dynamique du système de manière plus fine qu’avec des bilans 24 heures ou encore des échantillons ponctuels. Le pas de temps de l’enregistrement de la mesure est identique à celui utilisé pour les paramètres hydrauliques (5 min.) : le calcul de masse à chaque pas de temps sera ainsi possible

Devenir des polluants dans les ZRV. Devenir de l'azote et du phosphore

National audiencePrésentation du devenir de l'azote et du phosphore sous toutes leurs formes dans différents types de ZRV

Sédimentation des MES et formation des dépôts

National audiencePrésentation des résultats concernant les matières en suspension et la formation des dépôts lors de la journée de restituion sur les zones de rejet végétalisées du programme Irstea-AFB

In situ continuous monitoring of nitrogen with ion-selective electrodes in a constructed wetland receiving treated wastewater: An operating protocol to obtain reliable data

International audienceConstructed wetlands receiving treated wastewater (CWtw) are placed between wastewater treatment plants and receiving water bodies, under the perception that they increase water quality. A better understanding of the CWtw functioning is required to evaluate their real performance. To achieve this, in situ continuous monitoring of nitrate and ammonium concentrations with ionselective electrodes (ISEs) can provide valuable information. However, this measurement needs precautions to be taken to produce good data quality, especially in areas with high effluent quality requirements. In order to study the functioning of a CWtw instrumented with six ISE probes, we have developed an appropriate methodology for probe management and data processing. It is based on an evaluation of performance in the laboratory and an adapted field protocol for calibration, data treatment and validation. The result is an operating protocol concerning an acceptable cleaning frequency of 2 weeks, a complementary calibration using CWtw water, a drift evaluation and the determination of limits of quantification (1 mgN/L for ammonium and 0.5 mgN/L for nitrate). An example of a 9-month validated dataset confirms that it is fundamental to include the technical limitations of the measuring equipment and set appropriate maintenance and calibration methodologies in order to ensure an accurate interpretation of data

Rétention du phosphore par des filtres d'apatite : retour d'expérience des filtres en taille réelle et une nouvelle génération du produit Phosclean(R)

International audienceThe use of apatite, a natural phosphate rock, as a specific material which promotes phosphorous (P) adsorption/precipitation phenomena, has received particular attention in wastewater treatments in France in the last decade. Apatite filters are extensive systems for phosphorous removal which have been used together with constructed wetlands (CW) in wastewater treatment plants (WWTP) of small communities to deal with eutrophication problems in sensitive zones. There are more than 20 full-scale apatite filters installed in France, UK, Belgium and Austria, some of which are being operated for more than 5 years now. Consequently, a new research project gathering Irstea and Epur Nature, who have historically developed the use of apatite filter for P removal in France, and Timab, in charge of apatite pelletization which is marketed under the brandname Phosclean®, has started in 2017. The project named APPROVE is also co-funded by Rhône Méditerranée Corse and Adour Garonne French water agencies. The APPROVE research program is being developed in order to i) capitalize the lessons learnt from the full scale systems since their commissioning, ii) to evaluate and validate a new generation of apatite material (kinetics, lifespan, influences of environmental and operational conditions ...) and iii) to define the valorisation of P enriched final material. This poster will present the APPROVE project objectives and methodology as well as the first results obtained during 2017. Project methodology The APPROVE project comprises three axes of work. In first place, a number of field campaigns provide a feedback on the performances of full-scale apatite filters in France which operate with the 1st generation of Phosclean apatite pellets. This feedback allows a) to evaluate the pH increase during the commissioning phase, b) to identify the causes of dysfunctions sometimes observed in apatite filter's operation (e.g. clogging occurrence and/or the overcoming of discharge limits) and c) to evaluate the hydraulic and phosphorous retention performances of three hydraulically-different apatite filters (horizontal flow, vertical down flow and vertical up flow). In second place, a PhD thesis has started to assess the new generation of apatite product. The major aim of this work is to determine its maximum P-retention capacity and the influence of different parameters as Ca2+ concentration, pH, and the presence of competitive ions and biomass in retention's kinetic. Laboratory and pilot scale experiments are conducted to combine chemical speciation and hydraulics with the aid of the Hydrus® software

Devenir de deux souches d' Escherichia coli bêta-lactamase à spectre étendu en microcosmes de sédiments de zone de rejet végétalisée

International audienceFree water surface constructed wetlands (FWS CW) are efficient technologies to limit the transfer of antibiotic resistant bacteria (ARB) originating from urban effluents into the aquatic environment. However, the decrease in ARB from inflow to outflow through the FWS CW may be explained by their transfer from the water body to the sediment. To investigate the behavior of ARB in the sediment of a FWS CW, we inoculated three microcosms with two strains of extended-spectrum beta-lactamase producing Escherichia coli belonging to two genotypes. Microcosms were composed of two sediments collected at two locations of a FWS CW from which the strains were isolated. Phragmites were planted in one of the microcosms. The survival curves of the two strains were close regardless of the genotype and the type of sediment. After a rapid decline, both strains were able to survive at low level in the sediments for 50 days. Their fate was not affected by the presence of phragmites. Changes in the bla content and antibiotic resistance of the inoculated strains were observed after three weeks of incubation, indicating that FWS CW sediments are favorable environments for spread of antibiotic resistance genes and for the acquisition of new antibiotic resistance