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International audience; Phytoattenuation combines phytoextraction or phytostabilization with the economic valorization of the biomass produced on the contaminated soil. Sorghum bicolor is a suitable crop for this strategy, as it is known to be metal-tolerant and can be used for biogas or bioethanol production or in strategies toward biofortification. In the current investigation, two cultivars, Biomass 133 and Trudan Headless (HL), were studied in a metal-contaminated (Cd, Pb, Zn) field site located in northern France to assess their potential use in a phytoattenuation strategy. The biomass yield and the metal transfer in the produced biomass were monitored in three plots with different pollution levels. Both cultivars were tolerant to high levels of metal pollution in field conditions, with yields similar to that obtained on uncontaminated sites. Neither of the cultivars changed the metal mobility of the soil and both exhibited a metal-excluder behavior. Nevertheless, Cd concentration in the aboveground part of Trudan HL, and of Biomass 133 to a lesser extent, could restrict their use in some valorization options. However, biogas production was possible with the produced biomass, indicating anaerobic digestion to be a possible valorization route for sorghum grown on contaminated sites.

International audience; Phytomanagement uses plants and soil conditioners to create value on contaminated land while minimizing environmental risk. This work was carried out on a metal(loid)-contaminated site and aimed at assessing the suitability of Salvia sclarea L. (sage) and Coriandrum sativum L. (coriander) combined with an arbuscular mycorrhizal fungus (AMF) inoculant to immobilize metal(loid)s and produce essential oils (EO). The effect of the inoculant on the transfer of metal(loid)s (ML, i.e., Cd, Cu, Pb, Zn, As, Ni, and Sb) to plants and the ML soil mobility were investigated. The ML concentrations in EO from both plant species and the valorization options for the distillation residues (soil conditioner, animal fodder, and anaerobic digestion) were studied. Sage was a suitable candidate for this value chain because it presents an excluder phenotype and the residues of oil extraction could be used as a soil conditioner. The metal concentrations in the sage EO were similar to those obtained from plants cultivated on an uncontaminated soil. These results indicate the suitability of sage harvested on the contaminated soil according to the ML fate in the whole value chain. Like the EO of sage, ML concentrations in the coriander EO did not differ from those in the commercial EO that were obtained from plants grown on uncontaminated soil. However, the use of distillation residues of coriander was limited by their relatively elevated Cd concentrations. The use of a mycorrhizal inoculum did not decrease the Cd mobility in soil for the coriander.

Roadside grass cuttings and solid cattle manure are resources that are available as input for dry anaerobic co-digestion. Two series of measurements were carried out, one in June 2016 and one in October 2016. The methane potentials were determined on a laboratory scale and revealed a high degree of seasonality, 202.9 and 167.9 Nm3CH4.tVS−1, respectively. Moreover, these substrates were co-digested in reactors by the dry process on a pilot scale (60 L). Two strategies for filling and optimization, as layers or as a mixture, were compared. The seasonality also determined the physicochemical parameters and the hydrodynamic properties involved in percolation of the liquid phase recirculated in the dry digestion process. The production of methane depended on the filling method, the seasonality, and the nature of the input, which in some cases resulted in inhibition of 34.8–44.4 Nm3CH4.tVS−1.

Le secteur de la gestion et notamment de la valorisation des dechets est en plein essor et en constante evolution. Il s’agit d’un secteur vaste et complexe aux contours difficiles a delimiter, ou les enjeux de sante au travail sont nombreux. Dans ce cadre, l’Anses s’est autosaisie afin d’investiguer les risques sanitaires pour les professionnels de ce secteur. Dans une premiere expertise, l’Agence dresse un panorama general du secteur, puis propose une analyse suivie d’une categorisation des filieres de gestion des dechets en vue d’identifier des filieres sur lesquelles conduire prioritairement une evaluation des risques sanitaires. De maniere generale, l’Anses souligne le manque de donnees precises sur les risques sanitaires encourus par les travailleurs des dechets. La grande variete des dechets et des procedes mis en œuvre pour leur collecte, leur valorisation ou leur elimination, implique des expositions professionnelles a de multiples facteurs de risques notamment lies aux substances chimiques, bacteries et moisissures, aux bruits et vibrations mecaniques, ou encore aux contraintes organisationnelles. Des risques pour la sante psychique lies aux conditions de travail, a l’organisation et aux representations des metiers des dechets sont egalement a considerer. En France, le secteur de la collecte, du traitement et de l’elimination des dechets figure parmi les secteurs professionnels les plus sinistres. Globalement, l’Anses formule des recommandations afin d’ameliorer les connaissances sur les risques sanitaires pour les travailleurs ainsi que la prevention de ces risques. Elle preconise egalement une prise en compte des enjeux pour la sante de ces professionnels dans les activites d’ecoconception et souligne l’importance de sensibiliser les populations a ces problematiques afin de contribuer a une meilleure reconnaissance des travailleurs et metiers des dechets. Concernant l’analyse par filieres, un travail de categorisation, fonde sur l’etude de plusieurs criteres de differentes natures (niveau de documentation des risques sanitaires, estimation des potentiels de risques chimiques et biologiques, quantites de dechets, effectifs de travailleurs, evolutions economiques et techniques des filieres dans les annees a venir) a permis de regrouper des filieres presentant des caracteristiques communes. Six categories de filieres ont ainsi ete definies et, pour chacune de ces categories, des recommandations specifiques ont ete formulees afin de prevenir, evaluer et caracteriser les risques sanitaires pour les travailleurs. Une synthese des conclusions et des recommandations principales en matiere de prevention issues de cette premiere expertise sera presentee lors du Congres.

International audience; he environmental performance of mechanical biological pre-treatment (MBT) of Municipal Solid Waste is quantified using Life Cycle Assessment (LCA), considering one of the 57 French plants currently in operation as a case study. The inventory is mostly based on plant-specific data, extrapolated from on-site measurements regarding mechanical and biological operations (including anaerobic digestion and composting of digestate). The combined treatment of 46,929 tonnes of residual Municipal Solid Waste and 12,158 tonnes of source-sorted biowaste (as treated in 2010 at the plant) generates 24,550 tonnes CO2-eq as an impact on climate change, 69,943 kg SO2-eq on terrestrial acidification and 19,929 kg NMVOC-eq on photochemical oxidant formation, in a life-cycle perspective. On the contrary MBT induces environmental benefits in terms of fossil resource depletion, human toxicity (carcinogenic) and ecotoxicity. The results firstly highlight the relatively large contribution of some pollutants, such as CH4, emitted at the plant and yet sometimes neglected in the LCA of waste MBT. Moreover this study identifies 4 plant-specific operation conditions which drive the environmental impact potentials induced by MBT: the conditions of degradation of the fermentable fraction, the collection of gaseous flows emitted from biological operations, the abatement of collected pollutants and NOx emissions from biogas combustion. Finally the results underline the relatively large influence of the operations downstream the plant (in particular residuals incineration) on the environmental performance of waste MBT.

International audience; Biogas produced from anaerobic fermentation of organic substances represents an alternative renewable energy source. Its utilization would contribute to substantial reduction of the solid waste volume in land-filling and incineration. Biogas so produced could be utilized on site or it could be injected into the natural gas distribution network. Microbiological and chemical compositions of different biogas types were determined in order to conduct qualitative and quantitative risk assessments of the potential health hazards associated with biogas use for cooking. Biogas types that could be allowed for injection in the natural gas pipelines were listed with recommendations, while outlining the European biogas injection policy. Results indicated that the injection of the processed biogas in the distribution network did not present any additional chemical or microbiological risk to consumers when compared to natural gas, provided that the biogas resulted from the fermentation of non-dangerous waste. However, since this study did not examine the microbiological and chemical composition of biogas originating from wastewater sludges and/or industrial wastes, the injection of this type of biogas into the gas distribution network should not be allowed unless a similar risk evaluation study is conducted for each case.

The present state-of-the-art in gas detection does not allow the precise titration of a combustible gas in air with a single catalytic sensor, because the signal also depends on parameters other than the oxidation of the gas. This is why catalytic transducers always consist of both a detector and a compensating element. We present here a process that permits the avoidance of the compensating element, and, moreover, allows the identification of the combustible gas and the recognition of high concentrations of some gases.

International audience; The effects of concentration and temperature on the breakthrough volumes (V-b) Of 23 volatile organic compounds on Carbotrap B have been determined using the frontal chromatography method. From the measured V-b, Original isotherms have been produced and adsorption parameters based on the Langmuir, Freundlich, and Dubinin-Polyani adsorption models have been calculated. The calculated adsorption parameters describe the behavior of these VOC on Carbotrap B under the experimental conditions and are useful data for VOC sampling applications including adsorption modeling of pumped and diffusive sampling. Each of the adsorption models give similar results and are in good agreement with the experimental data in the ppmv concentration range. It will be shown that contrary to previous assumptions the Langmuir adsorption parameters obtained at ppmv concentrations cannot he used to predict l/b at ppbv concentrations and the calculated parameter m(max) does not represent the maximum adsorbent capacity. The Freundlich and Dubinin-Polyani models are shown to be more successful in describing the adsorption behavior of the VOC at ppbv levels where V-b is independent of concentration. The isosteric heats of adsorption (-DeltaH(st)) for some of the compounds have been determined using the Van't Hoff equation which can be used to predict the effect of temperature on V-b.

The kinetics of methane catalytic oxidation on platinum thin films have been studied in order to improve the lifetime and sensitivity of methane calorimetric sensors. The samples are placed in a quartz reactor and are heated up to 830 °C in isothermal conditions under a mixture of 1% methane in air with a flow rate of a few tens of cm 3 /min. The gas phase is analysed by mass spectrometry. The behaviour of thin platinum ribbons and of evaporated thin films has been compared. An Arrhenius plot of the reaction rate yields an activation energy of about 30–35 kcal/mole for platinum ribbons, which is consistent with previous determinations. After heating the obtained platinum films at a temperature higher than 730 °C in the reactive mixture, their activity becomes of the same order of magnitude as that of clean platinum ribbons.