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Due to the increasing interest in millimeter-wave (MMW) applications for wireless communication systems, the investigation of their potential biological effects is of utmost importance. In this paper, we report experimental results of the study of interactions between low-power radiation at 60 GHz and artificial models of biological membranes. In the first part of this study, we demonstrate an increase of superficial pressure of phospholipid monolayers during MMW exposure. Two of the most prominent in quantity lipid constituents of biological membranes, dipalmitoylphosphatidylcholine and dioleoylphosphatidylcholine, are considered. The role of different radiation parameters, namely, power density, polarization, amplitude modulation, permanent, and discontinuous exposure, is discussed. The results have proved to be reproducible in independent experiments. In the second part of this study, through atomic force microscopy analysis, we investigate the influence of MMW radiation on the microdomain distribution in mixed phospholipid monolayers with phase separation. No significant modifications are observed in microdomain distribution after 5 h of exposure. The main outcomes of this study lead to the conclusion that short-term low-power MMW exposures result in an increase of lateral pressure of the phospholipid monolayer, but their influence is not sufficiently strong to disturb phospholipid microdomain organization in biomembranes

WOS:000232724900134; International audience; Preparation of activated carbon is carried out from an abundant and very cheap waste by-product from wastewater treatment plant: sewage sludge. The first step of preparation consists in a carbonization process under a 10 mL min(-1) nitrogen flow, at 600 degrees C during 1 hour. The second step is a physical activation, performed with carbon dioxide. The experimental conditions of the activation were optimized using experimental design methodology. Three factors were studied: activation temperature (from 700 to 900 degrees C), activation duration (from 30 to 120 min) and CO2 flow rate (from 0.7 to 2.9 L min(-1)). The porous carbonaceous materials were characterized in terms of physico-chemical and structural properties (specific surface area, pore volumes, surface pH, surface functional groups) and adsorption properties in aqueous and gaseous phase, these characteristics constituting the responses of the experimental design. A surface response methodology enabled to define optimum values for the 3 factors (at 900 degrees C during 30 min for a CO2 flow rate of 2.9 L min(-1)) which involve an adsorbent with a specific surface area of 260 m(2) g(-1) and a pore size distribution comprising meso and micropores. Adsorption capacities of organic pollutants (phenol, dyes, VOC) are proportional to the specific surface area, apart from copper adsorption capacities (up to 80 mg g(-1)) due to an ion-exchange mechanism with Ca2+ ions present in the raw material. In order to decrease the high ash content in the produced material (51 wt.%) and thus to improve the pore development, carbonized sludge were washed with an acid (HCl, 3 M) at room temperature before the activation step. This oxidation pre-treatment allowed to reach a 4 10 m(2) g(-1) specific surface area with an ash content of 26.4 wt.%.

WOS:000189084600020; International audience; Sewage sludges produced from wastewater treatment plants continue to create environmental problems in terms of volume and method of valorization. Thermal treatment of sewage sludge is considered as an attractive method in reducing sludge volume which at the same time produces reusable by-products. This paper deals with the first step of activated carbon production from sewage sludge, the carbonization step. Experiments are carried out on viscous liquid sludge and limed sludge by varying carbonization temperature and heating rate. The results show that carbonized residue properties are interesting for activated carbon production.

International audience; Considering the wide use and production of NMs since last two decades, these trendy nanomaterials (NMs) are expected to end up in thermal disposal and waste incineration plants (WIP). It seems relevant to assess the risks related to the thermal disposal and incineration of waste containing NMs (WCNMs). The objective of this work is to present a first approach to develop a preliminary methodology for risk management in order (1) to give insights on nanosafety of exposed operators and on potential environmental risks related to the incineration and thermal disposal of WCNMs, and (2) to eventually support decision-makers and incineration plant managers. Therefore, the main challenge is to find (a) key parameter(s) which would govern the decision related to risk management of NMs thermal disposal. On the one hand, we focused on the relevant literature studies about experimental works on incineration of NMs. On the other hand, we conducted an introductory discussion with a group of experts. The review of this literature highlights that the nano-object's nanostructure destruction appears as a relevant indicator of the risks related to the NMs incineration. As a consequence, we defined a "temperature of nanostructure destruction" (TND) which would be the temperature from which the nanostructure will be destroyed. This parameter has been assumed to be a consistent indicator to develop a preliminary methodology. If the combustion chamber temperature is higher than the TND of the NM (or if they are close to each other), then the nanostructure will be destroyed and no risks related to NMs remain. If the TND of the NMs is higher than the combustion chamber temperature, then the nanostructure will not be destroyed and risks related to NMs have to be considered. As a result, five groups of NMs have been identified. WCNMs including carbonic NMs appear to be in good position to be destroyed safely in WIP. On the other hand, based on this criterion, there would be no available thermal disposal plants to safely manage WCNMs including CeO2 and ZrO2. Finally, a decision tree has been designed. TND is used as criteria to assess if a waste can be managed safely or not by a specific thermal disposal and which safety measures have to be taken.

International audience

Quantitative (CFU counting, ergosterol rate) and qualitative (SEM observations) analyses and a dedicated experimental set-up were combined in this study to examine the growth and release of a bacteria–fungi consortium collected by fibrous filters used in HVAC systems. The influence of three parameters was examined: air relative humidity (60%, 80% or close to 100%), the presence of airflow after microbial contamination of filters, and the nature of the fibrous media (glass or polypropylene fibers). First, the initial filtration efficiency of the microbial consortium, composed of bacterial cells of Staphylococcus epidermidis and fungal spores of Penicillium oxalicum , was analyzed and compared to the initial filtration with a polyvinyl-acetate aerosol. Then, microbial behavior was evaluated in terms of microbial growth onto filters (in the situation of a simulated airflow stop) and particles released from filters (after a simulated restart of the ventilation). The results demonstrated that, whatever the operating conditions, S. epidermidis did not grow onto filters. On the contrary, P. oxalicum demonstrated significant growth multiplying by more than 100 times its number of colonies (CFU) and by more than 10 times its ergosterol rate in saturated moist air conditions. SEM images provided information about microbial behavior. A significant mycelia development was observed after 48 h of filters conditioning at 100% RH, while after a longer period of conditioning (168 h), P. oxalicum spores were mostly observed. Regarding particle release, spores were detected downstream of the filters conditioned during 168 h when ventilation was restarted.

The photocatalytic degradation of three common indoor VOCs – acetone, toluene and heptane – is investigated in a dynamic photocatalytic oxidation loop using Box–Behnken designs of experiments. Thanks to the experimental results and the establishment of a kinetic rate law based on a simplified mechanism, a predictive model for the VOC degradation involving independent factors is developed. The parameters under investigation are initial concentration, light intensity and air velocity through the photocatalytic medium. The obtained model fits properly the experimental curves in the range of concentration, light intensity and air flow studied.

WOS:000086683900014; International audience; The pressure drop through plane single-layer filters of activated carbon fabric was determined experimentally with air and water as working fluids, for mean flow velocities covering the laminar and turbulent regimes in the upstream flow, and under various operating conditions. Observational evidence is given that common approaches consisting of linearly relating the pressure drop coefficient and the reciprocal of the particle Reynolds number with constant coefficients are inappropriate to fully describe the hydrodynamic behaviour of such systems. These coefficients were found to strongly depend on the nature of the circulating fluid and on the upstream flow regime as a result mainly of the property of fabrics to deform. Significant discrepancies are to be expected between their value in actual service conditions and those estimated from standard measurement procedures with the fabric at rest and in the absence of any flow, as is usually done in practice, with direct practical consequences. Data analysis using the pressure-flow models of Goodings (1964, Textile Research Journal, 34(8), 713-724.) and Comiti and Renaud (1989, Chemical Engineering Science, 44(7), 1539-1545.) corroborated the tentative conclusions that were reached as regards the effects of changes in the structure of fabrics with fibre deflection onto the hydrodynamic behaviour of single-layer fabric filters. (C) 2000 Elsevier Science Ltd. All rights reserved.

WOS:000081787300007; International audience; The aim of this work is to model the plugging curve of fibrous media for depth and surface filtration. The model links the evolution of pressure drop versus the injected mass of pollutants to structural properties of the media. Furthermore, thanks to the model, it is possible to predict the fibrous composition of a medium, which conforms to given filtration properties. First, a review of the typical fibrous media for engine oil filtration formed in our Laboratory is proposed, and, the measured filtration properties as well as the methods used for the characterization of structural properties of the media during plugging are presented. Then, an explanation of the evolution of structural properties is proposed. In the second part, the results of the structural property characterization during plugging are used to develop a model of the pressure drop evolution as a function of the injected mass of pollutants. Then, correlation laws linking the model parameters to the structural properties of the medium are given and the model is used to predict the plugging curve of two typical filtering media.

International audience; The aim of this study was to develop an experimental set-up and a methodology to uniformly contaminate several filter samples with high concentrations of cultivable bacteria and fungi. An experimental set-up allows contaminating simultaneously up to four filters for range of velocities representative of heating, ventilating and air-conditioning systems. The test aerosol was composed of a microbial consortium of one bacterium (Staphylococcus epidermidis) and one fungus (Penicillium oxalicum) and aerosol generation was performed in wet conditions. Firstly, the experimental set-up was validated in regards to homogeneity of the air flows. The bioaerosol was also characterized in terms of the number and particle size distribution using two particle counters: optical particle counter Grimm (R) 1.109 (optical diameters) and TSI APS 3321 (aerodynamic diameters). Moreover, stabilities of the number of particles generated were measured. Finally, concentrations of cultivable microorganisms were measured with BioSamplers SKC downstream of the four filters.

WOS:000317799700003; International audience; This study focuses on the photocatalytic oxidation of decane at ppb levels, close to indoor air conditions. Although these concentrations are typical of indoor air volatile organic compound (VOC) levels, such conditions have been poorly investigated to date. Decane conversion rates higher than 90% were reached within 15 h for the highest initial concentration tested in the operating conditions used. Despite this high decane conversion, 18 reaction intermediates were detected in the gas phase. The main compounds, in terms of concentration level in the gas phase, were formaldehyde, acetaldehyde and propanal. The amounts of these compounds in the gas phase were linearly dependent on the initial decane concentration. A reaction pathway is proposed, based on reaction intermediate temporal profiles and the literature. It consists of six main steps describing the oxidation process from decane to CO and CO2. The influence of the relative humidity level on the diversity and amounts of reaction intermediates was also studied. It was shown that moisture tends to shift the equilibrium of intermediates adsorption toward desorption, resulting in a relative increase in intermediate quantities in the gas phase. However, the monitoring of CO and CO2 formation highlighted that, at the end of the reaction, a high mineralization rate could be obtained. Finally, an overview of the photocatalytic reaction is given through the carbon mass balance determined for various reaction advancements. This approach gives an overall evaluation of the photocatalytic process performance, from primary compound removal to reaction intermediate and mineralization. (c) 2013 Elsevier B.V. All rights reserved.

International audience; Adsorption of Volatile Organic Compounds (VOCs) is one of the best remediation techniques for controlling industrial air pollution. In this paper, a quantitative predictor model for the characteristic adsorption energy (E) of the Dubinin-Radushkevich (DR) isotherm model has been established with R(2) value of 0.94. A predictor model for characteristic adsorption energy (E) has been established by using Multiple Linear Regression (MLR) analysis in a statistical package MINITAB. The experimental value of characteristic adsorption energy was computed by modeling the isotherm equilibrium data (which contain 120 isotherms involving five VOCs and eight activated carbons at 293, 313, 333, and 353 K) with the Gauss-Newton method in a statistical package R-STAT. The MLR model has been validated with the experimental equilibrium isotherm data points, and it will be implemented in the dynamic adsorption simulation model PROSIM. By implementing this model, it predicts an enormous range of 1200 isotherm equilibrium coefficients of DR model at different temperatures such as 293, 313, 333, and 353K (each isotherm has 10 equilibrium points by changing the concentration) just by a simple MLR characteristic energy model without any experiments.

International audience; In this research work, the three different VOCs such as acetone, dichloromethane and ethyl formate (with corresponding families like ketone, halogenated-organic, ester) are recovered by using temperature swing adsorption (TSA) process. The vapors of these selected VOCs are adsorbed on a microporous activated carbon. After adsorption step, they are regenerated under the same operating conditions by hot nitrogen regeneration. In each case of regeneration, Factorial Experimental Design (FED) tool had been used to optimize the temperature, and the superficial velocity of the nitrogen for achieving maximum regeneration efficiency (R(E)) at an optimized operating cost (OP(€)). All the experimental results of adsorption step and hot nitrogen regeneration step had been validated by the simulation model PROSIM. The average error percentage between the simulation and experiment based on the mass of adsorption of dichloromethane was 3.1%. The average error percentages between the simulations and experiments based on the mass of dichloromethane regenerated by nitrogen regeneration were 4.5%.

International audience; The regeneration experiments of dichloromethane from activated carbon bed had been carried out by both hot nitrogen and steam to evaluate the regeneration performance and the operating cost of the regeneration step. Factorial Experimental Design (FED) tool had been implemented to optimize the temperature of nitrogen and the superficial velocity of the nitrogen to achieve maximum regeneration at an optimized operating cost. All the experimental results of adsorption step, hot nitrogen and steam regeneration step had been validated by the simulation model PROSIM. The average error percentage between the simulation and experiment based on the mass of adsorption of dichloromethane was 2.6%. The average error percentages between the simulations and experiments based on the mass of dichloromethane regenerated by nitrogen regeneration and steam regeneration were 3 and 12%, respectively. From the experiments, it had been shown that both the hot nitrogen and steam regeneration had regenerated 84% of dichloromethane. But the choice of hot nitrogen or steam regeneration depends on the regeneration time, operating costs, and purity of dichloromethane regenerated. A thorough investigation had been made about the advantages and limitations of both the hot nitrogen and steam regeneration of dichloromethane.

International audience; Organic vapors emitted from solvents used in chemical and pharmaceutical processes, or from hydrocarbon fuel storage stations at oil terminals, can be efficiently captured by adsorption onto activated carbon beds. To recover vapors after the adsorption step, two modes of regeneration were selected and could be possibly combined: thermal desorption by hot nitrogen flow and vacuum depressurization (VTSA). Because of ignition risks, the conditions in which the beds operate during the adsorption and regeneration steps need to be strictly controlled, as well as optimized to maintain good performances. In this work, the optimal conditions to be applied during the desorption step were determined from factorial experimental design (FED), and validated from the process simulation results. The regeneration performances were compared in terms of bed regeneration rate, concentration of recovered volatile organic compounds (VOC) and operating costs. As an example, this methodology was applied in case of dichloromethane. It has been shown that the combination of thermal and vacuum regeneration allows reaching 82% recovery of dichloromethane. Moreover, the vacuum desorption ended up in cooling the activated carbon bed from 93°C to 63°C and so that it significantly reduces the cooling time before starting a new cycle.

WOS:000282926200003; International audience; This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (\textless0.05 mol L(-1)). In batch oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles. (C) 2010 Elsevier Ltd. All rights reserved.

La présente étude porte sur la détermination des capacités d’adsorption des mâchefers d’incinération d’ordures ménagères (MIOM). Deux échantillons contenant des mâchefers ont été caractérisés vis-à-vis de leur propriétés physico-chimiques et structurales : analyse élémentaire, pH de surface, volume poreux et surface spécifique, observation microscopique couplée spectrométrie X. Les propriétés d’adsorption de ces matériaux vis-à-vis de l’H2S ont été déduites de mesures d’isotherme et cinétique en réacteur batch et leur performance en réacteur continu a été évaluée à partir de courbes de percée réalisées en lit fixe.Les résultats des caractérisations physico-chimique et structurale indiquent que les deux matériaux testés présentent des structures poreuses ainsi que des compositions et chimie de surface très proches et favorables à l’adsorption de gaz acide tel que l’H2S.Les isothermes et cinétiques d’adsorption de l’H2S ont été réalisées pour différentes conditions d’humidité et de température du gaz et pour différentes teneurs en eau des matériaux. Les résultats obtenus montrent l’influence globale de l’eau (humidité de l’air mais surtout teneur en eau de l’échantillon) sur les performances d’adsorption. Ainsi, pour les teneurs en eau élevées, les matériaux présentent des capacités d’adsorption du H2S équivalentes à celles de charbon actif mais pour des temps de contact supérieur. Enfin, des tests d’adsorption de l’H2S réalisés en présence de CH4 dans la phase gaz indiquent qu’il n’y a pas de compétition d’adsorption entre ces 2 composés gazeux.L’étude en lit fixe a permis d’atteindre une bonne épuration initiale de l’H2S et le maintient de ce rendement sur l’ensemble de la durée du test (30 h). La courbe de percée obtenue montre une percée immédiate d’environ 1 % qui pourrait être évitée par l’augmentation de la hauteur de lit mis en œuvre dans la colonne.Ainsi cette étude a permis de mettre en évidence les bonnes performances de matériaux adsorbants à base de MIOM pour le traitement des gaz acides (H2S) pour des conditions opératoires favorisant la présence d’eau et des temps de contact suffisamment longs.

An existing geometrical pore‐scale model for flow through isotropic spongelike media is adapted to predict flow through anisotropic non‐woven glass fibre filters. Model predictions are compared to experimental results for the permeability obtained for a filter under different stages of compression to demonstrate the capability of the model to adjust to changes in porosity. The experimental data used are for a glass fibre paper with a uniform fibre diameter. The input parameters of the pore‐scale model are the porosity, fibre diameter and some measure of the anisotropy between the in‐plane and normal directions to the paper. Correlation between the predictions and the experimental results is satisfactory and provides confidence in the modelling procedure. It is shown that the permeability is very sensitive to changes in the level of anisotropy, i.e. the level of compression of the nonwoven material.

WOS:000253125900007; International audience; Due to their bad effects on human health and comfort, removing particles and volatile organic compounds from indoor air has become an issue of major interest. In this study, the potential use of five media for particle removal was investigated: a felt, a cloth, and a knitted fabric made entirely of activated carbon fibers, and two prototype nonwovens made of different proportions of activated carbon and glass fibers. Dynamic filtration measurements were performed in experimental conditions as representative as possible of indoor air, with alumina particles (modal diameter: 0.37 mu m), at an inlet concentration of 2,500 particles cm(-3) and for two different frontal velocities of air: 0.37 and 0.50 m s(-1). Although this medium was not designed for filtration, felt exhibited a high initial filtration efficiency (74%) for a low pressure drop (less than 210 Pa). Similarly, associating several layers of woven/knitted media in series led to high performances, as it reduced preferential paths for the airflow. Finally, prototype nonwovens appeared more efficient than activated carbon felt, but exhibited higher pressure drops.

International audience; A computer-aided design tool for the optimization of a three-dimensional integrated lens antennas (ILAs) is described. The optimization procedure is based on a genetic algorithm (GA) coupled to the hybrid geometrical/physical optics (GO/PO) method of analysis. It is the first time that this global numerical search technique has been applied to design 3-D shaped ILAs. To validate the proposed methodology and the numerical algorithms, two single-material ILAs are optimized and fabricated at 28 GHz. They radiate a sectoral beam and an elliptical Gaussian beam, respectively. The lens prototypes are fed by an aperture-coupled microstrip patch antenna. The influence of the lens dimensions and internal reflections on the far-field radiation patterns is also highlighted when designing shaped lenses. Comparison between experiments and numerical predictions (GO/PO and finite-difference time-domain) successfully validates our design tool.

WOS:000237177300027; International audience; With an objective of production of carbonaceous sorbent for industrial effluent treatment, physical activation by steam of biological sludge collected from the municipal wastewater treatment plant of Nantes (France) was studied and optimised using experimental design. Thus, this activation process consists of a carbonisation under N-2 atmosphere at 600 degrees C for 1 h, followed by a thermal oxidation using steam (760 degrees C, 0.5 h, 2.5 L/min). The global mass yield of the process is equal to 38%. The thermal treatment allows a specific surface area of up to 225 m(2)/g to be reached, the porous structure being composed of both micropores and mesopores. The content of acidic surface groups is 0.71 mEq/g whereas that of basic surface groups is 0.55 mEq/g. The adsorption properties of the sorbent made from sludge are estimated with regard to various pollutants representative of industrial pollution of wastewaters and compared with those of commercial activated carbon. Whereas the adsorption capacities of organic micropollutants are quite low because of proportionality to the microporosity, the important mesoporosity of the sorbent leads to interesting properties for macromolecules removal from aqueous solutions, such as dyes (q(m) = 175-200 mg/g). Furthermore, the surface functional groups and Ca2+ ions within the materials allow high copper ion adsorption capacities of 140 mg/g to be obtained. Finally, a techno-economic approach shows that the sludge activation process seems to be economically competitive with regard to incineration.

WOS:000240813000028; International audience; Different fibrous activated carbons were prepared from natural precursors (jute and coconut fibers) by physical and chemical activation. Physical activation consisted of the thermal treatment of raw fibers at 950 degrees C in an inert atmosphere followed by an activation step with CO2 at the same temperature. In chemical activation, the raw fibers were impregnated in a solution of phosphoric acid and heated at 900 degrees C in an inert atmosphere. The characteristics of the fibrous activated carbons were determined in the following terms: elemental analysis, pore characteristics, SEM observation of the porous surface, and surface chemistry. As the objective of this study was the reuse of waste for industrial wastewater treatment, the adsorption properties of the activated carbons were tested towards pollutants representative of industrial effluents: phenol, the dye Acid Red 27 and Cu2+ ions. Chemical activation by phosphoric acid seems the most suitable process to produce fibrous activated carbon from cellulose fiber. This method leads to an interesting porosity (S-BET up to 1500 m(2) g(-1)), which enables a high adsorption capacity for micropollutants like phenol (reaching 181 mg g(-1)). Moreover, it produces numerous acidic surface groups, which are involved in the adsorption mechanisms of dyes and metal ions. (c) 2006 Elsevier Ltd. All rights reserved.

La pollution de l’air, ou d’une atmosphere interieure, est due a la presence de particules, dans des concentrations pouvant suspecter un effet nefaste sur la sante ou un impact sur l’environnement. Ces particules varient grandement, suivant leur origine (applications ou secteurs d’activite, source naturelle), leur mode de formation, et au final leurs caracteristiques physico-chimiques. Les systemes d’elimination des particules doivent tenir compte de ces specificites, mais aussi de la concentration et des conditions environnementales.

WOS:000240293500005; International audience; Due to their good adsorption capacities, woven activated carbon filters are promising materials for the removal of volatile organic compounds (VOC) and odors in air treatment applications. As these fibrous media can easily be implemented in various filtration configurations, their use in a combined filter device for VOC and particulate matter (PM) removal is considered. For this purpose, experiments are performed to characterize their collection efficiencies versus particle size and mass loading for the removal of particulate matter smaller than 10 mu m. The specific fiber arrangement, due to multi-fiber yam weaving, prevents the use of initial collection efficiency models developed for non-woven media. This study aims to characterize collection efficiency during loading and to model initial collection efficiency in a woven structure made of multi-fiber yams. (C) 2005 Elsevier Ltd. All rights reserved.

WOS:000234352300003; International audience; Due to their bad effects on human health, removing Volatile Organic Compounds from indoor air has become an issue of major interest. In this study, the potential use of six commercial activated carbon felts and cloths for indoor toluene removal was investigated. Both batch and dynamic adsorption studies were performed, at toluene concentrations ranging from 21 to 18160 mg m(-3), for an air velocity representative of indoor air treatment (0.37 m s(-1)). Batch measurements showed that felts exhibited higher adsorption capacities at equilibrium than cloths at high toluene concentrations, whereas this trend may be inverted at low concentrations. Experimental isotherms and kinetics were satisfactorily fitted by the Langmuir-Freundlich model and the Linear Driving Force model respectively. No main differences between the adsorption kinetics of felts and cloths were reported. Dynamic adsorption capacities at saturation appeared to be higher than 120 mg g(-1) for both cloths and felts, irrespective of relative humidity levels and toluene concentrations. The influence of relative humidity on the adsorption capacity of felts was not significant for the higher toluene concentration studied in dynamics (307 mg m(-3)), whereas an increase in relative humidity induced a decrease in adsorption capacity at the lower toluene concentration (38 Mg m(.3)). Moreover, experimental curves of breakthrough time versus thickness of medium were satisfactorily fitted by the Adams-Bohart model, and the critical thickness determined by this model appeared to be below 1.3 mm, regardless of the medium or toluene concentration.

Issu de : WasteEng2005 - 1st International Conference on Engineering for Waste Treatment, Albi, FRANCE, 17-19 may 2005WOS:000239868100005; International audience; With an objective of production of carbonaceous sorbent for industrial effluent treatment, physical activation by steam of biological sludge collected from the municipal wastewater treatment plant of Nantes (France) is studied. This work focuses on the optimization of the carbonization and activation conditions on physico-chemical and adsorptive properties of adsorbent materials produced. The carbonization is performed in a vertical pyrolysis furnace. Its duration is fixed at 1 h, based on TGA analysis. The carbonization temperature is optimized between 400 and 1000 degrees C to improve the BET specific surface area, the micropore volume and the quantity of surface functional groups of the char. These parameters seem to be improved by a temperature increase, the specific surface area varying from 20 to 96 m(2) g(-1). An intermediate temperature of 600 degrees C is selected, in order to obtain an interesting specific surface area (60 m(2) g(-1)) and satisfying mass yield. The activation conditions are optimized in terms of temperature (750-850 degrees C) and duration (30-90 min). A factorial design is carried out, based on the following responses: mass yield, porosity (BET surface area, mesopore and micropore volume), surface chemistry and adsorption properties for current pollutants (phenol, copper ions, dyes and COV). The activation step shows an improvement of pore and adsorption characteristics of the adsorbent, with specific surface area reaching 230 m(2) g(-1) and equilibrium adsorption capacities of phenol and copper equal to 50 mg g(-1), and 80 mg g(-1), respectively. The adsorption of microorganic compounds and dyes may be related respectively with micro- and meso-porous properties, whereas copper adsorption efficiency is due to an ion-exchange mechanism as demonstrated by exchange with Ca2+ ions contained in the raw water sludge. Experimental design responses are optimized using surface response methodology and are validated experimentally. Finally, techno-economical analysis of the process shows a higher cost than farmland re-use but steam activation of sludge seems to be competitive towards incineration.

WOS:000226273100006; International audience; The objective of this study is to optimize experimental conditions of sorbent preparation from sewage sludge using experimental design methodology. Series of carbonaceous sorbents have been prepared by chemical activation with sulfuric acid. The sorbents produced were characterized, and their properties (surface chemistry, porous and adsorptive properties) were analyzed as a function of the experimental conditions (impregnation ratio, activation temperature and time). Carbonaceous sorbents developed from sludge allow copper ion, phenol and dyes (Acid Red 18 and Basic Violet 4) to be removed from aqueous solution as well as VOC from gas phase. Indeed, according to experimental conditions, copper adsorption capacity varies from 77 to 83 mg g(-1) , phenol adsorption capacity varies between 41 and 53 mg g 1 and VOC adsorption capacities (acetone and toluene) range from 12 to 54 mg g(-1). Each response has been described by a second-order model that was found to be appropriate to predict most of the responses in every experimental region. The most influential factors on each experimental design response have been identified. Regions in which optimum values of each factor were achieved for preparation of activated carbons suitable for use in wastewater and gas treatments have been determined using response surfaces methodology. In order to have. a high mass yield and to minimize the energetic cost of the process, the following optimal conditions, 1.5 g of H2SO4 g(-1) of sludge, 700 degreesC and 145 min are more appropriate for use of activated carbon from sludge in water and gas treatments. (C) 2004 Elsevier Ltd. All rights reserved.

WOS:000187466500013; International audience; no abstract

The hydrodynamic behavior of a plane fabric filter was investigated. The emphasis was put on the influence of cloth weave onto flow structure downstream from the filtering media. Experiments were performed on a 50:1 scaled-up glass model of a 3-ply twill textile sample used in water treatment applications. Air was used as working fluid. The Reynolds similarity criterion was applied to design the experimental facility used throughout this work. This entailed a mean flow velocity of 0.07 m/s. Particle Image Velocimetry (PIV) was used to observe and analyze the flow structure past inter-yarn pore models of various shape. Comparisons of mean velocity profiles upstream and downstream from the model were made to determine the distance over which wake effects remain noticeable case depending.

WOS:000172287100004; International audience; Fixed beds of anisotropic particles are commonly involved in chemical engineering processes: beds of cylindrical catalyst pellets or beds of wood shavings in paper industry. The characterization of the spatial variations of their structural properties is of great importance for flow modelling purposes. In this work, we intend to produce new data concerning a bed of long cylinder (h/ d = 5.29) and a bed of flat plates (e/a = 0.209). This study focuses on the characterization of top and bottom effects, as well as wall effects. The experimental procedure is based on the study of sections of packed beds consolidated with a resin. The captured images of successive transverse and longitudinal sections of the beds are treated and analysed, thanks to an image analysis software. The local variation of the voidage is determined in both the transverse and the longitudinal directions of the beds. Furthermore, mean intercept lengths and mean numbers of particles are measured and discussed. Concerning flat plates, an anisotropic ratio calculated from intercept measurements is compared to that previously obtained from pressure drop measurements. The main results of this work concern the enlightening of wall effects and end effects importance for the two studied beds compared to beds of spheres studied in the literature. (C) 2001 Elsevier Science B.V. All rights reserved.

International audience; This work deals with microbial growth onto filter media and focuses on the ability of microbial communities to proliferate onto filter media. Two microorganism types are studied: microorganisms from activated sludge of wastewater treatment plant (SM) and a toluene specific consortium (TSC). The filter media considered for this study contain activated carbon fibres (ACF), combined volatile organic compounds (VOC), particles treatment purposes, activated carbon fibres felt (ACFF) and activated carbon and cellulose fibres felt (AC(2)F(2)). Using a static growth procedure during 10 days under 100 % relative humidity, artificially contaminated filters are submitted to microbial colonisation. The final concentration of microorganisms per gram of filter have been assessed using a method developed in the lab, based on filter protein content assay. The average surface charge of inocula and filter's fibres are measured to assess the influence of microorganisms adhesion on contamination. The influence of soot particles on TSC proliferation onto AC(2)F(2) filter is then studied. Zeta measures enable the assessment of the implication of soot in microorganisms adhesion onto filter fibres. Consequences of microbial contamination on filter permeability and downstream particles released have then been assessed in a filtration device. Results demonstrate a better resistance of AC(2)F(2) to microbial colonisation. However, SM have more difficulties to proliferate on ACFF than TSC, whereas SM colonise easier AC(2)F(2) than TSC. Charge surface assay has defined an optimal electrostatic compatibility for TSC and AC(2)F(2) and a minimum for SM and ACFF. When soot is added to TSC solution before introduction in AC(2)F(2), high contamination shapes were observed whereas only a slight one occur without soot addition. Zeta potential measures show favourable charge conditions for adhesion of soot on AC(2)F(2) fibres and TSC on soot particles. The soot may thus have played an interface role in microbial adhesion onto media. This means that electrostatic compatibility between particles is a good approach for assessing microbial adhesion onto filters but could not explain the whole mechanism of microbial proliferation. Other parameters like nutrition preferences are certainly involved. The contamination have induced filter characteristics modification. Permeability have decreased until 20 % with microbial concentration. Colonised filters have released up to 450 microbial particles/cm3. Such a release was only observed when AC(2)F(2) was contaminated with fungi using spore as the reproduction vector (inoculum containing TSC and soot).

International audience

International audience

International audience; Gasification is a process that converts carbonaceous materials (coal, biomass, organic waste) into carbon monoxide and hydrogen by reacting the raw material at high temperatures with a controlled amount of oxygen and/or steam. The resulting gas mixture: syngas, can be used in energy production process. Syngas may be burned directly in internal combustion engines, used to produce methanol and hydrogen, or converted via the Fischer-Tropsch process into synthetic fuel. In addition, the high-temperature combustion refines out corrosive ash elements (chloride, potassium) allowing clean gas production after flying ash removal. Therefore, the main issue to syngas use in internal combustion engine is the removal of tarry product, ash and corrosive gaseous compounds. This paper consists in a state of the art on the composition of gaz from gazeifier considering the gasification operating conditions and the gazeified waste composition. The literature survey considers processes available to remove tarry products and particles from syngas produced in small scale gazeifier and to purify gas from unwanted gazeous compouds.

The design and performances is described of half Maxwell fish-eye (HMFE) and Luneburg lens antennas. Techniques to estimate the gradient index lens weights are first proposed and compared to measurements. Thanks to an analytical method based on spherical modal expansion, the radiation performances of Luneburg and HMFE lens antennas are then quantified and compared. The effects of the shell number, the lens diameter and the air gaps on the lens antenna directivity are investigated. Finally, a minmax optimized 9-shell 60 mm-diameter HMFE lens antenna is characterized at both 77 GHz and 110 GHz for on- and off- axis configurations to show its frequency behavior, focalization and beam scanning properties.

International audience

International audience

The objective of this study is to well describe the mechanisms involved in the resuspension of particles in ventilated duct by using an experimental methodology and taking into account the acceleration of the air flow which always precedes steady state. For that purpose, we chose an optical method in order to investigate the initial movement of particles, and to quantify the resuspension kinetics. In parallel we collected local data of the flow during acceleration and steady state.We observed that the resuspension kinetics starts during the acceleration period and extends to steady state. We highlighted the relevant velocity characteristics (critical velocity at the center duct and close to the wall, critical kinetic energy range) to explain this phenomenon. The resuspension start seems to be linked with a critical kinetic energy range.; L’objectif de cette étude est de bien décrire les mécanismes impliqués dans la remise en suspension des microparticules en conduite ventilée. Une méthodologie expérimentale est utilisée, et cela en tenant compte de la période d’accélération de l’écoulement qui précède l’atteinte du régime permanent. Une méthode optique a été choisi pour étudier le mouvement initial des particules, et leur cinétique de remise en suspension. Parallèlement, nous avons recueilli des données locales de l’écoulement en période d’accélération et au régime permanent.Le démarrage de la remise en suspension a été analysé relativement à l’évolution temporelle de trois paramètres pouvant influencer le démarrage de la remise en suspension, le premier est la vitesse instantanée en proche paroi, le second est l’intensité turbulente, et enfin le troisième est l’énergie cinétique turbulente. Le paramètre prépondérant sur le démarrage de la remise en suspension semble être l’énergie cinétique turbulente.

Filtration performance of a pulse-jet bag filter was evaluated at the laboratory-scale regarding submicronic particles with a nanosized fraction during clogging/unclogging cycles. The particle size distribution was representative to those encountered at the outlet of a nano-waste incineration device at laboratory-scale. The bag filter was operated in conditions as similar as possible to those found in flue gas treatment of waste incineration plants, in terms of temperature, humidity, filtration velocity, injection of sorbent reagents and unclogging conditions. The air flow and the bag filter were heated to 150°C, the water content was maintained in the air flow in the range of 10-12% (3% of relative humidity RH), and filtration velocity throughout the bag filter was fixed at 1.9 cm.s⁻¹. A mixture of submicronic suspended particles of activated carbon and sodium bicarbonate, both used in flue gas treatment systems mainly for the removal of dioxins/furans and acid gases, was generated simultaneously with the aerosol representative of combustion emissions.The study focused on the filtration performance at the beginning of the bag filter’s lifetime filter for the 11 first clogging-unclogging cycles before stabilizing the residual pressure drop reached after pulse-jet unclogging. The maximum pressure drop was set at 150 Pa for all filtration cycles. Once the maximum pressure drop was reached, the filter was unclogged using the pulse-jet system. The performance of the bag filter was evaluated in terms of the evolution of pressure drop, fractional and total particle collection efficiencies, during the clogging/unclogging cycles.Moreover, an experimental and theoretical study was carried out on the influence of different parameters on the filtration performance of bag filter and flat filter, such as influence of humidity (3% RH versus 0% RH at 150°C), temperature (150°C versus 24°C), filtration velocity (1.9 cm.s⁻¹ versus 1.4 cm.s⁻¹) and the influence of the injection of sorbent reagents.The main results of this study are: (i) high collection efficiency of the bag filter in representative conditions of flue gas treatment of waste incineration: minimun particle collection efficiency of 98.5% for particle diameter of 74 ± 15 nm (electrical mobility diameter), (ii) influence of residual particle cake at the beginning of the filtration cycles on the bag filter performance, (iii) significant influence of humidity on the porosity of the particle cake due to the capillary condensation of water between the particles in presence of humidity (150°C - 3% RH i.e. almost 100 g of water per kg of dry air). Faster increase of bag filter pressure drop in presence of humidiy (150°C - 3% RH) as compared to the dry conditions (150°C - 0% RH).; Les performances de filtration d’un filtre à manche vis-à-vis de particules submicroniques et nanométriques ont été évaluées à l’échelle du laboratoire durant plusieurs cycles de colmatage/décolmatage. La distribution granulométrique des particules (aérosol de combustion) était représentative de celle rencontrée en incinération de nano-déchets en sortie de chambre de combustion à l’échelle du laboratoire. Le filtre à manche opérait en conditions réalistes, représentatives de celles rencontrées dans les lignes de traitement des fumées d’incinération de déchets en termes de température, humidité, vitesse de filtration, présence de réactifs et conditions de décolmatage. Le flux d’air et le filtre à manche étaient chauffés à 150°C, la teneur en eau était de 10-12% (soit 3% d’humidité relative HR), et la vitesse de filtration était fixée à 1,9 cm.s⁻¹. Un mélange de particules de taille submicronique de charbon actif et de bicarbonate de sodium, utilisées dans les lignes de traitement des fumées d’incinération pour l’abattement des dioxines/furanes et des gaz acides, était généré simultanément avec l’aérosol de combustion. L’étude s’est centrée sur les performances de filtration au début de la durée de vie du filtre à manche, avant stabilisation de la perte de charge résiduelle du filtre résultant des précédents cycles de filtration. La perte de charge maximale du filtre était fixée à 150 Pa pour tous les cycles de filtration avant décolmatage par rétro-soufflage à air comprimé. Les performances du filtre à manche ont été évaluées en termes d’évolution de sa perte de charge et de son efficacité de collecte (totale et fractionnelle) au cours des cycles de colmatage/décolmatage. De plus, des études expérimentales et théoriques ont été menées afin d’étudier l’influence de divers paramètres sur les performances de filtration du filtre en configuration manche ou plane, tels que l’humidité de l’air (3% HR versus 0% HR à 150°C), la température (150°C versus 24°C), la vitesse de filtration (1,9 cm.s⁻¹ versus 1,4 cm.s⁻¹) et l’influence de l’injection de réactifs. Les principaux résultats de cette étude sont : (i) importante efficacité de capture des particules du filtre à manche en conditions représentatives des lignes de traitement des fumées d’incinération : efficacité minimale de collecte de 98,5% mesurée pour des particules de taille 74 ± 15 nm (diamètre de mobilité électrique), (ii) influence du gâteau résiduel de particules au début de chaque cycle de filtration sur les performances de traitement, (iii) influence significative de l’humidité de l’air sur la structure du gâteau de particules probablement due à l’augmentation des forces d’adhésion entre les particules en présence d’humidité (150°C – 3% HR soit environ 100 g d’eau par kg d’air sec) ; augmentation plus rapide de la perte de charge du filtre à manche en présence d’humidité (150°C – 3% HR) qu’en conditions d’air sec (150°C – 0% HR).

Filtration performance of a pulse-jet bag filter was evaluated at the laboratory-scale regarding submicronic particles with a nanosized fraction during clogging/unclogging cycles. The particle size distribution was representative to those encountered at the outlet of a nano-waste incineration device at laboratory-scale. The bag filter was operated in conditions as similar as possible to those found in flue gas treatment of waste incineration plants, in terms of temperature, humidity, filtration velocity, injection of sorbent reagents and unclogging conditions. The air flow and the bag filter were heated to 150°C, the water content was maintained in the air flow in the range of 10-12% (3% of relative humidity RH), and filtration velocity throughout the bag filter was fixed at 1.9 cm.s⁻¹. A mixture of submicronic suspended particles of activated carbon and sodium bicarbonate, both used in flue gas treatment systems mainly for the removal of dioxins/furans and acid gases, was generated simultaneously with the aerosol representative of combustion emissions.The study focused on the filtration performance at the beginning of the bag filter’s lifetime filter for the 11 first clogging-unclogging cycles before stabilizing the residual pressure drop reached after pulse-jet unclogging. The maximum pressure drop was set at 150 Pa for all filtration cycles. Once the maximum pressure drop was reached, the filter was unclogged using the pulse-jet system. The performance of the bag filter was evaluated in terms of the evolution of pressure drop, fractional and total particle collection efficiencies, during the clogging/unclogging cycles.Moreover, an experimental and theoretical study was carried out on the influence of different parameters on the filtration performance of bag filter and flat filter, such as influence of humidity (3% RH versus 0% RH at 150°C), temperature (150°C versus 24°C), filtration velocity (1.9 cm.s⁻¹ versus 1.4 cm.s⁻¹) and the influence of the injection of sorbent reagents.The main results of this study are: (i) high collection efficiency of the bag filter in representative conditions of flue gas treatment of waste incineration: minimun particle collection efficiency of 98.5% for particle diameter of 74 ± 15 nm (electrical mobility diameter), (ii) influence of residual particle cake at the beginning of the filtration cycles on the bag filter performance, (iii) significant influence of humidity on the porosity of the particle cake due to the capillary condensation of water between the particles in presence of humidity (150°C - 3% RH i.e. almost 100 g of water per kg of dry air). Faster increase of bag filter pressure drop in presence of humidiy (150°C - 3% RH) as compared to the dry conditions (150°C - 0% RH).; Les performances de filtration d’un filtre à manche vis-à-vis de particules submicroniques et nanométriques ont été évaluées à l’échelle du laboratoire durant plusieurs cycles de colmatage/décolmatage. La distribution granulométrique des particules (aérosol de combustion) était représentative de celle rencontrée en incinération de nano-déchets en sortie de chambre de combustion à l’échelle du laboratoire. Le filtre à manche opérait en conditions réalistes, représentatives de celles rencontrées dans les lignes de traitement des fumées d’incinération de déchets en termes de température, humidité, vitesse de filtration, présence de réactifs et conditions de décolmatage. Le flux d’air et le filtre à manche étaient chauffés à 150°C, la teneur en eau était de 10-12% (soit 3% d’humidité relative HR), et la vitesse de filtration était fixée à 1,9 cm.s⁻¹. Un mélange de particules de taille submicronique de charbon actif et de bicarbonate de sodium, utilisées dans les lignes de traitement des fumées d’incinération pour l’abattement des dioxines/furanes et des gaz acides, était généré simultanément avec l’aérosol de combustion. L’étude s’est centrée sur les performances de filtration au début de la durée de vie du filtre à manche, avant stabilisation de la perte de charge résiduelle du filtre résultant des précédents cycles de filtration. La perte de charge maximale du filtre était fixée à 150 Pa pour tous les cycles de filtration avant décolmatage par rétro-soufflage à air comprimé. Les performances du filtre à manche ont été évaluées en termes d’évolution de sa perte de charge et de son efficacité de collecte (totale et fractionnelle) au cours des cycles de colmatage/décolmatage. De plus, des études expérimentales et théoriques ont été menées afin d’étudier l’influence de divers paramètres sur les performances de filtration du filtre en configuration manche ou plane, tels que l’humidité de l’air (3% HR versus 0% HR à 150°C), la température (150°C versus 24°C), la vitesse de filtration (1,9 cm.s⁻¹ versus 1,4 cm.s⁻¹) et l’influence de l’injection de réactifs. Les principaux résultats de cette étude sont : (i) importante efficacité de capture des particules du filtre à manche en conditions représentatives des lignes de traitement des fumées d’incinération : efficacité minimale de collecte de 98,5% mesurée pour des particules de taille 74 ± 15 nm (diamètre de mobilité électrique), (ii) influence du gâteau résiduel de particules au début de chaque cycle de filtration sur les performances de traitement, (iii) influence significative de l’humidité de l’air sur la structure du gâteau de particules probablement due à l’augmentation des forces d’adhésion entre les particules en présence d’humidité (150°C – 3% HR soit environ 100 g d’eau par kg d’air sec) ; augmentation plus rapide de la perte de charge du filtre à manche en présence d’humidité (150°C – 3% HR) qu’en conditions d’air sec (150°C – 0% HR).

The pyrogasification is a thermochemical process that consists in converting biomass and/or waste into a gaseous energy carrier named syngas. This syngas is mainly composed of H2 and CO but also contains many pollutants (such as tars, H2S, HCl, particles…) that must be removed before further utilization of the syngas (electricity and heat production, synthesis of biofuel or chemicals…). The production of solid residues (chars) and the cost of the syngas purification process jeopardize the industrial development of this process. This thesis aims at studying the in-situ valorisation of the pyrolysis chars, functionalized or not, as sorbent or catalyst for the syngas cleaning. In this study, pyrolysis chars have been produced by the pyrolysis of wastes generated on cruise-ships: Used Wood Pallets (UWP), Coagulation-Flocculation Sludge (CFS) and Food Waste (FW). A set of multi-scale characterizations has been performed in order to identify relationships between the physico-chemical properties of the chars, the production conditions and the nature of the initial biomass. Chars from the mixture of FW/CFS have high mineral contents while chars from UWP are mainly carbonaceous materials. The steam activation only slightly modifies the chemical composition of the chars but significantly increases their porosity. Then, the study focused on the relationships between the physico-chemical properties of the chars and their purification efficiency. The H2S sorption capacity was strongly improved by high surface areas, large mineral contents and alkaline pH surfaces. The most important properties for the catalytic activity of the chars for tar cracking reactions were: high mineral contents, large surface areas and the presence of disorganized carbon structures in the char.; La pyrogazéification est un procédé de conversion thermochimique prometteur pour la valorisation énergétique des biomasses et des déchets. Ce procédé conduit à la production d’un vecteur énergétique gazeux appelé « syngas » composé principalement de CO et d’H2 mais contenant également de nombreux polluants issus des déchets entrants et/ou générés au cours de la conversion. En fonction de sa pureté, le syngas peut être valorisé dans de nombreuses applications. Cependant, la formation simultanée de résidus solides (chars) sans voie de valorisation, ainsi que le coût élevé de l'étape de purification du syngas freinent le développement industriel de cette filière. Cette thèse s'intéresse à ces deux problématiques en étudiant la valorisation des chars de pyrolyse, avec ou sans adjonction de fonctions chimiques, comme adsorbants et catalyseurs pour la purification du syngas. Dans cette étude, les chars ont été produits par pyrolyse de déchets générés sur des navires de croisière et générés en quantités importantes par les sociétés modernes : Bois de Palettes Usagées, Boues de Coagulation-Floculation et Déchets Alimentaires. Une séquence de caractérisations multi-échelle a été mise en place afin de relier les caractéristiques physico-chimiques des chars aux conditions de production ainsi qu’à la nature des déchets entrants. Les chars résultants du mélange BF/DA montrent une composition chimique riche en espèces minérales tandis que les chars produits à partir de BPU sont des matériaux très majoritairement composés de carbone. L’activation à la vapeur ne modifie pas significativement la composition des chars, mais permet de développer efficacement leur porosité. L’étude s’est ensuite intéressée aux relations existant entre les propriétés physico-chimiques des chars et leur efficacité épuratoire. La capacité d’épuration d’H2S des matériaux s’est trouvée significativement améliorée par des surfaces spécifiques élevées, de hautes teneurs en espèces minérales et un pH de surface basique. Les propriétés les plus influentes pour l’activité catalytique des chars pour le craquage des goudrons (l’éthylbenzène et le benzène sont pris comme références) en gaz légers sont : la présence d’espèces minérales, la porosité et la présence de structures carbonées désordonnées dans la matrice du char.

Nanocomposites have been widely studied and produced since the end of the nineties. These trendy materials containing nanomaterials are expected to end up in incineration waste plants due to the lack of specific recovery procedures. The aim of this work is to investigate the behavior and the fate of the nano-objects from nanocomposites during their incineration and to give insights on potential environmental risk related to the incineration of waste containing nanomaterials. Incineration tests have been performed at lab-scale using a specific tubular furnace and a cone calorimeter which have been modified in order to control the key incineration parameters within both the combustion and post-combustion zones. The influence of the nano-objects presence on the combustion mechanisms (aerosol release and decomposition) is investigated. It seems necessary to address the issue of the fate of nano-objects incorporated initially in the polymer: are they destroyed, do they undergo changes during their stay in the incinerator furnace, and where are they are released ? The combustion residues and the combustion aerosol (collected downstream the incinerator) have been characterized using various techniques devoted to the analysis of aerosols. Furthermore, it has been studied the influence of different parameters (temperature of combustion, oxygen rate, loading of nano-objects, type of nano-objects) on the nature of emissions. Finally, a decision tree has been proposed to decision-makers and incineration plant managers in order to facilitate the use of the results on an operational level.; Le développement des applications industrielles relatives aux nanotechnologies entraîne un accroissement du nombre et de la variété de déchets contenant des nanomatériaux générés par l'industrie, les consommateurs et les laboratoires de R&D. Des familles de matériaux émergents incorporant des nano-objets se développent de manière significative alors que l’adéquation des filières de fin de vie (recyclage et élimination) n’est que récemment évaluée vis-à-vis des risques potentiels liés aux nanomatériaux. Les nanocomposites - dont la fin de vie est susceptible d'être prise en charge par l'incinération - font l'objet de cette thèse. L’objectif est d’une part de connaître le devenir des nano-objets (incorporés dans le nanocomposite) lors de l’incinération du nanocomposite ; et d’autre part de connaître leur comportement dans la chambre de combustion. Les essais d’incinération ont été réalisés à l’échelle laboratoire dans un four tubulaire et un cône calorimètre spécialement modifiés dans le but de contrôler les paramètres clés de l’incinération. Les suivis temporels des concentrations en gaz et des concentrations en nombre de l’aérosol de combustion ainsi que l’imagerie en microscopie électronique nous ont permis d’étudier les émissions et la décomposition thermique. Par ailleurs, l’influence de différents paramètres tels que la température de combustion, l’oxygénation de l’échantillon, le taux d’incorporation et la nature du nano-objet incorporé, sur la nature des émissions, a été étudiée. Enfin, pour faciliter l’utilisation des résultats au niveau opérationnel, un arbre décisionnel a été proposé aux décideurs publics et aux exploitants d’unité d’incinération.

Landfill sites produce biogas by degradation of biodegradable organic matter. Biogas mainly composed of CH4 and CO2 represents a major environmental challenge. This study propose a method to estimate biogas surface emissions in landfill sites using atmospheric dispersion modeling of a tracer gas, in this case, methane. The spatial and temporal dynamics of CH4 and VOC concentrations have been followed on the studied landfill site (Séché Environnement) for several weather conditions. Measurement results show low atmospheric VOC and CH4 concentrations on the studied landfill site which validates low emissions of these compounds. Detected VOC are emitted by different sources, excluding the landfill site. The contribution of these sources on VOC concentrations is more important than that of the landfill site and no VOC could be identified as tracer of biogas emitted by landfill site. However, CH4 is emitted by the landfill site, its principal source. Two methods are proposed to estimate methane surface emissions using a Gaussian atmospheric dispersion model ADMS. Gaussian model is validated by comparison of the temporal dynamics and atmospheric concentrations of methane measured on the site and those modeled. The first method is based on an inverse approach and the second one is a statistical regression approach. CH4 emissions are estimated for the exposure period of the laser diode to the site emissions and for 4 weather scenarios identified by a hierarchical classification. Results validate the influence of meteorological parameters, especially the stability of the atmosphere, on the atmospheric dispersion and methane surface emissions.; Les ISDND produisent du biogaz par fermentation des déchets organiques. Le biogaz principalement composé de CH4 et CO2 représente un enjeu environnemental majeur. Cette étude propose un outil d’estimation des émissions surfaciques de biogaz d’une ISDND par modélisation de la dispersion atmosphérique d’un gaz traceur, en l’occurrence, le méthane. Les dynamiques spatiales et temporelles des concentrations en CH4 et en COV ont été suivies sur et dans l’entourage de l’ISDND d’étude (Séché Environnement) en fonction des conditions météorologiques. Les résultats montrent des faibles teneurs atmosphériques en COV et en CH4 sur le site d’étude validant une faible émission de ces espèces. Les COV mesurés sont émis par différentes sources dont la contribution est plus importante que celle de l’ISDND et aucun COV ne constitue un traceur de biogaz émis par le site. En revanche, l’ISDND apparait comme source principale du CH4 détecté. Deux méthodes sont proposées pour estimer les émissions surfaciques de méthane en utilisant un modèle de dispersion atmosphérique Gaussien ADMS, validé par comparaison des teneurs atmosphériques en méthane mesurées et modélisées et leur dynamique temporelle. La première méthode repose sur une approche inverse et la deuxième est une approche statistique par régression. Les émissions de CH4 sont estimées pour la période d’exposition de la diode laser aux émissions du site pour 4 scénarios météorologiques types identifiés par une classification hiérarchique. Les résultats valident l’influence des paramètres météorologiques, surtout de la stabilité de l’atmosphère, sur la dispersion atmosphérique et les émissions surfaciques en méthane.