Control of methane emissions issuing from lanffills: the Canadian case

[Abstract] During their storage in landfills, wastes are biodegraded, which results in the production of biogas and leachate. Over recent years, the handling of the leachate product has become one of major concern. However, in the case of biogas product, elimination or valorization processes are applied in a smaller proportion, even if the methane emissions, directly related to landfills, are some 25 % of the total anthropogenic methane emissions. Indeed, many older or smaller landfills are deprived of gas collection systems, thereby making impossible the application of gas combustion and/or valorization methods. Therefore, other processes have to be considered, e.g., the biofiltration of methane. In this paper, the results of an experiment, undertaken to confirm the stability of the biofiltration system that has been developed at Université de Sherbrooke by the Biocom group, are presented. At a methane inlet concentration of around 7500 ppmv and a gas flow rate of 0.25 m3/h, the conversion of the biofilter can be maintained at 22 % unchanged for a period of 150 days or more. Even after the cessation of methane feeding and biofilter irrigation for some 2 weeks, the biofilter performance was able to be restored, in only one week, to the same operating level as it was maintained before the deliberate shutdown

LES CRITERES DE PERFORMANCE DANS DIFFERENTS TYPES DE RESEAUX D'ENTREPRISE ELEMENTS DE REFLEXION

International audienceCet article présente des éléments de repérage du développement des coopérations interentreprises. Nous examinons plus particulièrement comment la notion de performance peut être déclinée et présentons une distinction de la performance selon 4 familles de réseaux d'entreprise

Characterization of a biotrickling filter treating methanol vapours

[Abstract] The aim of this research is to characterize a biotrickling filter (BTF) treating methanol vapour emissions. The parameters studied were the nitrogen concentration in the nutrient solution and the empty bed residence time (EBRT). The effect of continuously recycling the nutrient solution was also analyzed. At nitrogen concentrations as low as 0.001 gN L-1, the BTF presented removal efficiencies higher than 70 % for an inlet load of 110 g m-3 h-1. A nitrogen concentration of 0.005 gN L-1 was used to study the effect of EBRT and the continuous recirculation of nutrient solution. At a constant methanol inlet concentration of 1500 ppmv, the BTF was operated in a range of EBRT from 20 to 265 s and the removal efficiencies respectively attained were 40 and 90 %. Methanol vapours were absorbed into the lixiviate and were taken into account in analysing the results

The Use of Inorganic Packing Materials during Methane Biofiltration

The objective behind this study is to select a suitable inorganic packing material for methane biofiltration. Three packing materials are to be compared: two rock materials (average particles' sizes: 2 and 5 mm) and one porous clay particles (average particle size of 7 mm). The main parameter used to assess the efficiency of the packing material is the methane elimination capacity. The study reveals that the rock material having an average particle size around 2 mm is to be preferred. This result is probably due to its high specific surface area and to its good surface properties as compared to the other 2 tested porous materials. The influence of the nonirrigation with the nutrient solution of the biofilter is also investigated. It has been found that nonirrigation of biofilter causes the biofilter performance to decrease significantly (e.g., 45% decrease in 1 week) even with the humidification of the gas phase prior to its introduction into the biofilter

Les coopérations inter-entreprises : identification et interprétation des formes et des évolutions : proposition d'une grille de lecture, analyse au sein de filière et dans le cadre d'un environnement géographique de proximité

Not availableÀ partir du constat de la multiplicité des référentiels d'analyse des coopérations et du peu de recherches sur les facteurs d'évolution de ces dernières , nous proposons une grille de lecture rendant compte de la variété et de la variabilité dans le temps des coopérations. Nous procédons a une validation théorique par projection des principales théories et analyses ayant traite des coopérations inter-entreprises. Des expérimentations pratiques ont par ailleurs été réalisées, dans le cadre d'une filière de P.M.E. ( mécanique / métallerie), de même qu'au travers de l'analyse des facteurs d'évolution d'un réseau de proximité géographique. Nous envisageons également un ensemble de facteurs jouant un rôle sensible dans l'évolution des réseaux

Les coopérations interentreprises: une grille de lecture

This paper presents some elements to mark out the understanding of the forms and the determining factors in the development of interfirm cooperations. We propose a frame of interpretation which includes the dimensions of variety and variability, and which federates the main theories and analysis dealing with interfirm cooperations. After expressing the principal determining factors of each kind of network, we present specific examples of networks and their relation with the frame of interpretation.interfirm cooperations;frame of interpretation; variety;variability;development.

The Use of Inorganic Packing Materials during Methane Biofiltration

The objective behind this study is to select a suitable inorganic packing material for methane biofiltration. Three packing materials are to be compared: two rock materials (average particles' sizes: 2 and 5 mm) and one porous clay particles (average particle size of 7 mm). The main parameter used to assess the efficiency of the packing material is the methane elimination capacity. The study reveals that the rock material having an average particle size around 2 mm is to be preferred. This result is probably due to its high specific surface area and to its good surface properties as compared to the other 2 tested porous materials. The influence of the nonirrigation with the nutrient solution of the biofilter is also investigated. It has been found that nonirrigation of biofilter causes the biofilter performance to decrease significantly (e.g., 45% decrease in 1 week) even with the humidification of the gas phase prior to its introduction into the biofilter

Analyse des flux d’achat : une aide à la localisation commerciale

International audienceRetail attraction evolves with increasing consumer mobility. This article develops a method for analyzing purchase flows based on the use of localized databases, in order to estimate opportunities for sales outlets to capture customer stocks and flows in a market area. This method facilitates the evaluation of actual rather than speculative purchase behavior from a limited number of explanatory variables. It leads to new possibilities for evaluating purchase behavior induced by changes in the offering. The method is compared to traditional attraction models and shows greater reliability of results in measuring the attraction of outlets. It highlights the complementarities in local markets between territories and retail leakage phenomena. The method is an aid to decision making regarding the choice of location, size, format and product mix of stores.L’attraction commerciale évolue avec la mobilité croissante des consommateurs. Cet article développe une méthode d’analyse des flux d’achat fondée sur l’utilisation des bases de données localisées, afin de permettre l’estimation, pour des points de vente, des possibilités de captation de stocks et de flux de clientèle dans une aire de marché. Cette méthode facilite l’évaluation des comportements d’achat effectifs et non plus spéculatifs à partir d’un nombre restreint de variables explicatives. Elle débouche sur des possibilités nouvelles d’évaluation des comportements d’achat induits par des modifications de l’offre. Elle est comparée aux modèles traditionnels d’attraction et montre une meilleure fiabilité des résultats dans la mesure de l’attraction des points de vente. Elle souligne les complémentarités entre territoires et les phénomènes d’évasion sur les marchés locaux. La méthode constitue une aide à la décision quant aux choix de localisation, de taille, de format et d’assortiment des points de vente