Suchergebnisse

Many industrial sectors are likely to generate highly saline wastewater: these include the chemical, pharmaceutical, agro-food, petroleum, textile and leather industries. The discharge of such wastewater without prior treatment is known to adversely affect the aquatic life, water potability and agriculture. The consequences are even worse in the case of regions already affected by water scarcity, where the compensation of inorganic salt pollutants is impossible. Thus, legislation is becoming more stringent and the treatment of saline wastewater is nowadays compulsory in many countries. Saline effluents are conventionally treated through physico-chemical means, as biological treatment is strongly inhibited by salts (mainly NaCl). However, the cost of physico-chemical treatments being particularly high, alternative treatment systems are nowadays increasingly the focus of research. Most of such systems involve anaerobic or aerobic biological treatment made possible by use of salt-tolerant micro-organisms. These halophilic micro-organisms are retrieved in the oceans but also in other hypersaline environments such as salterns and soda lakes. This thesis studies their survival and diversity in hypersaline sludge, as well as their application to carbonaceous, nitrogenous and phosphorous depollution of hypersaline industrial wastewater (focusing on tannery wastewater). ; De nombreux secteurs industriels sont susceptibles de générer des effluents hypersalins : on peut notamment citer les industries chimique, pharmaceutique, agroalimentaire, pétrolière, textile et du cuir. Le rejet de ces effluents sans traitement préalable peut avoir un impact dramatique sur la vie aquatique, la potabilité de l'eau et l'agriculture. Les conséquences sont pires encore dans le cas de régions déjà affectées par les pénuries d'eau, où la compensation de la pollution saline est impossible. Par conséquent, la législation est de plus en plus stricte et le traitement des effluents salins est désormais imposé dans de nombreux pays. Les effluents ...

It is apparent that firms require efficient networks, including telecommunications networks. This affects their strategies and their capital expenditure which, in the case of large-sized firms, is often inter national. It is in the interest of states that efficient networks should exist as they are useful for firms that carry out takeovers (that is, firms with an attacking attitude), as well as those that have recourse to subcon tracting and franchising (that is, firms with a defensive attitude). The article deals with the impact of such networks on companies and discusses how changes take place in a geopolitical context.

Dans ce mémoire, un modèle théorique est développé pour analyser les impacts économiques de l'étiquetage des aliments génétiquement modifié (GM). Dans un premier temps, ce travail présente un cadre théorique d'offre et de demande qui s'applique aux diverses considérations des marchés des aliments GM et de ces substituts, soit les aliments dits conventionnel et biologique. Ainsi, des offres d'aliments différenciés fournis par des producteurs hétérogènes sont présentées. À cela, des demandes hétérogènes selon le concept de différenciation de produits empruntée au champ de l'organisation industrielle sont ajoutées. Ensuite, ce travail fait un exercice d'équilibre pour expliquer les impacts de cette politique publique sur les marchés des pays où il y a une grande production de culture GM. L'impact de la rigidité de la production de culture GM est aussi analysé en considérant des frictions au niveau de l'offre de culture conventionnelle et biologique. Les résultats montrent que, suite à l'étiquetage, il y a, en termes de bien-être économique, des bénéfices à tirer pour les producteurs et consommateurs d'aliment conventionnel, des pertes pour les producteurs et consommateurs d'aliments GM et que la rigidité de la production de cultures GM crée une mauvaise allocation des ressources. Celle-ci nuit à la consommation d'aliments conventionnelle et GM, bénéficie à la production de culture biologique lorsque les frictions prennent part dans la production conventionnelle et crée également une augmentation généralisée des prix des aliments issus des trois cultures. Il est ainsi recommandé de prendre en compte ces implications du marché dans les études de coûts de l'implantation d'un étiquetage obligatoire et de mettre en place des mesures permettant d'atténuer les effets de cette rigidité, advenant l'application d'une telle politique.

International audience ; Advanced oxidation processes (AOPs) have received a lot of attention over the years as advanced physicochemical polishing wastewater treatments to remove biorefractory pollutants. Additionally, many studies report their excellent degradation and mineralization performance as stand-alone technologies too, demonstrating the versatility of these processes; however, there is a lack of suitable methods to compare the performance (in terms of removal efficiency and operating costs) of different AOPs in the same conditions. In this context, the goal of this paper is to propose a systematic investigation by introducing a novel criterion, namely the accumulated oxygen-equivalent chemical-oxidation dose (AOCD), to systematically compare the diverse AOPs available: ozonation, H2O2 photolysis, Fenton, photo-Fenton, electro-Fenton and photoelectro-Fenton (paired with anodic oxidation, for the latter two). For each of these, the cost efficiency was determined by optimizing the operating conditions for the removal of phenol, selected as a model pollutant (1.4 mM, equivalent to 100 mg-C L-1). The operating costs considered sludge management, chemical use and electricity consumption. Among all AOPs, electro-Fenton was the most cost-effective (108-125 € m-3), notwithstanding the mineralization target (50%, 75% and 99%), owing to its electrocatalytic behavior. Chemical Fenton proved competitive too up to 50% of mineralization, meaning that it could also be considered as a cost-effective pre-treatment solution. AOCD was the lowest for electro-Fenton, which could be attributed to its excellent faradaic yield, while UV-based processes generally required the highest dose. The AOCD criterion could serve as a baseline for AOP comparison and prove useful for the legislator to determine the "best available techniques" as defined by the Industrial Emissions European Union Directive 2010/75/EU.

International audience ; Advanced oxidation processes (AOPs) have received a lot of attention over the years as advanced physicochemical polishing wastewater treatments to remove biorefractory pollutants. Additionally, many studies report their excellent degradation and mineralization performance as stand-alone technologies too, demonstrating the versatility of these processes; however, there is a lack of suitable methods to compare the performance (in terms of removal efficiency and operating costs) of different AOPs in the same conditions. In this context, the goal of this paper is to propose a systematic investigation by introducing a novel criterion, namely the accumulated oxygen-equivalent chemical-oxidation dose (AOCD), to systematically compare the diverse AOPs available: ozonation, H2O2 photolysis, Fenton, photo-Fenton, electro-Fenton and photoelectro-Fenton (paired with anodic oxidation, for the latter two). For each of these, the cost efficiency was determined by optimizing the operating conditions for the removal of phenol, selected as a model pollutant (1.4 mM, equivalent to 100 mg-C L-1). The operating costs considered sludge management, chemical use and electricity consumption. Among all AOPs, electro-Fenton was the most cost-effective (108-125 € m-3), notwithstanding the mineralization target (50%, 75% and 99%), owing to its electrocatalytic behavior. Chemical Fenton proved competitive too up to 50% of mineralization, meaning that it could also be considered as a cost-effective pre-treatment solution. AOCD was the lowest for electro-Fenton, which could be attributed to its excellent faradaic yield, while UV-based processes generally required the highest dose. The AOCD criterion could serve as a baseline for AOP comparison and prove useful for the legislator to determine the "best available techniques" as defined by the Industrial Emissions European Union Directive 2010/75/EU.

International audience ; Advanced oxidation processes (AOPs) have received a lot of attention over the years as advanced physicochemical polishing wastewater treatments to remove biorefractory pollutants. Additionally, many studies report their excellent degradation and mineralization performance as stand-alone technologies too, demonstrating the versatility of these processes; however, there is a lack of suitable methods to compare the performance (in terms of removal efficiency and operating costs) of different AOPs in the same conditions. In this context, the goal of this paper is to propose a systematic investigation by introducing a novel criterion, namely the accumulated oxygen-equivalent chemical-oxidation dose (AOCD), to systematically compare the diverse AOPs available: ozonation, H2O2 photolysis, Fenton, photo-Fenton, electro-Fenton and photoelectro-Fenton (paired with anodic oxidation, for the latter two). For each of these, the cost efficiency was determined by optimizing the operating conditions for the removal of phenol, selected as a model pollutant (1.4 mM, equivalent to 100 mg-C L-1). The operating costs considered sludge management, chemical use and electricity consumption. Among all AOPs, electro-Fenton was the most cost-effective (108-125 € m-3), notwithstanding the mineralization target (50%, 75% and 99%), owing to its electrocatalytic behavior. Chemical Fenton proved competitive too up to 50% of mineralization, meaning that it could also be considered as a cost-effective pre-treatment solution. AOCD was the lowest for electro-Fenton, which could be attributed to its excellent faradaic yield, while UV-based processes generally required the highest dose. The AOCD criterion could serve as a baseline for AOP comparison and prove useful for the legislator to determine the "best available techniques" as defined by the Industrial Emissions European Union Directive 2010/75/EU.