| Environnement, ingénierie & développement |  |
N°31 - 3ème Trimestre 2003
1. Éditorial n°31 Déchets Sciences et Techniques
Alain Navarro, alors rédacteur en chef de notre revue, présentait dans l’éditorial d’un précédent numéro (n° 13, 1er trimestre 1999) l’ouvrage écrit par Suren Erkman, intitulé « Vers une écologie industrielle » (Editions Charles Léopold Mayer). Cette publication a joué un rôle pédagogique important en présentant une vision alors originale pour l’analyse du fonctionnement des systèmes industriels et de ses conséquences sur les milieux « naturels ». Basée sur la compréhension de la « dynamique des stocks de matière et d’énergie liés aux activités humaines, depuis l’extraction et la production des ressources jusqu’à leur retour inévitable tôt ou tard, dans les processus biogéochimiques » (ce qui peut être qualifié de métabolisme industriel), l’écologie industrielle vise à déterminer les transformations susceptibles de rendre le système industriel compatible avec un fonctionnement normal des écosystèmes biologiques.Un nouvel ouvrage a été récemment publié, sous la direction éditoriale de Dominique Bourg et de Suren Erkman : « Perspectives on Industrial Ecology » (http://www.greenleafpublishing.com), qui est bienvenu au moment où la vague médiatique donnée au concept de Développement Durable peut laisser craindre un décalage croissant entre discours incantatoires et pratiques concrètes. Le grand mérite de cet ouvrage, qui réunit les contributions de spécialistes internationaux, universitaires et responsables […]
2. Vers une conception de produits plus consciente des contraintes de la valorisation en fin de vie: Utilisation d’indicateurs de recyclabilité en cours de conception
The recovery of end-of-life products is today becoming an important issue for manufacturers of complex products. However, recovery aspects are not currently fully integrated at the products’design stage as tools and methods are still unsatisfactory. In this paper, a new method of recovery conscious design is presented and applied. Its use allows product designers to understand and control the complexity and variability of recovery routes and to make design choices. The method includes an original modelling of recovery routes, a multicriteria and multiscenarii recyclability assessment and a procedure that leads to design guidelines. The method is applied to an existing electronic product. This validation underlines the originality and the benefits of the method. It is also showed that the obtained guidelines are efficient and relevant.
3. Éco-conception: Intégration de la notion d’évaluation dans la conception de produits
This paper relates to the integration of the constraints of recycling in the design of products. It presents, on the one hand, the study on the techniques used in the evaluation of product/process and the research done on écodesign. On the other hand, following the work on evaluation of the end of life products, we will present the various encountered problems, as well as the solutions considered such as the implementation of a self-diagnosis module which make easy the testability of products.
4. Impact de la collecte sélective sur le gisement de déchets non-recyclables
Generalisation of various selective collections has a direct impact on the household refuse remaining said non-recyclable and defined as grey waste. On a quantitative plan, the glass and the packaging & paper collections decrease the grey waste tonnage, respectively, in 13% and in 21%, and modify at the same time their average calorific value, respectively, of + 15% and – 16%. Globally, tonnage and calorific value decrease proportionally in the efficiency of the selective collection with a limit threshold defined in the case of an « ideal » collection which reaches – 42% for the tonnage of the grey waste and – 3% for their calorific value. But the sorting also influences the grey waste quality because it increases notably their content in fine elements, category particularly rich in heavy metals, among whom the part in grey waste increases from 16% without any selective collection to 33% with a complete system of selective collection.
5. Synthèse de résines échangeuses de cations fabriquées à partir de déchets plastiques
The objective of this work is to study the possible reuse of some plastic wastes mainly composed of polystyrene (yogourt packing and mug) as cationic exchangers. The resins, thus obtained, can be used as synthetic ion exchange resins (phenolic polymers as polystyrene).Polystyrene wastes were sulfonated to obtain a strong acid cationic exchanger with an exchange capacity (CEC) varying from 11,5 to 16,5 meq/l depending on the waste. These samples as well as a commercial resin, for which the CEC is equal to 27 meq/l, were use for water softning, and enabled us to reduce the water hardness from 11,6 meq/l to 2-3 meq/l. A striking feature was that the synthesized resins had a particular affinity towards divalent cations, as the commercial resins removed both divalent and monovalent cations. These results show the possible use of the sulofonated polystyrene wastes for an economic water softning. Indeed, it can be for a great industrial and domestic interest to reduce in an economic way the hardeness of the water feeding boilers or wash machine.
6. Phosphatation de résidus minéraux
The incineration of municipal solid waste generates mineral residues which contain soluble chlorides and heavy metal pollutants. The mineral residue is currently landfilled after a cement solidification. An alternative treatment, the new patented by Solvay process uses phosphoric acid to stabilise mineral residue by the formation of stable minerals such as calcium phosphates which are insoluble in natural environments and can incorporate heavy metals inside their crystalline structure. Two different water-washed municipal solid waste incinerator mineral residues are investigated during the phosphate treatment. Phosphoric acid reacts exothermically with mineral residues with rapid kinetics of the dissolution-precipitation type. Second order rate is observed with respect to the phosphate concentration and activation energies for the phosphate reaction are found to be small (near 20 kJ/mol). Mineral residues react with phosphoric acid mainly as calcium carbonate does. Precipitated amorphous calcium phosphates coat the more inert particles (silicoaluminates, silicates, and calcium sulphates…). The two mineral residues with different compositions show similar behaviour. This indicates the phosphate stabilisation procedure can be widely applied. This chemical treatment can be considered as a first essential step in the effective insolubilisation of extractable trace heavy metals in a mineral material that could find in the future an beneficial reuse after further processing as […]
7. Mise au point d’un procédé expérimental de quantification de la teneur totale en créosote dans les bois imprégnés
Organic preservatives like creosote are used to preserve wood from insects, fungi and water damage for many years. Poles for electric power or telephone and railroad sleepers are treated with this preservative and generate wood waste for which environmentally friendly treatment technologies need to be developed in the near future. These wood wastes which represent a large volume of material are classified as dangerous waste. These waste streams sum up to 100 000 ton of material per year in every major country of the European Community. While various types of creosotes have been extensively analysed as reported in various publications, a rapid method of evaluation of the quantity of creosote present in a given sample is not available. The present work is an attempt to validate such a protocol using Infrared spectroscopy, allowing the evaluation of the mass content of creosote in impregnated woods.