| Environnement, ingénierie & développement |  |
N°2 - 2ème Trimestre 1996
1. Éditorial n°2 Déchets Sciences et Techniques
Loi du 13 juillet 1995Par la loi de 1992, le Parlement a voulu éradiquer le gaspillage en incitant au recyclage et à la valorisation des matériaux contenus dans les déchets : « Arrêtez de jeter bête ! »Le législateur a également réaffirmé les principes fondamentaux qui guidaient la politique de gestion des déchets :- précautions,- prévention,- meilleure technologie disponible dans des conditions économiques acceptables,- proximité,- subsidiarité.Il a enfin défini la notion « ou l'objectif » des déchets ultimes qui seuls pourraient être acceptés en décharge à partir de 2002.Une mauvaise traduction de la loiIl est à noter dès lors, que cette échéance de 2002 a marqué les esprits, même si peu d'objectifs chiffrés ont été fixés en matière de recyclage et de valorisation.Certes, des moyens incitatifs ont été mis en place (Eco Emballages, FMGD...) mais il a été pensé que des interdictions de mise en décharge auraient une influence notable sur les maillons amont et donc sur les producteurs.Certains ont même traduit cela par « plus de décharge en 2002 ».Cela reviendrait alors, à ne recourir qu'au tout incinération, à l'inverse de la quasi totalité des pays dans le monde qui reconnaissent la décharge comme moyen de traitement.
2. Recherche sur les déchets en économie et en sociologie : un état de l’art: Partie 1. Recherche en économie
The article gives an overview (axes, some content and bibliography) of research on waste problems in economics and sociology. Waste has to be related not only to zero or negative economic value, but also to a whole system of socio-cultural values. The economic approaches are referring notably to the externalities and their internalization, scientific basement of environmental standards, instruments of regulation, public sector and industrial economy. The sociological approaches are referring to the behavior of social groups, psycho-sociological representations and logics of social actors, social forces and their dynamics. Research applies mainly on firms (in particular eco-industries), waste generation and management, separate collection, disposal options and the Nimby syndrome.
3. Première approche du contrôle industriel de la composition de résidus fortement hétérogènes, issus du broyage des automobiles et autres biens de consommation
At the present time, end of life vehicles and white goods are shredded in order to sort metals. Plastics, glass and others materials mixed with metallic dust and minerals are going to landfill. ln order to reduce residues dumping, the today solutions are mainly based on energy recovery and probably based in the future on material recycling after sorting. To implement energy valorisation networks, Renault has developped sampling and fast analysis methods wich allow to control the quality of residue before combustion. The objective is to get a fast operative procedure wich be able to compare the quality of residue to the list of requirements of the user's furnace. Firstable, a sampling procedure has been elaborated from GY's theories on minerals. This approach gives acceptable results for metallic and organics species. An analysis method based on X Fluorescence for metals and on oxygen bomb for chlorine has been then developed and gives acceptable results for a daily control.
4. Recyclage du poly (éthylène téréphtalate) par glycolyse
Treatment of bottles and fibers wastes, by alcoholysis, contribute to the development of environnemental processes. Depolymerization of polyethylene terephtalate by glycolysis in homogeneous phase (naphtalene as solvent) is studied, using different catalysts. Low molecular weight glycolysis products are quickly obtained with tetrabutylorthotitanate. These products are suitable for fabrication of raw materials in the plastics industries.
5. Influence de la longueur de chaine sur la décomposition thermique du polystyrène
The experimental works consist of a serie of pyrolysis at 350°C on three polystyrene standard samples with various molecular weight (Mn) and a polydispersity index close to unity. We have monitored the evolution of Mn as well as the quantity of oligomers and styrene formed during the pyrolysis using the Gel Permeation Chromatography. From this investigation, we can show that the main mechanisms are on the dependance of the macromolecular lenght of the initial polymer.
6. Limitation des émissions de NOx : du pilote expérimental à l’incinérateur industriel de déchets urbains
Experimental studies about NOx emissions control have been conducted both in a pilot reactor and in two municipal solid waste incinerators. NOx emissions can be reduced by combustion parameters optimization. The pilot is able to realize a lot of experiments whose results are transposable to the industrial scale; It is therefore a precious tool.
7. Les dioxines-furanes : de la réflexion à l’action
Physical and chemical nature of dioxins-furans - Occurring concentrations and difficulty of their measurement. - Sinks, sources and contamination of ecosystems by these pollutants • Ways of estimation of maximum acceptable level for human exposure - Regulatory answers worked out by industrialised States • lnterest of a harmonised approach and liability-involving information of the consumer-citizen.
8. Modélisation du comportement à long terme de déchets industriels ultimes stabilisés confinés dans un stockage
The long term behaviour of ultimate industrial waste was modellid by considering a “source term” made of stabilized waste, and a “transfer compartment” consists of a clay layer acting as a passive barrier between the waste and the aquifer underlying the disposal site. The possible pollutant release from the stabilized waste is accounted for via the diffusion of non-sorbeb species, so as chloride ions. The transfert of these pollutants throught the clay barrier is the result of the complete set up transport mechanisms through porous media, i.e. convection, diffusion and dispersion. Ion-exchange phenomena inside the clay barrier are also taken into account by instantaneous reversible adsorption mechanism. The first results of this modelling work highlights the respective influences of the waste stabilization, the disposal lay-out, the geochemical interaction phenomena within the clay barrier, and the properties of the underlying aquifer. Furthermore, this first set of calculations about no-retarded species (chloride ions) show that it should be possible, in all cases, to select appropriate combinations for the “stabilized waste + active barriers +passive barriers” system so that safety criteria (such as drinking water quality standards for the aquifer underlying the disposal site) can be met at any time.
9. L’application de la représentativité à l’aide à la décision
The representativeness is usually a qualitative property of a sample to represent a whole in such a way that the value of a studied property is the same in both the whole and the sample. Only the global approach proposed by GY allows the representativeness to be a quantitative notion, equal to a coefficient of variation cv for a correct sampling. The representativeness depends on the three following operations: the sample preparation, the test and the measurement. If the operating conditions are not correctly checked, the representativeness is not significant and can't be used for further decision.
10. Application des tests de lixiviation (NF X31-210) à des roches granitiques
Leaching tests of natural materials (granites) were carried out according to the experimental procedure recommended by the AFNOR NF X31-210 French standard relative to the characterization of ultimate industrial stabilised waste. The rocks were selected for: (i) their representativity of the main granite types outcroping at the earth's surface, (ii) their higher content in some elements compared to average compositions considered as toxic, however corresponding to important volumes of material (granite), (iii) their degree of alteration (samples have been selected in the B and C horizons of a soil profile developed on a granite rock). The cations solubilized into the aqueous solutions after leaching test were analyzed by ICP-MS. Fifteen metallic elements were determined : Cr, Mn, Co, Ni, Cu, Zn, As, Au, Ag, Cd, Sb, Hg, Pb, Th and U. Results of the cation analyzes allowed: (i) to estimate the leachability of the main toxic elements in granite rocks, (ii) to determine the different parameters controlling the solubility of these elements, (iii) to compare these results with the standard imposed to the industry for ultimate stabilized wastes. The most easily leached elements were Mn, As and U in altered or fresh granites. The main parameters controlling the solubilization of a given element were: the texture of the rock (mainly the grain size), the nature of the mineral phase in which the element was incorporated and the degree of alteration of the material. The […]
11. Le tri à payer
The 13th july 1992 law and its application decree (l4th july 1994) require to sort out and “valorize” (“to valorize” i.e. to reuse or to recycle or to recover energy from) industrial packages. They represent the greatest part of industrial non hazardous wastes (assimilated to domestic wastes, DIB in text) and their producers are directly concerned by this recent evolution of the reglementation. The objective of this study was to assess for every material the real ope· rating cost during 12 months in a sorting centre. This was done without any consideration bound to the market of recovered raw materials and besides any possible governmental subsidies that, very often, conceal partly the economic reality.
12. Traitement de surface : un outil pour évaluer les alternatives de traitement des rejets
The electroplating and surface finishing industry produces heavy metal bearing waste waters that must be treated before disposal. The choice of an appropriate treatment technique depends on good knowledge of the available means and of the parameters that determine their aplicability. In this context we are developing a decision data system to help the choice of treatment technologies oriented towards waste revaluation.