| Environnement, ingénierie & développement |  |
N°43 - Juillet-Août-Septembre 2006
1. Éditorial n°43 Déchets Sciences et Techniques: RECORD (Réseau coopératif de recherche sur les déchets). La recherche en action
Depuis plus de quinze ans, l’association RECORD permet la réalisation d’études et de recherches dans le cadre original d’une coopération tripartite entre industries, organismes publics et chercheurs. L’ADEME est fortement impliquée dans cette démarche depuis la création de RECORD.Les sujets d’étude et de recherche abordés s’articulent autour d’une problématique centrale qui est celle de la gestion des déchets. Les thèmes étudiés sont organisés autour de trois axes principaux :— Connaissance et caractérisation des déchets et des pollutions,— Traitement et valorisation des déchets et des sols pollués,— Evaluation des impacts sur la santé et sur le milieu naturel.Un quatrième axe est en développement, intitulé « Développement et intégration des connaissances issues des sciences sociales ». Cette nouvelle thématique correspond à un enjeu important, une prise de conscience renforcée et un défi. Car il faut faire se rencontrer des « tribus » différentes, faire en sorte qu’elles se comprennent et par viennent à des méthodes de travail communes.Outre les programmes réalisés, cette coopération a fait de RECORD un lieu privilégié d’échanges ainsi qu’un outil de veille technologique et scientifique.
2. Valorisation de poudrettes de pneus par incorporation dans du PE recyclé: Influence de la morphologie et des traitements de surface des poudrettes sur le comportement mécanique du matériau
In this study, polymer compounds consisting in a recycled polyolefin matrix (high or low density polyethylene (HDPE or LDPE)) and ground tyre rubber (GTR) powder are developed. The major problem in this two phase systems is the very poor interfacial adhesion between thermoplastic matrix and rubber filler, which impairs the mechanical properties of the compound. Two treatments have been tested to improve the adhesion and so the mechanical performances: GTR powder was oxidized either by reaction with potassium permanganate aqueous solution (0-20%wt of KMnO_4) or by irradiation (gamma-irradiation: 0-100 kGy). Oxidized GTR powders were then introduced into a HDPE matrix containing Maleic Anhydride grafted HDPE as a compatibilizing agent. While no significant improvement of mechanical properties was observed for the irradiated GTR powder, the KMnO_4 treatment lead to improved Young’s modulus and yield stress, but the adhesion mechanism involved was not clearly identified.
3. Lixiviation multi-échelles de cendres d'incinération d'ordures ménagères
Predicting the impact on the subsurface and groundwater, of a pollutant source such as domestic waste incineration residues, requires a knowledge of the so-called “source term”. The source term describes the manner in which concentrations in dissolved elements emitted by the waste evolve over time, for a given percolation scenario. If the source term is known, it can be fed to a model that simulates the fate and transport of dissolved constituents in the subsurface and the groundwater, in order to calculate a potential impact. The standardized laboratory upward-flow percolation test is generally considered as the relevant test for defining the source term for granular materials. The LIMULE project (Multiple-Scale Leaching) examined to what extent this test, performed in very specific conditions, could help predict the behaviour of the waste at other scales and for other percolation conditions. Three distinct scales of dynamic percolation were tested: the scale of the laboratory upward-flow percolation column, that of lysimeter cells and that of a large instrumented column of five meters height. The comparison between the concentration data collected from the different experiments suggests that for the case of soluble salts (Cl, Na, K, ...), the liquid versus solid ratio (L/S) allows an extrapolation from one scale to the other: if concentration data are plotted versus this ratio, the curves coincide reasonably well. On the other hand, in the case of reactive elements and […]
4. Evaluation du transfert des composés organiques des MIOM utilisés en sous-couche routière dans des ouvrages de construction récente
The management of the Municipal Solid Waste Incineration Bottom Ashes (MSWI-BA) and their reuse in the road construction are controlled by the regulation of 1994, 9th May. The organic components as PolyChloroDibenzo-para-Dioxines (PCDD) and PolyChloroDibenzoFurannes (PCDF) are not taken into account by the regulation. In this study, two scenarios of MIOM recycling are investigated: the embankment and the subgrade layer. Investigations were conducted to determine the PCDD/PCDF content and profiles of different congeners in the MSWI-BA used in the road construction. The eventual release of these components in the underlying soil was also estimated to evaluate the impact on the environment. The auscultation were realized in two sites containing MSWI-BA produced in 2002 and 2003. The MSWI-BA from the recent incinerator has revealed a weak PCDD/PCDF content varying from of 6,6 to 20 ng I-TEQ/kg MS. The PCDD/PCDF content in the underlying soil are in the same order of magnitude than the content of the reference soils sampling out of the MSWI-BA influence and the soils sampled in the urban zone, indicating no transfer of PCDD/PCDF from MSWI-BA to surrounding soil.
5. Rejets d’abattoir : caractérisation et étude d’impact sur le milieu marin récepteur
The annual rated capacity of the El Jadida’s slaughterhouse (Morocco) is 1 300 tons of carcasses producing approximately 590 tons of wastes/year. Considering its proximity with the sea, the effluent of this slaughterhouse is rejected there directly without any treatment. This work relates to the characterization of the total effluent gross generated by this slaughterhouse and the study of its impact on the quality of the receiving marine environment. The results of the characterization show that the studied effluent is rich in organic matter (COD: 170 g O2 per l) and in indicating fecal bacteria (FC: 7.108 cfu per ml and FS: 5.107 cfu per ml). The impact study shows that the vicinity of the collector of the slaughterhouse has an evolution towards a eutrophic state which results in an abundant development of algae (Enteromorpha intestinalis and Ulva lactuca) and a higher bacterial contamination of sea water, sediments and shells.
6. Précollecte des déchets ménagers dans les pays en développement : comment évaluer les actions menées ?
Management of solid waste in the cities of developing countries is one of the main challenges of the present decade. The primary collection, often necessary, intended to evacuate the waste away from the habitations of difficult accessibility for the traditional collection services, is the first stage. Operations are carried out, often supported by international programs, in order to implement special systems of primary collection adapted to the local conditions. But these operations seem to little take into account the lessons of the past. In addition, the real results are often difficult to approach, owing to the lack of communication on the details of the social, technical and financial organization. Our work has consisted in identifying primary collection operations, analyzing them on the basis of the available data, showing elements of success and failure and proposing an analysis framework indicating the data to collect in order to complete the analysis and make them useful for the future.