| Environnement, ingénierie & développement |  |
N°33 - 1er Trimestre 2004
1. Éditorial n°33 Déchets Sciences et Techniques: Le Japon : la pureté à tout prix ?
Le Japon est certainement le pays qui a dû faire face aux problèmes environnementaux les plus cruciaux, avec un développement industriel et urbain explosif pendant la deuxième moitié du siècle précédent. Il peut être extrêmement intéressant de comparer un certain nombre de situations et de problématiques en France et au Japon. Le cas de la gestion des résidus solides de l’incinération des ordures ménagères est à cet égard significatif.Ce pays a développé plus que la France l’incinération des déchets ménagers : 80 % des 50 MT/an d’OM subissent un traitement thermique, ce qui génère environ 1,2 MT/an de résidus de traitement des fumées et 6 MT/an de scories, qui ne sont jamais considérées comme des mâchefers valorisables . Près de 80 % de ces résidus solides sont finalement vitrifiés, soit dans l’unité de traitement des déchets elle-même par des procédés de pyrolyse/fusion, soit dans des unités annexes de fusion/vitrification des résidus de l’incinération. Près de la moitié des scories ainsi obtenues sont utilisées comme matières premières secondaires en travaux publics, les autres sont éliminées dans des décharges du type « classe III ».
2. La résistivité électrique comme outil pour la reconnaissance d'une friche industrielle
The industrial waste land in Montagne-du-Nord (France) has been occupied by a zinc and a lead smelter unit linked to sulphuric acid production. Then this factory has been razed and covered by coarse waste deposits below sandy fillings. Hydrological and geochemical studies have been systematically carried out by drillings and pits following a mesh of 50m x 50m. This waste land constitutes an area where the metallic contamination is important. The physical property of subsoil materials, sensitive to this contamination, is the electrical resistivity; it depends on water mineralization and quantity presented in all formations. Geophysical data allow to locate precisely mineralized soil and water with higher spatial resolution. A complete geophysical study, using methods based on electrical resistivity (slingram electromagnetic mapping, 2D and 3D electrical imaging, and electrostatic logging) has been carried out. The slingram mapping allows to determine conductive anomalies coincident with chemical anomalies obtained into the piezometers, and to locate the water seepage toward the river drain. The electrical imaging allows to indicate precisely the location of clayey alluvial deposits, and to describe the superficial seepage areas. The electrostatic logging gives an accurate description of the not saturated area in boreholes, near anomalies located with the two other methods. Those geophysical methodologies allow to obtain a 3D view of the site.
3. Intérêt des champignons telluriques dans des processus de bioremédiation de sols pollués par des hydrocarbures aromatiques polycycliques
Polycyclic aromatic hydrocarbons (PAH) are ubiquitous and persistent pollutants that cause great environmental and health concern, because of their genotoxic and carcinogenic properties. Among the processes whereby these compounds are removed from the environment, microbial degradation plays a major role in the remediation of contaminated sites. Numerous biodegradation studies have been done on fungi, especially on various white rot fungi such as Phanerochaete chrysosporium, under in vitro and in vivo conditions. The installation of these foreign fungi in non-sterile soils is quite hazardous due to intense negative interactions with indigenous soil microorganisms. Optimising the degradation of PAH by the indigenous microbial community that had already been adapted to the soil habitat would be probably more economical and equally efficient. In our studies, we focused therefore on the ability of telluric fungi for PAH field bioremediation processes. In particular, we isolated a Deuteromycete fungus Fusarium solani that was able to grow in liquid medium with benzo[a]pyrene as sole carbon source and to mineralise this PAH. In a batch fermentor, [7,10-14C]benz[a]pyrene mineralization occurred rapidly at early stages of fermentation (15 hr) during the germination of fungal spores and was not a continuous process as mineralization occurred in a biphasic pattern. Moreover, Fusarium solani showed an average rate of mineralization about 65 μg/g dry weight/day within 11 days of […]
4. Développement des solutions d'écologie industrielle et réglementation: Freins et leviers
Closing the loops of energy, water and materials, one of the main goals of industrial ecology, is subject to a complex regulation system. This paper aims at describing some parts of it in the French context and the following constraints and risks for two companies which are trying to exchange water, mass or energy flows. From the study of the environmental law mechanisms, their implementation, and interviews of managers, this work underlines some impacts of regulation on the interest of the synergies. The main problems are especially dedicated to situations where the flows are affected by the “waste “status. The economic efficiency of the exchanges could be altered, the duration of administrative process could be too long for the companies, they could be identified as “Waste treatment site” by the local residents…So, the regulation system could slow down the development of synergies, but some ways to face these problems are identified.This paper is based on a study performed between May and October 2002, from bibliographic investigatives, interviews of managers and stakeholders of environment protection.
5. Évaluation d'effets environnementaux par la méthode des prix hédoniques, appliquée à l'immobilier: Intérêt et limites
Among methods and tools of environmental valuation, hedonic prices have been applied notably to land and property values. The paper is quoting the principles and some applications, methodological and practical difficulties, duty of care concerning interpretation of the results, and – with these reserves – their interest. The tool may be used as analytic with the concern to separate an environmental factor or as an aggregator (synthetizer) of various effects which are associated to a plant; but which factors, with negative or positive effects, are reflected by the change of the value is? Moreover some chain effects have to be considered. At the end, the question of possible compensation of value losses is approached.
6. Évaluation du potentiel écotoxique de percolats de mâchefers d'incinération d'ordures ménagères au laboratoire: Comparaison de bioessais monospécifiques et d'un essai en microcosme
Two methodologies have been used to assess the impact of municipal solid waste incineration (MSWI) bottom ashes on lentic ecosystems, especially lake coastlines. One of the purposes is to assess their ecocompatibility in a scenario in which MSWI bottom ashes are reused as road embankment. A laboratory lysimeter was chosen to simulate a part of a road embankment built with MSWI bottom ashes. Leachates have been collected at three different massratios (water mass / bottom ash mass): from 0.5 to 1.5. The first methodology was based on three bioassays. Results led to the following ranking of these bioassays based on organisms sensitivity, in descending order: algae P. subcapitata > duckweed Lemna minor > cladoceran Daphnia magna. In the same time, leachates were assessed with a 2 L freshwater/sediment microcosm. As the mass-ratios rose, leachate toxicity decreased. All species were impaired. Toxicity effects raised with leachate concentration, from 1.56% to 8.0%. Comparison between bioassays and microcosm assays revealed the interest for multispecies approach. Ecosystem dynamics were approached with microcosms. The representativeness is higher in those systems. MSWI bottom ashes have been assessed in a simplified risk assessment procedure, for our scenario. Predicted environmental concentration is close to the concentration that caused first effects in microcosm. Recommandations have been made for MSWI bottom ashes used as road embankment.
7. Optimisation des prélèvements par accumulation et dosage par couplage GC/MS des COV présents dans les stockages d'ordures ménagères: Première approche de comparaison de méthodes analytiques
The present article is devoted to an approach of optimization of required conditions to traces VOCs analysis coming from household wastes stocked in specially designed pilots for studying maturation. A known volume of the gas phase goes through tubes filled with various adsorbents like Tenax, Chromosorb, Tenax-graphitized carbon and active charcoal. To extract VOCs, thermal desorption has been used for the first three adsorbents while CS2 extraction has been applied on active charcoal tubes. About 200 VOCs were surely identified and performances of the two sample preparation processes were compared: accumulation followed by thermal desorption or followed by solvent extraction. Both analysis techniques are compared in order to set all the precautions for a reliable quantitative analysis.