| Environnement, ingénierie & développement |  |
N°62 - Novembre 2012
1. La détermination des unités fonctionnelles d’un territoire, première étape pour appliquer l’analyse de cycle de vie à l’échelle territoriale
The implementation of the life cycle analysis methodology (LCA) applied at a regional scale is a challenge.A territory is by nature complex and multifunctional. Identify territorial functions, the first step for applying LCA at the territorial level, participates in the process of collective definition of territorial complexity, and thereby draws the outlines of a coherent collective action with real and perceived territorial issues. LCA should be used to identify environmental hotspots and to compare different scenarios of land planning.Thus, this article proposes several possible methodologies for the definition of territorial functional units. These solutions can be classified into two main bottom-up or top-down approaches.These solutions will be analyzed through different criteria (facility of identification and implementation, customer, consideration of the different subsystems,...).
2. Evaluation des risques écologiques liés à la restauration de cavités terrestres de la bande littorale à l’aide de sédiments de dragage portuaires traités : application de l’approche « substances » à trois sédiments tests
The discharging at sea of dredging seaport sediments is no longer possible in France because of recent changes in regulations. However, these materials are now without treatment solution on shore. In addition, the terrestrial cavities generated by human activities along the coastal strip are increasingly disliked by the people, due to the deterioration of the landscape and the loss of usable space they generate. The SEDIGEST Program concerns the implementation of an innovative management of dredged sediment, by using them, after treatment, for a physical and ecological restoration of terrestrial cavities of the same territory. This concept has required to develop a methodology for an ecological risk assessment (EDRE) specific, based on an « upstream » research. This methodology allows to check, for a given project, if it is truly compatible with the environment. The application of « substances » version of this method on three sediments from the French coast seaports concluded to an low ecological risk for aquatic ecosystems with the sediments « 1 » and « 2 » and to a significant risk with sediment « 3 ».
3. Conception des réseaux par biomimétisme : application au transport des déchets
Applied to waste fluxes in a Montreal industrial park, this approach is inspired by natural structures: its objective is to identify the network of matter exchanges between the different sources distributed on the territory. Based on the properties of the Physarum Polycephalum mold, the network configuration obtained through laboratory tests is compared to the ones recovered by three mathematical algorithms: one by simulating the organism growth and two by classical models of distance minimisation. The results demonstrate that the exchange network based on natural laws (biomimicry) has characteristics such as mesh creation and spur diversification. These characteristics imply among other things a number of stretches and a network length (likened to investment cost) almost twice as large as classical structures. They also offer a stronger resilience to breaks of exchanges: indeed, more than 50 % of the exchanges are maintained during a series of breaks, compared to less than 20 % for classical configurations. This ability to classify the supply chain between the key players favours the sustainable development of an industrial structure in a territory.
4. Développement durable de la gestion des ordures ménagères et financements carbone : les conditions d’une mise en œuvre conjointe dans les pays en développement
The urban waste management is an issue with both local and global implications. In developing countries, municipalities must manage large quantities of waste in exponential growth, with limited financial means.Under which conditions carbon finance, regulatory or voluntary, can complete local funding to ensure adequate management of urban waste in developing countries?This is to try to answer this question that Gevalor GoodPlanet joined in the Africompost project. It aims to study the conditions of transfer of know-how acquired in a composting operation in the city of Mahajanga in Madagascar (MORIZOT and al., 2011) in six other African cities, including Beira in Mozambique, Lome in Togo, and Dschang in Cameroon.The first result of the Africompost project was to develop for the studied sites, in consultation with the local teams, a method for rapid assessment of the feasibility of access to carbon finance.This paper presents this method, detailing the various points of the diagnosis to be made on factors that are potentially favorable or unfavorable to the development of a composting unit with access to carbon finance.
5. Caractérisation et traitement thermochimique des coques d’anacarde en vue de leur valorisation énergétique dans les procédés de transformation artisanale de noix de cajou
The use of wood and natural gas to cover the energy needs in transformation process of cashew nuts has a negative impact on the environment protection. Ligneous shells stemming from nuts shelling are soaked with CNSL and require an intermediate treatment before their energy valuation.The small scale transformation units of Burkina Faso face this problem of deficit of technical solutions efficiently applicable in their context. The objective of this study thus aims at characterizing cashew shells and at proposing possible ways of valuation. After an initial characterization of shells, thermochemical comparative study was realized in conditions of torrefaction (250°C) and of pyrolysis (450°C). The results of the realized tests show that the thermochemical treatment allows to obtain three types of products: solid (char), liquid (oil or condensable fraction of gases) and gaseous (incondensable gas), in proportions and quality relatively different proportions and quality according to the operating temperature. In 250°C (resp. 450°C), we produce 48.5 % (resp. 17.0 %) of char with 25.6 MJ/kg (resp. 27.2 MJ/kg) of LHV and 13.8 % (resp. %) of oil. The LHV (lower heating value) of produced oil are almost similar and are situated over 36 MJ/kg, so bordering those of petroleum products.Under reserve of the analysis of smokes emitted during the combustion of these products, the thermochemical treatment in anoxic conditions thus seems to be an interesting option to recover cashew nut […]
6. Conception, installation et fonctionnement d’une installation décentralisée de tri-compostage de résidus solides urbains dans les quartiers de Lomé
Des travaux antérieurs dans le cadre d’une recherche-action, ont permis de montrer que les Résidus Solides Urbains (RSU) générés dans les quartiers périphériques de Lomé, présentaient une forte proportion de fermentescibles, 60-70 %, (putrescibles, papiers-cartons, fines <20mm). Le choix du compostage s’avérait très intéressant pour produire un amendement indispensable pour les sols agricoles utilisés dans le cadre de l’agriculture péri-urbaine.Le procédé de compostage par retournement d’andains constitués par les RSU après le tri des recyclables a été optimisé en termes de tri, fréquence de retournement, apport d’eau et criblage final (<10mm et <30mm).L’installation de la plate-forme pour un taux de traitement de 5T/J a été rendue possible, après le transfert de la technologie optimisée auprès d’une ONG, ENPRO, chargée de la pré-collecte des ordures au niveau des ménages dans un des quartiers. La filière de valorisation agronomique a également été validée auprès de plusieurs groupes d’utilisateurs potentiels après des essais du compost produit sur parcelles agricoles et pour plusieurs cultures. Le financement de la construction de cette plate-forme à 5T/J produisant environ 20-30 % de recyclables et 30-40 % de compost <10mm, a été assurée par le FFEM (Fonds Français pour l’Environnement Mondial) sous couvert de l’AFD (Agence Française de Développement, Lomé). Elle est installée à coté d’un des […]
7. Savoirs traditionnels et gestion de l’environnement en Haïti : pour une approche intégrée
Sustainability is generally defined through economic, social and ecological aspects. But its implementation also requires to take other aspects into account such as culture and tradition. This is especially important in developing countries where the relationship between culture and natural resource management is very narrow.In this paper, we show the need to integrate and reconcile cultural and traditional practices in environmental management. They may encourage practices that promote sustainable development. In order to reach our goal, we will base ourselves from the example of developing countries, Haiti in particular.