Quantification des impacts relies a l'utilisation de la ressource eau en analyse du cycle de vie: Definition d'un cadre d'etude et developpement de facteurs de caracterisation.

摘要

This project has two main objectives. (1) To define a general framework for the consideration of the freshwater resource within LCA. (2) The second objective involves proposing elements for impact quantification.;The research hypothesis of this project is the following: impact intensity is dependent on the type of use, geographical context, quality and type of resource used. The first component of this project consists in the definition of a general framework. In order to distinguish different types of resource use within the inventory phase, it is necessary to define some water types, and to quantify and qualify the water entering and leaving the product system.;Following this step, three elements of environmental concern are distinguished: it is essential to have a sufficient resource supply for human needs; the resource should be sufficient for ecosystems; and it is essential to maintain a sustainable resource for future generations. An imbalance in one of these elements generates environmental burdens. They are expressed within the cause/effect chain.;An insufficient resource for human needs affects the new impact category named: "freshwater deprivation for human uses", and ultimately human life. However, if the area studied has sufficient economic wealth, it will adapt to the lack of resource through compensation processes (e.g. desalination, import). Impacts of these processes are assessed through a traditional LCA scheme.;An insufficient resource for ecosystems affects the new impact category named "freshwater deprivation for ecosystems", and ultimately, the biotic environment. An abusive use of the resource could lead to depletion. The new impact category named "freshwater depletion" expresses this phenomenon. It ultimately affects the abiotic environment.;The second component of this project aims to model various parts of the cause/effect chain. An applicable method for the inventory phase is proposed.;A scheme for the development of characterization factors for the impact category "freshwater deprivation for human uses" is presented. This characterization factor is calculated as a function of three parameters: the availability, the quality and the usage. The latter includes the ability of downstream users to adapt to the water shortage, and the potential uses of the considered water type. The result is expressed in "m3 - potable water equivalent - unavailable for human uses". The method is regionalized and characterization factors are calculated for some countries. Countries showing high characterization factors are those where freshwater issues are prevalent.;If economic resources are sufficient, the lack of potable water will be compensated trough processes allowing the use of alternative resources, such as nano-filtration or reverse osmosis. These compensation processes are modeled and additional impacts are estimated for several countries. High impacts are measured in countries where freshwater availability issues prevail. For example, high values are obtained for Jordan, Syria and Turkmenistan (3,879; 3,137; 4,207 m3 - potable water equivalent - unavailable for human uses/m3 of low quality surface water respectively). These countries correspond to areas under freshwater stress (Nil, Tigre and Euphrate and Aral Sea watersheds).;This project sets the basis for the elaboration of an LCA methodology to assess freshwater use. A general framework is defined. It is established that impacts vary among types of use, geographical context, quality and type of resource used. Although many elements for modeling remain to be developed, the presented work demonstrates the applicability of the proposed framework.