MULTISCALEXPER : traitabilité empirique des polluants et modélisation numérique multi échelles : avantages, inconvénients, redondances, manquements et solutions à chaque échelle et type d’approche
Résumé
To understand, evaluate and finely predict the spatiotemporal pollutants evolution in environments, under natural attenuation or remediation (by bio-or chemical treatment), it is necessary to resort to: i) geophysical, physical and chemical and biological measurements on site, ii) laboratory treatability experiments, and iii) numerical models. In practice, that results in the use of parameters and/or empirical models for modelling on the scale of an actual site. This use permits to reproduce the controlled tests in laboratory or on site, which are used then as validation tests. However, their use for predictive calculations is problematic for the tests, where it is impossible to sweep the whole of conditions and couplings met in the system of interest. Within the framework of a predictive model, the improvement or invalidation of the empirical parameters/models must thus be done based oncomprehension of the subjacent mechanisms and their mutual interactions. With this purpose, it is necessary to have recourse to mechanistic and multi-scale approaches, with uncertainties estimate, which makes it possible to choose, in a reasoned way, the dominating mechanisms and their simplified exemplification.MULTISCALEXPER project has as a principal objective to develop activities of multi-scale experimentation, utilizing numerical modelling on all the levels (from dimensioning to the interpretation of the results). These activities will be carried out using numerical tools and multi-scale pilots. More particularly, it is a question of defining a dimensioning methodology for multi-scale experiments, based on numerical approaches. This project aims at reinforcing the depollution techniques on: i) the small scales in order to be able to interact with academic laboratories, working at increasingly smaller scale, and especially ii) the great scales in order to be able to interact with depollution firms, directed in the opposite way of increasingly large scale as fast as possible.The first deliverable of the project was the critical analysis of about 15 BRGM collaborative projects, carried out in the depollution domain both of organic and inorganic pollutants. The projects were evaluated on the basis of a grid of techno-economic criteria and compared to the scale imitated, according to two approaches: 1) multi-scale experimentation (from a molecular scale to that of an actual site), in batch, column, plurimetric pilot, in situdemonstration, partial or total depollution of a site and 2) multi-scale numerical modelling.The advantages, disadvantages, redundancies and failures concerning each approach and scale were highlighted. It results very rich issues fromit, showing that only scientific and technical knowledge were not enough to solve complex problems. In a way much more pragmatic, it is shown that it is necessary to innovate in approaches and scales. In particular, in porous media, the feasibility of an integrated approach on a precise depollution subject depends on the pollutant behaviour characterization and treatability on a large scale. The work, in different media and contexts, will have to be organized to cover all the stages allowing pollutants treatability by controlled, reasoned and pragmatic implementation of the methods and scales.
Origine : Fichiers produits par l'(les) auteur(s)
Loading...