| Environnement, ingénierie & développement |  |
N°79 - N° Spécial, Congrès Sites Sols Pollués, mars 2019
1. Effet d’un traitement électrocinétique sur la structure d’une kaolinite mélangée au carbonate
The aim of this work is to study the structure evolution of kaolinite + carbonate mixture after an electrokinetic treatment. The aim is to understand how an electrokinetic treatment can change the mechanical properties of the samples. The X-rays diffraction analysis show that the orientation of the particles and their size depend on the composition of the samples and to the presence of lead. The mercury intrusion tests show that the porosity vary slightly after the electrokinetic treatment.
2. Aspects juridiques du recyclage foncier des sols pollués
Recycling polluted sites and soils following their rehabilitation is an option that saves soil and eliminates health and safety risks. However, it requires to clearly identifying who can be considered responsible for the clean-up necessary for this recycling (the author of the pollution, the land owner, the local community, a third party), defining the level of the clean-up for future use or a restoration to an "initial" state and including these functional into urban planning.
3. La reconversion des friches polluées au service du renouvellement urbain : enseignements technico-économiques
In a context of control of urban sprawl and tensions on land use, brownfield redevelopment is a challenge for the sustainable development of territories. They are indeed land opportunities to develop ambitious territorial projects that are part of a strategy of circular economy.To support public and private actors in the management of their planning development project on degraded land, ADEME provides technical and financial support to all project leaders, especially local authorities, aiming at brownfield redevelopment projects that require decision-making studies and polluted soil remediation.In this framework, more than 110 brownfield redevelopment projects were laureates in the 2010-2016 period.Beyond these macro figures, it is essential to analyze the projects, with a view to developing a technical and economic overview of brownfield redevelopment, whether in terms of pollution management or sustainable urban development, to identify best practices, provide expertise to stakeholders and improve ADEME practices.This paper presents the outcomes of two studies conducted in this perspective.The outcomes will be made available online: https://www.ademe.fr/reconversion-friches-polluees-service-renouvellement-urbain-enseignements-technico-economiques.
4. Effet de la vitesse d’écoulement sur la dynamique de transport des microparticules dans des lits de sable et de gravier
In this study, columns experiments are performed to investigate the effects of the flow velocity on the dynamics of particle transport at the micrometric scale (11µm in diameter) through porous media with various particle sizes under saturated conditions. A comparative study is conducted to characterize the influence of grain shape of the porous media on the critical velocity. Various flows are applied by considering porous bed with fine and coarse size grading at the aim to highlight the effect of the ratio of particle size to that of the grains. The experimental results show a decrease of the retention rate of particle with the increase of the velocity for both materials: sand and gravel. The dynamics of deposit differs with a progressive saturation of the retention sites in the case of the fine media, which increases with the increase of the flow velocity and results from it a decrease of the deposit kinetics. In opposite, the saturation of the retention sites is less fast with a constant retention rate because of the heterogeneity of the grains size despite a similar porosity.
5. Éditorial n°79 Déchets Sciences et Techniques
Comme nous l’avons déjà fait à plusieurs reprises, dernièrement avec le numéro 72 consacré au Colloque E3D 2016 (Eau, Déchets & Développement Durable, 7-11 mars 2016, Lomé, Togo), la revue DST ouvre à nouveau ses pages dans ce numéro spécial 79 à la publication d’une sélection d’articles présentés lors d’un congrès. Ce numéro de DST regroupe ainsi sept articles qui ont fait l’objet de communications orales aux deuxièmes Rencontres Scientifiques sur la Réhabilitation et la Valorisation des Sites et des Sols pollués (RV2S-2018) qui se sont tenues à l’École Nationale d’Ingénieurs de Saint-Etienne (ENISE) les 29 au 30 octobre 2018. Par cette démarche déjà pratiquée par de nombreux congrès et revues, nous souhaitons plus particulièrement accompagner des initiatives essentiellement francophones sur des thèmes voisins de ceux de la revue.
6. Suivi multiparamétrique de la première désorption thermique de PCB
Thermal desorption was pointed out, by several test phase, to be the only way to discard a PCBs contamination in 5000 t of soils. Many parameters were optimized to allow the whole mass of soil to be heated over 250°C, collecting in the same time all the nocuous vapors to ensure environmental safety of the works. Correct handling of all the parameters allowed driving a decay of more than 97 % in the whole mass of soil.
7. Approche géostatistique appliquée à l’évaluation d’un état de pollution des sols dans le cadre d’une session de site industriel
This study focuses on the estimation of masses of contaminants in place inside a production site and the quantification of the spatial uncertainty related to the location of these masses. The aim is to provide an assessment of the current soil contamination (current status) before the transfer of the site to another industrial company. The proposed methodological approach relies on geostatistical modeling of the soil contamination by using a simulation method that generates a large number of realistic and equiprobable 3D images of grades for soil contaminants of interest. The images are realistic because they reproduce the grade data and their observed spatial variability. They are equiprobable in that they all have the same probability to represent the actual soil contamination. To assess the soil contamination before the site transfer, the masses of contaminants in place and the associated uncertainty can be estimated from the simulations, for the whole site or by zone. Using the simulations, it can be identified the locations where potential soil contamination sources are likely to be or not found with high enough confidence, and those where the soil contamination is uncertain. The sources of contamination are defined as corresponding to the areas where the vertical accumulation of contaminant mass exceeds some critical threshold above the saturated zone.
8. Comment une pollution par le plomb influence-t-elle les propriétés d’une argile ?
In presence of water, the permeability of a carbonated clay is equal to 7.1 10-11 ms-1. In presence of lead at concentrations equal to 0.01 and 1 M, it becomes equal to 2.4 10-11 and 8.8 10-11 ms-1. Mercury Intrusion porosimetry shows that in the presence of lead, a reorganization of the pores distribution occurs. Chemical analysis show that, for the concentration 0.01 M, lead precipitates with carbonate whereas, for the concentration 1 M, the acidic pH of the samples leads to the carbonate dissolution.