Julien Couvidat1, Mostafa Benzaazoua1,2, Vincent Chatain3, Hassan Bouzahzah2. 1. Université de Lyon - INSA Lyon, Laboratoire DEEP - EA 7429 (Déchets Eaux Environnement Pollutions - Wastes Water Environment Pollutions), Bâtiment Sadi Carnot - 20 avenue Albert Einstein, 69621, Villeurbanne Cedex, France. 2. UQAT-Polytechnique, IRME (Institut de Recherche en Mines et Environnement (IRME), 445 Boul. de l'Université, Rouyn-Noranda, J9X 5E4, QC, Canada. 3. Université de Lyon - INSA Lyon, Laboratoire DEEP - EA 7429 (Déchets Eaux Environnement Pollutions - Wastes Water Environment Pollutions), Bâtiment Sadi Carnot - 20 avenue Albert Einstein, 69621, Villeurbanne Cedex, France. Vincent.Chatain@insa-lyon.fr.
Abstract
PURPOSE: Dredging of sediments, a requirement for harbor maintenance, removes millions of tons of mineral wastes, contaminated at varying degrees with trace metals, from the water. In previous investigations, Cu and Zn have been identified as highly concentrated trace metals associated to sulfides, mineral phases sensitive to oxidation. In order to ensure their sustainable management, the solidification/stabilization (S/S) and/or the valorization of contaminated sediments as secondary raw materials is a way to be promoted. Indeed, their reuse as a substitute of sand in cemented mortar formulation would allow combining both treatment and valorization of such wastes. METHODS: In the present study, the environmental assessment of mortars formulated with raw and weathered marine sediments (in particular contaminated with Cu, Pb and Zn), compared to sand reference mortars, was conducted through two kinetic leaching tests: weathering cell tests (WCTs), in which mortars were crushed and leached twice a week, and a tank monolith leaching test (MLT), in which leaching was performed on monolithic mortars with increasing leachate renewal time. RESULTS: In both leaching tests, calcium and sulfur were released continuously from sediment mortars, showing the oxidation-neutralization processes of sulfides and carbonates. In the MLT, Cu was released by sediment mortars through diffusion, particularly by weathered mortars, at low concentrations during 60 days of the test duration. With the more aggressive WCT, Cu concentrations were higher at the beginning but became negligible after 7 days of testing. Pb was released through diffusion mechanisms until depletion in both tests, whereas Zn was particularly well immobilized in the cemented matrices. CONCLUSIONS: The S/S process applied using hydraulic binders proved to be efficient in the stabilization of Cu, Pb, and Zn highly presents in studied sediments, and further valorization in civilian engineering applications could be considered.
PURPOSE: Dredging of sediments, a requirement for harbor maintenance, removes millions of tons of mineral wastes, contaminated at varying degrees with trace metals, from the water. In previous investigations, Cu and Zn have been identified as highly concentrated trace metals associated to sulfides, mineral phases sensitive to oxidation. In order to ensure their sustainable management, the solidification/stabilization (S/S) and/or the valorization of contaminated sediments as secondary raw materials is a way to be promoted. Indeed, their reuse as a substitute of sand in cemented mortar formulation would allow combining both treatment and valorization of such wastes. METHODS: In the present study, the environmental assessment of mortars formulated with raw and weathered marine sediments (in particular contaminated with Cu, Pb and Zn), compared to sand reference mortars, was conducted through two kinetic leaching tests: weathering cell tests (WCTs), in which mortars were crushed and leached twice a week, and a tank monolith leaching test (MLT), in which leaching was performed on monolithic mortars with increasing leachate renewal time. RESULTS: In both leaching tests, calcium and sulfur were released continuously from sediment mortars, showing the oxidation-neutralization processes of sulfides and carbonates. In the MLT, Cu was released by sediment mortars through diffusion, particularly by weathered mortars, at low concentrations during 60 days of the test duration. With the more aggressive WCT, Cu concentrations were higher at the beginning but became negligible after 7 days of testing. Pb was released through diffusion mechanisms until depletion in both tests, whereas Zn was particularly well immobilized in the cemented matrices. CONCLUSIONS: The S/S process applied using hydraulic binders proved to be efficient in the stabilization of Cu, Pb, and Zn highly presents in studied sediments, and further valorization in civilian engineering applications could be considered.
Authors: Julie Lions; Valérie Guérin; Philippe Bataillard; Jan van der Lee; Agnès Laboudigue Journal: Environ Pollut Date: 2010-07-07 Impact factor: 8.071
Authors: Julien Couvidat; Mostafa Benzaazoua; Vincent Chatain; Fan Zhang; Hassan Bouzahzah Journal: Environ Sci Pollut Res Int Date: 2015-03-18 Impact factor: 4.223