Characterization of how contaminants arise in a dredged marine sediment and analysis of the effect of natural weathering.

Millions of tons of contaminated sediments are dredged each year from the main harbors in France. When removed from water, these sediments are very reactive, therefore their geochemical behavior must be understood in order to avoid dispersion of contaminated lixiviates in the surrounding soils. In this objective, it is necessary to evaluate the principal physicochemical parameters, and also achieve advanced mineralogical characterization.

Environmental evaluation of dredged sediment submitted to a solidification stabilization process using hydraulic binders.

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.

An innovative coupling between column leaching and oxygen consumption tests to assess behavior of contaminated marine dredged sediments.

Contaminated dredged sediments are often considered hazardous wastes, so they have to be adequately managed to avoid leaching of pollutants. The mobility of inorganic contaminants is a major concern. Metal sulfides (mainly framboïdal pyrite, copper, and zinc sulfides) have been investigated in this study as an important reactive metal-bearing phase sensitive to atmospheric oxygen action.