Leaching behaviour of sintered contaminated marine sediments

Abstract

Contaminated marine sediments from Cantabrian estuaries have been compacted and fired to produce sintered ceramic materials. The effect of sintering on the leaching behaviour has been investigated by means of the comparison of concentrations of species proposed by the European Waste Landfill Directive present in leachates and regulatory limits for them. The impact of the specimens on the environment is assessed. In order to reach this objective, unfired and fired samples of marine sediments and clay were subjected to the Compliance Leaching Standard Tests EN 12457 1-2 using different liquid to solid ratios (L/S = 2 and 10). The concentrations of Se, As, Cr, Sb, Zn, Cd, Pb, Ni, Ba, Mo, Cu, fluoride, chloride and sulphate in leachates were analyzed, and the results compared with regulatory limits collected in 2003/33/CE Directive. The results revealed that the firing process decreases the leaching of the species analyzed, except for As. The comparison of the metal and metalloid concentrations in leachates and regulatory limits showed that all species fulfilled them, excepting As, fluoride, chloride and sulphate in unfired specimens. Thus, the potential environmental risk in relation to the leaching behaviour associated to the sintered contaminated marine sediments can be considered to be low versus to commercial clay.