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  • An innovative method for remediation of contaminated soil by utilizing recycled materials
    Oprčkal, Primož ...
    In many cases past industrial activities have left behind degraded areas, where different contaminants are present in high concentrations in the soil. For this reason such soils, containing hazardous ... substances and various species of trace elements in both mobile and bioavailable form, are often classified as hazardous waste. Such degraded areas represent "old burdens" which need to be rehabilitated in the most practical, economical, and environmentally acceptable way. One such old burden in Slovenia involves the area of the Old Zinc-Works near the town centre of Celje. There an area of 17 ha is covered by more than 1.5 M m3 of contaminated soil, which has been classified as hazardous waste according to the Slovenian legislation since it contains large quantities of water soluble species of different trace elements(As, Zn, Pb, Cd, Cu, Mo), as well as SO4 2- . An innovative remediation and rehabilitation method has been developed for the treatment of this heavily contaminated soil material in situ, and has been validated in thereal case treatment of the most contaminated soil from the above-mentioned old zinc-works area. An immobilization approach is used, where the bioavailable and mobile species of the trace elements are chemically and physically incorporated into a newly formed composite, which is a mixture of crushed and homogenised contaminated soil to which ash from paper sludge incineration, as well as electric arc furnace slag from secondary metallurgical processes, is added. After establishing the optimum moisture content, the composite is placed as compacted layers, i.e. as part of engineering fill. Due to the high degree of compaction and pozzolanic or hydraulic activity of the additives, a cement matrix is formed. In this process the contaminants are either physically microencapsulated, or chemically adsorbed onto the surface and/or incorporated into the crystalline lattice of the calcium silicate hydrate phases. The hydration products are similar to those of Portland cement. The alkaline pH values of the pore solution favour the formation of low soluble hydrolysis products of most of the trace elements. Hydraulic conductivity, too, is very low, which means thatvery little water is percolated, and that the rate of transport of chemical species of trace elements is thus very slow.
    Source: Program in knjiga povzetkov = Program and book of abstracts (Str. 184)
    Type of material - conference contribution ; adult, serious
    Publish date - 2015
    Language - english
    COBISS.SI-ID - 2159207

    Link(s):

    http://icmt23.com/e_files/content/Book%20of%20abstracts.pdf

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