Chemical performance of stabilized/solidified zinc-contaminated soil

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  • University of Greenwich

Abstract

Stabilisation / solidification has been found to be a relatively sustainable and economical method for managing risks associated with contaminated land. The technology has been employed extensively over the last three decades, particularly for the containment of heavy metals. However, since contaminants are not removed, there is a need to validate the long-term effectiveness of the technique. This requires knowledge of the containment mechanisms, the kinetics of contaminant release (equilibrium and disequilibrium conditions), and identification of the reactive surfaces that induce containment. In the present work, cement stabilised zinc contaminated kaolin clay containing 1% humic acid was tested to evaluate chemical performance in the long-term, Time dependent (chemical kinetics) and pH dependent (equilibrium conditions) and equilibrium porewater leaching were evaluated, using LeachXS and geochemical speciation modelling using ORCHESTRA (embedded in LeachXS). Results showed that zinc was effectively contained within the waste form matrix under the prevailing chemical conditions, with immobilisation increasing with hydration. Presence of humic acid increased the availability of zinc at early stage, but this decreased at later stages and was comparable to organic free-matrices

Details

Original languageEnglish
Pages (from-to)45-55
Number of pages11
JournalQuarterly Journal of Engineering Geology and Hydrogeology
Volume47
Issue number1
Early online date24 Jan 2014
Publication statusPublished - Feb 2014