Engineering Commons^™

Phosphate And Thermal Stabilization Of Heavy Metals In Dredged Sediments, Peter Kuria Ndiba

Dissertations

Treatment and reuse of dredged harbor sediments in construction as an alternative to disposal reduces costs and conserves resources. This research focused on leachability of metal contaminants subsequent to phosphate addition and thermal treatment at 700 °C. X- ray absorption spectroscopy (XAS) in combination with principal component analysis, target transformation, and linear combination revealed that in the untreated sediments Zn precipitated as the relatively soluble smithsonite (ZnCO₃) (67%) and adsorbed to hydrous iron oxides (15%) and hydrous manganese oxides (18%). Phosphate addition and calcination resulted in sparingly soluble phases, hopeite (Zn₃₍PO₄)₂.4H_{2 …}