Processing of MSW incineration bottom ash

The production of Municipal Solid Waste (MSW) is rising as the world population continues to increase. Consequently, the disposal of MSW becomes an increasingly serious problem. Although, incineration reduces the waste volume by about 90% and mass by about 70%, the remaining incineration ash has to be disposed by landfilling. In a land scarce country like Singapore, such waste management strategy may not be sustainable. New incineration plants may have to be constructed and new land fill have to be found for incineration ash disposal. A viable solution is to process the MSW ash for beneficial reuse. Incineration bottom ash displays the properties that are close to natural aggregates and have many potential uses in civil engineering applications. Numerous pre-treatment methods have been investigated to pre-treat the ash to reduce heavy metals leached into the environment that would otherwise cause undesirable effects. Phosphate stabilization and carbonation are the most promising pre-treatments. However, the operational cost of treatment is uncertain. Reuse of bottom ash is still low despite many available pre-treatment methods. Cement grouting and phosphate stabilization were carried out to determine the effectiveness of stabilizing metals from incineration bottom ash. It was held that the soluble phosphate reagent is effective in stabilizing Cd, Cr, Cu, Ni, Pb Zn and Fe. Cement grouting is only effective in stabilizing Pb, Fe and Cr. 0.32 M H3PO4 provides the optimum stabilization.Bachelor of Engineerin