Elution and Mechanical Characteristics of Municipal Solid Waste (MSW) Incineration Bottom Ash that has Undergone Accelerated Carbonation Treatment using CO₂ Recovered from Incineration Plant Exhaust

Abstract

Accelerated carbonation treatment for recycling MSW incineration bottom ash can simultaneously reduce CO₂ emissions. In this study, we designed a public implementation of this technology and conducted a test at the Saga City Incineration Plant, which has CO₂ separation and capture facilities. Two types of gas-exhaust gas from the same incineration plant and CO₂ separated and recovered from such exhaust gas-were ventilated through the bottom ash and used to investigate the elution characteristics of heavy metals (through (1) elution testing and (2) lysimeter testing) and the effects of carbonation treatment on their mechanical characteristics as civil engineering materials. Carbonation significantly reduced the Pb elution concentration in both (1) and (2), but the concentrations of Cr(VI) increased in both (1) and (2). There was no difference for B between untreated and treated bottom ash in (1), but in (2) the concentration was lower than that of untreated. Regarding mechanical characteristics, we confirmed that while carbonation reduced the modified CBR value and cone index, strength was satisfied as a material for roadbeds and embankments. For the gas types, there were differences in the carbonation reaction status and B concentration behavior.