In this work

microwave treatment was introduced to a hydrothermal treatment process to degrade PCDD/Fs (Polychlorinated dibenzo-p-dioxins and dibenzofurans) in municipal solid waste incineration (MSWI) fly ash. Three process additives (NaOH

Na

2

HPO

4

H

2

O)

temperatures (150℃

185℃

220℃) and reaction times (1 h

2 h

3 h) were investigated to identify their effect on the disposal of fly ash samples through orthogonal experiments. High-resolution gas chromatography-mass spectrometry (HRGC/MS) was applied to determine the PCDD/F concentrations in MSWI fly ash. The experimental results revealed that 83.7% of total PCDD/Fs was degraded. Reaction temperature was the most important factor for the degradation of the total PCDD/Fs. Both direct destruction and chlorination reactions (the chlorination degree of PCDFs increased) took part in the degradation of PCDD/Fs in fly ash

which was a new discovery. Several PCDD/F indexes determined by the concentration of indicative congeners were found to quantitatively characterize the dioxin toxicity of the fly ash. Furthermore

heavy metals in the fly ash sample were solidified using microwave-assisted hydrothe

rmal treatment

which provided an experimental basis for the simultaneous disposal of dioxins and heavy metals. Thus

the microwave-assisted hydrothermal process should be considered for the future disposal of MSWI fly ash.