Mass Concentrations of Polychlorinated Dibenzo-p-dioxins and Dibenzofurans (PCDD/Fs) and Heavy Metals in Different Size Fractions of Hospital Solid Waste Incinerator Fly Ash Particles

Guoxia Wei ； Hanqiao Liu ； Rui Zhang ； Yuwen Zhu ； Xian Xu

《Aerosol and Air Quality Research》 16卷7期 (2016/07) Pp. 1569-1578

https://doi.org/10.4209/aaqr.2016.01.0001

並列摘要

Hospital solid waste incinerator (HSWI) fly ash is an extremely complex mixture because it contains carbon constituents, toxic heavy metals, and polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). We investigated the distribution of carbon constituents, PCDD/Fs, and heavy metals in the five different particle size fractions (+106 μm, -106 + 75 μm, -75 + 38 μm, -38 + 25 μm, and -25 μm) of HSWI fly ash. The loss on ignition (LOI) in the particle size fraction of -25 μm was higher than that in the particle size fractions of other sizes. Moreover, 82.63% of the fly ash particles were in the size range of -75 + 25 μm, and this particle size range was suitable for direct flotation treatment. Because powder-activated carbon adsorbed a higher amount of low-chlorinated PCDD/Fs in the gaseous phase, the concentration of each PCDD/F congener, particularly of low-chlorinated PCDD/Fs, generally increased with a decrease in the particle size. The total toxic equivalent (TEQ) of the fraction of -75 μm did not satisfy the landfill site standard (3 ng-TEQ g^(-1)). The highest concentration of Pb, Zn, and Cd was observed in the fraction of -38 + 25 μm rather than in the fraction of -25 μm. The exchangeable speciation of Zn, Pb, and Cd was relatively high in the particle size fraction of -75 μm. The carbonate speciation of Pb and Zn was the highest in the particle size fraction of -38 + 25 μm. The leaching concentrations of Pb and Cd in all particle size fractions exceeded landfill allowable thresholds.

並列關鍵字

Hospital solid waste incinerator ； Fly ash ； Size distribution ； Heavy metals ； PCDD/Fs