Emission, partition, and formation pathway of polychlorinated dibenzo-p-dioxins and dibenzofurans during co-disposal of industrial waste with municipal solid waste

Growing amounts of industrial waste (IW) are being co-disposed in municipal solid waste incineration (MSWI) plants, whereas few studies have been conducted on the characterization of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) during co-incineration. The emission characteristics and formation pathways of PCDD/Fs are systematically analyzed during the co-disposal of MSW and IW of the textile/food industry in a fullscale MSWI plant. The emission of toxic PCDD/Fs in the chimney (CH) is far lower than the national standard (<0.005 ng I-TEQ/Nm3) in co-disposal, as well as fly ash (FA) (<50 ng I-TEQ/kg). Co-incinerating IW of the textile industry significantly influences the PCDD/Fs (total 136 kinds of congeners) emission in boiler outlet (BO), CH and FA, while co-incinerating IW of the food industry causes less impact. IW co-disposal also enables PCDD/Fs migration from BO into FA, probably attributing to chlorine (Cl) increment in IW. Furthermore, the distribution patterns of PCDD/F isomers are analogous under MSWI and IW co-disposal conditions. De novo synthesis in all states is generally the dominant formation route of PCDD/Fs, possibly due to the longer dwell time of carbon residues, and de novo synthesis is strengthened by IW co-disposal. Chlorophenol (CP)-route synthesis and dibenzofuran (DF) chlorination contribute less, which are slightly reduced by co-incinerating IW, while dibenzodioxin (DD) chlorination is somewhat strengthened. Major air pollutants in co-disposal, including CO, NOx, HCl and particulate matter (PM) are poorly related to PCDD/Fs (-0.33 <0.52), while SO2 is negatively correlated with PCDD/F homologues, indicating potential suppression by sulfur (S) in IW.

Automated summary

Growing amounts of industrial waste are being co-incinerated with municipal solid waste in incineration plants, but there have been few studies on the characterization of PCDD/Fs during co-incineration. This study analyzes the emission characteristics and formation pathways of PCDD/Fs during the co-disposal of textile/food industry waste and municipal solid waste in a fullscale incineration plant. It is found that the emission of toxic PCDD/Fs in the chimney and fly ash is below the national standard. The co-incineration of textile industry waste significantly influences PCDD/Fs emission, while the co-incineration of food industry waste has a lesser impact.