Abstract

Emissions of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) from the stack flue gases, fly ashes and bottom ashes of various stationary sources were investigated. The mean total PCDD/F I-TEQ concentration of flue gas ranged from 0.00681 to 0.703 ng I-TEQ/Nm 3 . However, the emission factor of PCDD/F from various incinerators was 0.00827 to 3.50 µg I-TEQ/ton, whereas it was 5.36 µg I-TEQ/body for a crematory (CM). In addition, the mean total PCDD/F I-TEQ content in fly ash from an electric arc furnace (EAF) and a secondary aluminium smelter (secondary ALS) were 74.0, and 49.9 ng I-TEQ/kg, respectively, whereas they are 21.3 and 0.494 ng I-TEQ/kg for bottom ash. Meanwhile, the removal efficiency of PCDD/F by bag filters from EAF was –44.4% which is attributed to the “memory effect”. The indicatory PCDD/Fs of EAF, and secondary ALS have the same congeners (1,2,3,7,8,9-HxCDF, 2,3,7,8-TeCDF, and 1,2,3,7,8-PeCDF). In addition, CM, joss paper-A (JP-A) and joss paper-B (JP-B) incinerators have similar indicatory PCDD/F (2,3,4,6,7,8-HxCDF, OCDF, 1,2,3,4,6,7,8-HpCDD, and OCDD). The high contribution of total PCDD/F is from fly ash (61.1-95.3%) for metallurgical facilities (EAF, secondary ALS), whereas 99.9% contribution of stack flue gas is from JP-A and JP-B. In conclusion, continually monitoring various PCDD/F emission sources is necessary to understand current PCDD/F emission (flue gas, fly/bottom ash) and the related removal efficiency of existing air pollution control devices. Information about both emission factors of PCDD/Fs and indicatory PCDD/F congeners are useful for the establishment of control strategies and for use as fingerprints with regard to the dominant congeners from different emission sources.

Highlights

  • Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were first detected in the flue gas and fly ash from municipal solid waste incinerators in 1977 (Olie, 1977)

  • The high contribution of total PCDD/F is from fly ash (61.1-95.3%) for metallurgical facilities (EAF, secondary ALS), whereas 99.9% contribution of stack flue gas is from joss paper-A (JP-A) and joss paper-B (JP-B)

  • This study investigates the characterization of PCDD/F emission from an electric arc furnace (EAF), a secondary aluminum smelter, a crematory (CM) and two joss paper incinerators (JP-A, JP-B) in southern Taiwan

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Summary

Introduction

Polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) were first detected in the flue gas and fly ash from municipal solid waste incinerators in 1977 (Olie, 1977). PCDD/Fs have received considerable attention due to concerns about the related adverse health effects and emission problems (US EPA, 2000). Various forms combustions, such as incinerations, are believed to be the main sources of PCDD/F to the environment (Rappe, 1992; US EPA, 2000). These pollutants can be transported over long distances in the atmosphere, and be deposited on the surrounding environment (Tysklind et al, 1993; VanJaarsveld et al, 1993; Lee et al, 2009). Regulations, control technology (devices), operating conditions and feeding materials can all affect PCDD/F emission and the related emission factors must be investigated yearly to develop appropriate control strategies

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