Mechanistic Relationships among PCDDs/Fs, PCNs, PAHs, ClPhs, and ClBzs in Municipal Waste Incineration

Abstract

An extensive investigation was conducted to understand polychlorinated dibenzo-p-dioxin and furan (PCDD/F) formation mechanisms and their relationship with other organic compounds. PCDD/F, chlorophenols (CIPhs), chlorobenzenes (CIBzs), polyaromatic hydrocarbons (PAHs), and polychlorinated naphthalenes (PCNs) were analyzed in the boiler exit gases of a field-scale municipal solid waste incinerator under various operating conditions. The TEQ value and the concentration of target compounds changed with incinerator operating conditions. Low mass PAHs and 246-triCIPh increased dramatically during shut downs; the latter was associated with increased 1368- and 1379-TeCDD. A strong correlation was observed between PCNs and PCDFs and adjacent PCNs homologue group were closely related to each other. This suggested that PCN formation is related with chlorination/dechlorination mechanisms similar to PCDFs. PCDDs were related with most of the CIPhs and the high chlorinated benzenes. Most of target compounds except PAHs had a positive correlation (R2 > 0.5) with TEQ and half of them showed a good relationship (R2 > 0.8) with PCDDs/Fs toxic equivalency (TEQ).

Characterization of polychlorinated naphthalenes in stack gas emissions from waste incinerators

“…To our knowledge, emissions of PCNs from medical waste incinerators, hazardous waste incinerators, and cement kilns with hazardous waste disposal have, however, not been reported. The concentrations of PCNs emitted from waste incinerators in this study were higher than those of five MSW incinerators reported by Abad et al (1999), but lower than that of raw gas from a MSW incinerator reported by Oh et al (2007). The dioxin-like toxicity of PCNs has been investigated in previous studies (Hanberg et al 1990;Blankenship et al 2000;Villeneuve et al 2000).…”

“…These compounds may be co-formed by similar mechanisms or may serve as reactants to form PCNs. Oh et al (2007) found that a strong correlation existed between PCNs and PCDFs and adjacent PCN homologue groups were closely related to one another. They suggested that PCN formation was related to chlorination/dechlorination mechanisms, similar to PCDFs formation.…”

“…The production and use of PCNs have been banned in the USA and Europe since the 1980s (Marti-Cid et al 2008). However, PCNs can be produced unintentionally by industrial thermal processes such as waste incinerators, secondary nonferrous metallurgical facilities, and coking industries and may eventually be released into the environment (Imagawa and Lee 2001;Oh et al 2007;Ba et al 2010;Liu et al 2010).…”

“…Some studies have been conducted to understand how PCNs form and several formation mechanisms have been suggested such as chlorination of naphthalene, de novo synthesis from polycyclic aromatic hydrocarbons (PAHs), and chlorophenol condensation (Weber et al 2001;Oh et al 2007;Jansson et al 2008;Liu et al 2010). To investigate the formation mechanisms, the relationships between PCNs and other incinerator emission compounds, such as naphthalene, PAHs, and PCDD/Fs, were examined.…”

A preliminary investigation of unintentional POP emissions from thermal wire reclamation at industrial scrap metal recycling parks in China

“…Although the total PCN concentrations were much higher than the total 2378-PCDD/Fs concentrations, the PCN TEQs were lower than the PCDD/Fs TEQs due to the lower RPFs of PCNs. The PCN concentrations emitted from flue gas during the thermal wire reclamation process were higher than from other industrial sources, including municipal waste incineration (MWI), the coking industry, and secondary copper and lead smelting [28][29][30]. This indicates that thermal wire reclamation might be an important PCN emission source in the scrap metal dismantling industry.…”