Catalytic decomposition of dioxins and other unintentional POPs in flue gas from a municipal waste incinerator (MWI) in China: a pilot testing

Abstract

Unintentionally produced persistent organic pollutants (UPOPs) include polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), dioxin-like polychlorinated biphenyls (dl-PCBs), pentachlorobenzene (PeCBz), and hexachlorobenzene (HxCBz). With the booming of municipal waste incinerators (MWIs) in China, the emission of UPOPs has generated great concern. As an alternative technology of dioxin control, catalytic decomposition has not been used in China, mainly due to the absence of national demonstration projects. Also, the simultaneous removal of various UPOPs has not been well investigated.In this study, a pilot-scale selective catalytic oxidative (SCO) system using a self-developed honeycomb catalyst was built and tested in a typical municipal waste incinerator (MWI) of China. The original concentration of PCDD/Fs in flue gas after the treatment of activated carbon injection (ACI) still exceeded the national emission standard (0.1 ng I-TEQ/Nm), while the concentrations of PeCBz and HxCBz were one order of magnitude higher than that of PCDD/Fs. For the testing temperature varying from 300 to 200 °C, the removal efficiency of PCDD/Fs range from 39 to 95 %, followed by dl-PCBs with the range of 56-89 %. PeCBz and HxCBz were also removed, though their removal efficiencies were lower than those of PCDD/Fs and dl-PCBs. Both temperature and degree of chlorination influence the removal efficiencies.

Removal of PCDD/Fs and CBzs by Different Air Pollution Control Devices in MSWIs

“…The removal efficiencies of 2,3,7,8-TCDF and 2,3,4,7,8-PeCDF could even reach as high as 93% and 90%, respectively. This result was in accordance with those obtained from pilot tests in full-scale MSWIs (Li et al, 2018). This is because highly chlorinated PCDD/Fs have higher vapor pressure and are easily adsorbed on the surface of catalysts to be decomposed.…”

“…This is because highly chlorinated PCDD/Fs have higher vapor pressure and are easily adsorbed on the surface of catalysts to be decomposed. Therefore, catalysts need higher oxidation potential to handle the more highly chlorinated PCDD/Fs (Li et al, 2018).…”

1,2,4-trichlorobenzene decomposition using non-thermal plasma technology

“…However, dioxins do not decompose completely, and they only transfer dioxins from flue gas to the solid residues. Developing effective technologies to decompose dioxin-like compounds has become an important issue in the fields of waste incineration and so on [6][7][8][9][10]. However, dioxin decomposition by NTP is relatively rare because of the limitations of the detection method and experimental platform.…”

The legacy of pesticides and POPs stockpiles—a threat to health and the environment

“…The PCDD/F pattern in the laboratory tests dominated by the 1,2,7,8-and 2,3,7,8-TetraCDFs, 1,2,3,7,8-PentaCDF, and 1,2,3,4,7,8-HexaCDF marker congeners were identical with PCDD/F congener patterns in soil samples from a PCDD/Fcontaminated site where chlor-alkali electrolysis had been operated for decades in Japan (Yamamoto et al 2017), demonstrating the contamination potential and ongoing risks of these (historic) operations. Li et al (2016) assessed the destruction of unintentional POPs (PCDD/F, PCBs and HCB/PeCB) in a pilot-scale selective catalytic oxidative (SCO) system using a self-developed honeycomb catalyst in a typical municipal waste incinerator in China. Both temperature and the degree of chlorination influenced the removal efficiencies, with highest destruction efficiency for PCDD/F (Li et al 2016).…”

“…Li et al (2016) assessed the destruction of unintentional POPs (PCDD/F, PCBs and HCB/PeCB) in a pilot-scale selective catalytic oxidative (SCO) system using a self-developed honeycomb catalyst in a typical municipal waste incinerator in China. Both temperature and the degree of chlorination influenced the removal efficiencies, with highest destruction efficiency for PCDD/F (Li et al 2016).…”