Abstract
This study investigated the emissions of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) from 45-hr cold start-up operations (from the ambient temperature) of two municipal solid waste incinerators (MSWIs). Fifteen samples were collected during the whole process, while the sampling period was divided as follows: (1) the initial stage (25–250°C); (2) the second stage (250–850°C), and the final stage (850–1000°C). The peak of total (PCDD/F + PCB) (WHO2005-TEQ) concentration occurred during the second stage of the cold start-up. This could because the temperature in the combustion chamber reached 295–359°C, within the temperature window (250–450°C) of PCDD/F reformation by de novo synthesis. However, both PCDD/F and PCB (WHO2005-TEQ) concentrations were still 2.8–3.8 times higher than the regulated standards in Taiwan 45 hours after the cold start-up began, demonstrating significant memory effects. Higher PCB/(PCDD/F + PCB) TEQ fractions were observed during the initial stage of cold start-up. This is probably due to the higher volatilities of memorized PCB-126 and -169 than PCDD/F congeners, thus making them more easily released into the flue gas. On the other hand, the total (PCDD/F + PCB) emissions during 45-hr cold start-up were estimated at 46–68 mg WHO2005-TEQ.The annual (PCDD/F + PCB) emissions from normal conditions are generally estimated by the normal operating emissions factor without the cold start-up. The normal annual (PCDD/F + PCB) emission rates of the two MSWIs were 70.7–101 mg WHO2005-TEQ, including once cold start-up emission, and these increased to 142–480 mg WHO2005-TEQ, up by 65–458%, if one to eight times of cold start-up were included. Therefore, reducing unnecessary start-ups could be more important with regard to controlling the PCDD/F and PCB emissions than only attempting to increase the pollutant removal efficiency in the steady operations of MSWIs.
Highlights
Polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs or dioxins) and dioxin-like polychlorinated biphenyls (PCBs) are both included in the five main groupsGuo et al, Aerosol and Air Quality Research, 14: 1593–1604, 2014PCBs are industrially produced chemicals with a broad range of commercial applications, such as heat transfer fluids, organic diluents, and plasticizers
This study investigated the emissions of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and polychlorinated biphenyls (PCBs) from 45-hr cold start-up operations of two municipal solid waste incinerators (MSWIs)
polychlorinated dibenzofurans (PCDD/F) were first discovered in the flue gases and fly ash of municipal solid waste incinerators (MSWIs) in 1977 (Olie and Vermeulen, 1977), and are byproducts which form during the synthesis of the primary industrial halogenated aromatics, from other commercial processes, or during combustion (Lohman and Seigneur, 2001)
Summary
Polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs or dioxins) and dioxin-like polychlorinated biphenyls (PCBs) are both included in the five main groupsGuo et al, Aerosol and Air Quality Research, 14: 1593–1604, 2014PCBs are industrially produced chemicals with a broad range of commercial applications, such as heat transfer fluids, organic diluents, and plasticizers. PCDD/Fs were first discovered in the flue gases and fly ash of municipal solid waste incinerators (MSWIs) in 1977 (Olie and Vermeulen, 1977), and are byproducts which form during the synthesis of the primary industrial halogenated aromatics, from other commercial processes, or during combustion (Lohman and Seigneur, 2001). Both PCDD/Fs and PCBs have become a serious issue in many countries because of their toxicological effects and consequent adverse health implications. The PCDD/F and PCB emissions in Taiwan are relatively low, because the MSWIs that operate in Taiwan are larger and have newer pollution control technologies than those in many other areas, and the related emissions limit (0.1 ng ITEQ/Nm3) is the most stringent in the world
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call