Emissions of PCDD/Fs, PBDD/Fs, dioxin like-PCBs and PAHs from a cement plant using a long-term monitoring system

Abstract

The aim of the present work was to assess the emission of different persistent organic pollutants from a cement plant over a period of one year, under normal operational conditions. Thus, a long-term sampling device was installed in the clinker kiln stack of the cement plant. The factory uses petroleum coke as primary fuel, but also alternative fuels such as solid recovered fuel (SRF), automotive shredder residue (ASR), sewage sludge, waste tires, and meat and bone meal (MBM) wastes, with an energy substitution level of about 40%. Both PCDD/Fs (together with dl-PCBs) and PBDD/Fs were continuously sampled, with a total of ten samples collected in 2–4 week periods. Also, PAHs were sampled during one-week periods, in order to evaluate their emissions in three different samples. The emission levels throughout the year were much lower than the set legal limits in all substances, being < 10 pg I-TEQ/Nm3 in the case of PCDD/Fs. The data obtained allowed calculation of updated emission factors for the cement sector, which were 8.5 ng I-TEQ/ton clinker for PCDD/Fs and 3.2 ng WHO-TEQ/ton clinker for PCBs. With respect to the congener distribution, 2,3,7,8-TCDF accounts for 60 to 68% of the total toxicity for PCDD/Fs, and in PBDD/F emissions, a clear predominance of octa-substituted species (both dioxin and furan) was found.