This project investigated the emission of dioxin sampled from stationary sources in Kaohsiung city. Major works included the emission source sampling of dioxin and heavy metals, the emission source inquiry of dioxin, the analyses of ambient environment (air‚ leaves and soil), risk assessment, the technical assistance of reducing dioxin, and the efficiency assessment of air pollution control device (APCD).
The mean total PCDD/Fs concentrations of stationary sources MSWI1-D1 and IWI5-D were 0.369 and 0.112 ng I-TEQ/Nm3, respectively. The values are higher than the regulation limit of Taiwan EPA. The emissions of PCDD/Fs from other stationary sources are lower than the regulation limit of Taiwan EPA. The estimated total annual emission of PCDD/Fs from these emission sources in Kaohsiung city was 5.57 g I-TEQ/yr (large-scale MSWIs, 5.55%; small-scale MSWIs, 0.0530%; industrial waste incinerators, 4.30%; medical waste incinerators, 0.114%; coke oven planes, 1.55%; cement kilns, 0.170%; sinter planes, 77.8 %; RHF, 0.231%; electricfurnaces, 6.00%, crematorium 2.98%; boiler electricity generation, 0.00493%; secondary aluminum smelters, 0.911%; secondary zinc smelters, 0.0433%; secondary copper smelters, 0.294%).
The existing emission sources of heavy metals were surveyed. The concentrations of Hg for IWI1-H1 and IWI1-H2 were 0.126 and 0.139 mg/Nm3, respectively. The values are higher than the regulation limit of Taiwan EPA (0.1 mg/Nm3). The emissions of heavy metals from other stationary sources are lower than the regulation limit of Taiwan EPA.
The total PCDD/F concentrations of ambient air, leaves and soil were 0.0267-0.0917 pg I-TEQ/Nm3, 0.832-3.21 ng I-TEQ/kg and 0.181-8.19 ng I-TEQ/kg, respectively. The mean PCDD/F concentrations of ambient air, leaves and soil were 0.0456 pg I-TEQ/Nm3, 2.14 ng I-TEQ/kg and 2.03 ng I-TEQ/kg, respectively. A maximum PCDD/Fs concentration in Siaogang district was carried out. The dominant contributions of PCDD/Fs concentration in Siaogang district were electricfurnaces and sinter planes.
AERMOD and multimedia transport modeling were used to estimate the health risks of the residents in Kaohsiung city. The maximum cancer risk of a resident living in Siaogang district was found. The risk harm is high when the district nears to pollution source. The inhalation was the main exposure route for carcinogenicity and non-carcinogenicity risks. Major emission contributors for most districts are SINTER, PP and MSWI1. IWI6 was major pollution source for Nanzi and Zuoying districts.
This project inverstigated the concentrations of PCDD/Fs and heavy metals at the inlets and outlets of the bag filter in four stationary emission sources. Removal efficiencies of PCDD/Fs by bag filters in ChinaSteel, Kuo-Chu, Hai-Kwang and Lung-Ching were 96.7-97.5%、92.2-94.9%、32.3-97.8%、-13.3-51.9%, respectively. The bag filters of ChinaSteel and Kuo-Chu have good control efficiencies for Pb, Cd, Hg, and As. The bag filters of Hai-Kwang and Lung-Ching have low efficiencies for the removal of As and Hg. Low removal efficiency of heavy metals for Lung-Ching was due to memery effect of bag filter.