| 英文摘要 |
This project is the 3rd year of a three-year medium-range project (2003~2006) “Management and Assistance of hazardous air pollutants from solid-waste incinerators and odorous materials”, which was carried out according to the methods used in the 1st and 2nd year. In addition, the conclusion and recommendation from the 2nd year project were also fully taken into consideration with corresponding actions being taken.
We have checked 66 incinerators, electric arc furnaces or stationary air pollution sources using general or industrial waste as fuel or auxiliary fuel located, all located in Taoyuan County. Currently, 33 are in operation, 29 stop operation, 3 stationary air pollution sources are relieved of restrain after changing process and not using waste as fuel, 1 is yet to start operation. In general, the operational incinerators and electric arc furnaces cohere to regulatory requirements, except the incinerators of GuangXuan Environmental Engineering Technologies Co., Ltd., and Chang Gung Memorial Hospital (Linkou branch) are currently under improvements due to exceeding dioxin effluent standard.
We have targeted Jin Lai Technologies Co., Ltd., Tung Ho Steel (TH) Enterprise Cooperation (Taoyuan branch), Petroleum Refinery (Taoyuan branch) of the Refining Division of Chinese Petroleum Cooperation (CPC) as candidates for field assistance and dioxin abatement. After field assistance and incinerator improvement plan, the dioxin emission form Jin Lai and M33 incinerators of CPC become accordance to regulatory requirements. The abatement amount was estimated to be 60% and 50%, respectively, indicating the concrete effects of field assistance.
We have surveyed levels of ambient dioxin and heavy metals in 7 industrial parks, 1 metropolitan region, and 3 potentially polluted regions. The survey results indicate that ambient dioxin concentrations in certain specific region of Taoyuan County are higher than the average in Taiwan (~ 0.1 pg I-TEQ/Nm3). The electric arc furnace of TH has effected the ambient dioxin in neighboring area. The ambient Pb and Cd concentrations in all surveyed region are well below the ambient standards. Risk assessment results indicate that dioxin exposure for Taoyuan adult and children are within acceptable range. The average cancer risk from exposure to cancer-causing heavy metals (As, Be, Cd, Ni, and Pb) is estimated to be 0.30x10-6. The contribution from As is about 57%. The cancer risk is below 10-6 and is within the acceptable range.
We also found that the soil in and out the TH plant is contaminated by both dioxin and heavy metals. We suggest continuing the survey to find out if the scope of contamination is being broadened or not. Furthermore, we also suggest conducting similar investigations on the other two electric arc furnaces in Taoyuan, aiming to understand if there were similar contaminations.
The dioxin emission in Taoyuan is estimated to reduce 6.80 g I-TEQ from 2003 to 2004, mainly from the shut-down of over 130 small solid waste incinerators and the implementation of Steel Industry Electric Smelting Furnace Dioxin Control and Emission Standard. Only 0.76 g dioxin was reduced from 2004 to 2005, which is about 7% and far lower than that in 2003~2004 period. Presumably due to the number of incinerators and electric arc furnaces remained about the same and all cohere to Waste Incinerator Dioxin Control and Emission Standard, Small and Medium Sized Incinerator Dioxin Control and Emission Standard, and Steel Industry Electric Smelting Furnace Dioxin Control and Emission Standard. The private sector has no incentive to further improve efficiency of air pollution abatement devices. The amount for further dioxin reduction is limited. Currently, electric arc furnaces contribute the most (~95%) to the dioxin emission among restrained dioxin emission sources. The control of dioxin emission from electric arc furnaces is critical to the overall dioxin emission and dioxin abatement efficiency in Taoyuan County.
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