降雨入滲對於地下水中含氯有機溶劑降解之影響

Abstract

本研究針對降雨入滲對於含氯有機溶劑污染場址降解之影響，藉由模擬地下水污染物溶質傳輸的現象，對降雨入滲影響含氯有機溶劑之差異分佈進行分析。利用Visual MODFLO W套裝軟體RT3D 數值模式來模擬含氯有機溶劑污染場址於地下水傳輸，評估各關切污染物對濃度分佈之影響。RT3D 可模擬四氯乙烯降解作用產生三氯乙烯、二氯乙烯、氯乙烯，各關切污染物的吸附作用使各污染物傳輸速度不同。模擬一假設場址於不同降雨量與降雨區塊影響其濃度與分佈和選用一國內著名含氯有機溶劑污染場址做研究案例。研究結果顯示，在假設場址模擬中，降雨量的大小與降雨區域性的不同不僅會影響含氯有機溶劑之濃度與也會改變溶解相污染團的形狀與移動方向。實際案例場址模擬結果顯示，降雨入滲對於地下水中含氯有機溶劑影響會因為都市區域有各式鋪面，雖然會使實際入滲量隨不同地表狀況降低，間接影響入滲到地層中的入滲量，但是入滲仍會影響污染團的濃度與分佈。

This research, evaluates the effect of rainfall infiltration on of chlorinated solvents in groundwater by numerical simulation of groundwater contaminant transport with MODFLOW and RT3D. The anaerobic degradation of tetrachloroethylene (PCE) and all its daughter products such as trichloroethylene(TCE),dichloroethylene (DCE), vinyl chloride (VC) is taken into account by RT3D. In order to assess the effect of infiltration on the plume of dissolved chlorinated solvents a hypothetical aquifer was established. Infiltra-tion was assumed to occur at various zones and rate to study the resulted change of the plume. In addition, a real site contaminated by chlorinated solvents in Taiwan was selected for the case study. The results of the research illustrated that the size and different regional of the rainfall will affect the concentration and the direction of plume migration. On the other hand, results of the Taiwan DNAPL site simulation showed that the pavement re-duced the effect of rainfall infiltration and, in turn, its effect on the plume of chlorinated solvents in groundwater.