由於滲透性反應牆(permeable reactive barrier, PRB)與含水層兩者的材料特性不同，因此污染物在滲透性反應牆-含水層系統的傳輸行為較為複雜。雙區污染傳輸解析解模式是評估滲透性反應牆-含水層系統功能表現的重要工具。前人所提出的雙區污染傳輸解析解模式多考慮單一物種污染物，而滲透性反應牆常處理的含氯有機溶劑污染物在傳輸的過程中會產生一序列的降解而產生其他產物，因此單一物種雙區污染傳輸解析解模式不適合來評估含氯有機溶劑污染物在滲透性反應牆-含水層系統的傳輸行為。過去雙區多物種傳輸解析解模式發展較少，且前人都考慮平衡吸附的情形。然而文獻指出，非平衡吸附作用對於溶質傳輸有很大的影響。本研究目的為發展考慮非平衡吸附的雙區多物種傳輸解析解模式來調查滲透性反應牆-含水層系統的傳輸行為。研究中利用Laplace轉換消去時間微分項來求解一組耦合的移流-延散方程式，並撰寫FORTRAN程式執行解析解模式的計算。所得解析解與相對應的數值解比較，兩者非常吻合，證明解析解的正確性與FORTRAN計算程式的準確性，所發展的模式調查滲透性反應牆-含水層系統的傳輸行為發現平衡吸附的假設會低估污染物的濃度，並高估滲透性反應牆的整治效率。;The transport behavior of contaminants in a permeable reactive barrier (PRB)- aquifer system is complicated because of the differences in the physical and chemical properties of the PRB and the aquifer. However, dual-domain contaminant transport models are efficient tools for predicting and describing the movement of contaminants in a PRB–aquifer system. Multispecies transport models should have the ability to account for mass accumulation of the parent species while simultaneously considering the distinct transport and reactive properties of both the parent and daughter species during the transport of a degradable contaminant such as a dissolved chlorinated solvent. For mathematical simplicity, the current multispecies dual-domain transport analytical models are derived assuming equilibrium sorption. However, experimental and theoretical studies have indicated that this assumption may not be adequate and that nonequilibrium sorption could have a profound effect upon solute transport in the subsurface environment. This study presents an analytical model for multispecies transport in a PRB-aquifer system subject to nonequilibrium sorption in which the first-order reversible kinetic sorption reaction equation systems are incorporated into two sets of simultaneous advection-dispersion equations coupled together by a sequential first-order decay reaction that describes multispecies nonequilibrium transport in both the PRB and the aquifer. The analytical solutions to the complicated governing equation systems are derived with the aid of the Laplace transform and verified by comparing the computational results against those obtained using a numerical model in which the same governing systems are solved using the advanced Laplace transform finite difference method. Finally, the derived analytical model is used to investigate how the sorption reaction rate influences the performance of a PRB-aquifer system.
