Analytical model for multispecies transport in a permeable reactive barrier- aquifer system subject to nonequilibrium

• Main Authors: Shih-Kai Wu, 吳士愷
• Other Authors: Jui-Sheng Chen
• Format: Others
• Language: en_US
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/26xht7

碩士 === 國立中央大學 === 應用地質研究所 === 106 === 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.