Development and field application of analytical model for two-dimensional multispecies transport involving multiple internal sources

The long term releases of multiple sources are common situation in remediation of contaminated site. However, most of the advective-dispersive equation from literatures are analytical model for solute transport developed only for boundary source, which could be limited to simulate the transport of contaminant for filed-scale site. Considering the analytical model for solute transport of inner source could simulate any position for the contaminant sources injection. The analytical model for single-species solute transport could not simulate the decay and transport of multispecies in the condition of sequential decay chain. This study presents an multiple sources analytical model for two-dimensional multi-species advective-dispersive equation which considered linear equilibrium sorption and first order decay reaction. The model could also be applied in predicting the behavior of decaying contaminant such as radionuclide, nitrogen transformation and dissolved chlorinated solvent. Generalized analytical solutions are derived through the sequential application of the Laplace, finite Fourier cosine and generalized integral transform to remove the temporal and spatial derivatives in the coupled partial differential equation. The system of coupled partial differential equation is tranform to a set of linear algebraic equations, and the solutions in the original domain are then obtained through consecutive integral transform inversions. The developed analytical solution is tested by comparing their results against the numerical solutions using a finite difference scheme. Results show perfect agreements between the analytical and numerical solutions. The developed model was applied to analyze field-scale transport and biodegradation processes occurring at the Area-6 site in Dover Air Force Base, and predict the distribution of PCE and TCE plumes in different scenario (10 years, 20 years, 30 years and 40 years). The developed model in this study is a useful tool for simulation sequential decay reactions between multispecies, and a foundation of a preliminary assessment to the remediation of the field site.