MODIFICATION OF A METHOD-OF-CHARACTERISTICS SOLUTE-TRANSPORT MODEL TO INCORPORATE DECAY AND EQUILIBRIUM-CONTROLLED SORPTION OR ION EXCHANGE

This report presents a modified method-of-characteristics solute-transport model that incorporates decay and equilibrium-controlled sorption or ion exchange. The objective of the research was to enhance the modeling capabilities for simulating solute transport in groundwater systems by factoring in the effects of decay and reactive transport processes. Methodologically, the modified model extends the general transport equation, incorporating various sorption isotherms, decay reactions, and related numerical methods. Evaluation of model results was conducted through simulations using both one-dimensional and two-dimensional transport scenarios, considering linear and nonlinear sorption and decay effects. Key results from the simulations demonstrate significant improvements in capturing the complexities of solute behavior in groundwater, particularly under conditions of decay and varying sorption dynamics. The findings suggest that the model can serve as a useful tool for researchers and practitioners in hydrology and environmental engineering, providing a more robust framework for predicting the fate and transport of contaminants in aquifers. These enhancements to the transport model emphasize the necessity of accounting for reactive processes in solute transport assessments.