A Groundwater Mass Transport and Equilibrium Chemistry Model for Multicomponent Systems

A mass transport model, TRANQL, for a multicomponent solution system has been developed. The equilibrium interaction chemistry is posed independently of the mass transport equations which leads to a set of algebraic equations for the chemistry coupled to a set of differential equations for the mass transport. Significant equilibrium chemical reactions such as complexation, ion exchange, competitive adsorption, and dissociation of water may be included in TRANQL. Here, a finite element solution is presented first for cadmium, chloride, and bromide transport in a one‐dimensional column where complexation and sorption are considered. Second, binary and ternary ion exchange are modeled and compared to the results of other investigators. Results show TRANQL to be a versatile multicomponent transport model, with potential for extension to a wide range of equilibrium reactions.