An Iterative Method of Modeling Pump-Treat-Injection System with “Partial Treatment”

Abstract:

Pump-and-treat has been one of the more commonly and widely used groundwater remediation technologies and continues to remain a necessary component of most groundwater remediation work. a necessary component of most groundwater remediation. This approach involves pumping contaminated groundwater to the surface for treatment. The treated water is often re-injected into the groundwater aquifer system to create a pressure ridge so that the pore-volume exchange rates can be increased. The water treatment system is to reduce the dissolved-phase contaminant concentrations sufficiently (herein referred to as “full treatment”) so that the groundwater complies with the cleanup standards or the treated water can be put back to beneficial use. However, in many cases multiple contaminants are present in groundwater, and the selected treatment system is not capable of reducing the dissolved-phase concentrations sufficiently for all contaminants (herein referred to as “partial treatment”).

When developing numerical models for pump-treat-injection systems, customarily under a “full treatment” scenario, the post treatment concentration of dissolved-phase contaminants in the injected water is assumed to be zero. However, under “partial treatment” scenarios, contaminant concentrations in the injected water may vary significantly, making the numerical modeling more challenging. This study presents an iterative approach to modeling pump-treat-injection systems under “partial treatment” scenarios in which the injected water concentration is linked to the modeled extracted water concentration. Numerical test runs show that the iterative simulation results converge to a viable final solution.