Design and cost analysis of rapid aquifer restoration systems using flow simulation and quadratic programming

Detailed two-dimensional flow simulation of a complex ground-water system is combined with quadratic and linear programming to evaluate design alternatives for rapid aquifer restoration. The design model ensures that a contaminant plume is removed and treated within four years at the least possible cost. Rapid restoration is accomplished by maintaining specified velocities around the plume perimeter toward a group of pumping wells located near the plume center. Ground-water velocities are adjusted to include the effects of solute retardation due to sorption. As a simplification, the model does not account for hydrodynamic dispersion. Results show how treatment and pumping costs depend dynamically on the type of treatment process, the capacity of pumping and injection wells, and the number of wells. The design for an inexpensive treatment process minimizes pumping costs, while an expensive process results in the minimization of treatment costs. Substantial reductions in pumping costs occur with increases in injection capacity or in the number of wells. Treatment costs are reduced by expansions in pumping capacity or injection capacity. The analysis identifies maximum pumping and injection capacities.