Effect of constraint severity on pumping rate and remediation time in optimal design of groundwater remediation
Abstract
Variation of decision variables for optimal remediation using the pump-and-treat method are examined to identify the effect of the degree of concentration constraint. The decision variables include pumping rates for each extraction well and time for remediation, which are used to calculate the total pumping volume. Simulation-optimization method is applied to minimize the total pumping volume. The simulation model solves flow and transport equations using MODFLOW and MT3DMS under the decision value yielded from the optimization model, and the optimization model evaluates the design through the result of the simulation model and optimizes the decision variables using genetic algorithm. Change of the concentration constraint causes change in decision values. If the contaminant concentration becomes severer, both the pumping rate and time for remediation are increased. However, the increase rates and patterns are different. In total volume minimization strategy, the remediation time increases rapidly prior to significant increase in pumping rates. The number and position of main extraction wells are also changed. As the constraint is set severer, the more wells are required and the well on the down-gradient direction of the plume hot-spot shows more efficient remediation performance than that on the hot-spot position. These results show that the more profitable strategy for remediation can be achieved by increasing the required remediation time than raising the pumping rate until the time reaches a certain limitation level. So, the remediation time has to be considered as one of the essential decision variables for optimal remediation design.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2002
- Bibcode:
- 2002AGUFM.H52B0853K
- Keywords:
-
- 1831 Groundwater quality;
- 1899 General or miscellaneous