Waste water disposal: Polluted aquifer cleanup optimization by using genetic algorithms

Water produced constitutes a large amount of waste fluids during the produc tion operation of an oilfield. Underground injection for disposing of the w astewater from hydrocarbon production is an engineering problem due to the possibility of leakage of injected pollutant material from the receiving me dium to a drinking-water source. In this study, for the remediation of a polluted aquifer, a computer progra m was developed by using an analytical model approach based on hydrodynamic isolation, and the program was incorporated with genetic algorithms (GAs) for optimum design solution. As a case study, a contaminated area was created by using a groundwater tra nsport simulator based on the method of characteristics (MOC). Then the com puter program was run to find the optimum solution for remediation, and the solution produced by the program was verified by using a groundwater simul ator. The plume was captured and the concentration level of chloride ion wi thin the aquifer was diminished by using extraction wells. The analytical m odel approach provided different alternatives for appropriate isolation of plume. GAs were used as an optimization technique for making a decision amo ng the alternatives, by considering operation time, number of wells, pumpin g rate, and drawdown as decision variables and constraints.