Impact of physical and chemical heterogeneities on optimal remediation design and costs

The impact of physical and chemical aquifer heterogeneities on optimal remediation design and costs is investigated by linking a genetic algorithm optimization library with a contaminant transport simulation model. Various levels of physical and chemical (sorption) aquifer heterogeneities are examined. In the first level, heterogeneity is limited to the hydraulic conductivity (K) field. Then systems with heterogeneity in both K and the distribution coefficient (Kd) are considered. The final level of heterogeneity combines variability in K, Kd, and the mass transfer rate (α). Consideration of Kd- and α-heterogeneities results in different policies and costs compared to cases where sorption heterogeneity is neglected. In general, the total pumping rate increases for systems with both chemical and physical heterogeneity as compared to systems with only physical heterogeneity. Although, an increase in K-heterogeneity decreases the impact of Kd- and α-heterogeneities on pumping rates and remediation costs, sorption heterogeneity can be as significant as the physical heterogeneity for the determination of effective remediation strategies