Analysis of the heterogeneity scale effects on pump and treat aquifer remediation design

Güngör Demirci, Gamze
The effect of heterogeneity correlation scale of hydraulic conductivity (K), equilibrium distribution coefficient (Kd) and mass transfer rate on the design and cost of the P&T remediation system for different heterogeneity levels (defined by the variance (σ2lnK)) and parameter distributions under the rate-limited sorption conditions was evaluated in this study. In addition, the impacts of initial amount of contaminant mass and plume configuration on the remediation design and cost were explored. The effects of different K heterogeneity and remediation design conditions on the length of remediation period, the influence of anisotropy of K, correlation between K and Kd, and Kd and , and the fraction of equilibrium sorption sites (f) on the pump-and-treat (P&T) design and cost were the other studied subjects. In this study, simulation-optimization approach, in which a groundwater flow and contaminant transport simulation model was linked with a genetic algorithm (GA) library, was used. Results showed that not only the amount of PCE mass initially present in the aquifer was important in terms of P&T design, cost and remediation time, but also the location and size of the high and low K regions defined by λlnK as well as the magnitudes of K represented by geometric mean and σ2lnK were influential. It was also found that P&T designs utilizing higher numbers of wells with lower pumping rates may be more robust predicting the time-to-compliance compared to a single well with higher pumping rate for aquifers heterogeneous in K. Homogenous Kd assumption might cause serious error in both the design and the cost of remediation. The magnitude of this error may change depending on the spatial distribution of K and Kd, λlnKd, σ2lnKd and σ2lnK. The effect of heterogeneity in on the design and cost of remediation may or may not be significant depending on K, Kd and distributions, ln and σ2ln. Increased amount of kinetically sorbed mass defined by decreased f value resulted in more costly remediation.


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Citation Formats
G. Güngör Demirci, “Analysis of the heterogeneity scale effects on pump and treat aquifer remediation design,” Ph.D. - Doctoral Program, Middle East Technical University, 2009.