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Improving the Efficiency of 3‐D Hydrogeological Mixers: Dilution Enhancement Via Coupled Engineering‐Induced Transient Flows and Spatial Heterogeneity
Author(s) -
Di Dato Mariaines,
de Barros Felipe P. J.,
Fiori Aldo,
Bellin Alberto
Publication year - 2018
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1002/2017wr022116
Subject(s) - dilution , plume , hydrogeology , aquifer , environmental science , transient (computer programming) , groundwater , environmental remediation , groundwater remediation , mixing (physics) , flow (mathematics) , residence time (fluid dynamics) , containment (computer programming) , volumetric flow rate , forcing (mathematics) , mechanics , soil science , computer science , geotechnical engineering , engineering , geology , contamination , thermodynamics , atmospheric sciences , ecology , physics , quantum mechanics , biology , programming language , operating system
Natural attenuation and in situ oxidation are commonly considered as low‐cost alternatives to ex situ remediation. The efficiency of such remediation techniques is hindered by difficulties in obtaining good dilution and mixing of the contaminant, in particular if the plume deformation is physically constrained by an array of wells, which serves as a containment system. In that case, dilution may be enhanced by inducing an engineered sequence of injections and extractions from such pumping system, which also works as a hydraulic barrier. This way, the aquifer acts as a natural mixer, in a manner similar to the industrialized engineered mixers. Improving the efficiency of hydrogeological mixers is a challenging task, owing to the need to use a 3‐D setup while relieving the computational burden. Analytical solutions, though approximated, are a suitable and efficient tool to seek the optimum solution among all possible flow configurations. Here we develop a novel physically based model to demonstrate how the combined spatiotemporal fluctuations of the water fluxes control solute trajectories and residence time distributions and therefore, the effectiveness of contaminant plume dilution and mixing. Our results show how external forcing configurations are capable of inducing distinct time‐varying groundwater flow patterns which will yield different solute dilution rates.