Journal Title
Title of Journal: Hydrogeol J
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Abbravation: Hydrogeology Journal
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Publisher
Springer-Verlag
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Authors: G Suresh Kumar
Publish Date: 2007/10/25
Volume: 16, Issue: 2, Pages: 235-249
Abstract
Matrix diffusion and sorption are among the key processes impacting the efficiency of natural attenuation in the subsurface While these processes have been studied extensively in fractured media limited information exists on the sorption nonlinearity To address this shortfall a numerical model has been developed that couples matrix diffusion and nonlinear sorption at the scale of a single fracture using the dualporosity concept The study is limited to a constant continuoussolutesource boundary condition The influence of sorption intensities on dispersivity and macrodispersion coefficient is investigated using a method of spatial moments Results suggest that mixing of solutes is significantly lowered by nonlinear sorptive behavior with respect to the mixing caused by matrix diffusion for linearly sorbing solutes Also the magnitude of time dependent dispersivity during the preasymptotic regime is lower for nonlinearly sorbing solutes with respect to the linearly sorbing solutes Reduced mixing is also observed for nonlinearly sorbing solutes under combined mechanisms of matrix diffusion and decayLes phénomènes de diffusion et de sorption comptent parmi les processus clés qui influent sur l’atténuation naturelle en subsurface Si ces processus ont été massivement étudiés en milieu fracturé il existe en revanche peu d’informations sur la nonlinéarité de la sorption Afin de combler cette lacune un modèle numérique a été développé il couple la diffusion dans la matrice et la sorption nonlinéaire à l’échelle d’une fracture unitaire en utilisant le concept de double porosité La seule condition aux limites fixée pour toute l’étude est une source de soluté constante et continue L’influence de l’intensité de la sorption sur la dispersivité et sur le coefficient de macrodispersion est étudié via une méthode utilisant les moments spatiaux Les résultats suggèrent que les mélanges de solutés sont significativement réduits par les phénomènes de sorption nonlinéaires comparativement aux mélanges causés par la diffusion pour des solutés à sorption linéaire C’est pourquoi la dispersivité dépendante du temps est plus faible pour les solutés à sorption nonlinéaire que pour les solutés à sorption linéaire lors du régime préasymptotique Des mélanges réduits ont également été observés pour des solutés à sorption nonlinéaire sous les mécanismes combinés de diffusion dans la matrice et de dégradationLa difusión intersticial y la adsorción se encuentran entre los procesos clave que impactan la eficiencia de la atenuación natural en el subsuelo Mientras que estos procesos se han estudiado extensamente en medios fracturados existe información limitada acerca de la no linealidad de la adsorción Para abordar esta situación se ha desarrollado un modelo numérico que acopla la difusión intersticial y la adsorción no lineal a la escala de una sola fractura usando el concepto de porosidad doble El estudio se restringe a condiciones limitantes de fuente de soluto constante y continuo Se investiga la influencia de las intensidades de adsorción sobre el coeficiente de dispersiónmacro y dispersividad usando un método de momentos espaciales Los resultados sugieren que la mezcla de solutos disminuye significativamente mediante comportamiento de adsorción no lineal en relación con la mezcla causada por difusión intersticial para solutos con adsorción lineal Se observa que la magnitud de la dispersividad dependiente del tiempo durante el régimen preasintótico es más baja para solutos con adsorción no lineales en relación a los solutos con adsorción lineal También se observa mezcla reducida para solutos con adsorción no lineal bajo mecanismos combinados de difusión intersticial y desintegraciónThanks are extended to the associate editor and the anonymous reviewers whose editorial and substantive comments improved the paper Thanks also go to the Managing Editor Prof C Simmons and Technical Editorial Advisor Mrs Sue Duncan for their editorial comments
Keywords:
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- Radiocarbon dating and the 36 Cl/Cl evolution of three Great Artesian Basin wells at Dalhousie, South Australia
- Influence of rainfall on the deformation and stability of a slope in overconsolidated clays: a case study
- Transport and deposition of suspended particles in saturated porous media: hydrodynamic effect
- Model of hydrological behaviour of the anthropized semiarid wetland of Las Tablas de Daimiel National Park (Spain) based on surface water–groundwater interactions
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- Using Hydrogeochemical Methods To Evaluate Complex Quaternary Subsurface Stratigraphy Block Island, Rhode Island, USA
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- Interactions between groundwater and surface water: the state of the science
- A hydrogeological conceptual approach to study urban groundwater flow in Bucharest city, Romania
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- Is self-regulation a myth? Case study on Spanish groundwater user associations and the role of higher-level authorities
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- Simulated impacts of artificial groundwater recharge and discharge on the source area and source volume of an Atlantic Coastal Plain stream, Delaware, USA
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