Informations et ressources scientifiques
sur le développement des zones arides et semi-arides

Titre : Modeling Soil Aquifer Treatment Processes during Managed Aquifer Recharge Considering Soil Heterogeneity and Parametric Uncertainty

مذجة عمليات المعالجة في التربة أثناء تغذية الخزان الجوفي مع اعتبار عدم تجانس التربة وعدم التيقن من قيم المعاملات

Auteur : Ahmed Amin M. Abdel-Rahman

Université de soutenance : Cairo University

Grade : Master of Science (MS) 2013

Résumé
Reclaimed wastewater is a valuable unconventional water resource that can be employed for various purposes to relief the increased pressure on our fresh water resources. Managed Aquifer Recharge (MAR) is a technique where the effluents form Waste Water Treatment Plants (WWTPs) can be recharged into the groundwater aquifers. MAR systems have shown a proven ability to enhance the quality of injected effluents through a series of Soil Aquifer Treatment (SAT) processes. A wide range of Organic Micro Pollutants (OMPs) is frequently detected in the treated effluents which might pose a groundwater contamination risk. Studies have proven the capability of SAT processes to remove most of these OMPs as they undergo sorption and biodegradation reactions in the unsaturated zone. However, these reactions vary greatly according to the type of contaminant as well as aquifer specific properties, therefore the ability of SAT to sufficiently remove these contaminants implies a great deal of uncertainty. The objective of this study is to assess the removal efficiency of a very wide range of contaminant types in different unsaturated soil conditions using Mont-Carlo Simulations. HYDRUS 2D/3D model is used to simulate SAT processes. Under a wide range of uncertainty in the parameters controlling SAT, a high contaminant mass removal efficiency was achieved in the top 6 meters of the unsaturated zone for most of the simulations. The total uncertainty in the contaminant mass removal is found to be mainly controlled by the uncertainty in the biodegradation rate, while the soil volume impacted by the contaminant plume is dominated by the saturated hydraulic conductivity of the aquifer soil. The output uncertainty is found to be larger in the case of parametric uncertainty than in the case of spatial heterogeneity in the saturated hydraulic conductivity of the aquifer.

Mots clés : Managed aquifer recharge, Soil aquifer treatment, Organic micro pollutants, Monte-carlo analysis, Soil heterogeneity, Parametric uncertainty

Présentation

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