Thesis (Ph.D.) - Cairo University - Faculty of Engineering - Department of Civil Engineering

Reuse of treated wastewater becomes one of the vital nonconventional water resources which increased in the last decades. In this work we evaluate the impacts of treated wastewater reuse in irrigation on soil and on aquifers by field investigations, lab experiments, data analysis, vadose zone and groundwater numerical modeling and a proposal for irrigation scenarios to evaluate the impacts of using treated wastewater in irrigation on soil and groundwater. Six contaminants of concern (Mg, Cl, Fe, NH3, NO3 and fecal coliform) were selected to be analyzed and were simulated. Seven testing scenarios were applied depending on irrigation water quality and irrigation rate: primary, secondary, oxidation pond, tertiary treated wastewater, tertiary for double field water duty, irrigation with two-year rotation (primary treated wastewater and groundwater) and in the last scenario the study area was divided into 3 zones and irrigated with tertiary treated wastewater, oxidation pond wastewater and groundwater. The results of the study showed the processes occurring through the vadose zone and the downward migration to groundwater aquifer. The recommended scenarios are the fourth, the fifth and the seventh scenario

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