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Arizona State University (2003)

Impact of water reuse applications on soil coating layers

Aboshanp, Waleed Abd Elmonem Mohamed

Titre  : Impact of water reuse applications on soil coating layers

Auteur  :Aboshanp, Waleed Abd Elmonem Mohamed

Université de soutenance : ARIZONA STATE UNIVERSITY

Grade : Doctor of Philosophy (PhD) 2003

Due to a depletion of water resources, water reuse is rapidly expanding. Irrigation with wastewater effluent and soil aquifer treatment (SAT) are common applications of water reuse. Soil aquifer treatment is a managed system where wastewater effluent is artificially recharged in wetting and/or drying cycles for the purpose of maintaining optimum performance. These techniques rely on soil treatment of the wastewater effluent to protect groundwater quality. The goal of this research is to examine the sustainability of soil as a natural attenuation barrier from wastewater effluent, and therefore provide adequate treatment of the constituents that may be of concern. Wastewater constituents may be retained on the soil surface and wastewater applications may remove soil layers. Effects on the soil layers may limit the growth of microbes. Dense coating layers may reduce infiltration rates for optimum performance. During irrigation, denser soil-coating layers may impact planted crops and indirectly affect grazing animals. They may also influence the growth rate of plants and lower irrigation efficiency. Sequential extractions were used to extract soil-coating layers from soils impacted by water reuse. Although, there was accumulation on soil layers near the surface in all applications, depletion of soil layers occurred at a one foot depth except for the irrigation site studied. Results suggested that these systems can sustain wastewater application. As a result of the lengthy process of chemical extraction, scanning electronic microscopy (SEM) was used to aid in determining the compositions of coating layers. This research also studied the impact of soil aquifer treatment technique on mobilization of arsenic from these soils. Arsenic is a naturally occurring metal that is toxic at very low concentrations. Results showed that arsenic could be mobilized by water recharged through an SAT system when anaerobic conditions developed.


ProQuest Digital Dissertations

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Page publiée le 17 septembre 2004, mise à jour le 9 janvier 2017