Soil Aquifer Treatment (SAT) systemscan be used for upgrading partially treated wastewater by allowing it to infiltrate into the soil for tertiary treatment and storage of water to meet the growing demand of wastewater reuse. In this study, a pilot plant of three soil columns of 2 m hight and 25 cm diametrwere designed and fabricated to study the quality improvement of the conventional effluent treated wastewater using three types of soil (fine, medium and coarse sand). The pilot was operated under three operational phases, The first phase was worked as 4 days wetting followed by 3 days drying cycle for a period of 6 months, the second phase was worked as 3 days wetting followed by 4 days drying for a period of two months. Meanwhile the third phase worked as 5 days wetting and 2 days drying for two months. The pilot plant of columns was feeding using the effluent of Qahasecondary wastewater treatment plant.
The results indicated that, the medium sandy soil operating with 3 days wetting/4 days drying cycles had the highest removal performance for BOD, COD and TSS (64%, 38 % and 86%) respectively. Fine, medium and Coarse soils can be operated under both 3 days wetting/4 days drying cycles and 5 days wetting/2 days drying cycles to meet the nitrification requirements of SAT under the Egyptian conditions