Journal of Earth Sciences and Geotechnical Engineering

Enhancement of the Efficiency of Infiltration Basins for Effluent Recharge

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• Abstract

  The Gaza Strip suffers from high pressure imposed on its water resources. There is a deficit of about 50 MCM (million cubic meters) every year, which has led to a declination of groundwater level and deterioration of groundwater quality. The Agricultural sector in the Gaza Strip consumes around 75-80 MCM of water annually. Water used for this purpose comes mainly from groundwater wells. New water resources are sought to fulfill the water deficit; among them is the artificial recharge of treated wastewater to groundwater by the mean of spreading basins. Recovery of the infiltrated treated wastewater is envisaged as a mean to support the agricultural sector in Gaza. In order to investigate the performance of the infiltration system in terms of quantity and quality, field experiments were performed. In addition to that, modeling of the unsaturated zone using theGreen-Ampt model (1911) was performed in order to predict the existing andenhanced infiltration rate. The results showed that the infiltration rate is affectedby the soil type, and its permeability, also with the quality of the effluent water to the basin. Removing the upper 2.0 meters of soil layer at IB1 and replacing it with new sand martial with high permeability introduced an efficient solution for the enhancement of the infiltration rate. Also penetrating the lower soil layers with 60 piles and filling the piles with gravel fine media with high permeability will increase the infiltration rate for whole of the basin according to the study.Performing 35 cycles of wetting and drying during the year with 2 days of wetting in summer and winter and 7 days of drying in summer and 12 days of drying in winter, will help to reach the optimal infiltration rate. Soil plowing after each drying cycle for the basin will maintain good infiltration rate and prevent accumulation of the organic matter (OM) in the top soil layer.