Assessment of Influence of Percolation Pits on Groundwater Quality in Gaza Strip (Khan Younis As Case Study)

Abstract

The majority of rural areas, which are not connected to an engineered-sewage system, depend primarily on Percolation Pits in order to dispose wastewater. Contemporary, 92% of rural houses dispose wastewater to either Percolation Pits or open channels. In most cases, the untreated water contained in septic tanks is likely to be leaked down into the soil and then into groundwater, collected by tank-vehicles or left flowing in the valleys without any treatment. These practices lead to significant deterioration of the environment and the quality of drinking water. Percolation Pits had been widely adopted in Khan Younis city before the establishment of the first sewerage system in 2008 serving 65 % of the population and covering 35% of the Khan Yunis area. During the development stage, 500 Percolation Pits were destroyed as they were blocking the routes of the new network. According to CMWU, Khan Yunis had approximately 2500 Percolation Pit’s in 2008. This study aims to assess the impacts of Percolation Pits on soil and groundwater in Khan Yunis because it is considered a strategic aquifer of ground water in the Gaza Strip. Two Percolation Pits are covered in this study. The first Percolation Pit is located in the eastern area “Satar Sharqi” where the ground water level is 37m below the ground. The second Percolation Pit is located in Al-Mawasi area where groundwater is only 4 meters below the ground (Al-nazaz water), several factors (e.g. location of Percolation pit, Type of soil ,Distance to surface water ,System Age , Soil / Topography) were taken into considerations while choosing the location of the study area. Soil samples were extracted from a distance of one and a half meters from the edge of the Percolation pit at different depths (1.5, 3, 6, 9, and 13) m beside the pits. Organic Matter, Total Nitrogen, and Fecal Coliform tests were carried out for all samples. Both Wastewater and groundwater were, to conduct various water-related tests (e.g. pH, BOD, COD, Total Suspended Solid, and TC). The study shows that the groundwater in Al-nazaz area contains significantly high contamination, therefore it is not suitable for both drinking and agricultural us. Accordingly, recommendation and future interventions are made to tackle the problem.