Effects of Municipal Reclaimed Wastewater Irrigation on Organic and Inorganic Composition of Soil and Groundwater in Souhil Wadi Area (Nabeul,Tunisia)

Abstract

Tunisia has mobilized the important amount of its conventional hydraulic resources (surface water and ground water). It is brought today, for considerations of saving of water but also in environmental ethics, to recycle its noconventional resources like municipal waste water and to applicant it for agriculture. The effect of treated wastewater (TWW), compared to the ordinary irrigation (with ground water (GW)) by means of tow irrigation methods (sprinkler (S) and integrated Gouttor (IG)) on the chemical properties of the sandy soil, and its organic composition, were investigated in 2004 at the experimental station of Oued-Souhil in Nabeul Governorate, NE Tunisia. Soil samples were collected from five depths (0–20, 20–40, 40–60, 60–80 and 80–100 cm) and were analyzed for electric conductivity (EC), pH, total nitrogen (TN), organic carbon (OC), potassium (K), phosphorus (P205) and nitrate (NO3 -). The results observed after a partner of irrigation show that the electric conductivity (EC) and pH of experimental soil decreased compared to his initial state. The irrigation has reduced the OC content in surface layer and has increased it in the deeper layer. The TN content varied in opposite direction. The P205, K and NO3 - concentrations decreased in the upper 40 cm at the end of the study for both TWW and GW irrigated soil; however the effect of TWW irrigation was significant only with potassium (K). The evolution of these elements in the soil during the study proves their important concentration in the GW.