Wastewater reclamation using discarded reverse osmosis membranes for reuse in irrigation in Djibouti, an arid country Mohamed Osman Awaleh, Moussa Mahdi Ahmed, Youssouf Djibril Soubaneh, Farhan Bouraleh Hoch, Samatar Mohamed Bouh and Elias Said Dirieh ABSTRACT The purpose of this paper is to establish the feasibility of recovering discarded reverse osmosis (RO) membranes in order to reduce the salinity of domestic treated wastewater. This study shows that the reuse of RO membranes is of particular interest for arid countries having naturally high mineralized water such as Djibouti. The pilot desalination unit reduces the electrical conductivity, the turbidity and the total dissolved salt respectively at 75–85, 96.7 and 95.4%. The water produced with this desalination unit contains an average of 254 cfu/100 mL total coliforms and 87 cfu/100 mL fecal coliforms. This effluent meets the World Health Organization standards for treated wastewater reuse for agricultural purposes. The annual cost of the desalination unit was evaluated as US $/m 3 0.82, indicating the relatively high cost of this process. Nevertheless, such processes are required to produce an effluent, with a high reuse potential. Mohamed Osman Awaleh (corresponding author) Farhan Bouraleh Hoch Laboratoire de Chimie, Institut des Sciences de la Terre, Centre d’Etude et de Recherche de Djibouti (CERD), Route de l’aéroport, B.P. 486, Djibouti E-mail: awaleh@gmail.com Moussa Mahdi Ahmed Laboratoire de Chimie de Provence (UMR6264), Université de Provence (Aix-Marseille I), Centre de Saint-Jérôme, av. Esc. Normandie Niémen, 13397 Marseille, France Youssouf Djibril Soubaneh Institut des sciences de la mer de Rimouski, Université du Québec à Rimouski, 310 Allée des Ursulines, Rimouski, QC, Canada G5L 3A1 Samatar Mohamed Bouh Service d’Epidemiologie, Laboratoire National de Santé Public, Ministère de la Santé de la République de Djibouti, B.P. 1974, Djibouti Elias Said Dirieh Hôpital Général Peltier, Ministère de la Santé de la République de Djibouti, B.P. 1974, Djibouti Key words | irrigation, membrane, reuse, reverse osmosis, wastewater INTRODUCTION The republic of Djibouti (23,000 km 2 , 818,000 inhabitants), which is located in the Horn of Africa, faces severe difficul- ties regarding water supply. About 70% of the population of the republic of Djibouti lives in the capital city of Djibouti. The drinking water used in Djibouti-city is abstracted from the Gulf basaltic aquifer. The continuous and drastic increase in water demand, due to the rapid development of the capital, particularly during the last two decades, has led to an intensive exploitation of this aquifer and has severely depleted its reserves and led to deterioration of its quality (Houssein & Jalludin ). According to the Djibouti national water supplier, 15.6 million m 3 of water were produced in 2010, while the needs were estimated at about 30 million m 3 , hence almost 48% of needs were not fulfilled (ONEAD ). In addition, almost 30% of the produced water was used for agricultural purposes. On the other hand, Djibouti-city’s tap water has an average electrical conductivity of 4,020 μS/cm. Over 1362 © IWA Publishing 2013 Water Science & Technology | 67.6 | 2013 doi: 10.2166/wst.2013.011