Water Reuse in Algerian Oasis Region: Institutional Management Bottlenecks and Demonstration of Operational Feasibility

International audience

English. In the Algerian Sahara, non-renewable groundwater resources estimated at 5 billion m3 thus constitute the indispensable support for irrigation. In the Berriane region in the north of Ghardaïa region (center of Algerian Sahara), an agricultural perimeter called Oued El Bir (300 ha in total) was officially created in 2013 downstream a wastewater treatment plant. A “frontier settlement” that proves the high value placed on this resource.As part of Massire project financed by IFAD (2018-2024), the objective of our study was to analyze the water reuse practices in this Berriane arid region, i.e. to study the importance of the institutional management of the treated wastewater reuse on the one hand. And on the other hand to show that the malfunctioning of the wastewater treatment plants can lead to many side effects such as the infiltration of raw sewage into the groundwater, illicit untreated wastewater irrigation and a slowdown in the development of the agricultural perimeter. Our research methodology is founded, firstly, on interviews with the local stakeholders (about 20 surveys with farmers and local institutions) and, secondly, on isotopic, chemical and biological water analyses that will be carried out soon to validate the hypothesis of infiltration of wastewater into the aquifer. In addition, to address the institutional opposition and issues relating to the technical sustainability of water reuse in the region, we implemented a water reuse demonstrator. The choice of location and equipment was determined in concertation with local stakeholders. The decentralized treatment process is based on a septic tank and a fixed bacterial filter (Advanced Enviro Septic) with 10 m3/day capacity. The treated wastewaters are used to irrigate a 1 ha surface of the new oasis area. As part of our study, we are investigating the sanitary and agronomic safety of this new treatment process for water reuse in the arid context.