Performance, Salinity Constraints, and Agricultural Reuse Potential of Treated Wastewater in a Hyper-Arid Oasis: The Timimoun WWTP Case Study, Southern Algeria

Today, the reuse of treated wastewater is considered an important and strategic driver for integrated and sustainable water and soil management in extremely arid desert regions, where significant constraints due to water scarcity, soil salinization, and the fragility of agricultural ecosystems within palm oases place a strain on all sustainable development policies. Through this study, we conducted a comprehensive evaluation of the performance of the treatment, as well as the constraints related to salinity and the implications for the land management of the activated sludge wastewater treatment plant located in the Timimoun desert oasis in southern Algeria. Through monthly monitoring over a 12-month period, we were able to perform an analysis of physicochemical, nutritional and microbiological parameters, as well as a seasonal analysis, in addition to calculating irrigation suitability indicators using first-order kinetic modeling of COD degradation. The results obtained showed high reduction rates for COD (90%), BOD5 (90,5%), and TSS (93.8%), confirming the resilience and effectiveness of biological treatment under very difficult and hostile climatic conditions. Furthermore, the ultraviolet disinfection process ensures microbiological quality that allows for reuse of treated water in agriculture. However, the residual salinity of this water remains a significant limiting factor for sustainable reuse, highlighting the need to integrate soil management strategies, crop selection, and irrigation management into regulatory frameworks for wastewater reuse. Therefore, this study provides us with important and useful scientific data for developing sound and sustainable water and land management policies in the harsh climate of Saharan oases.