Demineralization of brackish surface water using reverse osmosis: A case study of Zagora in the Draa-Tafilalet region, Morocco

The study brings into consideration and enriches the areas of hydrology, energy engineering, and sustainable development by the enhancement of the environmental and energy performance of a reverse osmosis (RO) plant in Zagora, Morocco, which is treating brackish surface water, very thoroughly. The whole idea is to check IMSDesign software predictions' reliability against operational data of more than a year. In simulations with Hydranautics ESPA2-LD membranes, a feed flow of 125 m³/h under 9.1 bar was forecasted eventually giving rise to 93.75 m³/h of permeate and a recovery rate of 75%. On the other hand, actual field measurements over a period of more than a year indicated always lower results. For instance, the first RO train averaged a feed flow of 109.1 m³/h at 9.8 bar with a 63% recovery, while the second train performed not much differently. Seasonal changes in water conductivity, temperature changes, and membrane fouling were found to be the main reasons for the discrepancy. Also, the actual reject flows (22.1–23.8 m3/h) were less than the predicted 31.25 m³/h. The modeling tool is still considered useful for the initial system design; however, this research indicates the need of continuous monitoring, adaptive maintenance strategies, and pretreatment efficiency evaluation especially by improving the environmental performance and energy efficiency of inland water treatment infrastructure in arid regions in arid areas.