Optimizing the energy performance of a demineralization unit using an energy recovery device: Application to the Moroccan context

The demineralization of brackish water through reverse osmosis (RO) represents a strategic and sustainable solution to meet the increasing water demands in the southeastern regions of Morocco, particularly in arid areas such as Zagora. Despite its effectiveness, the RO process remains highly energy-intensive, primarily due to the operation of high-pressure pumps, which account for 40% to 55% of total operating costs. Furthermore, a substantial amount of hydraulic energy is lost when the concentrated brine is discharged at atmospheric pressure, highlighting a major inefficiency. To address this challenge, the present study investigates the integration of an isobaric Pressure Exchanger (PX) as an energy recovery device to enhance the energy performance of a reverse osmosis unit. Using real operational data collected from the Zagora demineralization plant specifically pressure and flow rate readings from the OS1 and OS2 reject lines a detailed numerical simulation was conducted to quantify the recoverable hydraulic energy and analyze its variation over time. The results emphasize the critical role of energy recovery technologies in improving the sustainability, efficiency, and environmental footprint of desalination plants in Morocco. Integrating such systems aligns with the country’s strategic goals for resource optimization and the energy transition in water infrastructure.