Research subject: The scarcity of freshwater resources and the rapid growth of population have made the development and deployment of efficient desalination technologies an undeniable necessity for securing reliable supplies of drinking and industrial water. In this regard, the present study focuses on the modeling, validation, and techno-economic assessment of two widely applied technologies, reverse osmosis (RO) and multi-effect distillation (MED), as well as their integration in standalone and hybrid configurations.
Research approach: In the modeling stage, the key components of each process, including pumps, pressure exchangers, pretreatment units, and main desalination modules, were simulated with high accuracy using established mathematical correlations. Calibration and validation were carried out with the aid of WAVE software and field data from existing industrial plants, ensuring consistency between simulation results and practical operation. Four configurations, including RO, MED, RO-MED, and MED-RO, were investigated under identical feedwater conditions (50,000 m³/day, salinity of 30,000 mg/L) and defined operational constraints. The evaluation criteria included product water quality, recovery ratio, electrical and thermal energy consumption, and specific water production cost.
Main results: The results showed that, among the four standalone and hybrid RO and MED scenarios, the standalone RO system had the lowest levelized cost of water at 0.386 USD/m³, making it the most economical option. Its cost was about 38%, 19%, and 58% lower than MED, RO-MED, and MED-RO, respectively. In contrast, the product water quality of RO was 93%, 42%, and 47% lower than these alternatives. Sensitivity analysis revealed that increasing electricity price raised the cost of standalone RO by up to 78%, while higher fuel cost increased the MED cost by 85%. Moreover, variation in the interest rate had the strongest impact on MED-RO, raising its cost by up to 40%. In addition, the RO-MED hybrid configuration proved to be an economical alternative compared with other options, while ensuring higher water quality. These findings highlight that the optimal choice of technology strongly depends on local conditions such as energy price, availability of waste heat, and required product quality.