Desalination converts brackish or saline water to fresh water that is suitable for potable or industrial uses. The process is increasingly being used in both inland and coastal areas where conventional freshwater resources are unavailable or else currently used resources are being adversely impacted by overuse.
Desalination systems have four main components: the intake system, pretreatment steps, the actual desalination system and the concentrate disposal systems. Reverse-osmosis (RO) is now the most commonly used desalination process for new systems. However, multistage flash distillation (MSF), multiple-effect distillation (MED), electrodialysis reversal (EDR), and other processes are preferred in some circumstances. Raw water supply and concentrate disposal can be critical feasibility, regulatory, and economic issues.
Selection of the type of desalination plant is part of the overall optimization of the desalination/power cycle. Studies are performed covering water balance, water cost calculations, thermodynamic considerations, and material properties to ensure minimum cost and optimum process. Efficiency, reliability, and maintenance costs are forecasted, and reservoir capacity, blending plant, intake, and brine effluent systems are then considered to meet water consumption and site requirements.
