**1. Introduction**

Desalination is a process through which pure water is obtained from water with a high concentration of dissolved salt (seawater or brackish water). In general, in a desalination plant, there is an inlet flux of salted water and two outlet fluxes (**Figure 1**).

One of the outlet fluxes (the brine) has a concentration higher than the inlet flux, and the other has a much lower concentration than the inlet flux (drinking water). To achieve that high reduction of solute concentration, it is necessary to deliver a certain amount of energy. The consumption of energy of a desalination plant is generally evaluated in terms of the quantity of energy used for each cubic meter of drinking water obtained. This parameter is called the specific energy consumption expressed

**Figure 1.** *Simplified scheme of a desalination unit.*

in kWh/m3 . Among all desalination processes, we will briefly describe the reverse osmosis process for it is the one used with the system proposed in this chapter.
