Desalination is based on the principle of evaporation: The seawater that has been filtered through a thick mesh is evaporated in a stack of titanium plates so as to be able to remove the salt and impurities. Then, another array of plates condenses the steam into drinking water. An important factor in salt measurement is the residual salt content, which must be less than 4 ppm). If a 4-ppm minimum can be reliably maintained, then the desalinated water can be transferred to a storage tank and further treated by sterilization through ultraviolet radiation.