Water is a essential natural resource. Its shortage and contamination is one of the most important ecologic challenges in the future, and now it´s a crucial problem in a lot of south countries: a third of the population doesn´t have access to water with hygienic conditions, which is the origin of more than six million of deaths per year, according to OMC reports. In the future the situation will be more serious: with the growth in the consumption, the climatic change will be responsible of a reduction of the hydric resources, especially in the Mediterranean basin.