ABSTRACT
Water is vital for all forms of life and for all types of industrial development. Although it covers around 70% of the earth’s surface, only 3% of the earth’s water is fresh water and about 99% of this latter is locked in polar ice and not readily accessible as groundwater so that less than 0.1% of the global water resource is available for people and ecosystems (Drioli and Macedonio, 2012). The availability of drinking water has nowadays become a worldwide problem due to the continuous growth in water demand that has not been balanced by an adequate replenishment. Furthermore, water sources are suffering ever more frequently from a worsening of their quality due to the indiscriminate discharge of both domestic and industrial effluents without adequate treatment (Macedonio et al., 2012). The UN predicts that by 2025, two-thirds of the world’s population will live in areas of significant water stress, lacking sufficient safe water for drinking, industry or agriculture (United Nations, 2010). The lack of fresh water is further aggravated by factors such as pollution and the inequality of its distribution. People’s access to drinking water is therefore a major challenge for the coming decades, not only for developing countries but also for the industrialized states (Shannon et al., 2008). Another important and emerging issue is the removal of contaminants increasingly identified in water streams, such as hydrophilic organic compounds, disinfection byproducts, pharmaceutical compounds and also many different ions originating from electronic products which often end up in landfills, thus contaminating land, water and air (Macedonio et al., 2012).
