ABSTRACT
T h e g r o w t h in world population and the related increase in global economic activity represents a dramatic increase in pressure on natural resources. Among natural resources water is fundamental to life and its availability or scarcity represents a strategic parameter for planning sustainable development (The World Resources Institute, 1992). This fact, while of fundamental importance in arid regions, is of relevance also in countries that have a large amount of freshwater resources. According to the Falkenmark’s (1982) water scarcity index, and for the sake of comparison among countries, the availability of 1 0 0 0 m3 per person per year can be assumed to represent the “water barrier” below which chronic water scarcity occurs. The calculation includes only re newable internal resources while annual withdrawal takes into account both exterior inputs (e.g., river flows from different countries) and desalination capacities. This evaluation shows that even developed countries like France, Spain, Italy, and the UK (Ayoub and Alkward, 1996) are water-stressed regions. Due to an increase in exhaustion of resources, those countries could suffer a decline in water consumption, which would mean a decrease in the quality of life. As a consequence, severe water quality criteria are introduced for water use, water treat ment processes become more complex, and costly efforts in R&D are undertaken to make available cleaner and more efficient water treat ment technologies.
