الفهرس 
SUMMARYOnly 14 pages are availabe for public view
 |  | from | 148 |  |  |
| | | from | 148 | | |
Abstract
Water covers 71% of the Earth’s surface. It is vital for all known forms of life. On Earth, 96.5% of the planet’s water is found in seas and oceans, 1.7% in groundwater, 1.7% in glaciers and the ice caps of Antarctica and Greenland, a small fraction in other large water bodies, and 0.001% in the air as vapor, clouds (formed of solid and liquid water particles suspended in air) and precipitation. Only 2.5% of the Earth’s water is freshwater, and 98.8% of that water is in ice and groundwater. Less than 0.3% of all freshwater is in rivers, lakes, and the atmosphere, and an even smaller amount of the Earth’s freshwater (0.003%) is contained within biological bodies and manufactured products(1).
The water demand doubles globally every 21 years due to the rapid increase in population and the industrial activities. Compounded with this is the decrease in rainfall in the previous decade. More than 80 countries accounting for 40% of the world’s population are facing major water crises. It has been estimated by UN that by )2025(, 2.7 billion people will be affected by water deficiency. Many countries are facing the shortage of clean drinking water and it is estimated that 1.2 billion people are already drinking unclean water. Furthermore, 5-10 million people die annually due to various diseases caused by the consumption of contaminated water. Thus, exploitation of safe water sources to overcome the scarcity of water has been a global challenge for many countries. The increasing demand of clean water has attracted much of the government organizations and water industries to develop cost-effective technologies for water/wastewater treatment and reclamation(2,3).