Water is the foundation of life. Although 75% of the Earth’s surface is covered by water, 97% of the water is salty water, leaving only 3% as fresh water. However, two-thirds of the fresh water on Earth is frozen in snow and ice in glaciers and ice caps, which leaves only about 1% of all the Earth’s water as liquid and fresh, making it a very scarce natural resource. Nowadays, water scarcity is a severely growing problem in semi-arid desert regions, land-scarce countries, and in countries with high levels of economic activity. As more people put ever increasing demands on...