Sunday, 31 March 2013

Water Supply and Demand

Water supply:

Water supply system infrastructure for the collection, transmission, treatment, and storage of water for homes, professional businesses, industry, and irrigation, as well as for such public needs as firefighting and street flushing. Of all public services, provision of safe and clean water is perhaps the most vital. People depend on water for drinking, cooking, washing, carrying away waste materials, and other domestic needs. Water systems must also meet specifications for public, professional, and industrial activities. In all cases, water must fulfill both quality and quantity specifications.

Development in supply systems:

Water was an important aspect in the location of the first settled communities, and the progress of public water supply systems is tied directly to the growth of places. In the development water resources beyond their natural condition in rivers, ponds, and springs, the digging of superficial wells was probably the first innovation.

Construction of Qantas, a slightly sloping tunnels motivated into hillsides that included groundwater, probably originated in ancient Persia about 700 bce. From the hillsides the water was conveyed by gravity in open channels to nearby towns or cities.

Development in water treatment:

Water treatment is the alteration of a water source to experience a quality that fits specified goals. At the end of the 19th century and the beginning of the 20th, the definitive goal was reduction of dangerous water-borne diseases. The treatment of public drinking water to eliminate pathogenic, or disease-causing, harmful bacteria began about that time. Treatments methods included sand filtration system as well as the use of chlorine for disinfection. The virtual elimination of diseases such as cholera and typhoid in developed countries showed the success of this water-treatment technology.

Water Sources Demand:

Water is present in numerous amounts on and under the Earth's surface, but less than 1 percent of it is fluid water. Most of Earth's approximated 1.4 billion cubic km (326 million cubic miles) water is in the oceans or frozen in polar ice caps and glaciers. Sea water contains about 35 grms per liter (4.5 ounces per gallon) of dissolved minerals or salt, making it unsuitable for drinking and for most commercial or agricultural uses.