Urban Water Cycle Essay Example | Topics and Well Written Essays - 1250 words - 1

Urban Water Cycle - Essay Example Most urban centers receive their supply of water from a definite water entity such as a river, lake or a dam. The land area that surrounds the water source is its catchment. The level of cleanliness of a catchment area determines the water quality of the dam or river. A town that uses a dam or several dams as water reservoirs will receive water from rivers. In this regard, the state of the river will determine the water quality that enters the dam. The dam is the storage point for the water from rivers. It is normally built adjacent to a river to block a section of the flowing water and store it. It is from the dam that the urban population receive reliable water supply for their use. Although the water in the dam might look clear, it is not fit for human consumption yet. This is because it contains pollen, soil particles and dust. These particles contain viruses, bacteria together with several other microorganisms that can be harmful to human health. To remove these microorganisms, the water from the dam is first processed in a water treatment plant prior to its use. The water goes through some specific stages and steps at the treatment plant. Such stages include pre treatment, flocculation, filtration and chemical dosing. At the pre treatment level, a polymer called coagulant and alum is added to the water. The substances help to capture the solid particles that provide host to bacteria and viruses. The water free of the particles remains less turbid and clean. At the flocculation level, there is the removal of solid particle from the water. Mixing and circulation occurs for the solid particles captured in the pre treatment step to float on top in the form of froth. At the filtration level, the water is pumped through filters to get rid of the remaining particles. Finally, there is the addition of chlorine to get rid of the remaining microorganisms or germs, if any at the chemical dosing stage. This stage also involves the addition of fluorine for teeth prote ction and the adjustment of the pH level of the water.     After the above stages of treatment, the bulk main pipes supply carries the treated water to reservoirs allowing its distribution into smaller pipes into households. The reservoirs help the water stored to adjust with the changing demands. It also assists in the management of the pressure from users so that it flows to taps at expected speeds. Reservoirs can be either above or below the ground. The reservoirs supply water into homes through the service lines than branch from the mains pipe. After use at home, the water goes down the drain from where it enters the network of wastewater. The wastewater then flows into the sewerage system.