Essay On Filtration Of Water

Water is one of basic requirements for living things for survive. Our Earth has been occupied by about 70% of water (The National Aeronautics and Space Administration (NASA), 2007). According to American Water Works Association (2002), 97% of water on Earth is salt water, which consists of salt and other minerals. Human beings cannot consume salt water and it is hard to remove salt from salt water. It is need very high cost for removal of salt from salt water. Glacier ice at the North and South Poles are made up from water, which is 2 % from the water of Earth. Although glacier ice contains fresh water, but they take time to melt and difficult for living things to get the sources. Therefore, human beings only left less than 1 % of water can be used for daily life purposes such as drinking, transportation and cooking. Water treatment has been introduced to ensure water on Earth keeps clean and not being polluted. Water treatment is a process to produce safe water for consuming without risk by altering the characteristics and composition of water (Lonholdt,

Filtration is a process of removal of the fine particles such as silt, clay, colloids and microorganisms from water by passing through a porous medium normally is sand in the filter tank (Raju, 1995). Floc which are retaining in filter tank after coagulation and sedimentation will be removed in the filter tank. In the filter tank, water pressure exerted from above and absorption from bottom force water passed down through filter bed (Hammer, 2001). All the collected solid particles will be captured and water will pass through the sand. According to Vigil (2003), solid particles which are trapped in the filter will be removed by a process called backwashing in the filter tank. Process of backwashing is carried out periodically where the clean water moved backward again and water will collected in wash troughs located above the filter