Water purification is the process through which we remove the undesirable chemicals, contaminants, gases and suspended solids from the water to make it fit for drinking purposes or for other specific use. The methods used for purification of water include filtration, distillation, sedimentation or the biological processes that include slow sand filters and biologically active carbon or the chemical processes that include chlorination, flocculation and using electromagnetic radiation like the ultraviolet light.
International standards or the Government set up the standards for the drinking water quality. The standards denote the minimum and maximum amount of contaminants allowed which depends on the purpose of use of water. Analysing the water is essential for maintaining the health of the entire community. It involves looking and removing contaminants from the water including the unsafe levels of the inorganic, organic, microbial and the radioactive contaminants.
WATER PURIFICATION PROCESS
There are various types of water purification processes. Some of the methods include-
– Screening – Water from water bodies or the ground is passed through a screen as it slowly enters the
treatment plant. If the water is from a lake or river, the screen keeps out the large natural contaminants
like wood, plants or fish. If the water is from ground, there is no screening since water already went
through a number of layers of Earth for screening.
– Coagulation – The workers at the treatment plants add alum along with other chemicals in the water which
causes the tiny sticky particles called floc to form. The floc attracts the dirt particles which make them
heavy and they sink to the bottom of the storage tank.
– Sedimentation – The floc along with water flows into a sedimentation basin where the floc settles to the
bottom until its removal.
– Filtration – The water is passed through layers of gravel, sand and charcoal which helps in filtering out
the remaining particles. The layer of gravel is 1 foot deep and the sand layer is kept to be 2.5 feet deep.
– Disinfection – Water enters the reservoir where chlorine and other disinfecting chemicals are added into it
to kill the remaining micro-organisms for keeping it clean for distribution. If the water treatment
facility uses ground water s its source of water, then disinfection might be the only step required for
treating the water properly. After the purification, the water sits in the reservoir until it is supplied
to the households and the businesses.