Water purification is removal the contaminants from untreated water,then produce drinking water.
It is pure enough to use it after clean, commonly used to human consumption. During the process
of clean the drinking water,adsorb various impurities include suspended solids, bacteria, algae,
viruses, fungi, minerals such as iron, manganese and sulphur, and man-made chemical pollutants
including fertilisers.
It is important to take measures to make available water of desirable quality at the consumer end.
So, we should protect the treated water during conveyance and distribution after treatment. The
common practice is residual disinfectants in the treated water to kill any bacteriological contamination
after water treatment.
Generally all the world's drinking water should followed throughout the drinking water quality requirements
of World Health Organisation (WHO) guidelines . In addition to the WHO guidelines, each country or territory
or water supply body can have their own guidelines for consumers to use the safe drinking water.
Processes for drinking water
The following processes of water treatment is used to municipal drinking water treatment worldwide:
▲Pre-chlorination - for algae control and arresting any biological growth
▲Aeration - along with pre-chlorination for removal of dissolved iron and manganese
▲Coagulation - for flocculation
▲Coagulant aids, also known as polyelectrolytes - to improve coagulation and for thicker floc formation
▲Sedimentation - for solids separation, that is, removal of suspended solids trapped in the floc
▲Filtration - removing particles from water
▲Desalination - Process of removing salt from the water
▲Disinfection - for killing bacteria.
There is no unique solution (selection of processes) for any type of water. Also, it is difficult to standardise the
 solution in the form of processes for water from different sources. Treatability studies for each source of water
 in different seasons need to be carried out to arrive at most appropriate processes.
The above mentioned technologies are well developed and generalised designs are available which are used
by many water utilities (public or private). In addition to the generalised solutions, a number of private companies
provide solutions by patenting their technologies.