Outline of Water Treatment

Outline of Water Treatment

	Outline of Water Treatment Although certain treatment stages are common to both drinking water treatment and wastewater treatment, the two processes are entirely different and have their own requirements and aims. The primary aim in wastewater treatment is to reduce the BOD level whereas in water treatment the primary aim is to remove potential pathogens. The preliminary treatment in water purification is the removal of large floating and suspended solids through screening and straining.
The next stage is the aeration of raw water to allow the precipitation of iron and manganese compounds which can be removed by sedimentation or filtration. Thus the next stage involves the sedimentation of suspended solid matters. In certain cases sedimentation requires pretreatments like coagulation and flocculation. Alum is the widely used coagulant in water treatment. After sedimentation the water is subjected to filtration through porous media such as sand. There are two types of sand filters, rapid sand filters and slow sand filters.
Finally the treated water is disinfected with chlorine or other agents before discharge into the distribution system.It should be remembered that not all these processes are necessary for the purification of water. Depending upon the quality of raw water different process may be employed in combination. A detailed account of the treatment process is given in subsequent chapters.

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Disinfecion Drinking Water Chemical Disinfection Chemical Disinfection by Chlorine Chemical Disinfection by Ozone Chemical Disinfecion by Pottassium Permanganate Chemical Disinfection by Halogens Physical Disinfection by UV Radiation Germicidal Efficiency