screens may be used to remove rocks, sticks, leaves and other debris; chemicals may be added to control the growth of algae; and a presedimentation stage can settle out sand, grit and gravel from raw water.
Turbidity is a physical characteristic that makes water appear cloudy when suspended matter is present. The filtration process removes suspended matter, which can consist of floc, microorganisms.
Disinfection is normally the last step in purifying drinking water. Water is disinfected to destroy any pathogens which pass through the filters.Possible pathogens include viruses, bacteria.