There are FIVE stages in the water treatment process:
Alum and other chemicals are added to the water. The chemicals help to trap all the solid waste in the water to form “floc.”
During this stage, particles get stuck together and they become heavy and sink to the bottom of a big chamber.
As water passes slowly through this chamber, finer particles are filtered out over layers of sand, charcoal and gravel.
During this stage, chlorine or other kinds of disinfection methods are applied to kill all the bacteria, fungus and other living organisms that may be in the water. It is very normal and natural for fresh water to contain living organisms.
The water is then passed into large storage tanks and left for a while for the action of disinfection to be complete. At the end of the storage tank, huge pipes are connected to transport the fresh clean water into our homes and schools.
Does your city have a larger water tank for storing water?? That is one common method for storing clean water that has already been treated.