How is water treated for use in homes?
All over the world, fresh water is treated differently at a treatment center before it is sent to your home. Surface water is more often treated rigorously than underground water, as it has less contaminants.
The diagram below show a basic water treatment process for surface water.
Alum and other chemicals are added to the water at this stage. Suspended particles get stuck to the chemicals to form 'floc'.
As particles get stuck they become heavy and sink to the bottom of the chamber. At this stage, most of the particles are stuck to form sediments, sinking to the bottom. The water is passed onto the Filtration chamber.
As water passes slowly through this chamber, finer particles (sediments) are filtered out over layers of sand, charcoal and gravel.
Chlorine or other kinds of disinfection methods is applied to kill any bacteria 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 tail end of this storage tanks, huge pipes are connected to transport water to our homes and work places.