In the second step the gravel and sand sink to the bottom.
Explanation:
There are various techniques used for cleaning the water they are coagulation, sedimentation, filtration and disinfection.
Coagulation:
The process in which chemicals are added to water and the positive charge of the chemicals neutralizes the negative charge of dirt and other particles in water.
Sedimentation:
During this process the tiny mineral particles settle at the bottom of the water supply. This process of settling is known as sedimentation.
Filtration:
When the tiny particles has settled to the bottom of the water supply, the clear water will pass through the filters of varying compositions and pore sizes to remove the dissolved particles like dust, bacteria, viruses and chemicals.
Disinfection:
After filtration process a disinfectant like chlorine, chloromine are added to kill any remaining bacteria and viruses. The quality of water is tested and they are piped to all homes.