Water treatment is a process of purifying river or underground water so that it will be potable. This is different from the purification of raindrops, domestic water or industrial water into clean water. This is the reason why the water treatment process is more complicated. Suspended matter in source water is settled down in the grit chamber, and source water is mixed with cohesive agents with a flash mixing device, and then coagulated substance in cohesive sediment devices is sunk by clarifier and then is dehydrated at belt filter. Clean water at the top made from clarifier is filtered using a Duhamel media filter before arriving at the purifying plant and being made into drinking water with chemical treatment.