Sand (silica) in its different forms (sand, silex, gravel) is the oldest natural available granular filtration media. Even today, the use of sand remains popular for the treatment of municipal water in very big open gravity filters, in swimming pool filters and in pressurized filters for the treatment of ground water.
In a lot of groundwater applications the use of sand has been replaced with other granular filtration offering more benefits (faster flow rate, better quality of filtrate, lower in weight, etc.) such as Turbidex
