At the beginning of the 20th century, anthracite coal, which has been used as a filtration mineral, has been passed through various stages and is produced in appropriate size, uniformity and hardness. Due to its angled shape, less backwash is required compared to the filter sand. The reverse rinsing is also considerably lower.
Because it has a very low density, it functions as the top layer of multilayer filters.
Density: 50 lbs / ft3
Diameter: 0,6 - 2 mm
Uniform Coefficient: Less than 1.7
Mesh Size: varies from 14 x 30 to 4 x 12.
Spesific Weight: 1.6 gr / cm3
The bed height should be 60 cm - 76 cm (single media filter), 25 - 46 cm (multi media filters).
The service charge may be higher than 5 gpm / ft2 or depending on local conditions,
reverse rinsing 1 and 1.5 anthracite 1.5 to 25 gpm/ft2, number 2 anthracite should also be added with air backwash option.