Anthracite

• Higher service flows and longer filter runs than equivalent sand filters
• Close attention to gradation, hardness and purity assures consistent and reliable performance
• Unique density allows Clack Anthracite to be combined with other filtration media in multi-media filters
• Lower uniformity coefficient has less oversized and undersized particles resulting in a highly uniform bed

Although its potential for water treatment has been recognized since ancient times, anthracite coal was not used for this purpose until the beginning of the 20th century. Crushed Anthracite makes an excellent medium density filtration media. Clack Anthracite is mined from the finest Pennsylvania coal. It is specifically selected for water treatment, and during its production goes through several sizing inspections. Representative samples are randomly chosen for a complete laboratory quality control analysis for effective size, uniformity coefficient, specific gravity, acid solubility and hardness.

Because of its angular shape, some of the sediment penetrates deeper into the bed. When compared to equivalent filter sands, this means longer filter runs and less head loss. Backwash rates are also reduced.