Anthracite
Although its potential for water treatment has been recognized
since ancient times, anthracite coal was not used for
that purpose until the beginning of this century. Crushed
anthracite makes an excellent medium density filtration
media. Anthracite has been manufactured from the finest
Pennsylvania coal since 1932. It is specifically selected for
water treatment, and during its production goes through several
sizing inspections. Random samples are chosen for a
complete laboratory quality control analysis for effective size,
uniformity coefficient, specific gravity acid solubility and hardness.
Because of its fractured shape, some 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.
Anthracite, because of its unique density, can be used in
multi-media filters. At 56 lbs./ft.3 it will hydraulically classify
and remain above heavier medial such as Filter Sand or
Manganese Greensand providing a prefiltration layer.
Advantages:
- Higher service flows and longer filter runs than
equivalent sand filters.
- Close attention to gradation, hardness and purity assures
con sis tent
and reliable performance.
- Unique density allows Anthracite to be combined
with other filtration media in multi-media filters.
Physical Properties:
- Color - Black
-l Density - 50 lbs./cu. ft.3
- Effective Size - #1 (0.6-0.8 mm),
#1-1/2 (0.85-0.95 mm), #2 (1.7-2.0 mm)
- Uniformity Coefficient - #1 (1.5), #1-1/2 (1.6), #2 (1.5)
-l Mesh Size - #1 (14 x 30), #1-1/2 (10 x 20), #2 (14 x 12)
-l Sphericity - 0.6
-l Hardness - 3.0-3.8 (Moh's Scale)
-l Acid Solubility - <1%
-l Caustic Solubility 0 <1%
- Apparent Specific Gravity - 1.65
- Meets American Water Works Association Standard -
B100-89
Conditions for Operation:
- Bed Depth - 24 - 36 in.
-l Backwash Rate - #1 (12-18 gpm/ft.2),
#1-1/2 (18-25 gpm/ft.2),
#2 (use air scour)
-l Backwash Bed Expansion - 30-50% of bed depth
- Service Flow Rate - 5 gpm/sq. ft. or higher depending
upon local conditions. |
Anthracite