slow sand filter specifications

Slow Sand Filters, Iron Removing Filters, Roughing Filters

Slow Sand Filter Specifications

SSF- 1.25
Flow-rate: 1.25 gpm at a 0.1 g/ft2/minute maximum loading rate
Filter-vessel tanks: single NSF-rated linear polyethylene, 48 wide x 79 inch high.
Control tank: NSF-rated linear polyethylene, 29 inch wide x 49 inch high
Sand: 32 ft3 per tank, 0.35 mm effective size; uniformity-coefficient (uc) < 3
Under drain gravel: 6 ft3 of 3/8 inch pea gravel

SSF- 3
Flow rate: 1.25 gpm per cell, 2.50 gpm total, 3,619 gpd two cells total, at a 0.1 g/ft2/minute maximum loading rate.
Filter vessel tanks: minimum of 2 tanks; additional tanks can be manifolded: NSF-rated linear polyethylene, 48 inch diameter x 79 inch high each; includes piezometers to indicate head-loss in system.
Control tank: NSF-rated linear polyethylene, 29 inch wide x 49 inch high;
flow gauge (optional) and brass ball valve.
Sand: 32 ft3 per cell 0.35 mm effective size; uc < 3
Under drain gravel: 16 ft3 of 3/8” pea gravel per tank

SSF- 4
Flow-rate: 2.2 gpm per cell, 4.4 gpm total, 6,336 gpd two cells total, at a 0.1 g/ft2/minute maximum loading-rate.
Filter vessel tanks: minimum 2 tanks, additional tanks can be manifolded: NSF-rated linear polyethylene 64 inch wide x 79 inch high.
Control tank: linear polyethylene, 29 inch wide x 49 inch high; external piezometer for measuring head loss.
Sand: 67 ft3 per cell 0.35 mm effective size; uc < 3
Under-drain gravel: 8 ft3 of 1.5” gravel, 8 ft3 of 7/8” gravel, 8 ft3 of 3/8” pea gravel per tank

SSF- 6
Flow-rate: 2.82 gpm per cell maximum flow, 5.65 gpm total, 8,136 gpd two cells total; at a 0.1 g/ft2/minute maximum loading rate
Filter-vessel tanks: minimum of 2 tanks, additional tanks may be manifolded:
UV stabilized, NSF-rated linear polyethylene, 72 inch wide x 85 inch high each; external piezometer for measuring head loss.
Control tank: NSF-rated linear polyethylene, 29 inch wide x 49 inch high: flow gauge, brass metering valve for setting flow rate; brass float valves for maintaining tank water levels.
Sand: 85 ft3 per tank 0.35 mm effective size; uc < 3
Under-drain gravel: 9.5 ft3 of 1.5” gravel, 9.5 ft3 of 7/8” gravel, 9.5 ft3 of 3/8” pea gravel per tank

SSF- 8
Flow-rate: 3.8 gpm per cell maximum flow, 7.69 gpm total, 11,083 gpd two cells total; at a 0.1 g/ft2/minute maximum loading rate
Filter-vessel tanks: minimum of 2 tanks, additional tanks may be manifolded. Nestable tanks with removeable lids: UV stabilized, NSF-rated linear polyethylene, 84 inch wide x 84 inch high each; external piezometer for measuring head loss.
Control tank: NSF-rated linear polyethylene, 29 inch wide x 49 inch high: fixed orifice, brass metering valve for setting flow rate; brass float valves for maintaining tank water levels.
Sand: 115 ft3 per tank 0.35 mm effective size; uc < 3
Under-drain gravel: 13 ft3 of 1.5” gravel, 13 ft3 of 7/8” gravel, 13 ft3 of 3/8” pea gravel per tank

SSF- 10
Flow-rate: 5 gpm per tank, 7,200 gpd total, 14,400 gpd two tanks total; at a 0.1 g/ft2/minute maximum loading rate.
Filter-vessel tank: minimum of 2 tanks, additional tanks may be manifolded. Tanks 96 inch wide x 97 inch high; external piezometer for measuring head loss.
Control tank: 29 inch wide x 49 inch high; brass float valves for maintaining tank water levels; flow gauge, brass metering valve for setting flow rate
Sand: 149 ft3 per tank .35 mm effective size; uc < 3
Under drain gravel: 17 ft3 of 1.5” gravel, 17 ft3 of 7/8” gravel, 17 ft3 of 3/8” pea gravel per tank

Media Specifications

Gravel layers
6 inches of 1.5” gravel
6 inches of 7/8” gravel
6 inches of 3/8” pea gravel

Sand
0.35 mm silica sand. U.C.(uniformity coefficient) = 1.5-2

Sieve Analysis

sieve	mm	cum.	passing
#16	1.18
#20	0.85	100	+- 0
#30	0.6	92	+- 1
#40	0.43	34	+- 2
#50	0.3	7	+- 1
#70	0.21	1	+- 0
#100	0.15

Configuration for three SSF 10 filters manifolded together for a max. output of 30 gpm.