Liquid Process Criteria

Liquid Process Criteria 1995 2015
Preliminary Treatment
Mechanical Bar Screens
Number (including one standby) 3 3
Opening (in) 3/4 3/4
Influent Pumps
Number (including one standby) 4 4
Pump Capacity (mgd.) 27 27
Motor Horsepower 300 300
Aerated Grit Tanks
Number 2 2
Size: Length (ft) 46.5 46.5
Width (ft) 18 18
Sidewater depth (ft) 15.6 15.6
Detention Time at peak flow (min) 3.75 3.75
Air Supply (cfm per linear ft) 3-6 3-6
Capture Efficiency
(material >0.3mm dia. specific gravity 2.65)		 95% 95%
Grit Slurry Pumps
Number (including two standby) 4 4
Pump Capacity (gpm) 450 450
Motor Horsepower 15 15
Grit Blowers
Number (including one standby) 3 3
Capacity (cfm) 400 400
Motor Horsepower 25 25
Grit Washers
Number (including one standby) 3 3
Capacity 450 450
Motor Horsepower 1.5 1.5
Primary Settling Tanks
Number 6 6
Size: Length (ft) 130 130
Width (ft) (2 bays per tank) 48 48
Sidewater depth (ft) 12.25 12.25
Total Surface Area (sf) 37,440 37,440
Overflow Rate (gpd/sq ft)
Average Flow 708 791
Peak Flow 2,003 2,003
Detention Time (hrs)
Average Flow 3.1 2.8
Peak Flow 1.1 1.1
  1. Includes solids processing sidestreams
  2. High groundwater season
  3. For Maximum-Month Loadings during high groundwater season