Wastewater Plant Criteria
City of Fresno, Dept. of Public Utilities, Wastewater Division
Fresno/Clovis Regional Wastewater Reclamation Facility Design Criteria

Plant Capacity

Flow, mgd
Average day maximum month ........ 88
Average annual ................................ 80
Peak hour ....................................... 160
BOD 5 and suspended solids
Average concentration, mg/L ....... 240
Average loading 1,000 lb/day ...... 184

Headworks/Preliminary Treatment

Influent pumps
Number/capacity, mgd ......... 2 @ 32.4
................................................. 4 @ 46.1
Total capacity, mgd ....................... 203
Mechanical bar screens
Number ............................................... 4
Width, ft ............................................... 7
Bar spacing, in ..................................75
Grit basins
Diameter, ft.........................................24
Number ................................................4
Peak capacity (each), mgd ..............70
Total capacity, mgd .........................210
Grit pumps
Number .................................................6
Capacity, gpm .................................360
Parshall flumes
Number ................................................2
Width, ft ..............................................10
Total capacity, mgd ........................220

Primary Clarifiers

Number ............................................... 6
Diameter, ft .....................................140
Sidewater depth, ft .......................... 10
Overflow rates, gpd/sf ................ 1,010
Detention time, hrs ....................... 1.78
Weir loading, gpd/lf .................. 35,200

Primary Sludge Pump Stations Nos. 1 and 2

Primary sludge pumps - air diaphragm type
Number ............................................. 16
Capacity (each), gpm .................... 140
Primary scum pumps - air diaphragm type
Number ............................................... 4
Capacity (each), gpm .................... 140
Dewatering pumps - vertical non-clog centrifugal
Number ............................................... 2
Capacity (each), gpm ................. 1,300

Aeration Basins

Number ............................................... 8
Process design flow, mgd ............... 80
Volumetric loading, lb BOD 5/1,000 ft/day
........................................................48-58
Volume per basin, MG .................... 2.7
Sidewater depth, ft ...................... 15-17
Mixed liquor suspended solids,mg/L
............................................. 2,000-3,000
Carbonaceous oxygen requirements
lbs O2/lbs BOD ............................ 1.125

Aeration Air Blowers

Air blowers/capacity, cfm
.................................................4@27,000
.................................................3@18,400

Secondary Sedimentation Basins

Number ..............................................13
Process design flow, mgd ...............80
Sidewater depth, ft ......................13-14
Overflow rate, gpd/day/ft 2 .....532-577
Weir overflow, gpd/lf .........3,000-4,000

Effluent Disposal

Pond area, acres .........................1,400
Disposal pond freeboard, ft ................2
Average pond water depth, ft ........ 4-5

Sludge Thickening

Dissolved air flotation thickeners
Number .............................................. 2
Solids loading, lb/ft 2/day ................24
Diameter, ft .......................................40
Gravity belt thickeners
Width, meters..................................... 2
Number ...............................................2
Hydraulic loading, gpm ..................500

Anaerobic Digesters

Number .............................................12
Diameter, ft ...............................75-105
Volatile solids loading, lbs/ft^3/day... 0.12
Min. hydraulic retention time, days ...... 20
Sidewater depth, ft .....................26-29
Pumping mixing
Pump number ...................................16
Capacity (each), gpm ................5,000

Sludge Dewatering

Belt filter presses
Number ..............................................7
Width, meters ....................................2
Hydraulic loading, gpm .................180
Feed solids concentration, % ...... 2-3
Cake solids concentration, % .. 18-20

Sludge Storage Silos

Number ................................................1
Volume, cy .......................................430
Solids storage time, hrs ...................24

Plant Utilities

Steam boiler - horizontal fire tube
Number ...............................................1
Capacity, hp ...................................400
Air compressors - two-stage reciprocating type
Number ..............................................3
Size, scfm ......................................540+
Discharge pressure, psig ............125