ABSTRACT
In this book, the step-by-step design procedure for a medium-sized wastewater treatment facility has been developed. One Design Example has been carried through 17 chapters (Chapters 6–22) to present the theory, design procedure, operation and maintenance, and equipment specifications for various components of the wastewater treatment facility. The purpose of this chapter is to consolidate the basic design data that have been developed in the Design Example. The design data are summarized in Table 23-1. Reference has been made to various sections in which the details may be found. Summary of Basic Design Data and Dimensions of the Wastewater Treatment Facility Designed in <xref ref-type="book-part" rid="chapter6 chapter7 chapter8 chapter9 chapter10 chapter11 chapter12 chapter13 chapter14 chapter15 chapter16 chapter17 chapter18 chapter19 chapter20">Chapters 6</xref>–<xref ref-type="book-part" rid="chapter21">21</xref>
Item
Design Value or Description
Ref.
A. Existing Wastewater Treatment Facility
Chap. 6
The existing facility includes three small plants: (1) trickling filter on the east side, (2) stabilization pond on the west side, and (3) aerated lagoon on the northern end of town.
Table 6-4
Current sewered population served
46,750
Table 6-6
Current unsewered population
1,250
Table 6-6
Average flow to trickling filter, L/s
67
Table 6-6
Average flow to stabilization pond, L/s
95
Table 6-6
Average flow to aerated lagoon. L/s
80
Table 6-6
Total flow treated, L/s
242
B. Proposed Facility
Chap. 6
The proposed facility includes construction of two gravity intercepting sewers to divert flows from the trickling filter plant and stabilization pond area to the aerated lagoon site. Construct a new treatment plant at this location to treat the combined flows. The process train includes bar screen, pumping station, grit removal, primary sedimentation, enhanced biological nutrient removal (BNR), disinfection, and river outfall. The sludge treatment includes gravity thickening of combined sludge, anaerobic digestion, and dewatering by belt filter presses.
Sec 6-10
Initial year
2000
Table 6-9
Design year
2015
Table 6-9
Design flows
Table 6-9
Average wastewater flow, Lpcd
475
Table 6-9
Average flow, L/s
440
Table 6-9
Peak flow, L/s
1321
Table 6-9
Minimum flow, L/s
220
Table 6-9
Influent characteristics
BOD5 mg/L
250
Table 6-9
TSS, mg/L
260
Table 6-9
TS, mg/L
910
Table 6-9
pH
7.2
Table 6-9
Total P, mg/L
6.0
Table 6-9
NH 4 + -N https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203734209/9deb5955-ceed-4315-855b-55e44f703637/content/eq909.tif"/> , mg/L
19.0
Table 6-9
Org.-N, mg/L
17.0
Table 6-9
Total N, mg/L
36.0
Table 6-9
Effluent standards
Table 6-1
C. Intercepting Sewer
Chap. 7
Diversion sewer from trickling filter plant [line ii]
Table 7-5
Peak flow, m3/s
0.385
Table 7-6
Diameter, m
0.76
Table 7-6
Diversion sewer from stabilization pond area [line i]
Table 7-5
Peak flow, m3/s
0.590
Table 7-6
Diameter, m
0.91
Table 7-6
Existing intercepting sewer from central part of town [line iii]
Table 7-5
Peak flow, m3/s
0.331
Table 7-6
Diameter, m
0.76
Table 7-6
Final sewer to the plant [line iv]
Table 7-5
Peak flow, m3/s
1.321
Table 7-6
Diameter, m
1.53
Table 7-6
Bypass sewer to storage basin [line v]
Table 7-5
Peak flow, m3/s
1.321
Table 7-6
Diameter, m
1.22
Table 7-6
Junction box. Three incoming sewers join, and one sewer carries the flow to the plant. Manually operated stop gates are provided to close the line and divert the flow into the relief sewer in case of power outages.
Sec. 7-5-2 and Figs. 7-8 and 7-9
D. Bar Screen
Chap. 8
Number of mechanically cleaned bar screens
2
Sec. 8-6-1
Design capacity of each screen, m3/s
1.321
Sec. 8-6-1
Width of screen chamber, m
1.74
Sec. 8-6-2, Step B, 1
Maximum depth above floor, m
6.45
Fig. 8-7
Length of screen chamber, m
11.5
Fig. 8-7
Slope of screen to horizontal, °
75
Fig. 8-7
Total number of clear openings
50
Fig. 8-5
Clear openings between bars, mm
25
Fig. 8-5
Number of bars, each bar 10 mm × 50 mm (deep)
49
Fig. 8-5
Depth of flow in channel at peak design flow, m
1.28
Table 8-4
Velocity through rack at peak design flow, m/s
0.83
Table 8-4
Head loss clean bars, m
0.03
Table 8-4
Head loss 50 percent clogging, m
0.15
Table 8-4
Average quantity of screenings, m3/d
0.76
Sec. 8-6-2, Step E
Outlet structure, proportional weir, and free fall into wet well
Fig. 8-6
Rake cleaning
Front-cleaned
Sec. 8-8-3
Control system
Time cycle and high-level override
Sec. 8-8-6
E. Pumping Station
Chap. 9
Dry well dimensions, m × m
15.5 × 5
Fig. 9-15
Wet well dimensions, m × m
15.5 × 7
Fig. 9-15
Depth of pumping station above floor, m
11.38
Fig. 9-15
Total number of identical pumps, each vertical shafting, dry pit, mixed flow, centrifugal pump with variable-speed drive These pumps are arranged in parallel and discharge in a common header 92 cm in diameter. All pumps have 36-cm (14-in.) suction and discharge connections.
5
Sec. 9-9-1 and Fig. 9-17
Number of standby units
1
Sec. 9-9-1
Maximum static head (minimum wet well elev.), m
11.13
Figs. 9-13 and 21-1
Minimum static head (maximum wet well elev.), m
9.91
Figs. 9-13 and 21-1
Minimum station head and maximum station capacity when four pumps in operation (maximum wet well level), m and m3/s
12.70, 156
Table 9-9
Maximum station head and minimum station capacity when one pump is in operation (minimum wet well level), m and m3/s
11.30, 0.42
Table 9-9
Motor power, each variable-speed, kW
82
Sec. 9-9-2, Step C
Motor efficiency range, percent
81.7–83.4
Table 9-10
Method of pump control
Liquid level bubbler
Table 9-12
F. Flow Measurement
Chap. 10
Number of Venturi meter in the 92-cm diameter force main
1
Sec. 10-7-1
Flow range, m3/s
1.321–0.152
Sec. 10-7-1
Head loss at maximum and minimum flow ranges (1.321 and 0.152 m2/s), m
0.45 and 0.006
Sec. 10-7-2, Step C
The Venturi meter consists of a primary element with manual vent cleaners for high- and low-pressure connections, two pressure sensors and a differential pressure transmitter that translates differential pressure into an output signal. The sensor utilizes the isolating diaphragms to detect and transmit pressure.
Sec. 10-9-2
G. Aerated Grit Chambers
Chap. 11
Number of units
2
Sec. 11-10-1
Length, m
13.0
Sec. 11-10-2, Step A, 1
Width, m
3.5
Sec. 11-10-2, Step A, 1
Average water depth, m
3.65
Sec. 11-10-2, Step A, 1
Freeboard, m
0.8
Sec. 11-10-2, Step A, 1
Detention time at peak design flow (1.321 m3/s) when both units are in operation, min
4.2
Sec. 11-10-2, Step A, 2
Influent structure consists of a 1-m-wide submerged channel with 1 m × 1 m orifice with sluice gates to divert the flow into one or both chambers.
Fig. 11-6
Effluent weir is a 2.5-m freefalling rectangular weir.
Fig. 11-6
Air supply, L/s per m length coarse bubble, swing-type diffusers provided on one side of the chamber for spiral roll action
7.8
Sec. 11-10-2, Step B, 1
Number of blowers
2
See. 11-10-2, Step B, 1
Capacity of blowers, at 27.6 k.N/m2 (gauge), sm3/min
20
Sec. 11-10-2, Step B, 1
Grit is pushed into a hopper by a spiral conveyor and is removed by bucket elevator.
Sec. 11-12-4 and Fig. 11-6
Average quantity of gnt removed, m3/d
1.14
Sec. 11-10-2, Step I
H. Primary Sedimentation
Chap. 12
Number of rectangular basins
2
Sec. 12-8-2, Step A, 1
Length, m
46.33
Sec. 12-8-2, Step A, 1
Width, m
11.58
Sec. 12-8-2, Step A, 1
Average water depth at midlength, m
4.0
Sec. 12-8-2, Step A, I
Freeboard, m
0.6
Sec. 12-8-2, Step A, 1
Detention time
At average flow, both basins in operation, h
2.7
Sec. 12-8-2, Step A, 3
At peak design flow, both basins in operation, h
0.9
Sec. 12-8-2, Step A, 3
Overflow rate
At average flow, both basins in operation, m3/m2·d
35.4
Sec. 12-8-2, Step A, 2
At peak design flow, both basins in operation, m3/m2·d
106.4
Sec. 12-8-2, Slep A, 2
Influent structure consists of 1-m-wide channel with eight submerged orifices
Sec. 12-8-2, Step B, 1
Number of standard V-notch effluent weirs
765
Sec. 12-8-2, Step C, 3
Total length of weir plate, m
153.72
Sec. 12-8-2. Step C. 2
Average quantity of sludge produced, kg/d
6,227
Sec. 12-8-2, Step F. 2
Longitudinal sludge collector consists of chain, sprockets, wheels, flights, scrapers, and drive unit.
Sec. 12-10-3
Cross-collector consists of chain, sprocket, wheels, flights, and drive units.
Sec. 12-10-3
Number of self-priming centrifugal nonclog pumps per basin for sludge pumping
1
Sec. 12-8-1, Step F. 4, and Sec. 12-10-5
Skimmer consists of hand-operated scum trough, scum pit, and pump.
Sec. 12-10-7
I. BNR Facility
Chap. 13
Number of identical process trains
4
Sec. 13-11-2 Fig. 13-24
Influent quality after material mass balance analysis
Q, m3/d
42,000
Sec. 13-11-5
COD, mg/L.
350
Sec. 13-11-5
BOD5, mg/L
200
Sec. 13-11-5
TSS, mg/L
150
Sec. 13-11-5
Org.-N, mg/L
15
Sec. 13-11-5
NH 4 + -N https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203734209/9deb5955-ceed-4315-855b-55e44f703637/content/eq910.tif"/> , mg/L
20
Sec. 13-11-5
NO 3 − -N https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780203734209/9deb5955-ceed-4315-855b-55e44f703637/content/eq911.tif"/> , mg/L
0
Sec. 13-11-5
TN, mg/L
35
Sec. 13-11-5
TP, mg/L
6
Sec. 13-11-5
Anaerobic Zone
Number of square chambers in each process train arranged in series
3
Sec. 13-11-6, Step A, 1
Dimensions L × W, m
5.5 × 5.5
Sec. 13-11-6, Step A. 1
Depth, m
7.25
Sec. 13-11-6, Step A, 1
Freeboard, m
0.8
Sec. 13-11-6, Step A, 1
HRT based on Q, h
1.5
Sec. 13-11-5, Step A, 2
Anoxic Zone
Number of square chambers in each process train arranged in series
3
Sec. 13-11-6, Step A, 2
Dimension L × W. m
5.5 × 5.5
Sec. 13-11-6, Step A, 2
Depth, m
7.25
Sec. 13-11-6, Step A, 2
Freeboard, m
0.8
Sec. 13-11-6, Step A, 2
HRT based on Q, h
1.5
Sec. 13-11-5, Step B, 3
Aerobic Zone
Number of rectangular basins in each process train
1
Sec. 13-11-6, Step A. 3
Dimensions L × W, m
34 × 17
Sec. 13-11-6, Step A, 3
Depth, m
5
Sec. 13-11-6, Step A, 3
Freeboard, m
0.8
Sec. 13-11-6, Step A, 3
Aeration period based on Q, h
6.6
Sec. 13-11-5, Step C, 6
Food to MO ratio, kg BOD5/kg VSS·d
0.18
Sec. 13-11-5, Step G, 1
Organic loading, kg BOD5/m3·d
0.53
Sec. 13-11-5, Step G, 2
MLVSS, maintained, mg/L
3000
Sec. 13-11-1, Step A, 16
Ratio of MLVSS to MLSS
0.8
Sec. 13-11-1, Step A, 16
Mean cell residence time, d
12
Sec. 13-11-1, Step A, 16
Solids wasted from the aeration basin (MLSS), kg/d
2820
Sec. 13-11-5, Step D, 4
WAS, m3/d
752
Sec. 13-11-5, Step D, 2
Number of identical waste sludge pumps
5
Sec. 13-11-7, Step E, 2
Number of standby units
1
Sec. 13-11-7, Step E, 2
Solids lost in the effluent, kg/d
413
Sec. 13-11-5, Step D, 4
Returned sludge rates, Qr /Q
0.6
Sec. 13-11-5, Step F, 1
Recycle ratio, Q recycle/Q
1.7
Sec. 13-11-5, Step F, 3
Number of return sludge pumps
5
Sec. 13-11-8, Step H
Number of standby units
1
Sec. 13-11-8, Step H
Rated capacity of each pump, m3/s
0.182
Sec. 13-11-8, Step H
Volume of air required m3/min per basin
219
Sec. 13-11-7, Step B. 1
Diffusers are swing-type in 15 rows along the width of the basin. The diffusers are Dacron sock, standard tube, discharging 0.21 m3 standard air per min per tube.
Fig. 13-27
Total number of diffusers per basin
1080
Sec. 13-11-7, Step C, 2
Total number of centrifugal blowers
5
Sec. 13-11-7, Step D, 3
Total number of standby units
1
Sec. 13-7-4. Step D, 3
Power requirement of each blower, kW
277
Sec. 13-11-7, Step D, 4
Rated air supply capacity of each blower, m3/min
230
Sec. 13-11-7, Step D. 3
J. Final Clarifier
Chap. 13
Number of clarifiers
4
Sec. 13-11-1, Step B. 1
Diameter of each clarifier, m
40.7
Sec. 13-11-8, Step A, 4
Average water depth, m
5.0
Sec. 13-11-8, Step B, 4
Freeboard
0.5
Sec. 13-11-8, Step B, 5
Detention time
At average design flow plus recirculation, h
8.5
Sec. 13-11-8, Step C, 2
At peak design flow plus recirculation, h
4.0
Sec. 13-11-8, Step C, 2
Overflow rate
At average design flow plus recirculation, m3/m2·d
12.8
Sec. 13-11-8, Step A, 5
At peak design flow plus recirculation, m3/m2·d
26.8
Sec. 13-11-8, Step A, 7
Limiting solids flux
At average design flow plus recirculation, kg/m2·d
47.8
Sec. 13-11-8, Step A, 8
At peak design flow plus recirculation, kg/m2·d
100.4
Sec. 13-11-8, Step A, 8
K. UV disinfection
Chap. 14
Number of UV disinfection channels
4
Sec. 14-12-2 and Fig. 14-18
Length, m
12
Fig. 14-21
Width, m
1.02
Sec. 14-12-3, Step A, 7, and Fig. 14-21
Depth variable, at peak design flow, m
0.72
Sec. 14-12-3, Step A, 7, and Fig. 14-21
Freeboard, m
0.6
Sec. 14-12-3, Step A, 7
Effluent structure consists of an automatic level control gate in each channel
1
Sec. 14-12-3, Step A, 14
Number of UV banks in each channel
2
Sec. 14-12-3, Step A, 7
Number of modules per bank
17
Sec. 14-12-3, Step A, 7
Number of lamps pr module
12
Sec. 14-12-3, Step A, 7
Lamp length, m
1.5
Sec. 14-12-1, Step B, 3
UV output. W/m arc
18.2
Sec. 14-12-1, Step B, 3
Diameter of quartz jacket, cm
2.3
Sec. 14-12-1, Step B, 4
Flow measurement, Parshall flume
Sec. 14-12-3, Step B
Throat width, m
1.22
Sec. 14-12-3, Step B, 3
L. Outfall Structure
Chap. 15
The outfall structures consist of a concrete-lined trapezoidal channel, collection box, outfall pipe, and diffuser pipe Outfall channel
Bottom width, m
0.5
Fig. 15-2
Side slope
3H-IV
Fig. 15-2
Collection box, Length and width L × W, m
2 × 2
Fig. 15-2
Outfall pipe
Diameter, m
0.92
Sec. 15-4-2, Step C
Diffuser pipe
Diameter, m
0.92
Sec. 15-4-2, Step D, 3
Number of diffuser ports
6
Sec. 15-4-2, Step D, 3
Diameter of diffuser ports, m
0.27
Sec. 15-4-2, Step D, 3
M. Sludge Thickeners
Chap. 16
Number of gravity thickeners for combined primary and secondary sludge
2
Sec. 16-9-1
Diameter, m
12.2
Sec. 16-9-2, Step A, 4
Freeboard, m
0.6
Sec. 16-9-2, Step B, 4
Sidewater depth, m
3.9
Sec. 16-9-2, Step B, 4
Depth at the center, m
4.9
Sec. 16-9-2, Step B, 5
Solids loading, kg/m2·d
43.7
Sec. 16-9-2, Step A, 5
Hydraulic loading, m3/m2·d
9.1
Sec. 16-9-2, Step A, 5
Dimensions of blending tank, depth × diameter, m
3 × 8.2
Fig. 16-6
Thickened sludge withdrawal rate, m3/d
70.3
Sec. 16-9-2, Step G, 3
No. of sludge withdrawal pumps, plunger-type with time clock control
2
Sec. 16-9-2, Step G, 4
Thickened sludge solids, percent
6
Sec. 16-9-2, Step G, 3
Characteristics of blended and thickened sludge and supernatant
Table 16-10
N. Sludge Stabilization
Chap. 17
Number of anaerobic sludge digesters
2
Sec. 17-7-1
Diameter, m
13.7
Sec. 17-7-2, Step B, 1
Side water depth, m
8.5
Sec. 17-7-2, Step B, 1
Digestion period
At average flow, d
17.9
Sec. 17-7-2, Step C, 1
At extreme high flow, d
11.1
Sec. 17-7-2, Step C, 1
At extreme low flow, d
28.1
Sec. 17-7-2, Step C, 1
Solids loading
At average loading condition, kg VS/m3·d
2.5
Sec. 17-7-2. Step C, 2
At extreme minimum loading condition, kg VS/m3·d
2.1
Sec. 17-7-2, Step C, 2
At extreme high loading condition, kg VS/m3·d
2.6
Sec. 17-7-2, Step C, 2
Gas production, m3/d
2550
Sec. 17-7-2, Step D, 2, d
Diameter of gas storage sphere, m
15
Sec. 17-7-2, Step I, 1
Number of gas compressors
2
Sec. 17-7-2, Step I, 2
Power of gas compressors, kW
7.5
Sec. 17-7-2, Step I, 2
Digester mixing achieved by gas recirculation
Sec. 17-7-1
Total number of compressors for gas mixing, including one standby unit
3
Sec. 17-7-2, Step J, 1
Compressor power each unit, kW
15
Sec. 17-7-2, Step J, 1
Gas flow per digester, m3/s
0.14
Sec. 17-7-2, Step J, 2
Digested sludge
Quantity of digested solids produced, kg/d
5021
Sec. 17-8-2, Step E, 3, and Table 17-7
Volume of digested sludge, m3/d
98
Sec. 17-8-2, Step E, 3, and Table 17-7
Characteristics of digested sludge and digester supernatant
Table 17-7
O. Sludge Dewatering
Chap. 18
Belt filter operation, h/d (5-day week)
8
Sec. 18-6-1
Total number of belt filter assembly
3
Sec. 18-6-2, Step A, 2
Belt width, m
1.2
Sec. 18-6-2, Step A, 2
Sludge solids processed, kg/h
879
Sec. 18-6-2, Step A, 1
Hydraulic loading
1.3 L/m belt width·h
Sec. 18-6-2, Step A, 3
Polymer, kg/h
3.5
Sec. 18-6-2, Step C, 3
Total
882
Sec. 18-6-2, Step A, 1
Sludge cake moisture content, percent
25
Sec. 18-6-1
Total average quantity of sludge cake, kg/h
596
Sec. 18-6-2, Step B, 2
Average volume of sludge cake, 5 d/week basis, m3/d
18
Sec. 18-6-2, Step B, 2
Filtrate volume, m3/d
258
Sec. 18-6-2, Step B, 3
Characteristics of sludge cake and filtrate
Table 18-7
P. Biosolids Reuse and Residue Disposal
Chap. 19
Quantity of biosolids utilized over farmland, mt/yr
1350
Sec. 19-7-1, Step A, 1
Crops grown: corn and grain sorghum
Sec. 19-7-2, Step A. 3
Biosolids application rate, mt/ha·yr
6.2
Sec. 19-7-2. Step A, 5
Lime requirement, mt
1012
Sec. 19-7-2, Step A, 8
K supplement, kg/ha·yr
109
Table 19-13
P in excess, some N supplement needed
Table 19-13
Land area needed, ha
220
Sec. 19-7-2, Step A, 7
Disposal of screenings, grit, and skimmings and unused biosolids landfilled on the site
Sec. 19-7-1, Step B
Method of landfilling
Narrow trench cells
Sec. 19-7-1, Step B, 4
Number of trenches located perpendicular to flood protection levees
80
Sec. 19-7-2, Step B, 1, d
Total quantity of residues landfilled, m3/d
2.22
Table 19-11
Dimensions of the trench cells
Top dimension, m × m
20.4 × 8.4
Sec. 19-7-2, Step B, 1, d, and Fig. 19-8
Bottom dimensions, m × m
14 × 2
Sec. 19-7-2, Step B, 1, d, and Fig. 19-8
Excavated depth, m
3.5
Sec. 19-7-2, Step B, 1, d, and Fig. 19-8
Side slope
1:1
Sec. 19-7-2, Step B, 1, d, and Fig. 19-8
Impervious liner, compacted clay, drainage material, and drainage pipe
Sec. 19-7-2, Step B, 1, c
Top cover, m
1
Sec. 19-7-2, Step B, 1, e
Equipment needed
Number of backhoes with loader
1 each
Sec. 19-7-2, Step B, 4, b
Life of fill, year
14.6
Sec. 19-7-2, Step B, 2, c
888 889 890 891 892 893 894 895 896 897 898