Name of Work: 7.5 MLD Dhandhuka, Ahmedabad District ; Client: … · 2018-11-15 · n, Manning...
Transcript of Name of Work: 7.5 MLD Dhandhuka, Ahmedabad District ; Client: … · 2018-11-15 · n, Manning...
Prepared by:
SWA Environmental Consultants Engineers
Project Name: STP at Dhandhuka Date- 29-08-18
1 Inlet chamber 2.890 1.70 1.70 5.00 0.50 1
2 Bypass 1.20 1.20 2.50 0.50
3Screen Channel/
Chamber 5.5 6.65 0.83 0.70 0.50
1 operational mechanical and 1 manual
as standby; SWD for peak 1+1
4 Grit chamber 10.75 0.85 0.50 3.70 2
5 Parshall Flume 4.20 7.00 0.60 0.90 0.50 1
6Distribution
chamber/ channel 2.40 2.00 1.20 5.00 0.50
Channel directly connected to aeration
tank 2
7 Primary Clarifier 0.00
8 Anaerobic tank 147 131.3 26.3 4.6 5.7 5.0 0.60 Dimension of each basin 2
9 Anoxic tank 276 246.1 49.2 10.7 4.6 5.0 0.60 Dimension of each basin 2
10 Aeration Basin 1951 1742.0 348.4 16.4 21.2 5.0 0.60 Dimension of each basin 2
11 Secondary Clarifier 2298 1969.6 656.55 3.0 0.50 28.92 Dimension of each settling basin 1
12Chlorine contact
tank 207.6 167.71 76.88 12.40 6.20 2.20 0.50 1
13 Chlorine room 18.50 5.00 3.70 4.50
14 Sludge drying bed 105.6 64.18 82.81 8.28 10.00 0.78 0.50Not to be constructed (1 divided into 4
beds) 1
15 RAS Sump 204.1 164.1 80.08 2.0 0.50 10.10 1
16 Gravity thickner 215.1 194 43.01 4.50 0.50 7.40 1
17Thickened Sludge
sump 43.5 35 17.40 5.00 3.50 2.00 0.50 1
18 Recirculation Sump 3.5 1.60 1.50 1.50 0.50 1
19 Alum dosing tank 7.5 2
STP unit sizing summary
Name of Work: 7.5 MLD Dhandhuka, Ahmedabad District ; Client: GWSSB
Process Design and Hydraulic design for STP 7.5 MLD Dhandhuka (8.4 MLD Build Out)
No of
Unit/s
Sr.
No
Description of
Item
Area
(sq-m)
Length
(m)
Width
(m)
SWD/
Height
(m)
F.B
(m)
Dia
(m)Other Details
Vol each
(cum) w/o
FB
Vol
each
(cum)
Calculation by: Urv Patel 1 of 67
Prepared by:
SWA Environmental Consultants Engineers
Project Name: STP at Dhandhuka Date- 29-08-18
20 Admin Block 16.00 4 4 3.50 As per tender specifications
21 Blower Room 20.00 5 4 5.00 Adjoining Admin block First floor 1.00
22 MCC room 54.00 9 6 3.50 As per tender specifications
23 Workshop 20.00 5 4 3.50 Adjoining Admin block Groundfloor 1.00
24Secondary Clarifier-
2 Future expansion 3 0.5 10.02 0.9 MLD
25 Centrifuge house 18.80 4.70 4.00 3.5
26 Guard room 5.8 2.4 2.4 3 As per tender specifications 1
Calculation by: Urv Patel 2 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 7.5 MLD Intermediate
312.50 cum/hr
2 Recirculated flow 5.00 % Asssumed 5 %
3 Recirculated flowrate 15.63 cum/hr
4 Average flowrate 0.09 cum/s
5 Peak factor 2.25 As per CPHEEO
6 Peak flowrate 0.200 cum/s
7 Flowrate 8.4 MLD Ultimate
350.00 cum/hr
8 Recirculated flow 5.00 % Asssumed 5 %
9 Recirculated flowrate 17.50 cum/hr
10 Average flowrate 0.10 cum/s
11 Peak factor 2.25 As per CPHEEO
12 Peak flowrate 0.224 cum/s
4 HFL at discahrge point 20.65 m As per site condition and tender document;
HFL of discharge point
5 G.L 20.65 m As per site condition and tender document
6 Density of Water 1000 kg/cum
7 Dynamic viscosity at 20 C 1.002E-03 Pa-s/sqm
1R.L for discharge point 20.65 m
Length of pipe 2600 m
Diameter of pipe 0.60 m
C/S area 0.28 sqm
Velocity 0.79 m/s As per Ultimate Peak
MOC RCC NP2
Hazen William Coefficient 140As per CPHEEO Nov-2013, Table-3.14, Page-
3.33
Hydraulic Slope 0.000379 m
Head loss 0.9864 mMinor head loss due to
contraction 0.02 m Outlet chamber to Pipe
Total head loss 1.002 m
Hydraulic Flow Diagram Calculations
Design Parameters
Hydraulic Gradient Line Calculations
Effluent Chamber to Discharge point
STP capacity 7.5 MLD (8.4 MLD Built out)
Ultimate conditions
Intermediate conditions
Calculation by: Urv Patel Page 3 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Extra SWD for factor of
safety 0.230 m
W.L in Effluent chamber 21.89 m
2Downstream channel
Flow 805 cum/hr As per Ultimate Peak
Channel width after flume 0.60 m
Liquid depth provided 0.497 m
Free board provided 0.5 m
Length of channel 2.50 m
Mannings formulae
n, Manning Coefficient 0.013 Value for concrete
Available velocity 0.670 m/s
Wetted perimeter 1.59 m
C/S area 0.30 sqm
hydraulic radius 0.19
Slope 0.00
Head loss 0.001770892 m
Say 0.02 m
Water level at end of D/S
just before entering outfall 21.91 m
Head loss across the flume 0.41 m
Water level at start of D/S
channel 22.32 m
B.L of channel bottom at
start of D/S channel 21.42 m
Upstream ChannelFlow 805 cum/hr As per Ultimate Peak
Channel width 0.6 m
Liquid depth provided 0.497 m
Free board provided 0.5 m
Length of channel 2.5 m
Mannings formulae
n, Manning Coefficient 0.013
Available velocity 0.75 m/s
Wetted perimeter 1.5938 m
C/S area 0.2981 sqm
hydraulic radius 0.1871
Slope 0.0009
Head loss 0.0022 m
Say 0.02 m
Head loss in parshall flume channel - effluent chamber
Calculation by: Urv Patel Page 4 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Water level at start of the
U/S channel 22.34 m
B.L of channel bottom at
start of U/S Channel21.85
3Loss from CCT to Outlet
chamber
WL in CCT Outlet chamber 22.34
Exit loss
v 0.21 m/sec As per Intermediate peak
k 1.00
Head loss 0.0021 m
Say 0.02
Free fall provided 0.075 m
Head loss in CCT
Flow 0.200 cum/s As per Intermediate peak
Channel Width 1.0 m
Liquid depth provided 2.2 m SWD of CCT
Free board provided 0.5 m
Length of channel 42.37 m
Mannings formulae
n, Manning Coefficient 0.013 Value for concrete
Available velocity 0.088 m/s
Wetted perimeter 5.43 m
C/S area 2.27 sqm
hydraulic radius 0.42
Slope 0.0000042
Head loss 0.000176471 m
Say 0.01 m
WL in CCT 22.45 m
Loss from Inlet chamber to
CCT
Entry
V 0.21 m/sec As per Intermediate peak
k 0.50
Head loss 0.0011 m
Say 0.02
WL in CCT inlet chamber 22.47 m
Head loss in CCT tank & Chambers
Calculation by: Urv Patel Page 5 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
3
3-aa Length of pipe 40 m Assumed length
b Diameter of pipe 0.50 m
c C/S area 0.20 sqm
d Velocity 1.02 m/s As per Intermediate peak
e MOC DI K9
f Hazen William Coefficient 140As per CPHEEO Nov-2013, Table-3.14, Page-
3.33
g Hydraulic Slope 0.000747 m
h Head loss in pipe 0.0299 m
iMinor head loss due to
contraction 0.026 m Outlet chamber to Pipe
jMinor head loss due to
expansion 0.026 m Pipe to CCT inlet chamber
hW.L in the Outlet chamber
of Secondary Clarifier 22.56 m
g Free fall from launder outlet 0.200 m As per tender document 11.1.2
2-b
Design flow 0.20 cum/s As per Intermediate peak
Length of launder 87.67 m Circumference of the clarifier
Width of launder 1.00 m
Water depth in launder 0.42 m
C/S area of flow in launder 0.42 sqm
Manning formula
n, Manning coefficient 0.013AS per CPHEEO Nov-2013, Table-3.11, Page-
3.29
Velocity 0.48 m/s
Wetted perimeter 1.84
C/S area 0.42 sqm
Hydraulic radius 0.23
Slope 0.0003
Head loss 0.0240 m
Total head loss 0.03 m
HGL/WL at D/S of the
launder 22.76 m
HGL/WL at U/S of the
launder 22.79 m
2-c
Design flow 718.75 cum/hr As per Intermediate peak
Discharge over all V notch
weir 0.200 cum/s
Pipeline
Launder
Head loss across weir
Secondary Sedimentation tank to Chlorine contact tank
Calculation by: Urv Patel Page 6 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Circumference of clarifier 90.809 m
Spacing of each weir 0.30 m
Number of weirs 300.00 nos
Discharge over each weir 0.00067 cum/s
Angle of weir 90
Discharge coefficient 0.6 Based on the angle of V notch selected
Head over each weir 0.047 mFormulae changes if V notch angle is
changed
Round-off 0.05 m
Free fall 0.075 m
HGL/WL in clarifier 22.92 m
4
Pipe line a Length of pipe 25 m
b Diameter of pipe 0.70 m
c C/S area 0.38 sqm
d Velocity 1.04 m/sAs per intermediate peak + RAS +
Reciculated
e MOC DI K9
f Hazen William Coefficient 140As per CPHEEO Nov-2013, Table-3.14, Page-
3.33
g Hydraulic Slope 0.00052 m
h Head loss in pipe 0.0131 m
iMinor head loss due to
contraction 0.027 m Outlet chamber to Pipe
jMinor head loss due to
expansion 0.027 m Pipe to Secondary Clarifier
kMinor head loss due to
bend (90 deg)0.110 m Due to bend on pipe in central shaft
90 degree bends
No 2.00
V 1.04 m/sAs per intermediate peak + RAS +
Reciculated
k 0.75
Head loss 0.08 m
Exit loss
v 1.04 m/secAs per intermediate peak + RAS +
Reciculated
k 1.00
Head loss 0.05 m
Aeration tank to Secondary Clarifier
Calculation by: Urv Patel Page 7 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Entry
V 1.04 m/sec As per ultimate peak + RAS + Reciculated
k 0.50
Head loss 0.03 m
Total head loss from
Aeration tank Outlet
chamber to Secondary
clarifier
0.34 m
W.L In aeration tank outlet
chamber 23.26 m
Free Fall in Outlet chamber
from aeration tank 0.08 m
W.L in the aeration tank
oulet weir 23.33
Head loss across outlet
weir Aeration tank outlet weir
Design flow 2875 cum/hr
Peak Factor X ( Q + RQ ) X 2 ; R=1 ;
Intermedaite ; One basin pulled out of
operation
Discharge over all V notch
weir 0.799 cum/s
Length of weir 16.4 m Per Basin
Spacing of each weir 0.30 m
Number of weirs 53.33 nos
Discharge over each weir 0.01497 cum/s
Angle of weir 90
Discharge coefficient 0.6 Based on the angle of V notch selected
Head over each weir 0.162 mFormulae changes if V notch angle is
changed
Round-off 0.2 m
Free fall 0.075 m
HGL/WL in Aeration tank 23.61 m
Head loss across inlet weir Between Anoxic tank and Anaerobic tank
Design flow 2875 cum/hr
Peak Factor X ( Q + RQ ) X 2 ; R=1 ;
Intermedaite ; One basin pulled out of
operation
Discharge over all V notch
weir 0.799 cum/s
Length of weir 10.7 m Per Basin
Calculation by: Urv Patel Page 8 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Spacing of each weir 0.15 m
Number of weirs 71.00 nos
Discharge over each weir 0.01125 cum/s
Angle of weir 90
Discharge coefficient 0.6 Based on the angle of V notch selected
Head over each weir 0.144 mFormulae changes if V notch angle is
changed
Round-off 0.15 m
Free fall 0.075 m
HGL/WL in Anoxic tank
outlet weir 23.61 m
HGL/WL in Anoxic tank 23.83 m
Head loss across inlet weir Between Anaerobic tank and Anoxic tank
Design flow 2875 cum/hr
Peak Factor X ( Q + RQ ) X 2 ; R=1 ;
Intermedaite ; One basin pulled out of
operation
Discharge over all V notch
weir 0.799 cum/s
Length of weir 4.6 m Per Basin
Spacing of each weir 0.10 m
Number of weirs 46.00 nos
Discharge over each weir 0.01736 cum/s
Angle of weir 90
Discharge coefficient 0.6 Based on the angle of V notch selected
Head over each weir 0.172 mFormulae changes if V notch angle is
changed
Round-off 0.2 m
Free fall 0.075 m
HGL/WL in Anaerobic tank
outlet weir 23.83 m
HGL/WL in Anaerobic tank 24.11
Free fall in anaerobic tank
influent weir from inlet
chamber
0.075 m
W.L in Inlet chamber 24.18
5
Flow rate
Channel from parshal flume to aeration tank distribution chamber
Calculation by: Urv Patel Page 9 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Length of channel 1.50 m Circumference of the clarifier
Width of channel 0.60 m
Water depth in channel 0.50 m
C/S area of flow in channel 0.3 sqm
Manning formula
n, Manning coefficient 0.013AS per CPHEEO Nov-2013, Table-3.11, Page-
3.29
Velocity 0.75 m/s At ultimate peak
Wetted perimeter 1.59
C/S area 0.30 sqm
Hydraulic radius 0.19
Slope 0.0009
Head loss 0.0013 m
Say 0.02 m
Free fall in Aeration tank
Distribution chamber 0.075 m
WL at the end of channel
just before Secondary
treatment inlet chamber
24.26 m
WL at the start of channel
just after Parshall flume 24.28 m End of D/S
B.L of Channel to Bilogical
treatment units23.78 m
6Downstream channel
Flow 805 cum/hr At ultimate peak
Channel width after flume 0.6 m
Liquid depth provided 0.497 m
Free board provided 0.5 m
Length of channel 1.5 m
Mannings formulae
n, Manning Coefficient 0.013 Value for concrete
Available velocity 0.669642857 m/s
Wetted perimeter 1.59 m
C/S area 0.30 sqm
hydraulic radius 0.19
Slope 0.00
Head loss 0.001062535 m
Head loss in parshall flume channel
Calculation by: Urv Patel Page 10 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Say 0.03 m
Water level at start of D/S 24.31 m
Head loss across the flume 0.41 m
Water level at end of U/S
channel 24.72 m
B.L of channel bottom at
start of D/S channel 23.82 m
Upstream ChannelFlow 805 cum/hr At ultimate peak
Channel width 0.6 m
Liquid depth provided 0.497 m
Free board provided 0.5 m
Length of channel 1.5 m
Mannings formulae
n, Manning Coefficient 0.013
Available velocity 0.75 m/s
Wetted perimeter 1.5938 m
C/S area 0.2981 sqm
hydraulic radius 0.1871
Slope 0.0009
Head loss 0.0013 m
Say 0.02 m
Water level at start of the
U/S channel 24.74 m
B.L of channel bottom at
start of U/S Channel24.25 0.49
7
Head loss in Grit Chamber 0.001288 At ultimate peak
Say 0.01
Free Fall 0.2 As per tender document Clause 11.1.2
W.L in Grit Chamber 24.95
B.L of Grit Chamber 24.10Drop in bottom of Grit
Chamber relative to BL of
parshall Flume
0.15 m
Head loss in gates &
Channel from Screen to
Grit chamber
0.05 m
WL between Grit &
Screen 25.00 m
Grit Chamber to Parshall Flume
Calculation by: Urv Patel Page 11 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
8Depth of flow in D/S screen
channel 0.42 m
Head loss from D/S screen
channel to Grit chamber 0.05 m
W.L in D/S of screen
channel 25.05 m
B.L in D/S of Screen 24.63 m
Head loss across screen
(Max)0.28 m At ultimate peak
Drop in datum of U/S and
D/S0.15 m
B.L of U/S screen channel 24.78 m
W.L in U/S channel 25.18 m
Max head loss when screen
is 50% clogged 0.276 m
W.L in U/S channel (max) 25.34 mConsider this for calculation beyond as it is
the worst case scenario
W.L in the inlet chamber 25.39 m Incl Free fall of 0.05
4.74
7
Total Max head drop across
entire plant 3.50 m
This includes frictional head loss plus the
elevation choosen for last unit operation;
Not including 2600 m discharge line
Pumping required at or 5 m at inlet chamber
Total head loss
Screen Chamber
Calculation by: Urv Patel Page 12 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 8.4 MLD Ultimate
350.00 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 17.50 cum/hr
Average flowrate 0.10 cum/s Average + Reciculated
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.224 cum/s
1a Detention time required 60 sec
bVolume required for peak
flow rate 13.42 cum As per ultimate peak
c Side water depth 5 m
d Surface area 2.683 sqm
e Length 1.70 m
f Breadth 1.70 m
g Free Board 0.5As per tender document Clause 11.1.2, Page
23, Vol-lll, Part-1
2a Detention time required 15 sec
bVolume required for peak
flow rate 3.35 cum
c Side water depth 2.5 m
d Surface area 1.342 sqm
e Length 1.20 m
f Breadth 1.20 m
g Free Board 0.5As per tender document Clause 11.1.2, Page
23, Vol-lll, Part-1
Bypass chamber
Screen chamber / Screen
Inlet Chamber
Design Parameters
Design Calculations
STP capacity 7.5 MLD (8.4 MLD Built out)
Calculation by: Urv Patel Page 13 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 8.4 MLD
350.00 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 17.50 cum/hr
Average flowrate 0.10 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.224 cum/s
4 Width of rectangular bar 3 mm
5 Clear Spacing between bars 6 mm
6
Minimum velocity required
in the channel at average
flow
0.3 m/s As per CPHEEO page 5-30 Section 5.6.1.8
7Minimum velocity required
at peak flow 0.6 m/s As per CPHEEO page 5-30 Section 5.6.1.8
1
aAssume depth of flow in
screen chamber 0.4 m
b
Assume velocity of flow
through fine screen (Peak
flow)
1 m/s As per CPHEEO page 5-30 Section 5.6.1.8
cClear Area of opening
through fine screen 0.22 m
d Clear width of opening
through fine screen 0.56 m
f Total clear spacing 93 As per CPHEEO page 5-30 Section 5.6.1.8
g Total screen bar 92
h Total width 834 mm
0.83 m As per ultimate peak
iAngle of inclination to
horizontal 75 deg
2
a Velocity at peak flow 1.00 m/s
CHECK OKVelocity should be 0.6-1.2 m/s as per
CPHEEO page 5-30 Section 5.6.1.8
Velocity through screen openings
STP capacity 7.5 MLD (8.4 MLD Built out)
Fine Screen Chamber
Design Parameters
Design Calculations
Screen chamber / Screen
Calculation by: Urv Patel Page 14 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
b Velocity at average flow 0.46 m/s
CHECK OKVelocity should be 0.3-1.2 m/s as per
CPHEEO page 5-30 Section 5.6.1.8
3
a h (head loss) 0.13 m
CHECK OKAllowable head loss is 0.15 - 0.3 m as per
CPHEEO page 5-31 Section 5.6.1.9
4
a Width of channel 0.83 m
b Depth of flow 0.4 m
cVelocity of flow in screen
channel @Peak flow 0.67 m/s
As per Tender Document Page 30 of 731,
Vol-lll, Part-1
Velocity of flow in screen 0.31 m/s As per Tender Document Page 30 of 731,
fLength of channel U/S of
Screen 4.2 m
Should be 5 X Channel Width As per CPHEEO
page 5-30 Section 5.6.1.8 & Tender
Document Page 30 of 731, Vol-lll, Part-1
6
1 2
a Datum height (z) 0 -0.15 Change Z_2 if the solver does not converge
b Depth of flow (d) 0.40 0.42 m
c Velocity of flow (V) 0.67 0.64 m/s
dHead loss due to screen
(h_L)0.13 m
R.H.S L.H.S Dummy
0.42 0.42 0.0000
Head loss through fine screen
Actual Velcotiy & Depth of flow D/S of screen chamber
Section
Screen channel
𝒁𝟏+ 𝒅𝟏 +𝑽𝟏𝟐
𝟐𝒈= 𝒁𝟐 + 𝒅𝟐 +
𝑽𝟐𝟐
𝟐𝒈+ 𝒉𝑳
Calculation by: Urv Patel Page 15 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
7
1 2
a Datum height (z) 0 -0.15
b Depth of flow (d) 0.55 0.42 m
c Velocity of flow (V) 0.49 0.64 m/s
dHead loss due to screen
(h_L)0.28 m
R.H.S L.H.S Dummy
0.57 0.57 0.0000
ah_50 (Head loss at 50%
clogging) 0.276 m
Should be <0.6 m ; As per Metcalf and Eddy
5th Edition, Table 5-4 & 0.3 as per CPHEEO
CHECK OK m
b
Depth of flow at 50%
clogging U/S of screen
chamber
0.55 m
8
Angle of screen 75 deg
Length of screen 1.41 m0.5 Free board + 0.5 room for motor +
Length screen
Say 1.41 m
Projection length of screen
on D/S side 0.3649 m
Length of screen channel 1.36 m Projection length of screen + 1 m for bypass
Length of screen channel
D/S of screen as per
minimum criteria
2.49 m
Should be 3 X Channel Width As per CPHEEO
page 5-30 Section 5.6.1.8 & Tender
Document Page 30 of 731, Vol-lll, Part-1
Free Board 0.5 m As per tender document
Depth of screen channel 1.20 m0.5 Free Board + Datum height
compensation
ADepth of screen channel
provided 1.2 m
BLength of screen channel
U/S4.2 m
SUMMARY
Head loss through fine scree at 50% clogging
Screen Channel D/S Screen chamber
Section
Calculation by: Urv Patel Page 16 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
CLength of screen channel
D/S2.49 m
Length of screen channel
D/S2.50 Say
D Width of screen channel 0.83 m
E Angle of screen 75 deg
Head loss across screen
channel (Avg)0.13 m
Head loss across screen
channel (Max) 0.28 m
Free Board 0.5 mAs per tender document Clause 11.1.2, Page
23, Vol-lll, Part-1
Calculation by: Urv Patel Page 17 of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr Parameter Value Unit Remarks
1 Flowrate 8.4 MLD
350.00 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 17.50 cum/hr
Average flowrate 0.10 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.224 cum/s
4 Size of grit particle to be 0.15 mm As per tender document
5 Temperature_Minimum 18 C Change as per field conditions
6 Kinematic Viscosity of water 0.00000114 sq-m/s Change as per minimum temperature
7 Specific gravity of the grit 2.65 unitless As per tender document
8 Gravitational accelaration 9.81 m/s^2
1
aSettling Velocity as per
stokes law 0.0177 m/s
b Reynolds number 2.34 unitless
Check Use transitions
law
If reynolds number is between 0.5-1000
then transitoins law should be used to
calculate the terminal settling velocity
Stokes law equation
Grit Chamber
Design Parameters
Design Calculations Settling velocity of the grit particle
STP capacity 7.5 MLD (8.4 MLD Built out)
Calculation by: Urv Patel 18of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
cSettling Velocity as per
trasnitions law 0.0023 m/s
dSurface over flow rate for
100% removal 1533.46 m3/m2-d
In reality short circuting results inlower
efficiency
eEfficiency of removal of
desired particles0.78 %
f Measure of settling basin 0.13 fraction choose (1/8 for very good performance)
g Overflowrate for design 919.947 m3/m2-d < 959 m3/m2-d as per Tender document
2Dimension of Grit
chambers
Number of grit chamber 2 select
Surface area for each grit 10.50 sqm
Radius 1.83 m
Diameter 3.70 m
Water depth 0.85 mAs per Tender document Clause 14.4.3, Page
31, Vol-lll, Part-1
Hydraulic residence time for
peak flowrate 81.7 sec
> 60 sec as per Tender document Clause
14.4.3, Page 31, Vol-lll, Part-1
3Critical displacement
velcocity for resuspension
Trasnitions law eqaution
Calculation by: Urv Patel 19of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
aCritical displacement
velocity 0.197 m/s
As per CPHEEO page 5.42 section 5.6.2.7.1.4
crtical velocity range from 0.17 to 0.256 m/s
bHorizontal component of
the velocity in the chamber 0.036 m/s
As per CPHEEO page 5.42 section 5.6.2.7.1.4
0.15-0.3 m/s range is used
c CHECK OK
4 Head loss through girt
Head loss through girt
chamber 0.00129 m
Coefficient of drag 5 select
Horizontal component of 0.07 m/s
As per ultimate peak
Number of grit chamber 2
Diamenter of Grit Chamber 3.70 m
Depth of Grit chamber 0.85 m
Free board 0.5 m
Classifier Slope 0.375
Height of Screw Conveyor 1.5 m From the bottom of the Grit chamber
Horizontal projection length 4.00 m
Length of screw conveyor 4.272 m
Summary
Calculation by: Urv Patel 20of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 8.4 MLD
350.00 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 17.50 cum/hr
Average flowrate 0.10 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.224 cum/s
1
W 150
A 610
B (min) 600
C 315
D 391
F 300
G 600
K 75
Z 113
Parshal Flume
Design Parameters
Design Calculations
STP capacity 7.5 MLD (8.4 MLD Built out)
Dimensions of Plume
mm
Obtained from the Design parameter for
Parshall Flume (As per CPHEEO Nov-2013
Edition Page 5-46 Table 5.7 Section)
Calculation by: Urv Patel 21of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
2a No of units 1
b Design flow each 805 cum/hr Normal flowrate
c Throat Width (w) 150 mm As per parshall flume equations/charts
d Head over the flume; 0.83 m As per parshall flume equations/charts
eHead at downstream of the
flume; H_b = Ha X 0.50.41 m
f Head loss at flume 0.41 m
g Velocity 0.75 m/s
h Area 0.30 sq m
i Width of channel 0.60 m
j Depth of flow 0.50 m
k Free board 0.50 m As per tender document
l Total depth of channel 1.40 m
m Length of channel U/S 3.00 mAs per parshal flume design considerations
CPHEEO; 20 X Throadt width
n Length of the channel D/S 1.50 m 10 X Throadt width
o Length of the flume 1.50 m As per the dimesions selected below
p
Providing additional Length
at D/S chaanel for
allowance of bypass gate
1.00 m
q Total length 7.00 m
D/S Length Parhsall Flume 1.50 m
U/S Length of Parshall
Flume 3.00 m
Length of Parshal Flume 1.50 m
Total Length of Flume 7.00 m
Width of Flume 0.60 m
Depth of Flume 1.40 m
Head Loss in Flume 0.41 m
Dimensions of Plume
Summary
Calculation by: Urv Patel 22of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 7.5 MLD
312.50 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 15.63 cum/hr
Average flowrate 0.09 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.200 cum/s
1
aWidth of Parshall Flume
Channel 0.60 m
bNumber of distribution
chamber 1 m
cDetention time in each
chamber 60 sec
d Volume of each chamber 11.979 cum
h Width of channel 1.20 m
Water depth 5.00 m
Length 2.00 m
SWD 5.00 m
Length 2.00 m
Breadth 1.20 m
F.B 0.5 m
Summary
Distribution chamber
Design Parameters
Design Calculations
Distribution chamber dimension
STP capacity 7.5 MLD (8.4 MLD Built out)
Calculation by: Urv Patel 23of 67
Description Parameters Units COD
oxidation
NH4
oxidation
NO2
oxidation
Maxiumum Specific Growth rate µ_maxg bsCOD/g
VSS.d6.00 0.9 1
Half Velocity Constant K_s /K_nh4
/K_no2mg/L 8 0.5 0.2
Synthesis yield Ymg VSS/mg
sustrate0.45 0.15 0.05
Specific Endogenous Decay Rate b g VSS/g VSS.d 0.12 0.17 0.17
Fraction of Biomass that remain
as cell debrisf_d unitless 0.15 0.15 0.15
Half Velocity Constant for Oxygen K_o2 mg/L 0.2 0.5 0.9
Theta value Units COD
oxidation
NH4
oxidation
NO2
oxidation
µ_max unitless 1.07 1.072 1.063
b unitless 1.04 1.029 1.029
K_s /K_nh4
/K_no2unitless 1 1 1
TABLE-1 AERATION TANK DESIGN DATA (BIOKINETIC COEFFICIENT)
Reference: Metcalf & Eddy Edition-4, Section 8-3, Table-8.11, Page-705
Biokinetic parameter at 20 C
Temperature correction coeffcients for biokinetci parameters
µ_max = k * Y
Temperature 18 deg C
Description Parameters Units COD
oxidation
NH4
oxidation
NO2
oxidation
Maxiumum Specific Growth rate µ_maxg bsCOD/g
VSS.d5.24 0.783 0.88
Half Velocity Constant K_s /K_nh4
/K_no2mg/L 8 0.5 0.2
Synthesis yield Ymg VSS/mg
sustrate0.45 0.15 0.05
Specific Endogenous Decay Rate b g VSS/g VSS.d 0.111 0.161 0.161
Fraction of Biomass that remain
as cell debrisf_d unitless 0.15 0.15 0.15
Half Velocity Constant for Oxygen K_o2 mg/L 0.2 0.5 0.9
Description Parameters Units Range Typical
maximum specific sustrate
utilization rate k
g bsCOD/g
VSS.d4-12 6
half velocity constant Ks mg/L BOD 20-60 30
mg/L bsCOD 5-30 15
sysntesis yield coeficient Ymg VSS/mg
BOD0.4-0.8 0.6
mg VSS/mg
COD0.4-0.6 0.45
decay coeficient b g VSS/g VSS.d 0.06-0.15 0.1
Biokinetic parameter at T deg C
Biokinetic parameter at 20 C (Range of values)
Nitrification Flux (g NH4-N/sqm-
day)DO (mg/l)
Bulk liquid
NH4-N, mg/l
1.07 4 1
0.9 3 0.8
0.6 2 0.5
Pipe
Diameter
(inch)
Pipe Diameter
(mm)
Velocity
(m/min)
1-3 75-225 360-540
4-10 100-250 540-900
12-24 300-600 800-1200
30-60 750-1500 1100-2000
TABLE-2 AERATION TANK DESIGN DATA (NITRIFICATION FLUX IN BIOFILM)
However, Tender document
specifies 8 m/hr as max air
speed in aeration piping
TABLE-3 AERATION TANK DESIGN DATA (Design range of air veloicty in header pipe for Fine Bubble Membrane
diffusers )
WEF MOP & Reference: Metcalf & Eddy Edition-5, Table-9.25, Page-1007
Reference: Metcalf & Eddy Edition-5, Table-9.25, Page-1007
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr
No.Parameter Value Unit Remarks
1 Flowrate 7.5 MLD
312.50 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 15.63 cum/hr
Average flowrate 0.09 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.200 cum/s
4 Influent COD 425
5 Effluent COD desired 50
BOD 250
TCOD in
nbsCOD
nbpCOD
TSS 375 As per tender document
VSS 365 Assumed
VSS_COD 0.125
nbVSS 25
TKN 50 Ammonia + Organic Nitorgen
NH4-N 45TP 7.1
Select SRT 8.1 days
Changed based on the nutrient removal
req; For BOD removal use 3-5 days & For
BOD + Nitrification use 8-10 days
Select X,TSS 3000 mg/l Change based on process ASP, SBR,
Extended aeration
Temperature (Min) 18 deg C
Temperature (Max) 35 deg C
BOD 10
COD 50
TSS 10
Total Nitorgen 10 TKN + Nitrates
Total Phophorous 2
NH4-N 1Lower than prescribed upper limit of 5
mg/l
Aeration tank
Design Parameters
Enter Wastewater characteristics
Enter Design parameter
Treated Sewage Quality
mg/l
mg/l
STP capacity 7.5 MLD (8.4 MLD Built out)
Calculation by: Urv Patel 27of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
1-A
a Outlet BOD 0.375 mg/l
µmax, 20 deg C, g/g-d 0.90
Kn, mg/L 0.50
µmax theta 1.07
Kn, theta 1.00
bn, g/g-d 0.17
bn theta 1.03
Temperature, deg C 18.00
µmax, g/g-d 0.78
Kn 0.50
bn 0.16
DO 1.50 Choosing worst case scenario
Ko 0.50
Assumed effluent N, mg/L 0.50 Choosing lower than required effluent limit
µ, g/g-d for CSTR 1 stage 0.13
1 stg CSTR required SRT, days 7.51 days
SRT provided 8.10 days
b Initial Guess for Nox 34.92 mg/l Start with initial guess of 80% of TKN
c P_X,Bio,VSS Biomass Production
Heterotrophic Biomass Solids 754.80 kg/day
Non Biodegradable VSS in influent 101.747 kg/day
Nitrifier Biomass solids 17.08 kg/day
d Nox (Based on P_x, Bio) 35.03 First iteration
e P_X,Bio,VSS
Heterotrophic Biomass Solids 754.80 kg/day
Non Biodegradable VSS in influent 101.75 kg/day
Nitrifier Biomass solids 17.13 kg/day
f Nox (Based on P_x, Bio) 35.03 mg/l
CONVERGED
g P_X,Bio,VSS 873.7 kg/day
h P_X,VSS 1061.2 kg/day
i P_X,TSS 1290.4 kg/day Sludge production
Aeration tank size - BOD removal + Nitrification Single Stage
Design Calculations
Check what SRT is enough for complete
nitrification
Calculation by: Urv Patel 28of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Mass of VSS in aeration tank
j Mass of TSS in aeration tank 10451.9 kg
k Volume of Aeration tank 3484.0 cum Total for both the basins
Detention time (HRT) 10.62 hours Intermediate Average + Recirculated
F/M 0.22g BOD/g VSS
* d
0.15-0.25 as per Tender document clause
14.5.7 and MLVSS=0.8 MLSS
Number of aeration basin 2 nos
Side water depth of aeration
basin 5 m
Surface aera for each basin 348.4 sqm
Breadth of each aeration
basin 16.41 m
Length of each aeration basin 21.24 m
L/B ratio 1.29
1-B
a Active biomass 1549.8 mg/l Ref: Metcalf & Eddy Edition-4, Chapter-7,
Section-7.6, Page 592, Equation-7.42
b IR ratio
Recycle ratio operating normal 0.5
Recycle capcity provided 1 Times Q
Effluent Nitrates (Assumed) 8 mg/l Total Nitrogen effluent minus Ammonia
Nitrogen Effluent (2 mg/l)
IR (Iternal Recycle ratio)
required 2.88 Based on stoikiometry
IR capacity provided 4 Times QAs per tender document Volume-3A, part-
2, Clause-14.5
c Nox Feed to Anoxic tank
Nitrate concentration entering
via IR & R flow 8 mg/l
Total flowrate into anoxic tank 25340.63 cum/d (IR + R)*Q
Nox Feed to Anoxic tank 202725 g/d
d Anoxic tank volume
First iteration 2.5 h
Volume of anoxic tank 820.3125 cum
e F/M_b ratio 1.47 g/g-d
Denitrification Design
CHECKS
Calculation by: Urv Patel 29of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
f rbCOD/bCOD 30.00 %
gSpecific Denitrification Rate
(SDNR) @ 20 C 0.27 g/g-d
Using Curve generated from ASM1 model
simulations; Ref from Metcalf & Eddy
Edition-4, Section-8.5, Page-754-755,
Figure-8.23; Considering F/Mb ratio
calculated above & rbCOD as 30%
(assumed as per literature review)
SDNR temp corrections 0.3 g/g-d
SDNR IR corrections Based on Metcalf & Eddy Edition-4, Section-
8.5, Page-756, Equation-8.45 & 8.46
If IR = 2 0.24 g/g-d
If IR =3-4 0.23 g/g-d
SDNR selected 0.23 g/g-d
h Amount of NO3-N reduced 296493 g/d
Amount feed/Amount reduced 0.68
Excess capacity 31.6 % Lower detention time can be used
New HRT as per excess
capacity 0.79 hr
Reducing the size of Anoxix tank by the
excess capacity
New HRT provided for re-
evaluation 1.5 hr SDNR will be higher for smaller HRT
Volume of Anoxic tank (both
basins) 492.19 cum Intermediate Average + Recirculated
F/M_b 1.29 g/g-d
New SDNR values based on the
methodology mentioned
before
0.36 g/g-d
SDNR temp corrections 0.3 g/g-d
SDNR IR corrections Based on Metcalf & Eddy Edition-4, Section-
8.5, Page-756, Equation-8.45 & 8.46
If IR = 2 0.33 g/g-d
If IR =3-4 0.32 g/g-d
SDNR selected 0.32 g/g-d
Amount of NO3-N reduced 234347.3 Based on new HRT
Excess capacity ratio 1.16
Excess capacity 15.60 %
Number of Anoxic tank
provided 2.00
Volume of each Anoxic tank 246.09 cum Intermediate Average + Recirculated
Breadth of Anoxic tank 4.6 m 1200.65325
SWD of Anoxic tank 5 m 1240.619029
Length of Anoxic tank 10.7 m 2812.5
Calculation by: Urv Patel 30of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
L/B ratio 2.33 m
Anoxic zone mixing energy
required 10
kW/10^3
cum of tank
Anoxic zone mixing energy
required 2.46 kW per basin
3.30 hp
4.00 hp 1 in each basin
Internal recycle pump
sizing
IR fow rate required per basin 1414.06 cum/hr per basin (4 X Q X Peak + Reciiculated) /
number of basin
Pumping head required 8 mHeight of aeration tank + 2m as a factor
safety for head loss
Pumping power required 32.4 BkW
Efficiency of the pump 0.7 %
Shaft power required 61.98 hp
Shaft power required 46.24 kW @duty point metioned above
Shaft power provided 75 hpCheck with manufacturer data for a pump
match
1-C
Detention time 0.8 hours Flowrate 0.091 cum/sec As per average + Recirculated
Volume required 262.50 cum
Number of basins 2.00
Volume of each basin 131.25
SWD 5
Length 4.6
Breadth 5.7
Ratio 1.24
2-Aa Oxygen demand 2022.53 kg/day
Oxygen credit from
Denitrification 579.79 kg/day
Oxygen demand 60.11 kg/hr Considering denitrification
b Calculating SOTR Standard Oxygen Trasnfer Rate
EBPR or Phosphorous removal design
Aeration requirement -
Provide 1 nos (Working) + 1 nos (Standby) 75 hp Pumps for Internal recycle per basin
Calculation by: Urv Patel 31of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
c Temperature of wastewater 35 deg-C
Based on Maximum wastewater
temperate in the influent parameter
section
d AOTR 60.11 kg/hr Actual Oxygen Trasfer Rate required
e C, 20 deg cel 9.09 mg/l From Saturation table
fC, t deg cel
8.3 mg/l From Saturation table and temp of ww
g C, tank 2 mg/l For ASP
hAlpha
0.6 Typical value : 0.65 OR based on tender
iBeta
0.95 Typical value : 0.95 OR based on tender
j F 0.8 Typical value : 0.9 OR based on tender
k Mid depth correction factor 0.4 0.25-0.4
l Depth of diffusers 4.8
m Temp correction 0.70
n Elevation of site 30 m As per site elevation from sea level
o Std barometric pressure 0.997 atm
p Saturated DO due to pressure
from water column 10.78 mg/l
q Standard Oxygen Trasnfer Rate 298.03 kg/hr
r Trasfer efficiency 0.24 fraction 5% per meter submergence @ 4.8 m
sWeight of Oxygen per cum of
air 0.27623
kg O2/cum-
air0.27623
u Normal Temperature 20 .
v Temperature of Air 49
wAir Flowrate required in terms
of NTP (AOTR) 4495.6 Ncum/hr
Discharge side capacity; Will be lower if
trasfer eff is higher
x C/S are of both aeration tank 697 sqm
y Air volume for mixing 6.5 cum/hr-sqm > 1.8-2.7 cum/hr-sqm as per tender
2-D TOTAL HEAD LOSSa Total head loss in piping 10.0 mm Ref 2-C-1,2,3
bTotal head loss in in Elbow,
Valves, Tee & Meteres 80.8 mm Ref 2-C-1,2,3
cTotal head loss in blower
assembly 0.0 mm Ref 2-C-4
dHead loss in fine bubble
diffuser250.0 mm As per manufacturer data
e Submergence head 4800.0 mm 200 mm diffuser height
f Head loss due to clogging 257.0 mm 5 % of a+b+c+d
Detailed Head loss calculation for the air piping & piping diameter is provided under 2-B , 2-C-1,2,3,4 in a
sperate worksheet
Calculation by: Urv Patel 32of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
gTotal head loss across the
pneumatic system 5397.9 mm Desired blower pressure head required
SELECT BLOWER WITH :-Air Flowrate required 4495.6 Ncum/hr Discharge side capacity @ NTP
HEAD 5.40 m Submergence + Head loss in air piping
Inlet temp 322.15 K
Maximum assumed 49 C (for peak
estimate) as per tender notice Volume-3A,
Part-2, 5.1
Air flow @ Max Inlet
temprature 4940.29 cum/hr @ Max air temperature i.e. 49 C
Air flow @ 35 Inlet
temprature 4730.97 cum/hr @ Max air temperature i.e. 35 C
Density of air at 49 C 1.0914 kg/cum @ 49 C temp & 30 % Humidity
Weight of air flowrate 1.4977 kg/s @ Max air temperature i.e. 49 C
Universal gas constant 8.314 J/mole.K
Inlet temperature 322.15 K 49 dec C
Aboslute inlet pressure 0.98 atm
Absolute outlet pressure 1.52 atm
n 0.28
Molecular weight of dry air 28.97
Efficiency 0.75
Power requirement 86.6 kW Not actual motor rating
Power requirement 116.1 hp Not actual motor rating
Motor required as per Mfg.
datasheet 90.0 kW
Excess 112 kW 25% excess flow capacity
3-Ab Detention time 60 sec
c Volume required per CCT 11.979 cum As per intermedaite peak
d Side water depth 5 m
e C/S area 2.396 sqm
f Length 2.00 m
g Breadth 1.20 m
h Free board 0.5
3-B
a Detention time 60 sec
b Volume required 11.979 cum As per intermedaite peak
c Side water depth 4 m
d C/S of chamber 2.995 sqm
e Length 2.00 m
Outlet chamber
Inlet chamber
Calculation by: Urv Patel 33of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
f Breadth 1.50 m
g Free board 0.5
4Flowrate (Intermediate
Average)0.182 cum/s
At intermediate average + recirculated
Flowrate (Intermediate Peak) 0.399 cum/sAt Intermediate peak +RAS + reciculated
Velocity required at peak flow1.1
m/s
0.6-1.2 m/s as per Tender document and
CPHEEO
C/S area of pipe 0.3630 sqm
Diameter 0.6800 m
Diameter (provided) 700.00 mm Standard size
Velocity at ultimate peak flow 1.04 m/sShould be between 0.6-1.2 m/s as per
CPHEEO
Velocity at intermediate
average flow 0.47 m/s
Should be between 0.3-1.2 m/s as per
CPHEEO
5HRT for Anoxic Zone 1.5
Check total HRT for Biological Treatment Units
Pipe from aeration tank to secondary clarifier
Calculation by: Urv Patel 34of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 1.88 MLD 25 % of 7.5 MLD as per tender document
78.13 cum/hr 3
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 3.91 cum/hr
Average flowrate 0.02 cum/s
2 Peak factor 2.5 As per CPHEEO
3 Peak flowrate 0.057 cum/s
4Specific gravity of volatile
solids 1.00
5Specific gravity of fixed
solids 2.65
6Solids concentration in
sludge wasted 1 % w/w
7Specific gravity of 1% w/w
solids sludge 1.002
Based on Volatile Solids to Fixed solids ratio
of 70:30
1
aSludge wasting reqired per
day from SST 32.20 cum
Assuming 1 % w/w solid concentration and
1.002 sp gr
bSludge wasting as
percentage of total flow 0.43 %
Varied from 1-3 % depending on the SRT
and Secondary clarifier stability
c Fraction of volatile solids 0.7
d Fraction of fixed solids 0.3
eOverall specific gravity of
solids 1.23
fSpecific gravity of the
dewaterd sludge 1.04 20 % w/w
gVolume of Sludge after
dewatering to 20% w/w6.21 cum/day
hWeight of Sludge after
dewatering to 20% w/w6451.8 kg/day
iVolume of sludge drying
bed required for dewatering 24.84 cum
4 day drying cycle & 25% cacpcity as per
tender document
j SDB area required 82.81 sqm Considering 30 cm sludge layer depth for
optimum dewatering
k Length 10.00 m
l Breadth 8.28 m
Solids production & Sizing for sludge drying bed
Metcalf and Eddy Edition-5 Table 13-7 Page
1457
Metcalf and Eddy Edition-5 Table 13-7 Page
1457 OR TENDER DOCUMENT
Sludge Drying Bed
Design Parameters
Design Calculations
STP capacity 7.5 MLD (8.4 MLD Built out)
Calculation by: Urv Patel 35of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Number of sludge drying
bed 4
Length of each sludge
drying bed 8.3 m
mBreadth of each sludge
drying bed 2.5 m
nThickness of coarse sand
(Layer-1)0.3 m
oThickness of Broken stone
metal (Layer-2)0.075 m with size 25 mm
pThickness of Broken Stone
metal (Layer-4) 0.075 m with size 32 mm
qThickness of Broken Stone
metal (Layer-3) 0.075 m with size 75 mm
r Thickness of stone (Layer-4) 0.15 m with size 100-150 mm
sTotal height of Sludge
drying bed 1.275 m With 0.3 m Free board & 0.3 m Sludge layer
Calculation by: Urv Patel 36of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 8.4 MLD
350.00 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 17.50 cum/hr
Average flowrate 0.10 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.224 cum/s
4 Aeration basin SOP 1.00 mg/l As per tedner document Clause 14.5.18
5 Plant effluent target SOP 0.25 mg/l As per tedner document Clause 14.5.18
6 Commercial Alum form
7 Purity of Alum 99 % As per tedner document Clause 14.5.18
8 Alum Soution strength 10 % As per tedner document Clause 14.5.18
9Alum Solution Design
Storage period 2 days As per tedner document Clause 14.5.18
10 Dry Alum Storage period 30 days As per tedner document Clause 14.5.18
1Metal to Initial Soluble
phosphorous ratio
(Me_dose : P initial)
2.60Based on Figure 6-13 (Sazabo et al), Metcalf
& Eddy Edition-5 Section 6-4
Aluminium dose required 1.70 mg/l
Al dose required per day 14.27 kg/day
Fraction Al in Alum 0.04 Alum Molar mass=666.5 g/mole
Alum required per day 352.5 kg/day
Alum solution required 3525.11 Litre/day Assuming 10% w/w solution
Alum solution storage
required 7050.22 Litre/day
No of Alum dosing tank
provided 2.00
Total volume required 14100.45 Litre Considering 2 day storage period
Vol of tank provided 7050.2228 Litre
Vol of each tank provided 7500 Litre
Design Calculations
Calculation of Alum dosing
Alum Dosing tank STP capacity 7.5 MLD (8.4 MLD Built out)
Design Parameters
Calculation by: Urv Patel 37of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
2Alum storage required 10575.3 kg 30 day storage
Vol of alum 6.0 cum Assuming 1760 kg/cum of density
Height of storage area
required 2 m
Length of storage area
required 2 m
Breadth of storage area
required 1.50 m
Calculation of Alum storage area
Calculation by: Urv Patel 38of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 7.5 MLD Intermediate average
312.50 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 15.63 cum/hr
Average flowrate 0.09 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.200 cum/s
4 Assumed RAS flowrate 1
fraction of
plant flow
rate
Maximum assumed for peak loading ; In
reality it would not exceed 0.5
1-A
a Solids loading rate 80 kg/sqm-dayAs per tender 25-120 kg/sqm-day for
average flow
bSurface area required as per
SLR590.63 sqm
Based on 100 % RAS flow rate and above
SLR
c Solids loading rate (Peak) 170 kg/sqm-day As per tender 170 kg/sqm-day for peak flow;
d Surface area required as per
SLR (Peak)625.37 sqm Based on 100% RAS + Peak & Recirculated
e Surface overflow rate 12cum/sqm-
day
As per tender document 8-12 cum/sqm-day
for average flow; As per CPHEEO Nov-2013
Section 5.7.4.2.5, Table 5.8, Page 5.53 8-15
cum/sqm-day for average & 25-35 cum/sqm-
day for peak;
fSurface area required as per
SOR656.25 sqm Average + Reciculated
g Surface overflow rate (Peak) 35cum/sqm-
day
As per tender document 25-35 cum/sqm-
day for peak; As per CPHEEO Nov-2013
Section 5.7.4.2.5, Table 5.8, Page 5.53 8-15
cum/sqm-day for average & 25-35 cum/sqm-
day for peak;
hSurface area required as per
SOR (Peak)506.25 sqm Peak + Recirculated
h Surface area selected 656.25 sqm Maxiumum of al of the above
i Number of clarifier 1
Tank sizing -As per conventional ASP
Secondary Clarifier
Design Parameters
Design Calculations
STP capacity 7.5 MLD (8.4 MLD Built out)
Calculation by: Urv Patel 39of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
jSurface area of each
clarifier 656.25 sqm
k Diameter 28.92 m
n Side water depth (Sewage) 2.70 m
Sludge storage depth 0.30 m
Total SWD 3.00
OKBottom Slope 0.1 1:8 to 1:12 as per CPHEEO
Volume of each clarifier 1969.64 cum
HRT (Q+ RQ) 3.00 hrs For R=1, Considering RAS flow + Avg Q +
Recirculated
o Free board 0.5 m
p Total height 3.50 m
Total volume 2298.81 cum Including F.B
Check Weir loading rate 173.44 cum/m-day Should be <185 cum/day-m
OK
1-B1-B-1 Overflow in launder is from 1 side
a Flowrate 0.20 cum/s As per intermediate peak
b
Velocity of flow in the
launder to avoid deposition
of solids
1.00 m/s 0.6-1.2 m/s as per CPHEEO manual
c C/S area of flow 0.20 sqm
d Depth of flow 0.42 m
e Width of launder 0.48 m
f Width of launder provided 1.00 m
g Free fall provided 0.08 m
h Free Board 0.50 m
i Total depth of launder 1.00 m
jWidth of launder outlet to
Collection chamber 1.00 m
1-B-2
a Detention time 45 sec
b Volume required 8.98 cum As per intermediate peak
cSide water depth of outlet
chamber 2.70
m
d C/S of chamber 3.33 sqm
>3-3.5 As per CPHEEO Nov-2013 Section
5.7.4.2.5, Table 5.8, Page 5.53
Secondary clarifier detailing Launder
Outlet chamber
Calculation by: Urv Patel 40of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
e Length 1.83 m
f Breadth 1.83 m
g Free board 0.5 m
1-B-3
Bottom Slope 0.10 As per CPHEEO manual 1:8 to 1:12
A 3.50 m Including 0.5 m F.B.
B 1.80 m 0.5 clearance around central shaft
C 1.00 m
D 2.36 m
E 1.36 m
F 13.56 m
1-B-4
Flowrate 0.399 cum/s As per intermediate peak + 100% RAS
Velocity required 0.9 m/s AS per CPHEEO and tender document
C/S area 0.444
Diameter required 0.752 m
Diameter provided 0.8 m
1-B-5
Diameter of feed well 4.34 m10-20 % of tank diameter as per CPHEEO
Page 5-58 Section 5.7.4.2.7 Nov,2013
Height of feed well 2 m1-2 m as per CPHEEO Page 5-58 Section
5.7.4.2.7 Nov,2013
Downward velocity 0.01 m/s
CHECK velocity OKNO specifications in CPHEEO; <0.75 m/s as
per Metcalf and Eddy Edition-5, Page-387,
Section-5.6
Secondary clarifier dimensions
Clarifier
Feed Well
Central shaft of Clariflocculator
Calculation by: Urv Patel 41of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
1-B-6
Velocity provided @
intermedate peak flow +
100% RAS
0.25 m/s
0.1-0.25 m/s as per CPHEEO Page 5-58
Section 5.7.4.2.7 Nov,2013 ; 0.75 m/s at
peak flow and 0.3-0.45 m/s at average flow
as per Metcalf and Eddy Edition-5, Page-
387, Section-5.6
Area of outlet ports or slots 1.5972 sqm
Number of ports 3
Area for each port 0.5324 m
Length of each port 0.800 m
Breadth of each port 0.670 m
Total of breadth for all ports 2.010 m
Spacing bewteeen each port 0.126 m o/o distance; Should not be negative
Height of ports from water
level 0.3 m 0.3-0.6 from water level as per
Distance between the lower
feed port level and depth of
feedwell
0.900 mNo specification in CPHEEO; Ideally around 1
m to prevent short circuting
2-A
a Slude RAS flow per clarifier 0.20 cum/sec As per intermediate peak + 100% RAS
b Velocity of flow in pipe 1.20 m/s
cC/S area of sludge removal
pipe 0.17 sqm
d Diameter 0.460 m As per CPHEEO sludge pipe should be
minimum 150 mm in dia
11.69 inch
e Diameter provided 0.5 m
f C/S area 0.2 sqm
gVelocity during peak
flowrate 1.02 m/s 100 % RAS of 2.25 Peak Flowrate
hVelocity during 50% RAS of
Average flowrate 0.23 m/s
Assuming 50% RAS flowrate; Should be 0.3-
0.6 m/s as per CPHEEO manual
i Velocity during 30 % RAS 0.14 m/s Assuming 30% RAS flowrate; Should be 0.3-
0.6 m/s as per CPHEEO manual
hAt 50 % RAS flow of Average
flow
Intermittent
RAS flow
Regulation
required
Sludge piping (Secondary Clarifier to RAS sump)
Discharge ports on central column
Calculation by: Urv Patel 42of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
iAt 30 % RAS flow of Average
flow
Intermittent
RAS flow
Regulation
required
hRAS flow duration per hours
@ 30% RAS flowrate16.72 min/hr
Assuming a 0.5 m/s flow velocity ; This can
be also modified in terms of min/30 min,
min/20 min and so on based on the RAS
MLSS & Flowrate conditions
hRAS flow duration per hours
@ 30% RAS flowrate27.87 min/hr
Assuming a 0.5 m/s flow velocity ; This can
be also modified in terms of min/30 min,
min/20 min and so on based on the RAS
MLSS & Flowrate conditions
2-B
aVolume of sludge to be
widrawn per day128.78 cum/day
b Velocity of flow in pipe 1 m/s Valve controlled
cC/S area of sludge removal
pipe 0.001490 sqm
d Diameter 0.044 m As per CPHEEO sludge pipe should be
Minimum 150 mm in dia
1.11 inch Not as per standards
e Diameter provided 0.200 m
As per CPHEEO sludge pipe should be
Minimum 150 mm in dia & Tender Clause
13.1.15 Page 27 Vol lll Part-2
f C/S area 0.03 sqm
g Flowrate 2713.0 cum/day
1.9 cum/min
hWAS pumping duration per
4 hours 11.39 min
This can be modified as per the operator
requirement
WAS flow in each release 21.46 cum
WAS flowrate in each
release 113.04 cum/hr
WAS flow velocity in the
RAS pipe 1.00 m/s 0.6-1.2 as per CPHEEO manual
3-A
RAS flow required actually 359.4 cum/hr 50% RAS at intermedaite average flow for
both bains
Pumping head required 8 mHeight of aeration tank + 1m as a factor
safety for head loss
Sludge piping for WAS to Sludge thickner (Via T junction from Pumped RAS line to Aeration
tank)
Electro-mechanical equipment sizing for RAS pump
Calculation by: Urv Patel 43of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Pumping power required 7.98 BkW Actual for both basins
Efficiency of the pump 0.9 %Lower efficiency assumed; in reality it is
around 70-85 %
Shaft power required 11.89 hp
Shaft power provided 12.5 hpThis wil be the average power consumption
for RAS for both basins
Max RAS flowrate required
per basin 359.4 cum/hr
As per 100% RAS of intermedaite peak per
basin
Pumping head required 8 m
Pumping power required 7.98 BkW
Efficiency of the pump 0.75 % Efficiency assumed 70-85 %
Shaft power required 14.27 hp
Shaft power provided 15 hp Higher as a factor of safety
3-B-1
Flowrate required 41.0 cum/day
3.414 cum/hr 12 hours of operation
Pumping head required 7 mHeight of aeration tank + 3m as a factor
safety for head loss
Pumping power required 0.068 BkW
Efficiency of the pump 0.4 %Lower efficiency assumed due for Scre
Pump
Shaft power required 0.229 hp
Shaft power provided 1 hpCheck with manufacturer data for a pump
match
3-B-2Piping-1 from Sludge
Thickner to Thickned sludge
sump
200 mmMinimum size selected based on CPHEEO
Sludge gravity line
Piping-2 from Thickned
sludge sump to centrifuge 200 mm
As per teder document pumped line should
be >=200 mm as per Clause 13.1.15 Page 27
C/S are of pipe -2 0.031 sqm
Velocity 0.03 m/s Minimum velocity for sludge line should be
0.6 m/s
Decrease line
size
Electro-mechanical equipment sizing for WAS screw pump (From Sludge thickner to
Centrifuge)
Piping after Thickner
Provide 1 W + 1 S, 15 hp Pump per basin for RAS pumping
However, RAS flow capacity to be provided is as per 100% of Influent (Peak) flow rate
Installed Max capacity
Calculation by: Urv Patel 44of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
5Detention time (of 100 %
RAS ratio)0.5 hr
As per tender document Clause 14.5.14
Page 39 Vol lll Part-2
Volume 164.1 cum As per average + Reciculated flow
Diameter 10.1 m As per tender document Clause 14.5.14
Page 39 Vol lll Part-2
Surface area 80.1 sqm
Height 2.0 mAs per tender document Clause 14.5.14
Page 39 Vol lll Part-2
If rectangle
Length 10.0 m
Breadth 8.01 m
4
Solid loading rate 30 kg/sqm-d
Daily Sludge production 1290 kg/day in TSS
Surface area as per SLR 43.0 sqm As per Daily Sludge production
Diameter 7.4 m
Check Hydraulic loading 0.7 m3/m2-day Should be <4-8 cum/sqm-day as per Metcalf
& Eddy; Edition-4, Page 1492
Depth of Thickner
Assumed depth of thickning
zone 1.5 m
Volume of Sludge blanket 64.5 cum
Amount of Solids in
thickening zone as per 3%
Solids w/w
1993.6 kg
Quantity of solids held in
thickening zone 1290.4 kg/day
SRT in Thickening zone 1.5 days
SVR in Thickening zone 0.60.5-2 as per as per Syed Qasim Edition-2,
Page 654
Clear liquid zone 1 m0.5-1 m as per Syed Qasim Edition-2, Page
665
Settline zone 2 m1.5-2 m as per Syed Qasim Edition-2, Page
665
Thickening zone 1.5 m0.5-1 m as per Syed Qasim Edition-2, Page
665
Total liquid depth 4.5 m
Gravity thickner
RAS sump
Calculation by: Urv Patel 45of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Bottom Slope 0.17 m2:12 or 3:12 as per Syed Qasim Edition-2,
Page 655
Bottom Slope 0.17
A 4.50 m
B 1.00 m 0.5 clearance around central shaft
C 0.75 m
D 0.95 m
E 0.20 m
F 1.21 m
6
HRT required 10 hrs
Volume of thickened
sludge produced per day
after gravity thickening
41.76 cum 3% thickening assumed and 1.03 sp gr
Hours of operation for
Thickened Sludge
Pumping station
12 hr/day
Averaged flow rate
considering above hours
of operation
3.48 cum/hr
Volume of Thickened
sludge sump 34.8 cum
SWD of sump 2 m Limited to 2 m as per tedner document
C/S Area of sump 17.4 sqm
Diameter 4.7 m
if rectangle
Length 5
Breadth 3.48 m
say 3.5
Thickned Sludge sump
Gravity thickner dimension
Calculation by: Urv Patel 46of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
6Flowrate (Average) 0.09 cum/sec Intermedaite average + Recirculated
Flowrate (Peak) 0.200 cum/sec Intermedaite peak + Recirculated
Velocity required at peak
flow1.2 m/s
0.6-1.2 m/s as per Tender document and
CPHEEO
C/S area of pipe 0.17 sqm
Diameter 0.460 m
Diameter (provided) 500.00 mm Standard size
Velocity at peak flow 1.02 m/sShould be between 0.6-1.2 m/s as per
CPHEEO
Velocity at average flow 0.46 m/sShould be between 0.3-1.2 m/s as per
CPHEEO
Pipe from each secondary clarifier to chlorine contact tank
Calculation by: Urv Patel 47of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 7.5 MLD
312.50 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 15.63 cum/hr
Average flowrate 0.09 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.200 cum/s
4Coliform count after
aeration tank 1000000 per 100 ml
Adapted from Metcalf and Eddy Table 12-13
Edition-4 & US EPA Design Manual
5Required coliform count
after chlorination 80 per 100 ml As per tender document
Reduction required 99.99 %
6Residual chlorine
requirement 1 mg/l As per tender document
1-Aa Detention time at peak 14 min At intermediate peak
b
Volume required for peak
flow rate for both CCT
compartments
167.71 cum
c Retention time as per
avergae + Recirculated 30.67 min > 30 min at average flow
dSide water depth of chlorine
contact tank 2.2 m
e Surface area 76.2 sqm
f Number of compartments 2.0
gSurface area for each
compartment 38.1
h Length 6.20 m 12.4
i Breadth 6.20 m
n Ratio of length/breadth 1.00
oNumber of baffles along the
length 5
Baffle will divide along the length mentiond
in 1-A-h
p Spacing between the baffles 1.0 m
q Pass width 1.0 m
Chlorine contact tank
Design Parameters
Design Calculations
Chlorine contact tank size
STP capacity 7.5 MLD (8.4 MLD Built out)
Calculation by: Urv Patel 48of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
s Effective L/W ratio 41.0
> 8 Approaches plug flow as per Table 5.13,
Page 5-79, Chapter-5, CPHEEO Manual Nov,
2014 Edition; Around 40 as per tender
document
t Total travel length 42.4 m
1-Ba Detention time 45 sec
b Volume required per CCT 8.98 cum
c Side water depth 2.2 m
d C/S area 4.084 sqm For each CCT
e Length 2.03 m For each CCT
f Breadth 2.03 m For each CCT
g Free board 0.5
1-Ba Detention time 45 sec
b Volume required 8.98 cum
cSide water depth of outlet
chamber 2.2
m
d C/S of chamber 4.08 sqm
e Length 2.03 m
f Breadth 2.03 m
g Free board 0.5
2
Fraction removal desired 0.00008Ratio of Coliform remaining to initial
coliform
n (slope of inactivation
curve)2.8
Based on coefficient based on Metcalf and
Eddy Section 12-3 Edition 4
b (intercept of inactivation
curve) 4
Based on coefficient based on Metcalf and
Eddy Section 12-3 Edition 4 ; For coliform 4
and for feacal coliform 3
Ct (dosage X contact time)
value 116.2 mg-min/l Based on Colins selleck model
Chlorine dosage required 3.87 mg/lBased on 30 min contact time; Actual
contact time is higher for safer side
Collection chamber / Outlet chamber
Inlet chamber
Chlorine dosing required
Calculation by: Urv Patel 49of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
3a Summer temperature 28 deg C 22000
b Winter temperature 10 deg C
Activation energy at pH Value Unit
7 34,340
8.5 26,800
9.8 50,250
10.7 62810
c pH of wastewater assumed 8
dContact time required in
Summer 9.63 min
Based on Vant Hoff's Arrhenius Equation &
Peak flow detention time
eContact time required in
Winter 23.03 min
Based on Vant Hoff's Arrhenius Equation &
Peak flow detention time
fChlorine dosage required in
summer 1.22 mg/l Excluding the residual chlorine requirment
gChlorine dosage required in
winter 2.91 mg/l Excluding the residual chlorine requirment
hChlorine demand due to
decay 2
i
Total Chlorine dosage
required in summer (Peak
demad)
4.22 mg/l Including residual + Demand due to decay
j
Total Chlorine dosage
required in winter (Peak
demand)
5.91 mg/l Including residual + Demand due to decay
kTotal chlorine required daily
(Summer)31.62 kg/day
lTotal chlorine required daily
(Winter)44.31 kg/day
m 15 day storage for (Summer) 474.3 kg
n 15 day storage for (Winter) 664.7 kg
oNumber of toner units
required 1 unit/ 15 day Assuming standard size of toner as 990 kg
p Standby toner unit 1 unit/ 15 day As per tender document
Change in chlorine dosage required due to change in hypothetical contact time
Impact of temperature on Chlorine dose
J/mole
Calculation by: Urv Patel 50of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
4
Length of Chlorine toner 2.2 m As per standard dimensions of 990 kg toner
Diameter of Chlorine toner 0.8 m As per standard dimensions of 990 kg toner
Number of toner required 2
Spacing between tonner 1 m
Area required by the toner 7.92 sqm including 0.25 m spacing on all 4 sides
Area required by chlorine
dosing assembly 7.5 sqm
Extra area required for
shower, emergency
netralization tank etc.
2.64 sqm
Total area requried 18.06 sqm
Length of Chlorine room 5.00 m
Breadth of Chlroine room 3.70 m
Height of Chlorinator room 4.5 m
5
aFlowrate (Intermediate
Average)0.0911 cum/s
Considering Return flow ; Ref Secondary
Clarifier Calculations
bFlowrate (Ultimate Peak) 0.224 cum/s
Considering Return flow ; Ref Secondary
Clarifier Calculations
c
Velocity required at peak
flow1
m/s
0.6-1.2 m/s as per Tender document and
CPHEEO
d C/S area of pipe 0.2236 sqm
e Diameter 0.5337 m
f Diameter (provided) 600.00 mm As per tender document
gVelocity at peak flow 0.79 m/s
Should be between 0.6-1.2 m/s as per
CPHEEO
hVelocity at average flow 0.32 m/s
Should be between 0.3-1.2 m/s as per
CPHEEO
Length of Chlorine tank 12.40 m
Breadth of chlorine contact
tank 6.20 m
Summary
Chlorine room
Pipe from CCT Outlet chamber to Outfall
Calculation by: Urv Patel 51of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Side water depth of Chlorine
contact tank 2.20 m
Free Board 0.5 m
Number of baffles 5
Spacing between the baffles 1.0 m
Total travel length 42.36666667 m
Ratio of L/B 2.00
Chlorine required per day 44.31 kg Maximum required (In winter)
Chlorine required per cum 5.91 g/cum Maximum required (In winter)
Chlorine required per MLD 5.9 kg/MLD Maximum required (In winter)
Calculation by: Urv Patel 52of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 7.5 MLD
312.50 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 15.63 cum/hr
Average flowrate 0.09 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.200 cum/s
1 TSS generation 1290.35 kg/day
2 Percentage solids 1.00
3Actual WAS flow required
based on TSS generation 5.4 cum/hr Based on 1% w/w solids concentration
4 Percentage of Average flow 1.72 % Of Average flow
5 Percentage of Average flow 1.89 %10% factor of safety as per tender document
page 49Section 14.10.6
6Choosing worst case
scenario 5 %
More than 10% factor of safety over the
WAS flow
7 Recirculation sump flow 15.63 cum/hr
8 Dentention time 10 min As per tender
9 Volume of sump 2.60 cum
10 Volume of sump provided 3.5 cum
Depth 1.5 mAs per tender document page 49Section
14.10.6
C/S area 2.3
Length 1.60
Breadth 1.46
say 1.5
Design Calculations
Drain Sump STP capacity 7.5 MLD (8.4 MLD Built out)
Design Parameters
Calculation by: Urv Patel 53of 67
Prepared by:
SWA Environmental Consultants Engineers
Project Name: STP at Dhandhuka Date- 29-08-18
Item No Equipment Name Working
Units
Efficiency of
Equipment
(%)
B kW for
operatio
n
Motor-
Efficiency
(%)
Motor Rating (kW)
(For effective power
consumption- Not
actual motor rating)
Actual Total
Motor rating
(hp)
Operating
Hours
(h/day)
Total Power
Consumption
(kWh/day)
1 Mechanical Fine screen 1 90 1 98 1.1 1.5 12 13.6
2 Belt Conveyor 1 90 0.5 98 0.6 0.5 1 0.6
3 Grit Collector (Scraper) 2 80 0.45 98 1.1 1.5 12 13.8
4 Grit Clasiffier 2 90 0.45 98 1.0 1.0 6 6.1
5 Organic Return Pump 2 90 0.5 98 1.1 0.5 0.5 0.6
6 Anaerobic tank mixer 2 90 0.65 98 1.47 2.0 12 17.7
7 Anoxic tank mixer 2 90 1 98 2.3 4.0 12 27.2
8 Process Air blower 1 70 36 98 52.5 150.0 24 1259.5
9 RAS pump 2 90 2.7 98 6.1 30 24 146.9
10 WAS Screw Pump 1 50 0.44 98 0.90 1.00 2 1.8
11 Internal Recycle 2 90 9 98 20.4 150.0 24 489.8
12 Secondary Scraper 1 90 0.9 90 1.1 1.5 24 26.7
13 Dewatering unit 1 70 10 80 17.9 2 35.7
14 Agitator PE preparation 1 90 0.5 90 0.6 0.5 0.5 0.3
15 PE pump dosing 1 90 0.5 90 0.6 2 1.2
16 Pump chlorine booster 1 90 0.65 90 0.8 1.0 24 19.3
17 Lighting 15.0
18 Auto valves/ Sluice gate 15 90 1 90 16.7 1.0 0.5 8.3
19 EOT cranes
20Other miscellaneous
load 10.0
TOTAL 346.0 2094.1
Power Calculations
Calculation by: Urv Patel
Prepared by:
SWA Environmental Consultants Engineers
Project Name: STP at Dhandhuka Date- 29-08-18
279.2077
Calculation by: Urv Patel
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr No. Parameter Value Unit Remarks
1 Flowrate 7.5 MLD
312.50 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 15.63 cum/hr
Average flowrate 0.09 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.205 cum/s
Max dosing 10.00 mg/l
Max Chlorine requirement
per day 75.0 kg/day
Max Chlorine requirement
per MLD 10.00 kg/ML
Max Chlorine requirement
per cum10.00 g/cum
TSS generation 1290.35 kg/day
DWPE required per ton dry
solids 2.0 kg/ton
DWPE required per day 2.58 kg/day
DWPE required per MLD 0.34 kg/MLD
DWPE required per cum 0.34 g/cum
Alum required per day 352.51 kg/day For detailed calculation please see Alum
Dosing Calculation
Alum required per MLD 47.00 kg/MLD
Alum required per cum 0.047 kg/cum
DWPE requirement
Alum requirement
Chemical Calculations STP capacity 7.5 MLD (8.4 MLD Built out)
Design Parameters
Chlorine requirement
Calculation by: Urv Patel 56of 67
Prepared by: SWA Environmental
Consultants Engineers 29-08-18
Qmin Qmax W A B (min) C D F G K Z
0 5 75 460 450 175 255 150 300 25 56
5 30 150 610 600 315 391 300 600 75 113
30 170 225 865 850 375 566 300 750 75 113
45 250 300 1350 1322 600 831 600 900 75 225
170 250 450 1425 1397 750 1010 600 900 75 225
250 350 600 1500 1472 900 1188 600 900 75 225
350 500 900 1650 1619 1200 1547 600 900 75 225
500 700 1200 1800 1766 1500 1906 600 900 75 225
700 850 1500 2100 2060 2100 2625 600 900 75 225
850 1400 2400 2400 2353 2700 3344 600 900 75 225
As per CPHEEO Nov-2013 Edition Page 5-46 Table 5.7 Section 5.6.2.8.1
Flowrate capacity (MLD) Dimensions in mm
PARSHALL FLUME DESIGN DATA
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
Sr
No.Parameter Value Unit Remarks
2-B
Air flow per diffuser 9.0 Ncum/hr 5-12 Ncum/hr as per specification
Number of diffuser required
per each basin 250.0 nos for each basin
Diameter of diffuser 65.0 mm As per manufacturer
Length of diffuser 1000.0 mm As per manufacturer
Diffuser in each row & column
if the grid is square 15.8
Diffusers along the row 3.0 Along the breadth
Diffusers along the column 13.0 Along the length
Number of columns 3.0
Number of diffuser per column 13.0
Spacing between diffuser
along each column 1.3 m
Spacing between diffuser
along each row 4.1 m Should not be negative
OK
2-C2-C-
1Horizontal diffuser header 1st stage piping laterally along the grid
aNumber of diffuer in each
header16
b Air flow in each header 144.0 Ncum/hr
c Pipe diameter 3.0 inch
0.0762 m
d Velocity 526.5 m/min
Should be between 360-540 m/min for pipe
diameter between 1-3 inch as per Metcalf &
Eddy Edition-5, Table 5-29, Page 435
Head loss calculation
e f (friction factor) 0.023765
f D (Diameter) 0.0762 m
g Q (Air flowrate) 2.4Ncum/mi
n
h L (Length of pipe) 21.4 m Change according to difusser configuration
i P (Air supply pressure) 1.5 atm Atmospheric pressure + Depth of water
column
Aeration- Air piping head loss
Aeration- Air Piping
Air piping system - Extension from Aeration tank calculation sheet
Design Parameters
STP capacity 7.5 MLD (8.4 MLD Built out)
Calculation by: Urv Patel 58of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
jHead loss as per Darcy-
Weishbach 1.52 mm
k Number of Elbow 2.00
l Number of Tee 16.00
m Head loss due to Elbow 3.12490 mm
n Head loss due to Tee 50.00 mm
2-C-
2
Header pipe connecting 2
stage-1 pipe Stage-2 line
aNumber of diffuer in each
header32
b Air flow in each header 288.0 Ncum/hr
c Pipe diameter 4.0 inch
0.1016 m
d Velocity 592.4 m/min
Should be between 540-900 m/min for pipe
diameter between 4-9 inch as per Metcalf &
Eddy Edition-5, Table 5-29, Page 435
e Head loss calculation
f f (friction factor) 0.0216
g D (Diameter) 0.1016 m
h Q (Air flowrate) 4.8Ncum/mi
n
i L (Length of pipe) 10.62 m Along the breadth
j P (Air supply pressure) 1.5 atm Atmospheric pressure + Depth of water
column
kHead loss as per Darcy-
Weishbach 0.65 mm
l Number of Elbow 1.00
m Number of Tee 1.00
n Head loss in Elbows 2.52 mm
o Head loss in Tees 2.52 mm
2-C-
3
Header pipe connecting
Stage 2 head with Tee and
combining with piping from
second rank
Stage-3 line
aTotal number of diffuser in the
main header32
b Air flow in each header 288.0 Ncum/hr
c Pipe diameter 4.0 inch
0.1016 m
d Velocity 592.4 m/min
Should be between 540-900 m/min for pipe
diameter between 4-9 inch as per Metcalf &
Eddy Edition-5, Table 5-29, Page 435
Calculation by: Urv Patel 59of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
e Head loss calculation
f f (friction factor) 0.0
g D (Diameter) 0.1 m
h Q (Air flowrate) 4.8Ncum/mi
n
i L (Length of pipe) 20.0 mChange according to difusser configuration
& Blower Location
j P (Air supply pressure) 1.0 atm Atmospheric pressure + Depth of water
column
kHead loss as per Darcy-
Weishbach 1.23 mm
l Number of Elbow 2.00
m Number of Tee 1.00
n Head loss in Elbows 5.0 mm
o Head loss in Tees 2.5 mm
2-C-
4
Header pipe connecting
Stage 3 pipes from both
aeration tank
Stage-4 line
aTotal number of diffuser in the
main header64
b Air flow in each header 576.0 Ncum/hr
c Pipe diameter 4.0 inch
0.1016 m
d Velocity 1184.7 m/min
Should be between 540-900 m/min for pipe
diameter between 1-3 inch as per Metcalf &
Eddy Edition-5, Table 5-29, Page 435
e Head loss calculation
f f (friction factor) 0.02
g D (Diameter) 0.10 m
h Q (Air flowrate) 9.6Ncum/mi
n
i L (Length of pipe) 30.0 mChange according to difusser configuration
& Blower Location
j P (Air supply pressure) 1.0 atm Atmospheric pressure + Depth of water
column
kHead loss as per Darcy-
Weishbach 6.64 mm
l Number of Elbow 3.00
m Number of Tee 3.00
n Head loss in Elbows 7.6 mm
o Head loss in Tees 7.6 mm
2-C-
4
Head loss in blower
assembly
Calculation by: Urv Patel 60of 67
Prepared by: SWA Environmental
Consultants Engineers STP at Dhandhuka 29-08-18
a Air filter losses 40.0 mm
13-76 mm as per Wastewater Treatment
Plant by S.Qasim Second Edition, Table-13-
15, Page-514
b Silencer losses 13.0 mm
13-38 for centrifugal & 152-216 as per
Wastewater Treatment Plant by S.Qasim
Second Edition, Table-13-15, Page-514
c Check valve losses 100.0 mm
20-203 mm as per Wastewater Treatment
Plant by S.Qasim Second Edition, Table-13-
15, Page-514
2-D TOTAL HEAD LOSS
a Total head loss in piping 10.0 mm Ref 2-C-1,2,3
bTotal head loss in in Elbow,
Valves, Tee & Meteres 80.8 mm Ref 2-C-1,2,3
cTotal head loss in blower
assembly 153.0 mm Ref 2-C-4
dHead loss in fine bubble
diffuser250.0 mm As per manufacturer data
e Submergence head 5000 mm
f Head loss due to clogging 274.7 mm 5 % of a+b+c+d
gTotal head loss across the
pneumatic system 5768.5 mm Desired blower pressure head required
Calculation by: Urv Patel 61of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
From To
1 Pumping Station Inlet Chamber 500 306 DI K9 As per tender
2Inlet Chamber By-
PassDischarge invert 600 50 RCC NP2
Combines with
common by pass
3Parshall Flume By-
PassDischarge invert 600 75 RCC NP2
4Distribution
chamber Aeration tank
None; Directly
connected via
channel
5 Aeration tank Secondary Clarifier 700 25.0 DI K9
6Aeration tank By-
PassDischarge invert 600 25.0 RCC NP2
7 Secondary Clarifier Chlorine Contact tank 500 20 DI K9
8Chlorine Contact
tank Discharge invert 600 2600 RCC NP2
1 RAS Sump Anoxic tank-1 300 55 DI K9
As per peak
intermediate per
basin
2 RAS Sump Anoxic tank-2 300 60 DI K9
As per peak
intermediate per
basin
3 Aeration tank-1 Anoxic tank-1 600 30 DI K9
As per peak
intermediate per
basin
4 Aeration tank-2 Anoxic tank-2 600 30 DI K9
As per peak
intermediate per
basin
5 Seondary clarifier RAS Sump 500 20 DI K9
7 RAS Sump Gravity Thickner 200 5 DI K9
8 Gravity Thickner Thickned Sludge Sump 200 5 DI K9
9Thickned Sludge
Sump Centrifuge 200 10 DI K9
Sludge & Return piping
Hydrualic & Sludge Piping for STP
Pipeline connecting Sr No.
Diameter
(mm)
Approx.
Length
(m)
STP 7.5 MLD (8.4 MLD Built out)
MOC Remarks
Hydraulic piping
Calculation by: Urv Patel Page 62 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
From To
1 Pumping Station Inlet Chamber 0
2 Inlet chamber Bypass 450X450 1 Sluice gate
3 Inlet chamber Screen Channel 450X450 2 Sluice gate
4 Screen Channel Grit chambers 450X450 4 Sluice gate
5 Parshal Flume Bypass Channel 450X450 1 Sluice gate After Grit chamber
6Distribution
chamber
Biological treatment
unit450X450 2 Sluice gate
7 Primary Clarifier Sludge bleed tank 0 NA
8Primary Clarifier
sludge bleed tank Sludge sump 0 NA
9Primary Clarifier
drainage 0 NA
10
Aeration tank
Distribution
chamber
Outlet chamber 450X450 1 Sluice gate By-pass
11 Air line Aeration tank 200.00 2 Butterfly Isolating airflow to
each basin if required
12Aeration tank
Sludge Sludge sump 450.00 0 Sluice valve
Only applicable for
SBR type plant
13 Aeration tank Anoxic tank 600.00 2 Sluice valve For both the basin
14 Aeration tank Anaerobic tank Sluice valve For both the basin
15 Blower Aeration tank 300.00 4 Butterfly 2+2
16 Blower Aeration tank 300.00 4 NRV 2+2
17 Secondary clarifier RAS bleed 500.00 1Telescopic
arrange-ment
18 Seondary Clarifier RAS Sump 500.00 1 Sluice valve
19 RAS Sump Gravity Thickner 200.00 1 Sluice valve
20 RAS Sump Anaerobic tank 300.00 2 Sluice valve For both basin
21 RAS Sump Anoxic tank Sluice valve For both basin
22 RAS pumps 150.00 8 Sluice valve Isolation 4 for each
set per basin
23 Gravity thickner Thickned sludge sump 200.00 1Knife gate/
Sluice valve Due to thicker
24Thickened Sludge
sump Centrifuge 50.00 4 Sluice valve
isolation for
Centrifuge feed
pump
Gates & Valves STP 7.5 MLD (8.4 MLD Built out)
Sr No. Flow
Size Number Type Remarks
Calculation by: Urv Patel Page 63 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
25CCT distribution
chamber 450X450 2 Sluice gate NA if only 1 CCT
26DWPE dosing
system
Centrifuge & Thickened
Sludge Sump 12.70 12 Ball valve 3 inch manual
27Alum dosing
system
Post Aeration Outlet
chamber 12.70 12 Ball valve 3 inch manual
Valve/Gate Number
Sluice gate 13
Sluice valve 2
Sluice valve 4
Sluice valve 10
Sluice valve 10
Sluice valve 4NRV 4
Butterfly 4Butterfly 2
Ball valve 24 12.70
300.00
300.00
50.00
300.00
300.00
200.00
Size (mm)
450X450
600.00
200.00
Calculation by: Urv Patel Page 64 of 67
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
2 Parameter Value Unit Remarks
1 Flowrate 7.5 MLD
312.50 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 15.63 cum/hr
Average flowrate +
Recirculated 0.09 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.200 cum/s
1 Flowrate 8.5 MLD
354.17 cum/hr
Recirculated flow 5.00 % Asssumed 5 %
Recirculated flowrate 17.71 cum/hr
Average flowrate +
Recirculated 0.10 cum/s
2 Peak factor 2.25 As per CPHEEO
3 Peak flowrate 0.226 cum/s
1 By-pass line From all applicable units
Design Flow 0.23 cum/s Ultimate peak
C/S velocity 1.0 m/s
C/S area required 0.23 sqm
Diameter 0.537 m
Diameter provided 600 m
MOC RCC NP2
2Distribution chamber to
aeration tank
3 Aeration tank to SST
Design Flow 0.40 cum/s Ultimate peak
C/S velocity 1.2 m/s
C/S area required 0.33 sqm
Diameter 0.651 m
NO pipe, directly connected to aeration tank via channel
Design Calculations
Ultimate
Intermediate
Piping calculation STP capacity 7.5 MLD (8.4 MLD Built out)
Design Parameters
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
Diameter provided 700 m
MOC DI K-9
4 SST to CCT Secondary clarifier to Chlorine Cont Tank
Design Flow 0.20 cum/s Intermediate peak
C/S velocity 1.2 m/s
C/S area required 0.17 sqm
Diameter 0.460 m
Diameter provided 500 m
MOC DI K-9
5 Aeration tank to Anoxic
Design Flow 0.40 cum/s Intermediate peak per basin X 4
C/S velocity 1.5 m/s
C/S area required 0.27 sqm
Diameter 0.582 m
Diameter provided 600 m
MOC DI K-9
6 SST to RAS sump With telescopic arrangement
Design Flow 0.200 cum/s AS per 100% of intermedaite peak
C/S velocity 1.1 m/s
C/S area required 0.18 sqm
Diameter 0.48 m
Diameter provided 500 m
MOC DI K-9 m
7RAS pump to Anaerobic
tank 1 line for each basin
Design Flow 0.100 cum/s Intermediate peak per basin
C/S velocity 1.5 m/s
C/S area required 0.07 sqm
Diameter 0.29 m
Diameter provided 300 m
MOC DI K-9 m
8
aVolume of sludge to be
widrawn per day128.78 cum/day
b Velocity of flow in pipe 1 m/s Valve controlled
Sludge piping for WAS to Sludge thickner (Via T junction from Pumped RAS line to Aeration
tank)
Prepared by: SWA Environmental
Consultants Engineers
Project Name: STP at Dhandhuka 29-08-18
cC/S area of sludge removal
pipe 0.001490 sqm
d Diameter 0.044 m As per CPHEEO sludge pipe should be
Minimum 150 mm in dia
1.11 inch Not as per standards
e Diameter provided 0.200 m
As per CPHEEO sludge pipe should be
Minimum 150 mm in dia & Tender Clause
13.1.15 Page 27 Vol lll Part-2
f C/S area 0.03 sqm
g Flowrate 2713.0 cum/day
1.9 cum/min
hWAS pumping duration per 4
hours 11.39 min
This can be modified as per the operator
requirement
WAS flow in each release 21.46 cum
WAS flowrate in each
release 113.04 cum/hr
WAS flow velocity in the RAS
pipe 1.00 m/s 0.6-1.2 as per CPHEEO manual
9
Piping-1 from Sludge
Thickner to Thickned sludge
sump
200 mmMinimum size selected based on CPHEEO
Sludge gravity line
Piping-2 from Thickned
sludge sump to centrifuge 200 mm
As per teder document pumped line should
be >=200 mm as per Clause 13.1.15 Page 27
C/S are of pipe -2 0.031 sqm
Velocity 0.05 m/s Minimum velocity for sludge line should be
0.6 m/s Decrease line
size
Piping-2 from Thickned
sludge sump to centrifuge 50 mm
As per teder document pumped line should
be >=200 mm as per Clause 13.1.15 Page 27,
However 200 mm size contradicts with
minimum velocity criteria
C/S are of pipe -2 0.002 sqm
Velocity 0.76 m/s Minimum velocity for sludge line should be
0.6 m/s OK
Gravity thickner to Thickned Sludge Sump