BASIC DESIGN DATA

Flow rates
Average Flow 4000.00 m3/day
166.67 m3/h
Peak factor 2.00 m3/h
Peak flow 333.33
Peak flow rates 8000.00 m
Flow rates for the biological treatment
Max. monthly flow 4000.00 m
166.67 m3/h

Design flow rates=1.5*Qavg 6000.00 m3/day

Peak flow per hour 250.00 m3/h
Influent quality (Raw sewage)
COD 405.00 mg/l
Influent BOD 291.00 mg/l
Influent TSS 241.00 mg/l
VSS=(0.5-0.8) TSS 192.80 mg/l
Influent NH4 25.00 mg/l
Influent TKN 20.00 mg/l
Min temperature T min 23.00 ⁰c
Max temperature T max 25.00 ⁰c

Characteristics of Influent Wastewater to the system:

BOD 291.00 g/m3
COD 405.00 g/m3
TSS 241.00 g/m3
VSS 192.80 g/m3
Influent NH4 25.00 g/m3
Influent TKN 20.00 g/m3
biodegradable COD "bCOD" = 378.30 g/m3
nbCOD 26.70 g/m3
rbCOD 189.15 g/m3

Secondary treated effluent quality

BOD5 < 60.00 mg/l
SS < 50.00 mg/l
NH3-N 0.00 mg/l
TN 10.00 mg/l

INLET CHAMBER
Peak flow 8000.00 m3/day
333.33 m3/h
Max. monthly 166.67 m3/h
V
Breadth (B) B 1.50 m
Length (L) L 2.90 m
Water depth d max 1.00 m

Volume V 4.35 m3
check
Retention time at peak flow 46.98 sec (0.5-2) min,ECP 2018
,P.1/3
0.78 min
Retention time at average flow 93.96 sec

1.57 min

MECHANICAL COARSE SCREEN

Max. monthly flow 4000.00 m3/day
166.67 m3/h
0.05 m3/sec
Peak factor 2.00
Peak flow 333.33 m3/h
0.09 m3/sec
No. mechanical screen set (set) 1.00 nos, duty "n" can be taken 1 when
n having small Flow rates
,ECP 2018 ,P.6/3
Flow per each screen 333.33 m3/h
0.09 m3/sec
Bar width 10 mm (10-20) mm , ECP
e
2018,P.6/3
Frame thickness 20 mm As per manufacturer
s'
design
Space between bars 25 mm (15-25) mm , ECP
S
2018,P.6/3
Inclination angle 80 Degree (60-90) degree ,ECP
2018,P.6/3
Velocity in the screen channel=Q/area of 0.60 m/sec > = 0.6 m/sec ,ECP
screen channel v' 2018,P.6/3

Area of the screen channel A' 0.15 m2

Selected screen channel width 0.60 m
w
Depth of water at maximum flow 0.26 m
d
Velocity in the screen channel at peak flow 0.60 m/sec
v
Velocity in the screen channel at average flow 0.30 m/sec

No.of spaces bet. Bars (space) 16.29 nos

Selected No. of spaces bet. Bars (space) 17.00 nos

N
No. of bars in each screen = No. of spaces-1 16.00 nos

Total width of the each screen including 0.63

frame
taken 0.60
Inclined length of the screen (immersed in 0.26 m
water)
Effective inclined screen area 0.11 m2
A'
velocity in screen 0.85 m/sec ( 0.6-1.5) m/s ,ECP
V
2018,P.7/3

Q 2
( )
Head loss through the screen C∗A
H L=
2∗g

Head loss coefficient for a clean bar screen 0.60 ( 0.3-0.6) ,ECP 2018,P.8/3
c
0.11 m (0.8-1.4) m,ECP
HL
2018,P.8/3

Manual Screen
No. manual screen set (set) n 1.00 nos, duty
Flow per screen 100% from total flow 333.33 m3/h

0.09 m3/sec
Bar width s 10 mm
Frame thickness s' 20 mm
Space between bars e 50 mm
Inclination angle 45 Degree
Velocity in the screen channel Before screens 0.75 m/sec
V1
Area of the screen channel A' 0.12 m2
Selected screen channel width w 0.63 m
Depth of water at maximum flow d 0.20 m

Velocity in the screen channel at peak flow 0.75 m/sec

V1 peak
Velocity in the screen channel at average flow 0.38 m/sec
V1 average
No. of spaces bet. Bars (space) 9.92 nos

Selected No. of spaces bet. Bars (space) 9.00 nos

N
Bars in each screen 8.00 nos No. of bars = No. of
spaces-1
Total width of the each screen including 0.57 m wt=frame width*2+w
wt
frame
taken 0.60 m
Actual area of screens A' 0.09 m2
Velocity in screens@Peak =Q/(n*N*S*d) 1.04 m/sec ( 0.6-1.5) m/s ,ECP
V2 peak
2018,P.7/3
Velocity in screens@average =Q/(n*N*S*d) 0.52 m/sec ( 0.6-1.5) m/s ,ECP
V2 average
2018,P.7/3
Head loss coefficient for a clean bar screen 0.30 ( 0.3-0.6) ,ECP 2018,P.8/3
c
Head loss through the screen@peak

Head loss through the screen@peak 0.09 m (0.16-0.6) m,ECP

2018,P.7/3
Head loss through the screen@Average 0.02 m (0.16-0.6) m,ECP
2018,P.7/3

MECHANICAL FINE SCREEN

Max. monthly flow 4000.00 m3/day
166.67 m3/h
0.05 m3/sec
Peak factor 2.00
Peak flow 333.33 m3/h
0.09 m3/sec
No. mechanical screen set (set) 1.00 nos, duty "n" can be taken 1 when
n having small Flow rates
,ECP 2018 ,P.6/3
Flow per each screen 333.33 m3/h
0.09 m3/sec
Bar width 10 mm (10-20) mm , ECP
e
2018,P.6/3
Frame thickness 20 mm As per manufacturer
s'
design
Space between bars 6 mm (0.2-6) mm , ECP
S
2018,P.8/3
Inclination angle 80 Degree (60-90) degree ,ECP
2018,P.6/3
Velocity in the screen channel 0.40 m/sec > = 0.6 m/sec ,ECP
v'
2018,P.6/3
Area of the screen channel A' 0.23 m2
Selected screen channel width 0.60 m
w
Depth of water at maximum flow 0.39 m
d
Velocity in the screen channel at peak flow 0.40 m/sec
v
Velocity in the screen channel at average flow 0.20 m/sec

No.of spaces bet. Bars (space) 35.63 nos

0
Selected No. of spaces bet. Bars (space) 35 nos
N
No. of bars in each screen = No. of spaces-1 34 nos

Total width of the each screen including 0.59

frame
taken 0.60
Inclined length of the screen (immersed in 0.39 m
water)
Effective inclined screen area 0.08 m2
A'
velocity in screen 1.14 m/sec ( 0.6-1.5) m/s ,ECP
2018,P.7/3
V

Head loss through the screen Q 2

( )
C∗A
H L=
2∗g
Head loss coefficient for a clean bar screen 0.60 ( 0.3-0.6) ,ECP 2018,P.8/3
c
0.17 m (0.8-1.4) m,ECP
HL
2018,P.8/3

Manual Screen
No. manual screen set (set) n 1.00 nos, duty
Flow per screen 100% from total flow 333.33 m3/h

0.09 m3/sec
Bar width s 10.00 mm
Frame thickness s' 20.00 mm
Space between bars e 50.00 mm
Inclination angle 45.00 Degree
Velocity in the screen channel Before screens 0.39 m/sec
V1
Area of the screen channel A' 0.24 m2
Selected screen channel width 0.59 m
w
Depth of water at maximum flow 0.41 m
d

Velocity in the screen channel at peak flow 0.39 m/sec

V1 peak
Velocity in the screen channel at average flow 0.19 m/sec
V1 average
No. of spaces bet. Bars (space) 9.33 nos

Selected No. of spaces bet. Bars (space) 9.00 nos

N
Bars in each screen 8.00 nos No. of bars = No. of
spaces-1
Total width of the each screen including 0.57 m wt=frame width*2+w
wt
frame
taken 0.60
Actual area of screens A' 0.18 m2
Velocity in screens@Peak =Q/(n*N*S*d) 0.51 m/sec ( 0.6-1.5) m/s ,ECP
V2 peak
2018,P.7/3
Velocity in screens@average =Q/(n*N*S*d) 0.25 m/sec ( 0.6-1.5) m/s ,ECP
V2 average
2018,P.7/3
Head loss coefficient for a clean bar screen 0.60 ( 0.3-0.6) ,ECP 2018,P.8/3
c
Head loss through the screen@peak 1
H L= ¿]
C
Head loss through the screen@peak 0.009 m (0.16-0.6) m,ECP
2018,P.7/3
Head loss through the screen@Average 0.002 m (0.16-0.6) m,ECP
2018,P.7/3

GRIT CHAMBER
Average flow 4000.00 m3/day
Hourly average flow 166.67 m3/h
Peak flow 333.33 m3/h

No. of grit and grease chamber 2.00 nos, duty n>2 ,ECP 2018 ,P.14/3
n
Peak flow per each chamber 166.67 m3/h
0.05 m3/s
Depth of water d 0.60 m > 0.60m, ECP 2018,P.14/3
Width 0.65 m W > 2m ,Width to depth
w ratio=( 1-2), ECP
2018,P.14/3
Length 12.00 m L>7.5 m ,Length to depth
L ratio (20-30), ECP
2017,P.14/3
Area of the each chamber A' 7.80 m2
Volume of each chamber V 4.68 m3

All units under operation

Surface loading rate at average flow 256.41 m3/m2/d <1300 m3/m2/day,ECP
SLR
2018,P.14/3
Surface loading rate at peak flow 512.82 m3/m2/d <1300 m3/m2/day,ECP
SLR
2018,P.14/3
Retention time at average flow 3.37 min (40-60) sec, ECP
t
2018,P.14/3
Retention time at peak flow 1.68 min (40-60) sec, ECP
t
2018,P.14/3

Grit production
Specific grit production rate 0.20 m3/1000m3 of 100-250 lit/1000m3/d,
GPR
water/d ECP 2018,P.15/3
Total grit produced at average flow 0.80 m3/d

Total grit produced at peak flow 1.60 m3/d

Selected grit pump capacity 0.50 m3/h submersible

Pump head 5.00 m
Pump operation hours at average flow 1.60 hrs/day

Pump operation hours at peak flow 3.20 hrs/day

Grease production
Grease concentration removed 90.00 mg/l Assumed

Total grease produced at average flow 30.00 kg/d

Total grease produced at peak flow 60.00 kg/d

Specific gravity of the grease 0.90 kg/l

Volume of grease produced at average flow 33.33 l/d

Volume of grease produced at peak flow 66.67 l/d

Parshall flumes (Flow Measurement)

channel length L 4.50 m
width of throat W 0.30 m
12.00 inch
design flow Q 0.09 m3/s
water depth at the point of measurement 0.32 m
Ha
Hb 0.22 m
Cs 1.76
nf 1.52
nf
Cs W ( H a−H
S
b)
0.62
Q= ns ns 1.08
check
[−( log 10 S+0.0044 ) ]

Qcalc 0.09 m3/s

Dist. To IFAS
Peak flow 8000.00 m3/day
333.33 m3/h
Design flow rate 250.00 m3/h
V
Breadth (B) B 1.60 m
Length (L) L 3.00 m
Water depth d max 1.50 m

Volume V 7.20 m3
check
Retention time at peak flow 1.30 min (0.5-2) min, ECP 2018
,P.1/3
Retention time at average flow 1.73 min (0.5-2) min, ECP 2018
,P.1/3

IFAS TANK
Influent BOD 291.00 mg/l
Influent sBOD 174.60 mg/l
Influent TSS 241.00 mg/l
Influent VSS 192.80 mg/l TSS/VSS= 0.8
Influent NH4 25.00 mg/l
Influent TKN 20.00 mg/l

Min temperature T min 23.00 ⁰c

Max temperature T max 25.00 ⁰c

Average BOD load 1164.00 kg/d

Average TSS load 964.00 kg/d
AverageNH4 load 100.00 kg/d
Average TKN load 80.00 kg/d

Average flow 4000.00 m3/day

Design flow=1.5*Qavg 6000.00 m3/day
250.00 m3/h

Microorganism kinetic coefficients

Biomass Yield (theoretical) 0.40 gVSS/bCOD (0.4-0.8) , ECP 2019
Y
,P.29/3
Half velocity constant 60.00 mg/l (25-100) , ECP 2019
Ks
,P.29/3
Maximum specific growth rate 6.00 gVSS/gVSS.d μm=μmθ (T-20)
μm
Maximum specific growth rate 7.35 gVSS/gVSS.d at design temp.
μm
Endogenous decay coefficient 0.12 gVSS/gVSS.d (0.06-0.15) , ECP 2019
Kd
,P.29/3
Endogenous decay coefficient 0.13 gVSS/gVSS.d at design temp.Kd=Kdθ
Kd
(T-20)
Temperature activity coefficient 1.07 Unitless 0
θ for μ
Temperature activity coefficient 1.04 Unitless (1.03-1.08), ECP 2019
θ for Kd
,P.29/3
Temperature activity coefficient 1.00 Unitless 1, ECP 2019 ,P.30/3
θ for Ks
Friction of biomass remains as cell debris 0.15 gVSS/gVSS (0.08-0.2), ECP 2019
fd
,P.29/3
Biomass Yield (theoretical) 0.12 gVSS/g NOx (0.1-0.15), ECP 2019
Yn
,P.30/3
Endogenous decay coefficient for nitrifier 0.08 gVSS/gVSS.d (0.06-0.15) , ECP 2019
Kdn
,P.30/3
Endogenous decay coefficient for nitrifier at 0.09 gVSS/gVSS.d at design temp.Kd=Kdθ
field temp Kdn (T-20)

Design of aeration tank (BOD removal and nitrification)

MLSS 2000.00 mg/l (1000-3000) mg/L ,ECP
2019 ,P.50/3
SRT 15.00 day (5-15) days , ECP 2019
,P.50/3
MLVSS/MLSS 0.80 0 0.8, ECP 2019 ,P.50/3
16.00 mg/l 80% TKN

Sludge production
Influent substrate 378.30 mg/l
concentration(So)=biodegradable COD S0
"bCOD"

Effluent substrate concentration (Se) 1.69 mg/l

Se

Px, vss, total =Px, vss+(Q*nbvss)/1000 309.77 kg vss/d

nbvss~0.1 vss 19.28 mg/l

Sludge production including non 425.45 kg/d
Px, vss, total
biodegradable vss
Sludge production including inert matters
Px, Tss, total

Sludge production including inert matters 769.32 kg Tss/d

Px, Tss, total

Total IFAS tank volume

Media volume percent Vmedia 30.00 %
assume suspended solid process removal 25.30 %
efficeincy
BOD required by suspended growth process 0.5 influent 0.00 mg/L
BOD
influent BOD Li 291.00 mg/L
required by suspended growth process BOD 217.38 mg/L
Le
mixed liquor suspended solids 2000.00 mg/L
MLSS
Food to microorganism ratio 0.40 (0.1-0.4) , ECP 2019
F/M ratio
,P3/50
Volume of suspended growth Q des
∗(Li−Le )
F V suspended
=
M MLSS
V suspended 552.17 m3
Total volume V total 717.82 m3
Hydraulic detention time t av 2.87 hr (0.5-4) , ECP 2019 ,P3/50
Hydraulic detention time t peak 1.72 hr (0.5-4) , ECP 2019 ,P3/50
Amount of nitrogen converted to nitrate 1.80 mg/l
(Nox)=TKN-Ne-0.12*Px, vss/Q NOx

Selected tank dimensions

number of tanks n 4.00
Length L 6.00
width W 5.00
water depth d 6.00
Actual Total Volume 720.00 m3

Vtotal

Attached growth process

Biofilm surface area (ABF)
Q(N o −N e ) Metcalf & Eddy,5 th
A BF= edition, Vol(1),P.1006
JN

Ammonia Removal Flux

JN,max
1.90 g/m2/d 100∗A BF (1.1-2.9)Metcalf&Eddy,5
Fill %= th edition,Vol(1),P.983
m2
ABF 78947.37 V∗Media
m2 Specific area( )
required fill fraction(%) m3
Fill %

Active Cell 450 specific area 402.00 m2/m3 Manufacturer Specs,(200-

Sp.Area 680) m2/m3 , ECP 2019
,P.3/50
0 Fill % 27.28 %
Media volume percent 30.00 % (30-70)%,ECP 2019
% of Vmedia
,P.3/50
Media Volume Vmedia 216.00 m3
Total media Area Amedia 86832.00 m2
Total BOD loading per day W 873.00 Kg/day

Surface loading rate for media (W) 873.00 Kg/day

W
BOD loading Flux,gBOD /m2/d 10.05 gBOD/m2.d (20-25) g/m2/d,Metcalf &
Eddy,5 th
edition,Vol(1),P.1007
BOD removal flux 6.00 g/m2.d From Figure (9-24)
,Metcalf & Eddy,5 th
edition,Vol(1),P.1007
Total removed BOD 520.99 Kg/d
ET =E20∗Ɵ(T −20)
removal efficiency 0.60
Actual Attached growth removal efficiency 59.68 %
E1
Efficiency @ certain temp.

Temperature coefficient Ɵ 1.03

temperature in summer T summner 25.00 ⁰c
temperature in winter T winter 23.00 ⁰c
Suspended growth removal efficiency @ 69.18 %
E summer
summer
Suspended growth removal efficiency @ 65.21 %
E winter
winter
Total removal efficiency in summer 94.48
Etotal,Summer
Total removal efficiency in winter 90.51
Etotal,Winter
BOD effluent BOD effluent 27.61 mg/l < 60 mg/L OK

Excess sludge
Sludge production including inert matters 769.32 kg Tss/d
Px, Tss, total
Sludge specific gravity 1.01
Sludge concentration C2 9000 mg/l
Sludge to be waste 84.63 m3/d

Return sludge
MLSS 2000.00 mg/l
Return sludge ratio (RAS)=MLSS/ (C2-MLSS) RAS 0.29 of total flow
taken 0.50 (50-100) % , ECP 2019
RAS
,P50/3
Required return sludge flow Q' 3000.00 m3/d

Oxygen requirement (BOD removal and nitrification)

Actual oxygen transmission rate 1866.65 kg/d AOTR= Q(S0-Se)-1.42*Px,
AOTR
vss+4.33*Q*NOx
77.78 kg/hr
Correction factors for standard conditions
from field conditions (Air diffuser)

α correction factor α 0.80

Salinity correction factor β 0.95 0.7-0.98 Typical 0.95
Diffuser fouling factor F 0.70
Plant elevation Zplant 1.00
Gravity acceleration g 9.81 m/s2
Air molecular weight M 28.97 kg/kg-mole
Gas constant R 8314.00 kg.m2/s2.kg-mole.k
Temp. in Kelvin Tkelvin 273.15
Ln (Pplant/P) 0.0001 Pplant/P=exp-
[(gM(Zplant-Z)]/RT
(Pplant/P) 1.00
Oxygen saturation at 25 degree 8.26 mg/l (8.063-8.263)Metcalf
C25
Eddy, Appendix E ,P.1923
Oxygen saturation at 20 degree 8.87 mg/l (9.092-8.874)Metcalf
C20
Eddy, Appendix E ,P.1923
Oxygen saturation at 25 degree & Plant 8.26 mg/l CS,T,H=(Pplant/P)*C25
CS,T,H
elevation
Atmospheric pressure at plant elevation 10.34 m Patm,
Patm, H
H=(Pplant/P)*Patm/γ
Percent of oxygen concentration leaving tank 18.00 0 18-20
Ot
Average oxygen concentration at T&H 9.87 mg/l CS-,T,H=0.5*CS,T,H*[((Pat
CS-,T,H m, H+Pw, Eff
depth)/Patm, H)+Ot/21]
Standard oxygen transmission rate 148.46 kg/hr SOTR=AOTR[Cs,
SOTR 20/(αF(βCS-,T,H-
CL))]1.024(20-T)
Percentage of oxygen in the air 0.23

Air density at 25 degree 1.10 kg/m3

Air diffuser efficiency 0.50
Air flow rate 1173.59 m3 air/hr Air flow
rate=SOTR/(Percentage of
Taking factor of safety 1.3 1760.38 m3 air/hr oxygen in the air*Air
density *Air diffuser
efficiency)
Number of duty air blower n 2.00 total 3 (2 duty + 1 stand by)
Air blower capacity 880.19 m3 air/hr
Selected air blower capacity 1700 m3 air/hr
Differential pressure 0.65 Bar

Dist. To FST

Peak flow 8000.00 m3/day

333.33 m3/h
Design flow rate 250.00 m3/h
V
Breadth (B) B 1.60 m
Length (L) L 3.00 m
Water depth d max 1.50 m

Volume V 7.20 m3
check
Retention time at peak flow 1.30 min (0.5-2) min,ECP 2018
,P.1/3
Retention time at average flow 1.73 min (0.5-2) min,ECP 2018
,P.1/3

FINAL SEDIMENTATION TANK

Average flow rate 4000.00 m3/day

 166.67 m3/h

Design flow rate 6000.00 m3/day

250.00 m3/h
Peak factor 2.00
Peak flow 333.33 m3/h
Return sludge 0.00
MLSS 2000.00 mg/l

Return sludge ratio RAS' 0.50

Return sludge at average flow 3000.00 m3/d
Qr

Overflow rate at average flow 28.00 m3/m2/day (16-28) m3/m2/day, for

avg flow, ECP
OFR 2018,P.3/52 , (40-64)
m3/m2/day, for peak
flow, ECP 2018,P.3/52
Solid loading rate 5.00 kg/m2/hr (1-5) Kg/m2/hr,ECP
SLR
2018,P.3/52
120.00 Kg/m2/day
Total surface area of the clarifiers 250.00 A'1=Q*(1+RAS)/OFR
A'1
Total surface area of the clarifiers 116.67 m2 A'2=Q*(1+RAS)*MLSS/SLR
A'2
Selected total area of clarifiers 250.00 m2 Biggest of A'1&A'2
A'
Selected number of clarifiers n 2 nos
Area of each clarifier A'' 125.00 m2
Diameter of each clarifier D' 12.62
Selected diameter D' 11.50 m
Actual area of each clarifier A 103.87 m2
Selected water side depth 3.50 m (3.5-6) m ,ECP
h
2018,P.3/52
Total volume V 727.08 m3

Checks
Retention time at average flow 2.91 hr (1.5-2) hours , ECP, P.83
t
Retention time at Peak flow t 1.45 hr (1.5-2) hours , ECP, P.83
Overflow rate at average flow 19.26 (16-28) m3/m2/day, for
OFR avg flow, ECP
2018,P.3/52 ,
Overflow rate at peak flow 38.51 (40-64) m3/m2/day, for
OFR' peak flow, ECP
2018,P.3/52
Solid loading rate at average flow 2.41 (5-8) Kg/m2/hr,ECP
SLR
2018,P.3/52
Solid loading rate at peak flow 4.81 (5-8) Kg/m2/hr,ECP
SLR'
2018,P.3/52
Weir loading rate at average flow 55.36 m3/m/day
WLR
Weir loading rate at peak flow 110.72 m3/m/day
WLR'
V notch weir pitch 0.30 m
Weir length for each clarifier 36.13 m
No. of V notches unit 120.43
Selected No. of V notches unit 120

Average flow per notch q 16.67 m3/day

0.0002 m3/sec
Peak flow per notch q' 33.33 m3/day
0.0004 m3/sec

Excess sludge
Sludge production including inert matters 769.32 kg Tss/d
Px, Tss, total
Sludge specific gravity 1.01
Sludge concentration C2 9000 mg/l
Sludge to be waste 84.63 m3/d

Return sludge
MLSS 2000
Return sludge ratio RAS 0.50 of total flow RAS=MLSS/ (C2-MLSS)
Required return sludge flow Q' 3000 m3/d

sludge collection zone

Volume Vsludge 42.32 m3/day/tank
Each tank is desludged 3 times a day 20.00 times

Sludge storage volume 2.12 m3

R 2.30 m
r 1.00 m
sludge collection zone height h' 0.90 m

Waste & Return sludge Pump station

RAS pumps
Required return sludge flow Q' 3000.00 m3/d
selected number of RAS pumps 1.00
nr
RAS Pump Flow Rate 125.00 m3/hr
Pump Head 15.00 m
1.50 bar
WAS pumps
waste excess sludge flow Qexcess 84.63 m3/d
selected number of RAS pumps 1.00
nr
RAS Pump Flow Rate 3.53 m3/hr
Pump Head 15.00 m
 1.50 bar
CHOLORINATION CONTACT TANK

Average flow 4000.00 m3/day

Hourly average flow 166.67 m3/h

Design flow rate 6000.00 m3/day

250.00 m3/h

Peak factor 2.00

Peak flow 333.33 m3/h

no. of fecal coli-form after time T 3000 ECP 2018,P.3/54

Nt
no. of fecal coli-form @influent of CCT tank 600000000 ECP 2018,P.3/54
No
chlorine dose 15.00 (5-20) ppm,ECP 2018
C
,P.3/52
Min. required Time T 16.66 min

No. of tanks N 1 nos

Water Depth d 3 m
Length L 12 m
Width W 5 m
Volume V 180.00 m3

Checks
Retention time at peak flow 0.54 hr
32.40 min 10-30 min,ECP
2018,P.3/53
Retention time at average flow 0.72 hr

43.20 min 10-30 min,ECP

2018,P.3/53

SLUDGE GRAVITY THICKENER

Total sludge weight 769.32 kg TSS/day

Sludge concentration C 0.50 %
Sludge density ρsludge 1.01 Kg/m3
Total Flow for thickeners 152.34 m3/day

Selected number of thickeners 2.00

n
Selected diameter D 6.00 m
Actual area of each thickener A 28.27 m2
Retention time at average flow 27.00 hr (12 - 48) hour ,ECP 2018 ,
t
P.3/92
Total volume of the thickeners 171.38 m3
V
Water side depth 3.0 m (2-3.5) m , ECP 2018,
h
P.3/93
Check
Solid loading rate 13.60 Kg/m2/d (20-30) Kg/m2/day , ECP
SLR
2018, P.3/92
Hydraulic loading rate 2.69 4-8 m3/m2/day for excess
HLR
sludge
Solid capture efficiency SCE 60.00 % 60-85% for excess sludge

Thickened Sludge
Thickened sludge solids concentration 2.00 % 2-3% for thickened excess
sludge
Sludge specific gravity 1.05
Thickened sludge weight 461.59 kg TSS/day
Thickened sludge flow 21.98 m3/day
Supernatant (sludge liquor) water flow 130.36 m3/day

Thickener Depth
Thickened sludge depth=Thickened sludge 0.39 m
flow/Total area H thickened

Settling zone depth H settling 1.80 m Minimum settling depth

Supernatant (sludge liquor) depth 0.90 m Minimum settling depth
H supernatant
Side Water Depth 3.09 m
Free board depth 0.50 m Assumed
Total Side Tank depth 3.59 m
Thickener Bottom Slope 11.00 Cm/m 1:4 to 1:6 , ECP 2018,
P.3/93
Total Drop 0.33 m
Total thickener Depth in Center Total Side Tank depth+Total Drop

Total thickener Depth in Center 3.92 m

DRYING BEDS

Thickened sludge weight 461.59 kg TSS/day

Sludge to be dried 21.98 m3/day
0.00
Thickened sludge volume 21.98 m3/day
Retention time of the sludge over the bed 4.00 day

Sludge thickness over the drying beds 0.15 m

d
Total surface area of the drying beds 586.15 m2
At
Length L 20.00 m
Width W 10.00 m
number n 2.93
Number 6.00 Use as large area as
n possible ,ECP 2018
,P.108/3

Thickened sludge solids concentration 0.25 (20-30)%

Specific gravity 1.05

Dried sludge volume (m3/day) 1.76 m3/day

Supernatant water 20.22 m3/day