Population 12000 BOD per capita 75

per capita flow 350 lps BOD LOAD 900

per capita flow 0.25 m3/capita BOD,mg/l 300

1 Flow 2 Wastewater Quality Inlet Outlet Units

Average 3000 m3/d BOD 300 10 mg/l

125 m3/hr TKN 40 1 mg/l

2.1 m3/min Ammonia 24 1 mg/l

0.035 m3/s TSS 300 10 mg/l

Peak factor 2.50 Assumptions

Peak duration 2 Elevation 50.000

Peak flow 7500 m3/d Yield coefficient, Y 0.650

312.5 m3/hr Kd 0.050

5.2 m3/min Clean water efficiency 5.500

0.087 m3/s Alpha 0.5

2 Balancing Tank Beta 0.950

Effective volume 375 m3 Sewage Temperature 35

HRT at Qavg,hrs 3.0 hrs O2 solu.Tap water, field condnC'sw 6.9

Air required for effective mings 375 m3/hr O2 solu.Tap water, 20deg C ,Csw 9.1

SBR feed Pumps 125 DO 2.000

Sleetced feed Pumps 125 m3/hr Fine Bubble effeciency 0.236

Fill hours 3 hours Design Air temperature 45

3 SBR- operating details 4 SBR Sizing

Operating cycle time 6 hrs Volume per cycle per basin 375.0 m3

No of SBR 2 no BOD load, per SBR 450.0 kg/d

No of cyles per basin 4 MLSS to be maitained 3500 mg/l

Total fill time 3 hrs F/M to be maintained 0.1 d-1

Anoxic ( non aerated) fill time 0.5 hrs Sludge Volume Index 0.15 m3/kg

Aerated fill time 2.5 Size

Aeration time 0.5 Approach -I, F/M based

Settlement Time 1 Sludge required 4500 kgs

Decant time 1 Sludge after decant,concn 6 kg/m3

Idle time 0.5 Sludge Volume 733.3 m3

Total cycle time 6 Approach -2, SVI based

No of cycles per basin 4 settled sludge volume 675 m3

Selected volume of SBR 733.3 m3

5 SBR dimesnions add volume of decant 375.0 m3

Side water Depth 5 Volume per basin 1108.3 m3

Area 266 add band betn Sludge layer/decant 221.67 m3

Length 19 Total Volume 1330.0 m3

Width 14 6 Water Levels in SBR and MLSS

Selected dimesnions area 266 Depth of decant volume 1.410 m

Total volume 1330 LWL 3.6 m

Volume at LWL 955.0 m3

MLSS Concentration 4712.0 mg/l

MLSS Concentration(without band) 6136.4 mg/l

7 Decanter Sizing 8 Chlorine Contact Tank

Decant Volume/cycle 375.0 Flow rate to filters 125 m3/hr

No fo SBR in decant mode at a time 1 Max decant rate 468.75 m3/hr

Decant Time in Hours 1 Duration of Decant 0.8 hours

Rate of flow 375 m3/hr Volume of CCT 275 m3

6.25 m3/min CCT contact period 35.2 min

Selected decnater (25 % extra for 7.8125 m3/min for 45 minutes HRT volume 351.56 m3

operational flexibility)

9 Sludge Production 10 WasteSludge Pump

Sludge Production rate 0.7 kg/kgBODr Sludge conc after decant 4.7 kg/m3

Sludge Produced 609.0 kg/d Sludge Volume 125.5 m3

SRT,d 14.1 days Per reactor per cycle 15.7 m3

Sludge Wasting Pump cap 31 m3/hr

11 Sludge Thickener 12 Sludge Digestor

Solids Loading rate(25-60) 35 kg/m2/d VS destruction 30 %

Surface loading rate ( 16-30) 24 m3/m2/d Degree days(from M&E) 300

Solids flow rate 150.46 kg/hr HRT 7 Days

Area of thickener 103.17 m2 Volume of sludge to be digested 129.243 m3/d

Diameter 11.46 m Volume as 7/5 concept 129.243 m3/d

Selected dia 10 m Volume of digestor 904.7

Area of thickener 78.5 Sludge in reactor at 2 % conc 18637 kg

Conc of thickened sludge 20 kg/m3 Temperature at winter 22 degC

Volume of thickned sludge 29.563 m3/d Sludge age required 13.636

Depth of Thickenening Sludge to be withdrawn everyday 1366.7 kg/d

at top 4.71 kg/m3 Volume of sludge withdrawn 66.345 m3/d

at bottom 20 kg/m3 Consider sludge withdrawal 20 m3/d

average 12.35602 kg/m3 Size of digestor

Volume of sludge 47.852 m3 Depth 6

Depth 0.610 m Length 12.279

Depth of settling zone 1.5 m Width 12.279

Clear effluent depth 1 m

Free Board 0.5

SWD Depth 3.11 m 1.53

13 Air requirements

a Balancing Tank, at 1 m3/m3/hr 375 SBR

Sludge Yield 0.3814 kg/BOD

b Sludge Digestor Sludge Produced 471.19 kg/d

Expected VS Destruction 30% Kg of BOD removed 1278.9 kg/d

VS destroyed 146.16 Nitrogen to be nitrified 534.69 kg/d

O2 required 2 Kg/kgVSr AOR 1342.4 kg/d

O2 required 292.32 SOR 3734.7 kg/d

AOR/SOR for fine bubble 0.4 Air Required 2382.7 m3/hr

SOR 730.8 kg/d Air required at Inlet 2586 nm3/hr

diffuser effeciency 29% Duty blowers 1

Air required 391.9749 m3/hr Each Blower 2586 m3/hr

Air supplied per m3 of digestor vol 0.433263 m3/m3/hr Fill time (Anoxic+Aerated) 3

Anoxic fill 0.5

Aerated fill time 2.5

Settel time 1

Decant time 1

Idle 0.5

available aeration time 0.5

Total aeration Time 3