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Design sludge storage siloDesign sludge storage silo

Dr. Hasan HamoudaDr. Hasan Hamouda

Design sludge storage siloDesign sludge storage silo

Design a sludge storage silo for one Year capacity

Given are with following WWTP Data:

QIn = 50000 m3, C = 200 mg BOD5/l, QR/Q0 = 0.58

= 0.9 kg TS / kg BOD5

SS removal in PS = 60%

BOD5 removal in PS = 30%

TS Effluence = 10 mg/l

TS Biology = 4 g/l

TS max from Thickening tank = 4%

TS max from Pressing machine = 18%

TS of final dewatering process = 36%

Sludge treatmentSludge treatment

Dewatering

Anaerobic

Stabilization

Landfill

agricultural recycling

thermal recycling

Sludge

Thickening

Tank

Pressing LimingTS~18%TS~4%

Silo

TS~36%

Polymer Dosage

Coagulation

Flocculation

Dewaterd

Sludge

36%

Excessive

Sludge

4%Lime

18%

H2O

64%

Pressed

Sludge

18%

Sludge

4%

H2O

96%

wastewater treatment plants-treated sludgewastewater treatment plants-treated sludge

Solution

Load in Influence = 50000 m3/d X 200 mg/l = 10000 kg BOD5 ,

From BOD5 removal in PS = 30%, Load after PS 10000 kg BOD5 X 0.7 = 7000 kg BOD5

From s = 0.9 kg TS / kg BOD5, calculate the m Excess = 7000 X 0.9 = 6300 kg TS/d

From SS removal in PS = 60%, calculate the m Primary sludge = 10000 X 0.6 = 6000 kg TS/d

From TS Eff = 10 mg/l, calculate the m Excess, Eff = 50000 X 10 mg/l = 500 kg TS/d (flow in the per flooder)

S M total = S m Excess + m Primary sludge + m Excess, Eff = (6300 + 6000 + 500) kg TS/d = 12800 kg TS/d

s total = 12800 kg TS/d /10000 kg BOD5/d = 1.28 kg TS / kg BOD5,elimenated

S m total, to Dewatering = S m Excess + m Primary sludge = (6300 + 6000 ) kg TS/d = 12300 kg TS/d

Assumption: TS primary = 20 g/l and from the QR/Q0 Ratio calculate TSR = 10 g/l (for example)

So TS to the thickening tank = (20+10)/2 = 15 g/l,

Q sludge from the thickening tank = (12300 kg TS/d) / (15 kg/m3) = 820 m3/d

Q sludge to the Dewatering machine = (12300 kg TS/d) / (40 kg/m3) = 307.5 m3/d

Q sludge to the liming machine = (12300 kg TS/d) / (180 kg/m3) = 68.3 m3/d

Q sludge to the sludge Silo = (12300 kg TS/d + 12300 kg TS( lime)/d ) / (360 kg/m3) = 68.3 m3/d

V silo (for one year) = 68.3 m3/d X365 d = 25000 m3