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Uplow Anaerobic Sludge Blanket Systems - UASBs

An OnLine Primer

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ANAEROBIC WASTEWATER TREATMENT CASE STUDIES

Let's calculate an estimate of the solids retention time for two UASB installations using the iterative formula - all data self-explanatory. Please be aware that these calculations are a simplification of the actual operating plant data. For example, actual solids inventories could be smaller or bigger and all other derived magnitudes adjusted accordingly. SRT is thus about ballpark.

SRT Sludge Age Sizer
T 20 °C
Yo 0.2 UASB Average Flow
Kd 0.024 High Rate Anaerobic System
flow in 13233 m3/d 3.496 mgd
CODin 3805 mg/L 110813 lbCOD/day 50265 kgCOD/day
DAF rem 0 % COD pretreatment removal by DAF
Percent 100 % COD goes to anaerobic 50265 kgCOD/day to anaerobic reactor or 3805 mg/L
Percent 87 % sCOD removed
Vreactor 2400000 gallon 9084 m3 (from order of magnitude sizing)
2.4 mg 5.53 kgCOD/day per m3
Target MLVSS
35000 mg/L 699720 lb bugs 317391 kg bugs
SRT     91.78 days (iterates automatically) f/m 0.158 kgCOD/d per kg bugs
Yn = 0.079
biomass yield = 3458 kg/day bugs
HRT = V / Q = 0.7 days
16 hours

 

As said before, please be aware that these calculations are a simplification of the actual operating plant data. For example, actual inventories (both bio and non bio) would be smaller or larger and all other derived magnitudes adjusted accordingly. SRT is thus about ballpark.

SRT Sludge Age Sizer
T 20 °C
Yo 0.15 UASB
Kd 0.024 High Rate Anaerobic System
flow in 860 m3/d 0.227 mgd
CODin 3400 mg/L 6435 lbCOD/day 2919 kgCOD/day
DAF rem 0 % COD pretreatment removal by DAF
Percent 100 % COD goes to anaerobic 2919 kgCOD/day to anaerobic reactor or 3400 mg/L
Percent 90 % sCOD removed
Vreactor 210000 gallon 795 m3 (from order of magnitude sizing)
0.21 mg 3.67 kgCOD/day per m3
Target MLVSS
6000 mg/L 10495.8 lb bugs 4761 kg bugs
SRT     16.52 days (iterates automatically) f/m 0.613 kgCOD/d per kg bugs
Yn = 0.110
biomass yield = 288 kg/day bugs
HRT = V / Q = 0.9 days
22 hours

 

ASB

Willie

Need Some Help? answers@engineeringfundamentals.com - James C. Young Environmental - Balestie, Irwin & Balestie