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Let's calculate an estimate of the solids retention time for a number of anaerobic 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 larger and all other derived magnitudes adjusted accordingly. SRT is thus about ballpark.

SRT Sludge Age Sizer | ||||||||||

T | 20 | °C | ||||||||

Yo | 0.2 | EGSB | Average Flow | |||||||

Kd | 0.024 | High Rate Anaerobic System | ||||||||

flow in | 18526 | m3/d | 4.895 | mgd | ||||||

CODin | 5221 | mg/L | 212870 | lbCOD/day | 96557 | kgCOD/day | ||||

DAF rem | 0 | % COD pretreatment removal by DAF | ||||||||

Percent | 100 | % COD goes to anaerobic | 96557 | kgCOD/day to anaerobic reactor | or | 5221 | mg/L | |||

Percent | 67 | % sCOD removed | ||||||||

Vreactor | 2055000 | gallon | 7778 | m3 | (from order of magnitude sizing) | |||||

2.055 | mg | 12.41 | kgCOD/day per m3 | |||||||

Target MLVSS | ||||||||||

24000 | mg/L | 410835.6 | lb bugs | 186354 | kg bugs | |||||

SRT | 21.00 | days | (iterates automatically) | f/m | 0.518 | kgCOD/d per kg bugs | ||||

Yn = | 0.137 | |||||||||

biomass yield = | 8876 | kg/day bugs | ||||||||

HRT = V / Q = | 0.4 | days | ||||||||

10 | hours | |||||||||

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 |