Direction: An activated sludge system (sketched below) is operating at equilibrium with the following information. Waste water related data: flow rate = 500 m³/hour, influent BOD = 150 mg/l, effluent BOD = 10 mg/l. Aeration tank related data: hydraulic retention time = 8 hours, mean-cell-residence time = 240 hours, volume = 4000 m³, mixed liquor suspended solids = 2000 mg/l. 
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The mass (in kg/day) of solids wasted from the system is
-
- 24000
- 1000
- 800
- 33
Correct Option: C
| Sludge age (Qc) = | ||
| Mass of biomass leaving the system |
Therefore,
| Mass of biomass leaving system = | ||
| Qc |
| = | ||
| Qc |
| = | ||
| 240 |
| = | kg/l = 800 kg/day. | |
| 240 |
