Home » Municipal Solid Waste » Municipal solid waste miscellaneous » Question

Municipal solid waste miscellaneous

Municipal Solid Waste

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.

  1. The mass (in kg/day) of solids wasted from the system is
    1. 24000
    2. 1000
    3. 800
    4. 33
Correct Option: C

Sludge age (Qc) =
Mass of biomass in system
Mass of biomass leaving the system

Therefore,
Mass of biomass leaving system =
Mass of biomass in system
Qc

=
Volume × MLSS
Qc

=
4000 × 10-3 2000 × 10-6
240

=
8000
kg/l = 800 kg/day.
240



Your comments will be displayed only after manual approval.