Question

Sludge wasting rate (Qw) from the solids residence time (Thetac = mcrt) calculation. Given the following information from the previous problem. The total design flow is 15,000 m3/day. Theoretical hydraulic detention time (Theta) = 8 hours. The NPDES limit is 25 mg/L BOD/30 mg/L TSS.

Assume that the waste strength is 170 mg/L BOD after primary clarification.

XA=MLSS = 2200 mg/L,
Xw = Xu = XR = 6,600 mg/L,
qc = 8 days.

Make sure you account for the solids in the discharge.

What volume of sludge (Qw=m3/day) is wasted each day from the secondary clarifiers?

Answer 1

The volume of sludge wasted each day from the secondary classifiers is Qw = 208.33 m^3 / day

Step-by-step explanation:

Check the file attached for a complete solution.

The volume of the aeration tank was first calculated, V = 5000 m^3 / day.

The value of V was consequently substituted into the formula for the wasted sludge flow. The value of the wasted sludge flow was calculated to be Qw = 208.33 m^3 / day.