The Lolla Hart hospital has a small activated sludge plant totreat its wastewater. The average daily hospital discharge is 1,500L per day per bed, and the average soluble BOD5 afterprimary settling is 500 mg/L. Their permit dictates that theeffluent BOD5 and TSS cannot exceed 30 and 20 mg/L,respectively, on an annual basis. Assume the MLVSS concentration inthe aeration basin will be maintained at 3,000 mg/L. Also, assumethat the concentration of BOD5 of the suspended solidsis equal to 60% of the suspended solids concentration. Thebiokinetic coefficients were measured and determined to be:
Ks=70 mg/L BOD5
um=2.5 day-1
kd = 0.06 day-1
Y = 0.6 mg VSS/mg BOD5 removed
Find:
SRT in days
The Aeration basin volume (L)
The Aeration period (days)
The kg of secondary solids wasted each day
