The city of Annandale has been directed to upgrade its primary wastewater treatment plant to a secondary treatment plant with sludge recycle that can meet an effluent standard of 11 mg/l BOD5. The following data are available: Flow = 0.15 m3/s, MLSS = 2,000 mg/L. Kinetic parameters: Ks = 50 mg/L, µmax = 3.0 d–1, kd = 0.06 d–1, Y = 0.6 Existing plant effluent BOD5 = 84 mg/L. a. Calculate the SRT (?c) and HRT (?) for the aeration tank.
b. Calculate the required volume of the aeration tank.
c. Calculate the food to microorganism ratio in the aeration tank.
d. Calculate the volumetric loading rate in kg BOD5/m3-d for the aeration tank.
e. Calculate the mass and volume of solids wasted each day, when the underflow solids concentration is 12,000 mg/L.