Consider a wastewater treatment system which consists of the three identical complete mix reactors arranged in series. The dimensions of each reactor are as follows:
- Width= 40 feet
- Depth= 16 feet + 2.5 feet freeboard
- Length= 200 feet
The BOD5 of the influent wastewater is 150 mg/L and the first-order reaction rate for the degradation of BOD5 is 0.6/hr at 20°C. If the required effluent BOD5 is 20mg/L, determine:
a) The maximum allowable flow in the treatment system in million gallons per day (mgd)
b) The hydraulic retention time in the treatment system in hours
c) If the temperature of the wastewater drops to 10°C during the winter months, determine the maximum allowable flow in mgd to achieve an effluent BOD5 of 20mg/L.