Two biotowers operating in parallel are to be designed to treat a flow of 16,000 m3/d. The BOD5 in the influent to the primary clarifier is 200 mg/L and the clarifier removes 35% of the BOD5. The minimum wastewater temperature is expected to be 14∘C. The value of k is assumed to be 0.210 (Lps)0.5/m2 at 20∘C and an effluent BOD5 concentration of 20 mg/L is to be achieved. The biotower depth = 6.1 m. Determine:
a. The radius (m) of each biotower.
b. The volume (m3) of biotowers.
c. The recycle flow (Lps/ft2) around the biotowers if the minimum wetting rate is 0.5 Lps/ft2.
d. The recycle ratio (R).
