A two-stage high-rate trickling filter with 100% recycle will be used to treat 5,000 m3/d. The influent BOD to the primary clarifier is 220 mg/L and the primary removes 33% of the incoming BOD. The effluent BOD should be 20 mg/L or less. Assume that the design BOD loading to the trickling filter system is 1.0 kg BOD/(d ⋅ m3), and a depth of 1.83 m will be used. Use the NRC equations for designing the trickling filter system and assume that the operating temperature is 18∘C. The coefficient 0.0561 in Equation (7.181) can be replaced with 0.443, and the organic loadings must be expressed in kg/d and the volume of media in cubic meters. Determine:
a. The diameter (m) of the high-rate trickling filter system.
b. The effluent BOD concentration (mg/L).
