The town of Camp Verde has been directed to upgrade its primary WWTP to a second plant that can meet an effluent standard of 25.0 mg/L BOD₅ and 30 mg/L suspended solids. They have selected a completely mixed-activated sludge system for the upgrade. The existing primary treatment plant has a flow rate of 2,506 m³/d. The effluent from the primary tank has a BOD₅ of 240 mg/L. Using the following assumptions, estimate the required volume of the aeration tank:

 

1. BOD5 of the effluent suspended solids is 70% of the allowable suspended solids concentration. 2. Growth constant values are estimated to be: K, = 100 mg/L BOD5; ka = 0.025 d; Mm = 10 d; Y = 0.8 mg VSS/mg BOD5 removed. 3. The design MLVSS is 3,000 mg/L.