Question

A beverage manufacturer has recently commissioned a 500 m3 aerated tank to biologically treat 4×105 L/d of wastewater prior to discharge. The tank is a single–pass configuration not catering for recycle. Regulations are particularly stringent requiring that the discharged waste not exceed 10 mg BOD/L owing to the sensitive receiving environment. You have been specifically asked to determine whether the current tank volume is adequate. If not, determine the maximum flow that can be treated while still meeting the BOD discharge requirement with the existing tank. If the mixed liquor suspended solids concentration in the tank is to be set at 1500 mg /L, determine the maximum concentration of BOD in the influent that may be adequately treated. Quantify how much solid material will be discharged per day.

[data: μmax = 3 mg VSS/mg VSS.d; Ks = 30 mg/L as BOD; Y = 0.6 mg VSS/mg BOD]

Answer 1