Engineering, 08.05.2021 04:20 luhzara1

A municipality is currently operating a conventional waste activated sludge treatment system that receives two million gallons of wastewater per day with an average BOD concentration of 165 mg/L. The aeration basin has a volume of 100,000 ft. The mixed liquor suspended solids (MLSS) concentration is maintained at 2,800 mg/L and the effluent suspended solids concentration from the secondary clarifier is 25 mg/L. Assume that the secondary treatment system wastes 38,000 gal/day from the recycle line and that the MLSS concentration of the recycle flow is 9,000 mg/L. Determine the following process parameters: A. Hydraulic detention time of the aeration basin in hrs.
B. Volumetric BOD loading rate of the aeration basin in lb/1000 ft day
C. Food/Microorganism ratio in lb BOD/lb MLSS. D. Mean cell residence time in days.

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