It is desired to design an activated sludge process to treat 20,000 m3/d of settled wastewater with a BOD of 250 mg/L and nbVSS concentration of 10 mg/L. If the effluent BOD is not to exceed 20 mg/L, calculate the volume of the aeration tank required, sludge wastage rate, sludge return rate, oxygen requirements, F/M ratio, specific utilization rate, specific growth rate, and maximum specific growth rate. The following data and coefficients are applicable. i. Mean cell residence time = 5 days ii. Y = 0.5 gVSS/g BOD iii. Kd = 0.10 /d iv. K = 5 /d v. Return sludge concentration = 8,000 mg/L VSS vi. Mixed liquor volatile suspended solids concentration = 2500 mg/L vii. Effluent contains 20 mg/L suspended solids of which 65% are biodegradable. viii. Fraction of biomass remaining as cell debris = 0.15 ix. BOD5/BODu = 0.68
It is desired to design an activated sludge process to treat 20,000 m3/d of settled wastewater with a BOD of 250 mg/L and nbVSS concentration of 10 mg/L. If the effluent BOD is not to exceed 20 mg/L, calculate the volume of the aeration tank required, sludge wastage rate, sludge return rate, oxygen requirements, F/M ratio, specific utilization rate, specific growth rate, and maximum specific growth rate. The following data and coefficients are applicable.
i. Mean cell residence time = 5 days
ii. Y = 0.5 gVSS/g BOD
iii. Kd = 0.10 /d
iv. K = 5 /d
v. Return sludge concentration = 8,000 mg/L VSS
vi. Mixed liquor volatile suspended solids concentration = 2500 mg/L
vii. Effluent contains 20 mg/L suspended solids of which 65% are biodegradable.
viii. Fraction of biomass remaining as cell debris = 0.15
ix. BOD5/BODu = 0.68
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