Question

Question 2 A complete mix activated sludge process is to be used for biological treatment. Assume the following for the activated sludge process: • Plant influent BODs of 156 mg/L • Sludge age is 8 days Biomass yield (Y) of 0.54 kg biomass / kg BOD • Endogenous decay rate (kd) = 0.05 day! • Ks=10 g BOD/m3 Biomass concentration (X) of 2700 mg/L • recycle biomass concentration (Xr) of 12,000 mg/L The fresh flow rate treated is 1000 m²/day k=125 g COD/g day Determine the following: a) Determine the substrate conversion b) Determine the reactor detention time, in hours c) Determine the reactor volume in cubic meters. d) Determine the mass and volumetric rates of the sludge wasted in (kg/day) and (m/day) respectively assuming that Xe is negligible. e) Determine the sludge recycle ratio and the recycle flow rate in m3/day f) Determine the food to microorganism ratio. g) Specific substrate utilization rate

Answer 1

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30 Realtion volume fm3). S ksi+kd 0) oc(Min - kd) Assume Mama 5-od- - 26.165. S1011+12=5+8) 8(5-0-0-05)- to y (5-5) .kd. ost 0:54* (1000) ** (156–26.165) -0.05 2700 #V है 25,967 0.05 N VE .148:38m?

Detentiontine i hours) tr 148.38 - V = 0.148 days. 1000 3.552 hours. Secondary sludge mass wasting rate są w X = XV mass wasting rate (kg/day) Q w ko = Xv. 2.7 X 148.38 8 50.08 kg / doing Volume wasting rate (m3/day) Ow= Q W xj Ow 50.08% 12 4.2 . Recycle How rate (mo/day) QN QX - QwX 10007 2:7 - 150.08 Xorx -12-27 2649.92 9.3 - 284.94 MB s/day Recycle Ratio R= 284.94 0.285 Q 1000 flim ratio : 1000X156* 1000 106 2.7 X 148-38 +0.389 kg - Bed I'd kg: vss

Specific substrate utilization Rate & U = sous 156-26.165 Ox 0.148.40237 129.835 0.39.96 U = 324.91