An activated-sludge waste treatment system is required to reduce the amount of BOD₅ from 1000 mg/l to 20 mg/l at the exit. The sedimentation unit concentrates biomass by a factor of 3. Kinetic parameters are µ_m = 0.2 h-1 , K_s = 80 mg/l, k_d = 0.01 h-1 , and Y ^M _X/S = 0.5 g MLVSS/g BOD₅. The flow of waste water is 10000 l/h and the size of the treatment basin is 50,000 l. What is the value of the solids residence time?

#Question id: 14168

#Section 4: Fundamentals of Biological Engineering

Corn-steep liquor contains 2.5 % invert sugars and 50% water; the rest can be considered solids. Beet molasses containing 50% sucrose, 1% invert sugars, 18% water and the remainder solids, is mixed with corn-steep liquor in a mixing tank. Water is added to produce a diluted sugar mixture containing 2% (w/w) invert sugars. 125 kg corn-steep liquor and 45 kg molasses are fed into the tank.

What is the concentration of solids in the final mixture?

#Question id: 14168

#Section 5: Bioprocess Engineering and Process Biotechnology

Corn-steep liquor contains 2.5 % invert sugars and 50% water; the rest can be considered solids. Beet molasses containing 50% sucrose, 1% invert sugars, 18% water and the remainder solids, is mixed with corn-steep liquor in a mixing tank. Water is added to produce a diluted sugar mixture containing 2% (w/w) invert sugars. 125 kg corn-steep liquor and 45 kg molasses are fed into the tank.

What is the concentration of solids in the final mixture?

#Question id: 14169

#Section 4: Fundamentals of Biological Engineering

Unsweetened condensed milk is a shelf-stable canned milk product. If 100kg of fresh milk, containing 87% water and the rest milk solids, is condensed using an evaporator to remove 60% of the water from the fresh milk, calculate:

 The mass of water evaporated

#Question id: 14169

#Section 5: Bioprocess Engineering and Process Biotechnology

Unsweetened condensed milk is a shelf-stable canned milk product. If 100kg of fresh milk, containing 87% water and the rest milk solids, is condensed using an evaporator to remove 60% of the water from the fresh milk, calculate:

 The mass of water evaporated

#Question id: 14170

#Section 4: Fundamentals of Biological Engineering

Unsweetened condensed milk is a shelf-stable canned milk product. If 100kg of fresh milk, containing 87% water and the rest milk solids, is condensed using an evaporator to remove 60% of the water from the fresh milk, calculate:

The final mass and composition of condensed milk produced

#Question id: 14170

#Section 5: Bioprocess Engineering and Process Biotechnology

Unsweetened condensed milk is a shelf-stable canned milk product. If 100kg of fresh milk, containing 87% water and the rest milk solids, is condensed using an evaporator to remove 60% of the water from the fresh milk, calculate:

The final mass and composition of condensed milk produced