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 treatme nt basin is 50,000 l. What value of the recycle ratio must be used?

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TLS Online TPP Program

#Question id: 19486

#Section 4: Fundamentals of Biological Engineering

The growth of S.cerevisiae on glucose under anaerobic conditions can be described by the following reaction:

C₆H₁₂O₆ + aNH₃ → 0.59 CH_1.64N_0.16O_0.52 (biomass) + 0.43 C₃H₈O₃ + 1.54CO₂ + 1.3C₂H₅OH + 0.036H₂O 

and determine the product yield coefficient Y etoh/s and determine coefficient a.

TLS Online TPP Program

#Question id: 19487

#Section 4: Fundamentals of Biological Engineering

What is the yield coefficient if the initial substrate concentration is 20 g/l and biomass is 0.2 g/l. The substrate is then consumed and produces 6.0 g/l of biomass?

TLS Online TPP Program

#Question id: 19488

#Section 4: Fundamentals of Biological Engineering

What is the yield coefficient if the initial substrate concentration is 10 g/l and biomass is 0.1 g/l. The substrate is then consumed and produces 5.3 g/l of biomass?

TLS Online TPP Program

#Question id: 19489

#Section 4: Fundamentals of Biological Engineering

The yield coefficient is not used in growth kinetic relationship of which of the following growth kinetics?

TLS Online TPP Program

#Question id: 19530

#Section 4: Fundamentals of Biological Engineering

If air consists of 77% by weight of nitrogen and 23% by weight of oxygen calculate:

(i) the mean molecular weight of air,

(ii) the mole fraction of oxygen,

(iii) the concentration of oxygen in mole/m3 and kg/m3  if the total pressure is 1.5 atmospheres and the temperature is 25 °C.

TLS Online TPP Program

#Question id: 19531

#Section 4: Fundamentals of Biological Engineering

According to the Balances on steady-state processes, the accumulation is equal to?