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: 21730

#Section 5: Bioprocess Engineering and Process Biotechnology

In the first-order decomposition of dinitrogen pentoxide at 335 K,

N2O5(g) → 2 NO2(g) + ½ O2(g)

if we start with a 2.50-g sample of N2O5 at 335 K and have 1.50 g remaining after 109 s, 

(a) What is the value of the rate constant k? 

(b) What is the half-life of the reaction? 

TLS Online TPP Program

#Question id: 21731

#Section 5: Bioprocess Engineering and Process Biotechnology

The smog constituent peroxyacetyl nitrate (PAN) dissociates into peroxyacetyl radicals and NO2(g) in a first order reaction with a half-life of 32 min. 

If the initial concentration of PAN in an air sample is 2.7×10¹⁵ molecules/L, what will be the concentration 2.24 h later?

TLS Online TPP Program

#Question id: 21732

#Section 5: Bioprocess Engineering and Process Biotechnology

Rate constants for the first-order decomposition of acetonedicarboxylic acid

CO(CH2COOH)2(aq) → CO(CH3)2(aq) + 2 CO2(g)

are k = 4.75 ×10^–4 s^–1 at 293 K and k = 1.63 ×10^–3 at 303 K. What is the activation energy, Ea, for this reaction?

TLS Online TPP Program

#Question id: 21733

#Section 5: Bioprocess Engineering and Process Biotechnology

A rate law __________.

TLS Online TPP Program

#Question id: 21734

#Section 5: Bioprocess Engineering and Process Biotechnology

Consider the following balanced equation.

Al₂O₃+6NaOH+12HF=2Na₃AlF₆+9H2O

The rate law for this reaction is rate=k[Al₂O₃]²[NaOH].

What is the rate constant for this reaction if the reaction proceeds at an initial rate of 0.005Ms when all of the reactants have initial concentrations of 0.02M?

TLS Online TPP Program

#Question id: 21735

#Section 5: Bioprocess Engineering and Process Biotechnology

Given the following equation (2A+B  3C). Which of the following correctly displays the rate of the reaction?

I. -Δ[A]/2Δt

II. Δ[B]/Δt

III. Δ[C]/3Δt