Module 3 (I & II) Flashcards
T/F: The performance of bioprocesses for the treatment or conversion of organic waste depends on the dyanamic of microbial growth and substrate utilization, which are proportional.
False: they are inversely proportional (or INTERCORRELATED)
List the phases of bacterial growth in a batch system in order
- Lag
- Exponential growth
- Stationary
- Death
_______ _______ _______ is the ratio of biomass produced to the amount of substrate consumed.
Biomass synthesis yield
T/F: Biomass synthesis yield is defined relative to the electron acceptor used
False: electron DONOR (substrate)
T/F: The biomass synthesis yield can be expressed in measurable quantities - g biomass/g COD consumed, but NOT g biomass/g BOD consumed.
False: both g biomass/g COD and g biomass/g BOD can be equated to the biomass synthesis yield.
____ is the parameter used most commonly to follow _______ _______ in full-scale bio wastewater treatment systems because its measurement is _______, and minimal _______ is required for analysis.
VSS
biomass growth
simple
time
What is the formula for biomass synthesis yield?
VSS (g)/ BOD (g) OR COD (g)
What is the formula for the substrate utilization rate (r_su)?
dS/dt = r_su = (kXS) / (K_s + S)
What is “k” and what are its units?
maximum specific sub utilization rate (g sub/g microorgg*d)
What is “K_s” and what are its units?
half-velocity constant (sub concentration @ 1/2 max specific substrate utilization rate), g/m^3
What does the “b” in bCOD stand for
biodegradable COD
T/F: If S is infinitely larger than K_s, then r_su = kX
True
T/F: If S «< K_s, r_su = kX/K_s + S
False: remove the S from the denominator
What is the formula for bacterial growth rate from substrate utilization (in cases of limiting substrate)?
dX/dt = r_g = (mu_max*XS) / (K_s + S)
T/F: The bacterial growth rate and the substrate utilization rate are related by the biomass synthesis yield.
True: r_g = Y*r_su
Which case do we deal with the most in biological treatment processes, and why?
- K_s»_space;> S
- K_s «< S
Case 1: the purpose of treatment is to reduce S in the outlet stream
What is the formula for net biomass growth rate (r_X)?
r_X = (Y*r_su) - bX
*Rate of biomass growth minus the endogenous respiration rate (or dead rate)
b = specific endogenous decay coefficient, g VSS/g VSSd
T/F: The biomass synthesis yield for VSS on BOD will be smaller than that for VSS on COD
True: COD is a theoretical case, so will always be higher than BOD
What is the formula for the rate of O2 uptake in aerobic biological processes?
r_o = r_su - (1.42*r_x)
What is the significant number 1.42 seen in this course?
The COD of biomass: g COD/g VSS
Temperature influences not only the _______ _______ of the microorganism, but also a significant impact on performance-related factors such as gas-transfer rates, _______ of biomass, etc.
Metabolic activities
settleablity
What is the formula for the reaction rate constant?
k_T = k_20*(theta^(T-20))
theta = temperature-activity coefficient (can vary from 1.02 to 1.25)
T/F: In batch reactors, S is constant, while in CSTRs, S is not constant.
False: opposite is true
When does “t” start in a batch reactor?
t begins at the start of the REACTION
