WASTEWATER PRACTICE EXAM 4
COMPREHENSIVE WASTEWATER TREATMENT
STUDY GUIDE 2026
◉ A composite sample must be?
A. sporadically collected in the treatment plant
B. taken at one time
C. analyzed immediately
D. representative and sub-samples time spaced over 15 minutes
apart.
Answer: D. representative and sub-samples time spaced over 15
minutes apart
◉ What is the standard volume for a BOD sample bottle?
A. 150 mL
B. 200 mL
C. 300 mL
D. 500 mL.
Answer: c. 300 mL
,◉ If you have a lime slurry feed line, what is the best valve to use?
A. plug valve
B. butterfly valve
C. RPZ dual check valve
D. gate valve.
Answer: A. plug valve
◉ 5. If you notice a predominance of rotifers in your activated sludge
sample while looking at it under a microscope, what does this
indicate?
A. healthy sludge
B. young sludge
C. old sludge
D. middle age sludge.
Answer: C. old sludge
◉ Calculate the BOD using the given information:
Initial DO: 8.3
Final DO: 5.9
Milliliters of sample used: 2
,a. 360 mg/L
b. 210 mg/L
c. 856 mg/L
d. 36 mg/L.
Answer: a. 360 mg/L
◉ If your activated sludge plant begins to nitrify, what conditions
would you expect to decrease?
A. settling in clarifiers
B. chlorine demand
C. BOD effluent
D. TSS in effluent.
Answer: a. settling in the clarifiers
◉ How do you calibrate a chemical feed pump?
A. by measuring the pump output
B. using the SWAG method
C. jar test
D. with a microscope.
, Answer: A. by measuring the pump output
◉ What is the chemical formula for sulfuric acid?
a. HNO3
b. HCl
c. NaOH
d. H2SO4.
Answer: d. H2SO4
◉ What is the most common type of activated sludge package
plants?
a. extended aeration
b. sequential batch reactor
c. oxidation ditch
d. bardenpho.
Answer: a. extended aeration
◉ What is the most appropriate method of reducing the F:M ratio?
A. increase wasting
COMPREHENSIVE WASTEWATER TREATMENT
STUDY GUIDE 2026
◉ A composite sample must be?
A. sporadically collected in the treatment plant
B. taken at one time
C. analyzed immediately
D. representative and sub-samples time spaced over 15 minutes
apart.
Answer: D. representative and sub-samples time spaced over 15
minutes apart
◉ What is the standard volume for a BOD sample bottle?
A. 150 mL
B. 200 mL
C. 300 mL
D. 500 mL.
Answer: c. 300 mL
,◉ If you have a lime slurry feed line, what is the best valve to use?
A. plug valve
B. butterfly valve
C. RPZ dual check valve
D. gate valve.
Answer: A. plug valve
◉ 5. If you notice a predominance of rotifers in your activated sludge
sample while looking at it under a microscope, what does this
indicate?
A. healthy sludge
B. young sludge
C. old sludge
D. middle age sludge.
Answer: C. old sludge
◉ Calculate the BOD using the given information:
Initial DO: 8.3
Final DO: 5.9
Milliliters of sample used: 2
,a. 360 mg/L
b. 210 mg/L
c. 856 mg/L
d. 36 mg/L.
Answer: a. 360 mg/L
◉ If your activated sludge plant begins to nitrify, what conditions
would you expect to decrease?
A. settling in clarifiers
B. chlorine demand
C. BOD effluent
D. TSS in effluent.
Answer: a. settling in the clarifiers
◉ How do you calibrate a chemical feed pump?
A. by measuring the pump output
B. using the SWAG method
C. jar test
D. with a microscope.
, Answer: A. by measuring the pump output
◉ What is the chemical formula for sulfuric acid?
a. HNO3
b. HCl
c. NaOH
d. H2SO4.
Answer: d. H2SO4
◉ What is the most common type of activated sludge package
plants?
a. extended aeration
b. sequential batch reactor
c. oxidation ditch
d. bardenpho.
Answer: a. extended aeration
◉ What is the most appropriate method of reducing the F:M ratio?
A. increase wasting
