WW Class 3 Latest Exam Review 2026 (With
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What is the predominant organism in A. Stalked Ciliates
a healthy activated sludge treatment
plant?
A. Stalked ciliates
B. rotifers
C. nematodes
D. amoebas
A composite sample must be? D. representative and sub-samples time spaced
over 15 minutes apart
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
,What is the standard volume for a c. 300 mL
BOD sample bottle?
A. 150 mL
B. 200 mL
C. 300 mL
D. 500 mL
If you have a lime slurry feed line, A. plug valve
what is the best valve to use?
A. plug valve
B. butterfly valve
C. RPZ dual check valve
D. gate valve
5. If you notice a predominance of C. old sludge
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
,Calculate the BOD using the given a. 360 mg/L
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
If your activated sludge plant begins a. settling in the clarifiers
to nitrify, what conditions would you
expect to decrease?
A. settling in clarifiers
B. chlorine demand
C. BOD effluent
D. TSS in effluent
How do you calibrate a chemical A. by measuring the pump output
feed pump?
A. by measuring the pump output
B. using the SWAG method
C. jar test
D. with a microscope
What is the chemical formula for d. H2SO4
sulfuric acid?
a. HNO3
b. HCl
c. NaOH
d. H2SO4
, What is the most common type of a. extended aeration
activated sludge package plants?
a. extended aeration
b. sequential batch reactor
c. oxidation ditch
d. bardenpho
What is the most appropriate b. decrease wasting
method of reducing the F:M ratio?
A. increase wasting
b. decrease wasting
c. reduce BOD from influent flow
D. add polymer to RAS to increase
settling
An operator notices a portion of the b. unequal air distribution caused by a blown
aeration tank with large bubbles diffuser
rising up. What is the most likely
problem?
a. equal air distribution
b. unequal air distribution caused by
a blown/clogged diffuser
c. normal operation
d. reason to believe the air filter in
the blower is clogged