NEWEST ADVANCED WATER TREATMENT
OPERATOR CERTIFICATION EXAM OFFERED
BY CALIFORNIA-NEVADA SECTION OF AWWA |
COMPLETE EXAM Q&A WITH RATIONALES
**1.** What is the primary removal mechanism in
microfiltration (MF) membranes?
A) Diffusion
B) Adsorption
C) Size exclusion
D) Electrostatic attraction
Correct answer: C
Rationale: MF membranes have pores typically 0.1–
0.5 µm; particles larger than the pores are physically
retained via size exclusion.
**2.** A hollow‑fiber UF membrane shows a rapid
pressure drop during a pressure decay test (PDT)
after 30 seconds. This most likely indicates:
A) Membrane integrity is sound
B) A large leak in the system
C) Severe membrane fouling
,D) Pump overload condition
Correct answer: B
Rationale: A pressure decay test measures how
quickly pressure falls when feed is stopped; a rapid
drop signals a leak that bypasses the membrane.
**3.** PVDF is commonly used for hollow‑fiber UF
membranes because it provides:
A) Excellent chemical resistance and low fouling
B) Highest water permeability
C) Lowest manufacturing cost
D) Biodegradability
Correct answer: A
Rationale: PVDF resists acids, bases, and oxidants;
its smooth surface reduces fouling, making it ideal for
UF applications.
**4.** In a reverse osmosis system, the feed spacer
primarily serves to:
A) Increase membrane surface area
B) Reduce concentration polarization
,C) Provide structural support
D) Lower operating pressure
Correct answer: B
Rationale: Feed spacers create flow channels that
enhance mixing, mitigating concentration
polarization and improving mass transfer.
**5.** Which parameter most directly indicates
membrane fouling in an MF system?
A) Permeate conductivity
B) Transmembrane pressure (TMP) increase
C) Feed flow rate
D) Membrane surface temperature
Correct answer: B
Rationale: Fouling reduces water permeability,
causing TMP to rise for a given feed flow; other
parameters are less sensitive.
**6.** In an RO system with 96% salt rejection, what
percent of feed salt appears in the permeate?
A) 2%
, B) 4%
C) 6%
D) 8%
Correct answer: B
Rationale: Salt passage = 100% – rejection = 100% –
96% = 4% of feed salt passes into the permeate.
**7.** Which chemical is most commonly used for
chemical cleaning of MF membranes to remove
organic deposits?
A) Hydrochloric acid
B) Sodium hypochlorite
C) Sodium hydroxide (NaOH)
D) Citric acid
Correct answer: C
Rationale: NaOH effectively hydrolyzes organic
matter without damaging polymeric MF membranes;
acids target inorganic scaling.
OPERATOR CERTIFICATION EXAM OFFERED
BY CALIFORNIA-NEVADA SECTION OF AWWA |
COMPLETE EXAM Q&A WITH RATIONALES
**1.** What is the primary removal mechanism in
microfiltration (MF) membranes?
A) Diffusion
B) Adsorption
C) Size exclusion
D) Electrostatic attraction
Correct answer: C
Rationale: MF membranes have pores typically 0.1–
0.5 µm; particles larger than the pores are physically
retained via size exclusion.
**2.** A hollow‑fiber UF membrane shows a rapid
pressure drop during a pressure decay test (PDT)
after 30 seconds. This most likely indicates:
A) Membrane integrity is sound
B) A large leak in the system
C) Severe membrane fouling
,D) Pump overload condition
Correct answer: B
Rationale: A pressure decay test measures how
quickly pressure falls when feed is stopped; a rapid
drop signals a leak that bypasses the membrane.
**3.** PVDF is commonly used for hollow‑fiber UF
membranes because it provides:
A) Excellent chemical resistance and low fouling
B) Highest water permeability
C) Lowest manufacturing cost
D) Biodegradability
Correct answer: A
Rationale: PVDF resists acids, bases, and oxidants;
its smooth surface reduces fouling, making it ideal for
UF applications.
**4.** In a reverse osmosis system, the feed spacer
primarily serves to:
A) Increase membrane surface area
B) Reduce concentration polarization
,C) Provide structural support
D) Lower operating pressure
Correct answer: B
Rationale: Feed spacers create flow channels that
enhance mixing, mitigating concentration
polarization and improving mass transfer.
**5.** Which parameter most directly indicates
membrane fouling in an MF system?
A) Permeate conductivity
B) Transmembrane pressure (TMP) increase
C) Feed flow rate
D) Membrane surface temperature
Correct answer: B
Rationale: Fouling reduces water permeability,
causing TMP to rise for a given feed flow; other
parameters are less sensitive.
**6.** In an RO system with 96% salt rejection, what
percent of feed salt appears in the permeate?
A) 2%
, B) 4%
C) 6%
D) 8%
Correct answer: B
Rationale: Salt passage = 100% – rejection = 100% –
96% = 4% of feed salt passes into the permeate.
**7.** Which chemical is most commonly used for
chemical cleaning of MF membranes to remove
organic deposits?
A) Hydrochloric acid
B) Sodium hypochlorite
C) Sodium hydroxide (NaOH)
D) Citric acid
Correct answer: C
Rationale: NaOH effectively hydrolyzes organic
matter without damaging polymeric MF membranes;
acids target inorganic scaling.
