CALIFORNIA WASTEWATER TREATMENT
OPERATOR EXAM PREP SOLVED
QUESTIONS ACCURATE ANSWERS
PREMIUM REVIEW
◉ How will a decrease in water temperature affect the disinfecting
action of chlorine?
Answer: The disinfection is less effective
◉ Examples of protozoa that must be removed from drinking water
to protect public health
Answer: Giardia and Cryptosporidium
◉ How is water prevented from entering a gas chlorinator?
Answer: A check valve
◉ Of the following characteristics of raw water, the least likely to
cause health issues in consumers is ______?
Answer: physical
,◉ What is the never-ending transmission of water from the Earth
into the atmosphere and back again?
Answer: The Hydrologic Cycle
◉ What fraction of the earth surface is covered with water?
Answer: Three-Quarters (3/4)
◉ What is the process by which water becomes a gas and rises?
Answer: Evaporation
◉ To deliberately form chloramines, a water supplier mixes chlorine
gas with _____?
Answer: Ammonia (ammonia + chlorine = chloramines)
◉ To remove a calcium scale deposit from the liquid head of a
chemical feed pump, remove it, then soak it in_____?
Answer: A weak solution of hydrochloric acid
◉ Why is turbidity in drinking water is considered undesirable?
Answer: Because it necessitates extensive treatment and produces
greater amounts of sludge
, ◉ What does HTH (high test hypochlorite), a dry white granular
compound, contain?
Answer: 65 to 70% chlorine
◉ What is a non-halogenic oxidizing chemical that may be
substituted for pre-chlorination to avoid formation of DBP's?
Answer: Potassium Permanganate
◉ Which of the following forms the strongest disinfectant in
solution?
Answer: Dichloramines
◉ The Colilert Method can detect the presence of both total and fecal
coliforms after how many hours of incubation?
Answer: 18 to 24 hours
◉ At what temperature is a fusible plug on a chlorine cylinder
designed to melt and release chlorine gas?
Answer: 158 to 165°F
◉ What alternative disinfectant is most commonly used to avoid the
formation of THM's (trihalomethanes) at larger water treatment
plants?
Answer: Ozone (oxygen)
OPERATOR EXAM PREP SOLVED
QUESTIONS ACCURATE ANSWERS
PREMIUM REVIEW
◉ How will a decrease in water temperature affect the disinfecting
action of chlorine?
Answer: The disinfection is less effective
◉ Examples of protozoa that must be removed from drinking water
to protect public health
Answer: Giardia and Cryptosporidium
◉ How is water prevented from entering a gas chlorinator?
Answer: A check valve
◉ Of the following characteristics of raw water, the least likely to
cause health issues in consumers is ______?
Answer: physical
,◉ What is the never-ending transmission of water from the Earth
into the atmosphere and back again?
Answer: The Hydrologic Cycle
◉ What fraction of the earth surface is covered with water?
Answer: Three-Quarters (3/4)
◉ What is the process by which water becomes a gas and rises?
Answer: Evaporation
◉ To deliberately form chloramines, a water supplier mixes chlorine
gas with _____?
Answer: Ammonia (ammonia + chlorine = chloramines)
◉ To remove a calcium scale deposit from the liquid head of a
chemical feed pump, remove it, then soak it in_____?
Answer: A weak solution of hydrochloric acid
◉ Why is turbidity in drinking water is considered undesirable?
Answer: Because it necessitates extensive treatment and produces
greater amounts of sludge
, ◉ What does HTH (high test hypochlorite), a dry white granular
compound, contain?
Answer: 65 to 70% chlorine
◉ What is a non-halogenic oxidizing chemical that may be
substituted for pre-chlorination to avoid formation of DBP's?
Answer: Potassium Permanganate
◉ Which of the following forms the strongest disinfectant in
solution?
Answer: Dichloramines
◉ The Colilert Method can detect the presence of both total and fecal
coliforms after how many hours of incubation?
Answer: 18 to 24 hours
◉ At what temperature is a fusible plug on a chlorine cylinder
designed to melt and release chlorine gas?
Answer: 158 to 165°F
◉ What alternative disinfectant is most commonly used to avoid the
formation of THM's (trihalomethanes) at larger water treatment
plants?
Answer: Ozone (oxygen)
