DRIVER-OPERATOR / WATER TREATMENT OPERATOR
LEVEL 1 OPERATOR CERTIFICATION VERIFIED EXAM
QUESTIONS AND ANSWERS - LATEST VERSION
1. Which of the following is classed as a surface water source?
A. A drilled well
B. A lake
C. A confined aquifer
D. A deep borehole
Correct Answer: B Explanation: Lakes, rivers and reservoirs are
surface sources; wells and boreholes draw groundwater.
2. Compared with surface water, groundwater generally has
A. higher turbidity and wider temperature swings
B. more algae and floating debris
C. lower turbidity and a more stable temperature
D. greater exposure to storm runoff
Correct Answer: C Explanation: Soil and rock filter groundwater
and insulate it from rapid temperature change.
3. An aquifer is best described as
A. an underground layer of rock, sand or gravel that holds and
transmits water
B. a pipe that carries water to a treatment plant
C. a tank used to store finished water
D. a surface depression that collects rainwater
Correct Answer: A Explanation: Aquifers are natural underground
formations that store water.
Page 1 of 41
,4. Raw water is
A. water that has passed through filtration
B. untreated water entering the treatment plant
C. water stored in the distribution reservoir
D. water that has been chlorinated and tested
Correct Answer: B Explanation: Raw water has received no
treatment.
5. Finished water is water that
A. has just been pumped from the source
B. contains the highest level of suspended solids
C. has completed all treatment steps and is ready for distribution
D. is waiting for coagulant to be added
Correct Answer: C Explanation: Finished water is the final product
leaving the plant.
6. Turbidity is a measure of
A. the cloudiness of water caused by suspended particles
B. the amount of dissolved oxygen in water
C. the acidity of water
D. the hardness of water
Correct Answer: A Explanation: Turbidity is measured in
nephelometric turbidity units (NTU).
7. The main purpose of an intake screen is to
A. kill bacteria in the raw water
B. remove dissolved minerals
C. remove large debris such as sticks and leaves
D. adjust the pH of the water
Correct Answer: C Explanation: Screens protect pumps and
downstream equipment from large objects.
8. A pH value of 7 indicates that water is
A. strongly acidic
B. strongly alkaline
C. highly corrosive
D. neutral
Correct Answer: D Explanation: Values below 7 are acidic and
values above 7 are alkaline.
Page 2 of 41
,9. Water hardness is caused mainly by dissolved
A. sodium and potassium
B. calcium and magnesium
C. chlorine and fluoride
D. iron and copper
Correct Answer: B Explanation: Calcium and magnesium salts are
the principal causes of hardness.
10. Alkalinity in water refers to its ability to
A. conduct electricity
B. remove turbidity
C. neutralize acids and resist changes in pH
D. kill microorganisms
Correct Answer: C Explanation: Alkalinity acts as a buffer against
pH change.
11. The main goal of a water treatment plant is to produce water that is
A. completely free of all minerals
B. as soft as possible
C. warm enough for immediate use
D. safe to drink and pleasant to taste
Correct Answer: D Explanation: Treatment aims for safe, palatable
water that meets standards.
12. The multi-barrier approach to water safety means
A. relying on chlorine alone
B. using several successive protections so one failure does not
endanger the supply
C. treating water only at the customer's tap
D. building several intake structures
Correct Answer: B Explanation: Source protection, treatment,
disinfection and distribution control all work together.
13. Heavy algal growth in a raw water source commonly causes
A. a decrease in turbidity
B. an increase in water hardness
C. taste and odour problems and a higher chemical demand
D. a drop in water temperature
Correct Answer: C Explanation: Algae add organic matter that
affects taste, odour and treatment.
Page 3 of 41
, 14. The usual order of processes in conventional surface water treatment
is
A. coagulation, flocculation, sedimentation, filtration, disinfection
B. disinfection, filtration, sedimentation, coagulation, flocculation
C. filtration, coagulation, disinfection, flocculation, sedimentation
D. sedimentation, disinfection, coagulation, filtration, flocculation
Correct Answer: A Explanation: Particles are clumped, settled and
filtered before final disinfection.
15. Seasonal turnover in a deep reservoir can
A. permanently remove all pollutants
B. stop all biological activity
C. suddenly change raw water quality
D. eliminate the need for treatment
Correct Answer: C Explanation: Mixing of layers may bring up iron,
manganese, nutrients and poor-quality water.
16. Which of the following is a waterborne protozoan?
A. Escherichia coli
B. Hepatitis A virus
C. Salmonella typhi
D. Giardia lamblia
Correct Answer: D Explanation: Giardia is a protozoan parasite;
the others are bacteria or a virus.
17. Total dissolved solids (TDS) is a measure of
A. the dissolved minerals and salts in water
B. the number of bacteria in water
C. the amount of suspended clay
D. the dissolved chlorine level
Correct Answer: A Explanation: TDS is often estimated from
conductivity.
18. Colour in raw water is often caused by
A. excess chlorine
B. high dissolved oxygen
C. dissolved organic matter from decaying vegetation
D. low alkalinity
Correct Answer: C Explanation: Tannins and humic substances
give water a yellow-brown colour.
Page 4 of 41
LEVEL 1 OPERATOR CERTIFICATION VERIFIED EXAM
QUESTIONS AND ANSWERS - LATEST VERSION
1. Which of the following is classed as a surface water source?
A. A drilled well
B. A lake
C. A confined aquifer
D. A deep borehole
Correct Answer: B Explanation: Lakes, rivers and reservoirs are
surface sources; wells and boreholes draw groundwater.
2. Compared with surface water, groundwater generally has
A. higher turbidity and wider temperature swings
B. more algae and floating debris
C. lower turbidity and a more stable temperature
D. greater exposure to storm runoff
Correct Answer: C Explanation: Soil and rock filter groundwater
and insulate it from rapid temperature change.
3. An aquifer is best described as
A. an underground layer of rock, sand or gravel that holds and
transmits water
B. a pipe that carries water to a treatment plant
C. a tank used to store finished water
D. a surface depression that collects rainwater
Correct Answer: A Explanation: Aquifers are natural underground
formations that store water.
Page 1 of 41
,4. Raw water is
A. water that has passed through filtration
B. untreated water entering the treatment plant
C. water stored in the distribution reservoir
D. water that has been chlorinated and tested
Correct Answer: B Explanation: Raw water has received no
treatment.
5. Finished water is water that
A. has just been pumped from the source
B. contains the highest level of suspended solids
C. has completed all treatment steps and is ready for distribution
D. is waiting for coagulant to be added
Correct Answer: C Explanation: Finished water is the final product
leaving the plant.
6. Turbidity is a measure of
A. the cloudiness of water caused by suspended particles
B. the amount of dissolved oxygen in water
C. the acidity of water
D. the hardness of water
Correct Answer: A Explanation: Turbidity is measured in
nephelometric turbidity units (NTU).
7. The main purpose of an intake screen is to
A. kill bacteria in the raw water
B. remove dissolved minerals
C. remove large debris such as sticks and leaves
D. adjust the pH of the water
Correct Answer: C Explanation: Screens protect pumps and
downstream equipment from large objects.
8. A pH value of 7 indicates that water is
A. strongly acidic
B. strongly alkaline
C. highly corrosive
D. neutral
Correct Answer: D Explanation: Values below 7 are acidic and
values above 7 are alkaline.
Page 2 of 41
,9. Water hardness is caused mainly by dissolved
A. sodium and potassium
B. calcium and magnesium
C. chlorine and fluoride
D. iron and copper
Correct Answer: B Explanation: Calcium and magnesium salts are
the principal causes of hardness.
10. Alkalinity in water refers to its ability to
A. conduct electricity
B. remove turbidity
C. neutralize acids and resist changes in pH
D. kill microorganisms
Correct Answer: C Explanation: Alkalinity acts as a buffer against
pH change.
11. The main goal of a water treatment plant is to produce water that is
A. completely free of all minerals
B. as soft as possible
C. warm enough for immediate use
D. safe to drink and pleasant to taste
Correct Answer: D Explanation: Treatment aims for safe, palatable
water that meets standards.
12. The multi-barrier approach to water safety means
A. relying on chlorine alone
B. using several successive protections so one failure does not
endanger the supply
C. treating water only at the customer's tap
D. building several intake structures
Correct Answer: B Explanation: Source protection, treatment,
disinfection and distribution control all work together.
13. Heavy algal growth in a raw water source commonly causes
A. a decrease in turbidity
B. an increase in water hardness
C. taste and odour problems and a higher chemical demand
D. a drop in water temperature
Correct Answer: C Explanation: Algae add organic matter that
affects taste, odour and treatment.
Page 3 of 41
, 14. The usual order of processes in conventional surface water treatment
is
A. coagulation, flocculation, sedimentation, filtration, disinfection
B. disinfection, filtration, sedimentation, coagulation, flocculation
C. filtration, coagulation, disinfection, flocculation, sedimentation
D. sedimentation, disinfection, coagulation, filtration, flocculation
Correct Answer: A Explanation: Particles are clumped, settled and
filtered before final disinfection.
15. Seasonal turnover in a deep reservoir can
A. permanently remove all pollutants
B. stop all biological activity
C. suddenly change raw water quality
D. eliminate the need for treatment
Correct Answer: C Explanation: Mixing of layers may bring up iron,
manganese, nutrients and poor-quality water.
16. Which of the following is a waterborne protozoan?
A. Escherichia coli
B. Hepatitis A virus
C. Salmonella typhi
D. Giardia lamblia
Correct Answer: D Explanation: Giardia is a protozoan parasite;
the others are bacteria or a virus.
17. Total dissolved solids (TDS) is a measure of
A. the dissolved minerals and salts in water
B. the number of bacteria in water
C. the amount of suspended clay
D. the dissolved chlorine level
Correct Answer: A Explanation: TDS is often estimated from
conductivity.
18. Colour in raw water is often caused by
A. excess chlorine
B. high dissolved oxygen
C. dissolved organic matter from decaying vegetation
D. low alkalinity
Correct Answer: C Explanation: Tannins and humic substances
give water a yellow-brown colour.
Page 4 of 41
