Water Solutions You Can Trust

1. What is the primary purpose of coagulation in water treatment?

a) Remove hardness

b) Remove pathogens

c) Remove suspended particles

d) Adjust pH

2. Which of the following is an example of a coagulant?

a) Sodium hydroxide

b) Alum

c) Chlorine

d) Activated carbon

3. What is the ideal pH range for effective coagulation using alum?

a) 4.5 – 5.5

b) 6.0 – 7.0

c) 5.5 – 8.0

d) 8.5 – 9.5

4. What is the purpose of adding lime during water treatment?

a) Disinfection

b) Corrosion control

c) Softening

d) Coagulation

5. What is turbidity measured in?

a) Parts per million (ppm)

b) Nephelometric Turbidity Units (NTU)

c) Grains per gallon

d) Milligrams per liter (mg/L)

6. What is the typical free chlorine residual range in drinking water distribution systems?

a) 0.2 – 0.5 mg/L

b) 1.0 – 4.0 mg/L

c) 5.0 – 10.0 mg/L

d) 0.02 – 0.1 mg/L

7. Which of the following processes is used to remove dissolved gases like hydrogen sulfide?

a) Filtration

b) Aeration

c) Chlorination

d) Sedimentation

8. What is the maximum contaminant level (MCL) for nitrate in drinking water?

a) 5 mg/L

b) 10 mg/L

c) 15 mg/L

d) 20 mg/L

9. Which piece of equipment is used to measure water flow in a pipe?

a) Turbidity meter

b) Flowmeter

c) Pressure gauge

d) Hydrometer

10. In reverse osmosis, which type of pressure is applied?

a) Vacuum

b) Osmotic

c) Hydraulic

d) Static

11. What is the purpose of backwashing a filter?

a) Clean the filter media

b) Remove pathogens

c) Reduce alkalinity

d) Adjust chlorine residual

12. Which of the following is a common indicator organism for water quality?

a) Giardia

b) E. coli

c) Cryptosporidium

d) Salmonella

13. What is the most common disinfection method in water treatment?

a) Ozonation

b) UV light

c) Chlorination

d) Membrane filtration

14. What is the typical detention time in a sedimentation tank?

a) 1 – 3 hours

b) 4 – 8 hours

c) 8 – 12 hours

d) 24 hours

15. Hardness in water is mainly caused by:

a) Sodium and potassium

b) Calcium and magnesium

c) Iron and manganese

d) Chlorides and sulfates

16. What is a jar test used for?

a) Determine chlorine dosage

b) Optimize coagulant dosage

c) Measure alkalinity

d) Test filter efficiency

17. What type of pump is most commonly used in water treatment plants?

a) Centrifugal pump

b) Diaphragm pump

c) Screw pump

d) Peristaltic pump

18. What is the term for water with a pH below 7?

a) Neutral

b) Acidic

c) Basic

d) Alkaline

19. Which federal regulation sets drinking water quality standards in the United States?

a) Clean Water Act

b) Safe Drinking Water Act

c) National Environmental Policy Act

d) Water Quality Act

20. What is the primary purpose of a sand filter?

a) Remove heavy metals

b) Remove biological contaminants

c) Remove suspended particles

d) Remove dissolved gases

(Additional questions continue to test knowledge of microbiology, chemistry, hydraulics, regulatory standards, and operational troubleshooting.)

Answers

1. c

2. b

3. c

4. c

5. b

6. a

7. b

8. b

9. b

10. c

11. a

12. b

13. c

14. a

15. b

16. b

17. a

18. b

19. b

20. c