Wastewater Exam Study Guide 2026/2027 |
Wastewater Operations Study Guide | Wastewater
Operator Certification Exam Preparation | Practice
Questions and Answers
Wastewater Treatment Overview and Preliminary Treatment
Description: These questions cover the basic purposes of wastewater treatment,
sources of wastewater, preliminary treatment processes, and preliminary treatment
equipment.
Key Words: preliminary treatment, screening, grit removal, influent, wastewater sources,
headworks, flow equalization
1. What is the primary purpose of wastewater treatment?
A) To produce drinking water
B) To protect public health and the environment ✅
C) To generate electricity
D) To create fertilizer only
2. Which of the following is a source of domestic wastewater?
A) Industrial discharge
B) Household activities ✅
C) Stormwater runoff
D) Agricultural runoff
3. What is the first unit process in most wastewater treatment plants?
A) Primary clarification
B) Preliminary treatment ✅
C) Secondary treatment
D) Disinfection
,4. What is the purpose of screening in wastewater treatment?
A) Remove dissolved gases
B) Remove large debris and objects ✅
C) Remove nutrients
D) Remove pathogens
5. What is grit?
A) Organic solids
B) Heavy inert material like sand and gravel ✅
C) Dissolved oxygen
D) Bacteria
6. Why is grit removal important?
A) It improves taste
B) It prevents wear on pumps and equipment ✅
C) It adds nutrients
D) It increases flow
7. What is the headworks of a treatment plant?
A) The final stage
B) The initial stage where influent enters ✅
C) The sludge digester
D) The disinfection unit
8. What does influent mean?
A) Water leaving the plant
B) Water entering the plant ✅
C) Treated water
D) Sludge
9. What does effluent mean?
A) Water entering the plant
B) Water leaving the plant ✅
,C) Raw sewage
D) Grit
10. What is flow equalization?
A) Increasing flow
B) Storing flow to balance variations ✅
C) Stopping flow
D) Heating flow
11. Which type of screen has openings smaller than bar screens?
A) Coarse screen
B) Fine screen ✅
C) Grit screen
D) Rotary screen
12. What is a comminutor?
A) A device that grinds solids into smaller pieces ✅
B) A pump
C) A clarifier
D) A filter
13. What is the purpose of a grit chamber?
A) Remove organic matter
B) Remove heavy inorganic solids ✅
C) Remove pathogens
D) Add chlorine
14. What velocity is typically maintained in a grit chamber?
A) 0.1 ft/sec
B) 1 ft/sec ✅
C) 10 ft/sec
D) 100 ft/sec
, 15. What happens if grit is not removed?
A) Better treatment
B) Equipment abrasion and clogging ✅
C) Improved settling
D) Increased oxygen
16. What is a bar screen?
A) A screen with parallel bars to catch large objects ✅
B) A chemical filter
C) A type of pump
D) A disinfection unit
17. What is manual raking?
A) Automatic cleaning
B) Cleaning screens by hand ✅
C) Chemical cleaning
D) Biological cleaning
18. What is a macerator?
A) Grinds solids ✅
B) Removes grit
C) Adds oxygen
D) Filters water
19. What is the typical purpose of a wet well?
A) Store chemicals
B) Collect wastewater before pumping ✅
C) Disinfect water
D) Digest sludge
20. What is a pump station?
A) Moves wastewater to treatment plant ✅
B) Treats sludge
Wastewater Operations Study Guide | Wastewater
Operator Certification Exam Preparation | Practice
Questions and Answers
Wastewater Treatment Overview and Preliminary Treatment
Description: These questions cover the basic purposes of wastewater treatment,
sources of wastewater, preliminary treatment processes, and preliminary treatment
equipment.
Key Words: preliminary treatment, screening, grit removal, influent, wastewater sources,
headworks, flow equalization
1. What is the primary purpose of wastewater treatment?
A) To produce drinking water
B) To protect public health and the environment ✅
C) To generate electricity
D) To create fertilizer only
2. Which of the following is a source of domestic wastewater?
A) Industrial discharge
B) Household activities ✅
C) Stormwater runoff
D) Agricultural runoff
3. What is the first unit process in most wastewater treatment plants?
A) Primary clarification
B) Preliminary treatment ✅
C) Secondary treatment
D) Disinfection
,4. What is the purpose of screening in wastewater treatment?
A) Remove dissolved gases
B) Remove large debris and objects ✅
C) Remove nutrients
D) Remove pathogens
5. What is grit?
A) Organic solids
B) Heavy inert material like sand and gravel ✅
C) Dissolved oxygen
D) Bacteria
6. Why is grit removal important?
A) It improves taste
B) It prevents wear on pumps and equipment ✅
C) It adds nutrients
D) It increases flow
7. What is the headworks of a treatment plant?
A) The final stage
B) The initial stage where influent enters ✅
C) The sludge digester
D) The disinfection unit
8. What does influent mean?
A) Water leaving the plant
B) Water entering the plant ✅
C) Treated water
D) Sludge
9. What does effluent mean?
A) Water entering the plant
B) Water leaving the plant ✅
,C) Raw sewage
D) Grit
10. What is flow equalization?
A) Increasing flow
B) Storing flow to balance variations ✅
C) Stopping flow
D) Heating flow
11. Which type of screen has openings smaller than bar screens?
A) Coarse screen
B) Fine screen ✅
C) Grit screen
D) Rotary screen
12. What is a comminutor?
A) A device that grinds solids into smaller pieces ✅
B) A pump
C) A clarifier
D) A filter
13. What is the purpose of a grit chamber?
A) Remove organic matter
B) Remove heavy inorganic solids ✅
C) Remove pathogens
D) Add chlorine
14. What velocity is typically maintained in a grit chamber?
A) 0.1 ft/sec
B) 1 ft/sec ✅
C) 10 ft/sec
D) 100 ft/sec
, 15. What happens if grit is not removed?
A) Better treatment
B) Equipment abrasion and clogging ✅
C) Improved settling
D) Increased oxygen
16. What is a bar screen?
A) A screen with parallel bars to catch large objects ✅
B) A chemical filter
C) A type of pump
D) A disinfection unit
17. What is manual raking?
A) Automatic cleaning
B) Cleaning screens by hand ✅
C) Chemical cleaning
D) Biological cleaning
18. What is a macerator?
A) Grinds solids ✅
B) Removes grit
C) Adds oxygen
D) Filters water
19. What is the typical purpose of a wet well?
A) Store chemicals
B) Collect wastewater before pumping ✅
C) Disinfect water
D) Digest sludge
20. What is a pump station?
A) Moves wastewater to treatment plant ✅
B) Treats sludge
