Texas Water Treatment Operator – TCEQ Class B Exam Prep |
questions & answers & rationale | 2025/2026 | Latest Update|
Instant download!!
1. Which of the following is true regarding Class B water treatment plants compared to Class A?
A. Treat larger flows than Class A
B. Only handle groundwater sources
C. Treat moderate flows and generally less complex than Class A (correct answer)
D. Do not require disinfection
Rationale: Class B operators manage moderate-size water systems with less complex treatment than Class
A plants.
2. A water plant receives 1 MGD of raw water and uses 4 mg/L of chlorine. How many pounds of
chlorine are required per day?
A. 33.4 lbs
B. 33.36 lbs (correct answer)
C. 25 lbs
D. 50 lbs
Rationale: lbs/day = Flow × Dose × 8.34 = 1 × 4 × 8.34 ≈ 33.36 lbs/day.
3. Which of the following is the main purpose of coagulation?
A. Disinfect water
B. Aggregate fine particles into larger flocs for sedimentation (correct answer)
C. Adjust pH
D. Remove dissolved salts
Rationale: Coagulation forms flocs to remove suspended solids effectively.
,4. A clarifier has a surface area of 2,000 sq ft and treats 2 MGD. What is the surface loading rate in
gpd/sq ft?
A. 1,000 gpd/sq ft
B. 1,000 gpd/sq ft (correct answer)
C. 500 gpd/sq ft
D. 2,000 gpd/sq ft
Rationale: Surface loading rate = Flow ÷ Area = 2,000,000 ÷ 2,000 = 1,000 gpd/sq ft.
5. Which of the following is true regarding turbidity in treated water?
A. Turbidity does not affect disinfection
B. High turbidity reduces disinfection effectiveness (correct answer)
C. Only affects taste
D. Only affects pH
Rationale: Suspended particles shield microorganisms, reducing chlorine effectiveness.
6. Which of the following is true regarding flocculation?
A. Randomly mixes water
B. Gently mixes to allow floc growth after coagulation (correct answer)
C. Only adds chemicals
D. Only adjusts pH
Rationale: Flocculation allows particles to collide and form settleable flocs.
7. A water sample has a hardness of 120 mg/L. What is the hardness in grains per gallon (gpg)?
A. 5 gpg
B. 7.02 gpg (correct answer)
C. 10 gpg
D. 12 gpg
, Rationale: gpg = mg/L ÷ 17.1 = 120 ÷ 17.1 ≈ 7.02 gpg.
8. Which of the following is true regarding pH adjustment in water treatment?
A. Only affects taste
B. Optimizes coagulation and reduces corrosion (correct answer)
C. Removes turbidity
D. Increases hardness
Rationale: Correct pH improves coagulant performance and protects pipes.
9. Which of the following is true regarding chlorine residuals in the distribution system?
A. Only initial chlorine dose matters
B. Maintains disinfection throughout the system (correct answer)
C. Only pH matters
D. Only TDS matters
Rationale: Residual chlorine ensures microbial protection to the point of use.
10. A water treatment plant treats 1.5 MGD of water using 25 mg/L of PACl. How many pounds per
day are required?
A. 200 lbs
B. 250 lbs
C. 313 lbs (correct answer)
D. 350 lbs
Rationale: lbs/day = Flow × Dose × 8.34 = 1.5 × 25 × 8.34 ≈ 313 lbs/day.
11. Which of the following is true about rapid sand filters?
A. Removes dissolved salts
B. Removes remaining suspended solids after sedimentation (correct answer)
questions & answers & rationale | 2025/2026 | Latest Update|
Instant download!!
1. Which of the following is true regarding Class B water treatment plants compared to Class A?
A. Treat larger flows than Class A
B. Only handle groundwater sources
C. Treat moderate flows and generally less complex than Class A (correct answer)
D. Do not require disinfection
Rationale: Class B operators manage moderate-size water systems with less complex treatment than Class
A plants.
2. A water plant receives 1 MGD of raw water and uses 4 mg/L of chlorine. How many pounds of
chlorine are required per day?
A. 33.4 lbs
B. 33.36 lbs (correct answer)
C. 25 lbs
D. 50 lbs
Rationale: lbs/day = Flow × Dose × 8.34 = 1 × 4 × 8.34 ≈ 33.36 lbs/day.
3. Which of the following is the main purpose of coagulation?
A. Disinfect water
B. Aggregate fine particles into larger flocs for sedimentation (correct answer)
C. Adjust pH
D. Remove dissolved salts
Rationale: Coagulation forms flocs to remove suspended solids effectively.
,4. A clarifier has a surface area of 2,000 sq ft and treats 2 MGD. What is the surface loading rate in
gpd/sq ft?
A. 1,000 gpd/sq ft
B. 1,000 gpd/sq ft (correct answer)
C. 500 gpd/sq ft
D. 2,000 gpd/sq ft
Rationale: Surface loading rate = Flow ÷ Area = 2,000,000 ÷ 2,000 = 1,000 gpd/sq ft.
5. Which of the following is true regarding turbidity in treated water?
A. Turbidity does not affect disinfection
B. High turbidity reduces disinfection effectiveness (correct answer)
C. Only affects taste
D. Only affects pH
Rationale: Suspended particles shield microorganisms, reducing chlorine effectiveness.
6. Which of the following is true regarding flocculation?
A. Randomly mixes water
B. Gently mixes to allow floc growth after coagulation (correct answer)
C. Only adds chemicals
D. Only adjusts pH
Rationale: Flocculation allows particles to collide and form settleable flocs.
7. A water sample has a hardness of 120 mg/L. What is the hardness in grains per gallon (gpg)?
A. 5 gpg
B. 7.02 gpg (correct answer)
C. 10 gpg
D. 12 gpg
, Rationale: gpg = mg/L ÷ 17.1 = 120 ÷ 17.1 ≈ 7.02 gpg.
8. Which of the following is true regarding pH adjustment in water treatment?
A. Only affects taste
B. Optimizes coagulation and reduces corrosion (correct answer)
C. Removes turbidity
D. Increases hardness
Rationale: Correct pH improves coagulant performance and protects pipes.
9. Which of the following is true regarding chlorine residuals in the distribution system?
A. Only initial chlorine dose matters
B. Maintains disinfection throughout the system (correct answer)
C. Only pH matters
D. Only TDS matters
Rationale: Residual chlorine ensures microbial protection to the point of use.
10. A water treatment plant treats 1.5 MGD of water using 25 mg/L of PACl. How many pounds per
day are required?
A. 200 lbs
B. 250 lbs
C. 313 lbs (correct answer)
D. 350 lbs
Rationale: lbs/day = Flow × Dose × 8.34 = 1.5 × 25 × 8.34 ≈ 313 lbs/day.
11. Which of the following is true about rapid sand filters?
A. Removes dissolved salts
B. Removes remaining suspended solids after sedimentation (correct answer)
