Page 1 of 123
TCEQ Class A Water Operator Exam QUESTIONS
AND DETAILED SOLUTIONS JUST RELEASED
TCEQ Class A Water Operator Exam
Practice Questions with Answers & Rationales
EXAM COVERAGE AREAS (MOST TESTED)
1. Water Treatment Processes – Coagulation, flocculation, sedimentation, filtration, disinfection
2. Surface Water Treatment – Conventional treatment, membrane filtration, GAC contactors
3. Groundwater Treatment – Iron/manganese removal, softening, aeration
4. Distribution Systems – Pumping, storage, water quality maintenance, flushing
5. Regulatory Requirements – TCEQ rules, SDWA, LT2, DBP rules, Stage 2 DBP
6. Water Quality Parameters – TOC, turbidity, pH, alkalinity, hardness, LSI
7. Laboratory & Sampling – Coliform sampling, chlorine residual, SDI, jar testing
8. Math & Calculations – Chemical feed rates, detention time, filtration rates, MGD conversions
9. Safety – Confined space, chlorine safety, lockout/tagout, personal protective equipment
10. Management & Administration – Recordkeeping, public relations, emergency response plans
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### QUESTIONS 1-250
1. A surface water treatment plant treats 4.0 MGD. Liquid alum (17% active Al₂O₃, specific gravity 1.32,
weighing 11.0 lbs/gal) is fed at a dosage of 25 mg/L. What is the daily liquid alum feed rate in gallons per
day?
A) 223 gpd
B) 315 gpd
C) 446 gpd
D) 892 gpd
Answer: C - Active lbs = 4.0 × 25 × 8.34 = 834 lbs/day. Product lbs = .17 = 4,905.8 lbs/day. Gallons
per day = 4,905..0 = 445.98 ≈ 446 gpd .
2. Under TCEQ and federal LT2 Enhanced Surface Water Treatment Rule requirements, what log removal
credit for Cryptosporidium is typically assigned to a properly operated conventional granular media
filtration plant?
, Page 3 of 123
A) 1.0-log removal credit for Cryptosporidium oocysts
B) 2.0-log removal credit for Cryptosporidium oocysts
C) 3.0-log removal credit for Cryptosporidium oocysts
D) 4.0-log removal credit for Cryptosporidium oocysts
Answer: C - Conventional filtration meeting strict turbidity performance criteria is awarded a 3.0-log
removal credit for Cryptosporidium oocysts .
3. What does a negative Langelier Saturation Index (LSI) indicate regarding water stability in a
distribution system?
A) The water is scale-forming and supersaturated with calcium carbonate
B) The water is corrosive, undersaturated with calcium carbonate, and tends to dissolve protective pipe
scales
C) The water is perfectly balanced and non-corrosive
D) The water has high alkalinity and will form scale over time
Answer: B - A negative LSI indicates the water is corrosive and undersaturated with calcium carbonate,
which means it will tend to dissolve protective pipe scales and may cause corrosion .
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4. What is the primary mechanism of contaminant removal when utilizing Granular Activated Carbon
(GAC) contactors in advanced drinking water treatment?
A) Biological digestion of heavy metals by microorganisms on the carbon surface
B) Physical-chemical adsorption of synthetic organic compounds and taste/odor molecules onto internal
microporous surfaces
C) Precipitation of calcium carbonate scale onto the carbon media surface
D) Ion exchange of sodium ions for calcium and magnesium hardness removal
Answer: B - GAC provides an extensive internal surface area that captures dissolved organic
contaminants through physical adsorption forces .
5. A filter bed measures 20 feet by 30 feet (600 sq ft total area). If the flow rate through this filter is 1.8
MGD, what is the filtration rate in gallons per minute per square foot?
A) 1.50 gpm/sq ft
B) 2.08 gpm/sq ft
C) 3.45 gpm/sq ft
D) 4.10 gpm/sq ft
TCEQ Class A Water Operator Exam QUESTIONS
AND DETAILED SOLUTIONS JUST RELEASED
TCEQ Class A Water Operator Exam
Practice Questions with Answers & Rationales
EXAM COVERAGE AREAS (MOST TESTED)
1. Water Treatment Processes – Coagulation, flocculation, sedimentation, filtration, disinfection
2. Surface Water Treatment – Conventional treatment, membrane filtration, GAC contactors
3. Groundwater Treatment – Iron/manganese removal, softening, aeration
4. Distribution Systems – Pumping, storage, water quality maintenance, flushing
5. Regulatory Requirements – TCEQ rules, SDWA, LT2, DBP rules, Stage 2 DBP
6. Water Quality Parameters – TOC, turbidity, pH, alkalinity, hardness, LSI
7. Laboratory & Sampling – Coliform sampling, chlorine residual, SDI, jar testing
8. Math & Calculations – Chemical feed rates, detention time, filtration rates, MGD conversions
9. Safety – Confined space, chlorine safety, lockout/tagout, personal protective equipment
10. Management & Administration – Recordkeeping, public relations, emergency response plans
, Page 2 of 123
---
### QUESTIONS 1-250
1. A surface water treatment plant treats 4.0 MGD. Liquid alum (17% active Al₂O₃, specific gravity 1.32,
weighing 11.0 lbs/gal) is fed at a dosage of 25 mg/L. What is the daily liquid alum feed rate in gallons per
day?
A) 223 gpd
B) 315 gpd
C) 446 gpd
D) 892 gpd
Answer: C - Active lbs = 4.0 × 25 × 8.34 = 834 lbs/day. Product lbs = .17 = 4,905.8 lbs/day. Gallons
per day = 4,905..0 = 445.98 ≈ 446 gpd .
2. Under TCEQ and federal LT2 Enhanced Surface Water Treatment Rule requirements, what log removal
credit for Cryptosporidium is typically assigned to a properly operated conventional granular media
filtration plant?
, Page 3 of 123
A) 1.0-log removal credit for Cryptosporidium oocysts
B) 2.0-log removal credit for Cryptosporidium oocysts
C) 3.0-log removal credit for Cryptosporidium oocysts
D) 4.0-log removal credit for Cryptosporidium oocysts
Answer: C - Conventional filtration meeting strict turbidity performance criteria is awarded a 3.0-log
removal credit for Cryptosporidium oocysts .
3. What does a negative Langelier Saturation Index (LSI) indicate regarding water stability in a
distribution system?
A) The water is scale-forming and supersaturated with calcium carbonate
B) The water is corrosive, undersaturated with calcium carbonate, and tends to dissolve protective pipe
scales
C) The water is perfectly balanced and non-corrosive
D) The water has high alkalinity and will form scale over time
Answer: B - A negative LSI indicates the water is corrosive and undersaturated with calcium carbonate,
which means it will tend to dissolve protective pipe scales and may cause corrosion .
, Page 4 of 123
4. What is the primary mechanism of contaminant removal when utilizing Granular Activated Carbon
(GAC) contactors in advanced drinking water treatment?
A) Biological digestion of heavy metals by microorganisms on the carbon surface
B) Physical-chemical adsorption of synthetic organic compounds and taste/odor molecules onto internal
microporous surfaces
C) Precipitation of calcium carbonate scale onto the carbon media surface
D) Ion exchange of sodium ions for calcium and magnesium hardness removal
Answer: B - GAC provides an extensive internal surface area that captures dissolved organic
contaminants through physical adsorption forces .
5. A filter bed measures 20 feet by 30 feet (600 sq ft total area). If the flow rate through this filter is 1.8
MGD, what is the filtration rate in gallons per minute per square foot?
A) 1.50 gpm/sq ft
B) 2.08 gpm/sq ft
C) 3.45 gpm/sq ft
D) 4.10 gpm/sq ft
