Texas Class C Surface Water Exam
Review Questions and Answers |
Latest Version | 2025/2026 | Correct &
Verified
What is the main purpose of coagulation in surface water treatment?
✔✔To destabilize suspended particles so they can clump together.
What is the function of flocculation in water treatment?
✔✔To gently mix water so particles form larger, heavier flocs.
What is the primary purpose of sedimentation in surface water treatment?
✔✔To allow heavy particles and flocs to settle out.
Why is filtration important in surface water treatment?
✔✔To remove remaining suspended solids and microorganisms.
What is the primary purpose of disinfection in drinking water treatment?
✔✔To kill or inactivate harmful pathogens.
1
,What does turbidity measure in water?
✔✔The cloudiness of water caused by suspended particles.
What unit is commonly used to measure turbidity?
✔✔Nephelometric Turbidity Units (NTU).
What is the maximum turbidity limit for drinking water set by the EPA?
✔✔0.3 NTU in 95% of samples.
Why is chlorine commonly used as a disinfectant in water treatment?
✔✔It is effective, inexpensive, and provides a residual in the distribution system.
What is chlorine residual?
✔✔The amount of chlorine left in the water after disinfection.
What is the minimum free chlorine residual required in a distribution system in Texas?
✔✔0.2 mg/L.
2
, What is the maximum allowable chlorine residual in Texas drinking water?
✔✔4.0 mg/L.
What is the purpose of pH adjustment in water treatment?
✔✔To control corrosion and improve disinfection efficiency.
What is the acceptable pH range for drinking water?
✔✔6.5 to 8.5.
What does TTHM stand for in water treatment regulations?
✔✔Total Trihalomethanes.
Why are trihalomethanes regulated in drinking water?
✔✔They are harmful disinfection by-products formed when chlorine reacts with organics.
What is the maximum contaminant level (MCL) for TTHMs?
✔✔0.080 mg/L.
3
Review Questions and Answers |
Latest Version | 2025/2026 | Correct &
Verified
What is the main purpose of coagulation in surface water treatment?
✔✔To destabilize suspended particles so they can clump together.
What is the function of flocculation in water treatment?
✔✔To gently mix water so particles form larger, heavier flocs.
What is the primary purpose of sedimentation in surface water treatment?
✔✔To allow heavy particles and flocs to settle out.
Why is filtration important in surface water treatment?
✔✔To remove remaining suspended solids and microorganisms.
What is the primary purpose of disinfection in drinking water treatment?
✔✔To kill or inactivate harmful pathogens.
1
,What does turbidity measure in water?
✔✔The cloudiness of water caused by suspended particles.
What unit is commonly used to measure turbidity?
✔✔Nephelometric Turbidity Units (NTU).
What is the maximum turbidity limit for drinking water set by the EPA?
✔✔0.3 NTU in 95% of samples.
Why is chlorine commonly used as a disinfectant in water treatment?
✔✔It is effective, inexpensive, and provides a residual in the distribution system.
What is chlorine residual?
✔✔The amount of chlorine left in the water after disinfection.
What is the minimum free chlorine residual required in a distribution system in Texas?
✔✔0.2 mg/L.
2
, What is the maximum allowable chlorine residual in Texas drinking water?
✔✔4.0 mg/L.
What is the purpose of pH adjustment in water treatment?
✔✔To control corrosion and improve disinfection efficiency.
What is the acceptable pH range for drinking water?
✔✔6.5 to 8.5.
What does TTHM stand for in water treatment regulations?
✔✔Total Trihalomethanes.
Why are trihalomethanes regulated in drinking water?
✔✔They are harmful disinfection by-products formed when chlorine reacts with organics.
What is the maximum contaminant level (MCL) for TTHMs?
✔✔0.080 mg/L.
3
