TEXAS WASTEWATER CLASS B EXAM Q&A PACK
NEWEST 2026 UPDATE ACTUAL PREP EXAM
COMPLETE 100 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
Most Tested Content Areas: Activated Sludge Process
Control • Solids Handling • Disinfection • Laboratory
Analysis • Safety • Collection Systems • Pumps &
Hydraulics • Regulations & Compliance • Nutrient
Removal • Troubleshooting
1. The primary purpose of primary clarification is to remove:
A. Dissolved solids
B. Suspended settleable solids
C. Pathogens
D. Nutrients
Answer: B
Primary clarifiers remove settleable suspended solids by gravity before
biological treatment.
2. Sludge age (MCRT) represents the:
A. Hydraulic detention time
B. Age of water in aeration tank
C. Average time solids remain in the system
D. Oxygen demand of wastewater
Answer: C
, Mean Cell Residence Time measures how long biomass stays in the
treatment process.
3. High sludge volume index (SVI) indicates:
A. Excellent settling
B. Poor settling sludge
C. Low MLSS
D. High dissolved oxygen
Answer: B
A high SVI means sludge is bulky and settles poorly, often due to filamentous
growth.
4. The main purpose of return activated sludge (RAS) is to:
A. Waste excess solids
B. Maintain biomass concentration
C. Add oxygen
D. Remove nutrients
Answer: B
RAS recycles settled microorganisms back to aeration to sustain treatment.
5. Dissolved oxygen in aeration tanks is typically maintained at:
A. 0–0.5 mg/L
B. 0.5–1.0 mg/L
C. 1.0–3.0 mg/L
D. 5–8 mg/L
Answer: C
Maintaining about 2 mg/L supports aerobic microbes without wasting
energy.
6. Filamentous bulking is commonly caused by:
A. Excess chlorine
B. Low food-to-microorganism ratio
C. High alkalinity
D. High pH
, Answer: B
Low F/M favors filamentous organisms that outcompete floc-formers.
7. The food-to-microorganism (F/M) ratio compares:
A. Flow to sludge age
B. BOD load to biomass
C. Oxygen to nitrogen
D. TSS to pH
Answer: B
F/M indicates how much “food” is available per unit of microorganisms.
8. Secondary clarifiers primarily remove:
A. Dissolved nutrients
B. Floating grease
C. Biological floc
D. Pathogens
Answer: C
They settle activated sludge floc from treated wastewater.
9. Excess sludge removed from the system is called:
A. RAS
B. WAS
C. Scum
D. Return flow
Answer: B
Waste Activated Sludge controls solids inventory.
10.Denitrification occurs under:
A. Aerobic conditions
B. Anaerobic conditions
C. Anoxic conditions
D. High pH only
Answer: C
Anoxic zones allow bacteria to convert nitrate to nitrogen gas.
NEWEST 2026 UPDATE ACTUAL PREP EXAM
COMPLETE 100 QUESTIONS AND CORRECT
DETAILED ANSWERS (VERIFIED ANSWERS)
|ALREADY GRADED A+||BRAND NEW!!
Most Tested Content Areas: Activated Sludge Process
Control • Solids Handling • Disinfection • Laboratory
Analysis • Safety • Collection Systems • Pumps &
Hydraulics • Regulations & Compliance • Nutrient
Removal • Troubleshooting
1. The primary purpose of primary clarification is to remove:
A. Dissolved solids
B. Suspended settleable solids
C. Pathogens
D. Nutrients
Answer: B
Primary clarifiers remove settleable suspended solids by gravity before
biological treatment.
2. Sludge age (MCRT) represents the:
A. Hydraulic detention time
B. Age of water in aeration tank
C. Average time solids remain in the system
D. Oxygen demand of wastewater
Answer: C
, Mean Cell Residence Time measures how long biomass stays in the
treatment process.
3. High sludge volume index (SVI) indicates:
A. Excellent settling
B. Poor settling sludge
C. Low MLSS
D. High dissolved oxygen
Answer: B
A high SVI means sludge is bulky and settles poorly, often due to filamentous
growth.
4. The main purpose of return activated sludge (RAS) is to:
A. Waste excess solids
B. Maintain biomass concentration
C. Add oxygen
D. Remove nutrients
Answer: B
RAS recycles settled microorganisms back to aeration to sustain treatment.
5. Dissolved oxygen in aeration tanks is typically maintained at:
A. 0–0.5 mg/L
B. 0.5–1.0 mg/L
C. 1.0–3.0 mg/L
D. 5–8 mg/L
Answer: C
Maintaining about 2 mg/L supports aerobic microbes without wasting
energy.
6. Filamentous bulking is commonly caused by:
A. Excess chlorine
B. Low food-to-microorganism ratio
C. High alkalinity
D. High pH
, Answer: B
Low F/M favors filamentous organisms that outcompete floc-formers.
7. The food-to-microorganism (F/M) ratio compares:
A. Flow to sludge age
B. BOD load to biomass
C. Oxygen to nitrogen
D. TSS to pH
Answer: B
F/M indicates how much “food” is available per unit of microorganisms.
8. Secondary clarifiers primarily remove:
A. Dissolved nutrients
B. Floating grease
C. Biological floc
D. Pathogens
Answer: C
They settle activated sludge floc from treated wastewater.
9. Excess sludge removed from the system is called:
A. RAS
B. WAS
C. Scum
D. Return flow
Answer: B
Waste Activated Sludge controls solids inventory.
10.Denitrification occurs under:
A. Aerobic conditions
B. Anaerobic conditions
C. Anoxic conditions
D. High pH only
Answer: C
Anoxic zones allow bacteria to convert nitrate to nitrogen gas.
