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Nevada Wastewater Treatment Plant Operator Grade II EXAM
QUESTIONS AND CORRECT VERIFIED SOLUTIONS LATEST
UPDATE THIS YEAR – JUST RELEASED
Exam Domains & Coverage
Based on the ABC standardized exam structure and Nevada requirements, the Grade II exam
covers:
Approximate
Domain Key Topics
%
Preliminary Treatment 10% Screening, grit removal, flow equalization
Primary Treatment 10% Sedimentation, clarification, scum removal
Secondary Treatment (Activated
25% Aeration basins, MLSS, RAS/WAS, F/M ratio, SV
Sludge)
Secondary Treatment (Fixed Film) 10% Trickling filters, RBCs
Filtration, disinfection (chlorine, UV), nutrient
Tertiary Treatment 10%
removal
Thickening, digestion (aerobic/anaerobic),
Sludge Handling & Disposal 10%
dewatering
Safety & Lab Procedures 10% PPE, sampling, BOD, TSS, pH, dissolved oxygen
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Approximate
Domain Key Topics
%
Maintenance & Instrumentation 5% Pumps, motors, SCADA, preventive maintenan
Regulations & Administration 10% NPDES permits, reporting, effluent limits
Practice Questions with Answers & Rationales
Domain 1: Preliminary Treatment (Questions 1–20)
1. What is the primary purpose of screening in a wastewater treatment plant?
• A. To remove dissolved organic matter
• B. To remove large solids and debris
• C. To equalize flow
• D. To disinfect the wastewater
Answer: B
Rationale: Screens remove large solids and debris (rags, sticks, plastics) from wastewater to
protect downstream equipment from damage or clogging .
2. A bar screen with 1-inch openings is classified as what type of screen?
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• A. Fine screen
• B. Medium screen
• C. Coarse screen
• D. Micro screen
Answer: C
Rationale: Coarse screens typically have openings of 6 mm (0.25 inches) to 150 mm (6 inches).
Fine screens have openings of 1.5 mm to 6 mm .
3. What is the purpose of a grit removal system?
• A. To remove organic solids
• B. To remove sand, gravel, and heavy inorganic materials
• C. To remove dissolved metals
• D. To equalize flow
Answer: B
Rationale: Grit removal systems remove sand, gravel, eggshells, and other heavy inorganic
materials that would otherwise cause wear on pumps and equipment .
4. A flow equalization basin is designed to:
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• A. Remove grit from wastewater
• B. Balance flow and pollutant load fluctuations
• C. Disinfect the wastewater
• D. Thicken sludge
Answer: B
Rationale: Equalization basins even out fluctuations in flow rate and pollutant strength,
providing stable influent characteristics to downstream processes .
5. What is the typical velocity range maintained in a grit channel to settle grit while keeping
organics suspended?
• A. 0.1-0.5 ft/s
• B. 1.0-1.5 ft/s
• C. 2.0-3.0 ft/s
• D. 5.0-10.0 ft/s
Answer: B
*Rationale: Grit channels are designed to maintain a flow velocity of approximately 1.0-1.5
ft/s to allow heavier grit particles to settle while keeping lighter organic solids suspended.*
6. Which type of screen uses a rotating drum with mesh to remove fine solids?
Nevada Wastewater Treatment Plant Operator Grade II EXAM
QUESTIONS AND CORRECT VERIFIED SOLUTIONS LATEST
UPDATE THIS YEAR – JUST RELEASED
Exam Domains & Coverage
Based on the ABC standardized exam structure and Nevada requirements, the Grade II exam
covers:
Approximate
Domain Key Topics
%
Preliminary Treatment 10% Screening, grit removal, flow equalization
Primary Treatment 10% Sedimentation, clarification, scum removal
Secondary Treatment (Activated
25% Aeration basins, MLSS, RAS/WAS, F/M ratio, SV
Sludge)
Secondary Treatment (Fixed Film) 10% Trickling filters, RBCs
Filtration, disinfection (chlorine, UV), nutrient
Tertiary Treatment 10%
removal
Thickening, digestion (aerobic/anaerobic),
Sludge Handling & Disposal 10%
dewatering
Safety & Lab Procedures 10% PPE, sampling, BOD, TSS, pH, dissolved oxygen
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Approximate
Domain Key Topics
%
Maintenance & Instrumentation 5% Pumps, motors, SCADA, preventive maintenan
Regulations & Administration 10% NPDES permits, reporting, effluent limits
Practice Questions with Answers & Rationales
Domain 1: Preliminary Treatment (Questions 1–20)
1. What is the primary purpose of screening in a wastewater treatment plant?
• A. To remove dissolved organic matter
• B. To remove large solids and debris
• C. To equalize flow
• D. To disinfect the wastewater
Answer: B
Rationale: Screens remove large solids and debris (rags, sticks, plastics) from wastewater to
protect downstream equipment from damage or clogging .
2. A bar screen with 1-inch openings is classified as what type of screen?
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• A. Fine screen
• B. Medium screen
• C. Coarse screen
• D. Micro screen
Answer: C
Rationale: Coarse screens typically have openings of 6 mm (0.25 inches) to 150 mm (6 inches).
Fine screens have openings of 1.5 mm to 6 mm .
3. What is the purpose of a grit removal system?
• A. To remove organic solids
• B. To remove sand, gravel, and heavy inorganic materials
• C. To remove dissolved metals
• D. To equalize flow
Answer: B
Rationale: Grit removal systems remove sand, gravel, eggshells, and other heavy inorganic
materials that would otherwise cause wear on pumps and equipment .
4. A flow equalization basin is designed to:
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• A. Remove grit from wastewater
• B. Balance flow and pollutant load fluctuations
• C. Disinfect the wastewater
• D. Thicken sludge
Answer: B
Rationale: Equalization basins even out fluctuations in flow rate and pollutant strength,
providing stable influent characteristics to downstream processes .
5. What is the typical velocity range maintained in a grit channel to settle grit while keeping
organics suspended?
• A. 0.1-0.5 ft/s
• B. 1.0-1.5 ft/s
• C. 2.0-3.0 ft/s
• D. 5.0-10.0 ft/s
Answer: B
*Rationale: Grit channels are designed to maintain a flow velocity of approximately 1.0-1.5
ft/s to allow heavier grit particles to settle while keeping lighter organic solids suspended.*
6. Which type of screen uses a rotating drum with mesh to remove fine solids?
