Florida Environmental Operator Exam Level III
PRACTICE QUESTIONS WITH CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A
| INSTANT DOWNLOAD PDF
1. The primary purpose of chlorine in water treatment is to:
A) Remove turbidity
B) Adjust pH
C) Disinfect water
D) Reduce hardness
Rationale: Chlorine is primarily used to kill pathogenic microorganisms
in water.
2. Which process removes dissolved organic matter in water
treatment?
A) Sedimentation
B) Coagulation and flocculation
C) Filtration
D) Chlorination
Rationale: Coagulation and flocculation help remove colloidal and
dissolved organic matter.
3. The typical range of pH for drinking water is:
A) 4.5–5.5
B) 6.0–6.5
C) 6.5–8.5
D) 8.5–9.5
Rationale: Drinking water pH is maintained between 6.5 and 8.5 to
prevent corrosion and maintain taste.
,4. The term “BOD” stands for:
A) Biological Oxidation Demand
B) Biochemical Oxygen Demand
C) Bacterial Oxygen Demand
D) Biochemical Oxidation Depth
Rationale: BOD measures the oxygen required by microorganisms to
decompose organic matter.
5. Which method is most effective for removing suspended solids?
A) Chlorination
B) Sedimentation
C) Aeration
D) Fluoridation
Rationale: Sedimentation allows suspended particles to settle by
gravity.
6. In wastewater treatment, trickling filters are primarily used for:
A) Sludge digestion
B) Biological treatment
C) Filtration
D) Disinfection
Rationale: Trickling filters use microbial biofilms to biologically treat
wastewater.
7. Which of the following is a common coagulant?
A) Sodium hypochlorite
B) Aluminum sulfate
C) Activated carbon
D) Calcium carbonate
Rationale: Aluminum sulfate (alum) is widely used for coagulation in
water treatment.
, 8. The removal of nitrogen from wastewater is called:
A) Flocculation
B) Sedimentation
C) Nitrification and denitrification
D) Disinfection
Rationale: Nitrification converts ammonia to nitrate, and denitrification
converts nitrate to nitrogen gas.
9. Total coliforms are indicators of:
A) Chemical contamination
B) Heavy metals
C) Microbial contamination
D) pH imbalance
Rationale: Total coliforms indicate potential presence of pathogenic
microorganisms.
10. The first step in wastewater treatment is usually:
A) Disinfection
B) Aeration
C) Screening
D) Chlorination
Rationale: Screening removes large debris and solids from influent
wastewater.
11. What is the primary purpose of aeration in wastewater
treatment?
A) Remove solids
B) Increase dissolved oxygen for microorganisms
C) Adjust pH
D) Remove chlorine
Rationale: Aeration supplies oxygen to support aerobic microbial
activity.
PRACTICE QUESTIONS WITH CORRECT ANSWERS
(VERIFIED ANSWERS) PLUS RATIONALES 2026 Q&A
| INSTANT DOWNLOAD PDF
1. The primary purpose of chlorine in water treatment is to:
A) Remove turbidity
B) Adjust pH
C) Disinfect water
D) Reduce hardness
Rationale: Chlorine is primarily used to kill pathogenic microorganisms
in water.
2. Which process removes dissolved organic matter in water
treatment?
A) Sedimentation
B) Coagulation and flocculation
C) Filtration
D) Chlorination
Rationale: Coagulation and flocculation help remove colloidal and
dissolved organic matter.
3. The typical range of pH for drinking water is:
A) 4.5–5.5
B) 6.0–6.5
C) 6.5–8.5
D) 8.5–9.5
Rationale: Drinking water pH is maintained between 6.5 and 8.5 to
prevent corrosion and maintain taste.
,4. The term “BOD” stands for:
A) Biological Oxidation Demand
B) Biochemical Oxygen Demand
C) Bacterial Oxygen Demand
D) Biochemical Oxidation Depth
Rationale: BOD measures the oxygen required by microorganisms to
decompose organic matter.
5. Which method is most effective for removing suspended solids?
A) Chlorination
B) Sedimentation
C) Aeration
D) Fluoridation
Rationale: Sedimentation allows suspended particles to settle by
gravity.
6. In wastewater treatment, trickling filters are primarily used for:
A) Sludge digestion
B) Biological treatment
C) Filtration
D) Disinfection
Rationale: Trickling filters use microbial biofilms to biologically treat
wastewater.
7. Which of the following is a common coagulant?
A) Sodium hypochlorite
B) Aluminum sulfate
C) Activated carbon
D) Calcium carbonate
Rationale: Aluminum sulfate (alum) is widely used for coagulation in
water treatment.
, 8. The removal of nitrogen from wastewater is called:
A) Flocculation
B) Sedimentation
C) Nitrification and denitrification
D) Disinfection
Rationale: Nitrification converts ammonia to nitrate, and denitrification
converts nitrate to nitrogen gas.
9. Total coliforms are indicators of:
A) Chemical contamination
B) Heavy metals
C) Microbial contamination
D) pH imbalance
Rationale: Total coliforms indicate potential presence of pathogenic
microorganisms.
10. The first step in wastewater treatment is usually:
A) Disinfection
B) Aeration
C) Screening
D) Chlorination
Rationale: Screening removes large debris and solids from influent
wastewater.
11. What is the primary purpose of aeration in wastewater
treatment?
A) Remove solids
B) Increase dissolved oxygen for microorganisms
C) Adjust pH
D) Remove chlorine
Rationale: Aeration supplies oxygen to support aerobic microbial
activity.
