Supervisor Practice Exam Questions And

Industrial Waste Treatment Plant Supervisor Practice Exam Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• What is the main purpose of an industrial waste treatment plant?

a) To increase industrial productivity

b) To reduce pollutants in wastewater before discharge

c) To recycle solid waste only

d) To neutralize air emissions

Rationale: The primary goal is to remove or reduce pollutants in industrial

effluent to protect water quality and comply with environmental regulations.

2. The pH scale measures:

a) Conductivity 1 / 4

b) Acidity or alkalinity

c) Turbidity

d) Solids concentration

Rationale: pH indicates hydrogen ion concentration, determining whether

a solution is acidic or basic.

3. The most common coagulant used in chemical treatment is:

a) Sodium hydroxide

b) Aluminum sulfate (alum)

c) Sodium chloride

d) Ammonium nitrate

Rationale: Alum is widely used for coagulation to remove suspended solids

and turbidity.

4. Sludge volume index (SVI) is used to evaluate:

a) BOD removal efficiency

b) Settling characteristics of activated sludge

c) Filtration rate

d) Chlorination efficiency

Rationale: SVI indicates how well activated sludge settles, guiding

operational control in secondary treatment.

• / 4

5. The typical range for dissolved oxygen (DO) in an aeration tank is:

• 0–1 mg/L
• 1–3 mg/L
• 5–8 mg/L
• 10–15 mg/L

Rationale: Maintaining DO around 1–3 mg/L supports aerobic microbial

activity without excessive energy use.

• What is the main function of equalization in industrial wastewater

treatment?

a) Chemical neutralization

b) To balance flow and pollutant load

c) Sludge digestion

d) Disinfection

Rationale: Equalization tanks buffer variations in flow and concentration

to stabilize treatment performance.

7. BOD stands for:

a) Basic Oxygen Demand

b) Biochemical Oxygen Demand

c) Biological Oxidation Data

d) Biogas Output Determination 3 / 4

Rationale: BOD measures oxygen consumed by microorganisms degrading

organic matter.

• Which process removes suspended solids by gravity?

a) Aeration

b) Sedimentation

c) Filtration

d) Disinfection

Rationale: Sedimentation tanks allow heavier particles to settle out by

gravity.

• Which test determines the strength of organic waste?

a) COD

b) TSS

c) TDS

d) BOD

Rationale: BOD measures biodegradable organic strength in wastewater.

10. Chlorine is used in wastewater treatment primarily for:

• pH correction

b) Disinfection

c) Odor control

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