Treatment Operator Practice Exam

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

• What is the main source of wastewater in pulp and paper mills?
• Boiler blowdown
• Pulp washing and bleaching
• Cooling water
• Office sanitary discharge

Rationale: Pulp washing and bleaching generate the largest volume of

high-strength wastewater containing lignin, chlorinated compounds, and organics.

• Which type of pulp process produces the most pollutants per ton of

pulp? 1 / 4

• Mechanical pulping
• Chemical pulping (kraft or sulfite)
• Semi-chemical pulping
• Thermomechanical pulping

Rationale: Chemical pulping uses chemicals that release dissolved organics

and sulfur compounds into wastewater.

• What is the primary pollutant removed in primary clarification?
• Dissolved solids
• Suspended solids
• Nutrients
• Dissolved oxygen

Rationale: Primary clarifiers settle suspended solids and remove floating

materials before biological treatment.

4. The main function of secondary treatment is to:

• Remove grit
• Separate fibers
• Reduce biochemical oxygen demand (BOD)
• Neutralize acidity

Rationale: Biological treatment in secondary systems targets BOD

reduction by converting organics into biomass and CO₂. 2 / 4

• The most common biological treatment in pulp and paper wastewater

is:

• Trickling filter
• Activated sludge
• Anaerobic lagoon
• Sand filtration

Rationale: Activated sludge systems are widely used for effective BOD and

COD removal.

6. Excessive foam in aeration tanks usually indicates:

• Lack of nutrients
• Too much dissolved oxygen
• Low sludge age or filamentous growth
• High alkalinity

Rationale: Young sludge or filamentous bacteria cause stable foam

formation.

• What parameter indicates organic loading in wastewater?
• pH

B. TSS

C. BOD₅ 3 / 4

• Conductivity

Rationale: BOD₅ measures the amount of oxygen microorganisms require

to stabilize organic matter.

8. A high F/M ratio means:

• High food and low microorganisms
• Low food and high microorganisms
• Low oxygen transfer
• High sludge age

Rationale: High F/M means the system has a high organic load relative to

the biomass.

• Which process converts ammonia to nitrate?
• Denitrification
• Nitrification
• Anaerobic digestion
• Chlorination

Rationale: Nitrifying bacteria oxidize ammonia to nitrate under aerobic

conditions.

• Which chemical is most used for pH neutralization of acidic waste?
• Sulfuric acid
• / 4