Landfill Operator Licensing Exam

Landfill Operator Licensing Exam Practice Questions And Correct Answers (Verified Answers) Plus Rationales 2026 Q&A | Instant Download Pdf

• Which of the following is the primary purpose of a landfill liner?
• To provide structural support
• To allow water to drain freely
• To prevent leachate from contaminating groundwater
• To promote biodegradation

Rationale: A landfill liner is designed to contain leachate and prevent

contamination of surrounding soil and groundwater.

• What is leachate?
• Gaseous emissions from waste
• Solid decomposed waste
• Liquid formed when water filters through waste
• Compacted soil 1 / 4

Rationale: Leachate is liquid that percolates through waste, potentially

carrying harmful chemicals.

• What is the primary greenhouse gas produced in landfills?
• Carbon monoxide
• Nitrous oxide
• Methane
• Ozone

Rationale: Methane is produced during anaerobic decomposition of

organic waste and is a potent greenhouse gas.

• What is the primary purpose of daily cover at a landfill?
• To increase waste volume
• To speed up decomposition
• To control odors, pests, and windblown debris
• To generate leachate

Rationale: Daily cover minimizes odor, litter, pests, and vectors such as

birds and rodents.

• What is the best management practice for hazardous waste at a

landfill?

• Mix with regular waste
• Store separately and follow regulations for disposal
• Burn onsite
• Spread thinly across landfill cells 2 / 4

Rationale: Hazardous wastes must be managed according to strict

regulations to prevent environmental contamination.

• Which of the following gases must be monitored at landfills to prevent

explosion risks?

• Oxygen
• Carbon dioxide
• Methane
• Hydrogen

Rationale: Methane is flammable and can accumulate in landfill gas

collection systems or nearby structures.

• What is the primary function of a leachate collection system?
• To speed up decomposition
• To recycle water
• To collect and remove leachate to prevent contamination
• To stabilize landfill cover

Rationale: Leachate collection systems prevent leachate from infiltrating

soil and groundwater.

• Which of the following is NOT a common method of landfill gas

control?

• Gas collection wells
• Gas flaring 3 / 4

• Soil compaction
• Energy recovery systems

Rationale: Soil compaction is used for waste stability, not gas control.

• What is the typical minimum thickness of a compacted clay liner?
• 6 inches
• 12 inches
• 24 inches
• 36 inches

Rationale: A compacted clay liner of at least 24 inches provides adequate

hydraulic conductivity to reduce leachate migration.

• What is the purpose of groundwater monitoring at landfills?
• To reduce waste volume
• To speed up decomposition
• To detect potential contamination from landfill activities
• To control odors

Rationale: Groundwater monitoring ensures early detection of pollutants

to protect public health and the environment.

• What is the maximum allowable leachate head on a landfill

liner?

• 6 inches
• 12 inches
• / 4