CPWM Landfill Design and Operations 2

Question 1

What is the primary purpose of a leachate collection and removal system (LCRS) in a municipal solid waste landfill?

Accepted Answer

To collect and remove contaminated liquid that percolates through waste

Answer

An LCRS collects leachate—liquid that has percolated through waste and picked up contaminants—and removes it to prevent liner breaches and groundwater contamination.

Question 2

Under RCRA Subtitle D, what minimum slope is typically required for the bottom liner of a municipal solid waste landfill to ensure proper leachate drainage?

Accepted Answer

2%

Answer

Subtitle D regulations require a minimum 2% bottom slope to ensure leachate drains toward collection pipes rather than pooling on the liner.

Question 3

Which type of soil is most commonly specified as a component of composite liner systems because of its low hydraulic conductivity?

Accepted Answer

Compacted clay

Answer

Compacted clay with hydraulic conductivity ≤1×10⁻⁷ cm/s is specified under RCRA regulations as the soil component of composite liner systems.

Question 4

What is the function of a geomembrane in a landfill liner system?

Accepted Answer

To act as a primary barrier preventing leachate migration

Answer

A geomembrane (typically HDPE) serves as a flexible, near-impermeable barrier that prevents leachate from migrating into native soil and groundwater.

Question 5

Daily cover is required at active landfills primarily to:

Accepted Answer

Control odors, vectors, and fire, and reduce litter

Answer

Daily cover—typically 6 inches of soil or approved alternative—controls odors, vectors (rodents, birds), blowing litter, and fire hazards.

(CPWM) Certified Professional in Waste Management Practice Test

(CPWM) Certified Professional in Waste Management Practice Test

CPWM Landfill Design and Operations 2