, Question 1
A Virginia landfill operator is evaluating leachate generation using the HELP
model. Which factor most significantly increases leachate volume in a closed
landfill with a low-permeability final cover?
A. Increased waste compaction density
B. High evapotranspiration rates
C. Perched water within the cover system
D. Reduced waste biodegradation
Correct Answer: C - Perched water within the cover system
RATIONALE
Perched water within the cover system occurs when infiltrated water
cannot drain laterally, increasing percolation through the cover into
the waste. This leads to higher leachate generation. Compaction and
evapotranspiration reduce leachate, while reduced biodegradation
decreases moisture release but is less direct.
Question 2
During a groundwater monitoring event at a Virginia landfill, the operator
observes a statistically significant increase in chloride and TDS in a
downgradient well. Which regulatory response is required first under
9VAC20-70?
A. Immediately notify EPA and initiate corrective action
B. Resample the well within 30 days to confirm the exceedance
C. Assess whether the increase is due to natural variability or a release
D. Install additional monitoring wells downgradient
Correct Answer: C - Assess whether the increase is due to natural
variability or a release
Page 2
, RATIONALE
Under 9VAC20-70-280, upon detecting a statistically significant
increase, the owner/operator must determine whether the change is
due to natural variation or a release from the landfill. This assessment
is the first step before any corrective action or notification. Immediate
EPA notification is not required until a release is confirmed.
Question 3
A landfill gas extraction system is designed with a vacuum of 30 inches of
water at the wellhead. Which condition would most likely indicate subsurface
air intrusion?
A. Increased methane concentration in the gas
B. Decreased oxygen concentration in the gas
C. Increased nitrogen concentration in the gas
D. Increased carbon dioxide concentration in the gas
Correct Answer: C - Increased nitrogen concentration in the gas
RATIONALE
Air intrusion introduces atmospheric nitrogen, raising N2 levels in
extracted gas. Methane and CO2 are generated by waste
decomposition, while oxygen is consumed. Thus, increased nitrogen is
the key indicator of air intrusion.
Question 4
In Virginia, a landfill operator must demonstrate financial assurance for
closure. Which instrument is NOT acceptable under 9VAC20-70?
A. Trust fund
B. Surety bond
C. Letter of credit
D. Corporate guarantee without financial test
Correct Answer: D - Corporate guarantee without financial test
Page 3
, RATIONALE
A corporate guarantee is acceptable only if the owner/operator passes
a financial test demonstrating financial strength. A bare corporate
guarantee without the financial test is not compliant. Trust funds,
surety bonds, and letters of credit are explicitly allowed.
Question 5
A landfill operator is planning to place a final cover over a closed cell. Which
sequence of layers is required by Virginia regulations for a composite final
cover?
A. Vegetative layer, drainage layer, geomembrane, compacted clay
B. Compacted clay, geomembrane, drainage layer, vegetative layer
C. Geomembrane, compacted clay, vegetative layer, drainage layer
D. Drainage layer, vegetative layer, compacted clay, geomembrane
Correct Answer: B - Compacted clay, geomembrane, drainage
layer, vegetative layer
RATIONALE
The typical composite final cover from bottom to top is: compacted
clay (low permeability), geomembrane (synthetic liner), drainage
layer, and vegetative layer. This sequence minimizes infiltration and
promotes lateral drainage.
Question 6
Which of the following best describes the purpose of a leachate collection
system's sump and riser?
A. To provide aeration for aerobic decomposition
B. To allow removal of leachate and inspection of the collection system
C. To recirculate leachate for enhanced methane generation
D. To store leachate for off-site disposal
Correct Answer: B - To allow removal of leachate and inspection
Page 4
A Virginia landfill operator is evaluating leachate generation using the HELP
model. Which factor most significantly increases leachate volume in a closed
landfill with a low-permeability final cover?
A. Increased waste compaction density
B. High evapotranspiration rates
C. Perched water within the cover system
D. Reduced waste biodegradation
Correct Answer: C - Perched water within the cover system
RATIONALE
Perched water within the cover system occurs when infiltrated water
cannot drain laterally, increasing percolation through the cover into
the waste. This leads to higher leachate generation. Compaction and
evapotranspiration reduce leachate, while reduced biodegradation
decreases moisture release but is less direct.
Question 2
During a groundwater monitoring event at a Virginia landfill, the operator
observes a statistically significant increase in chloride and TDS in a
downgradient well. Which regulatory response is required first under
9VAC20-70?
A. Immediately notify EPA and initiate corrective action
B. Resample the well within 30 days to confirm the exceedance
C. Assess whether the increase is due to natural variability or a release
D. Install additional monitoring wells downgradient
Correct Answer: C - Assess whether the increase is due to natural
variability or a release
Page 2
, RATIONALE
Under 9VAC20-70-280, upon detecting a statistically significant
increase, the owner/operator must determine whether the change is
due to natural variation or a release from the landfill. This assessment
is the first step before any corrective action or notification. Immediate
EPA notification is not required until a release is confirmed.
Question 3
A landfill gas extraction system is designed with a vacuum of 30 inches of
water at the wellhead. Which condition would most likely indicate subsurface
air intrusion?
A. Increased methane concentration in the gas
B. Decreased oxygen concentration in the gas
C. Increased nitrogen concentration in the gas
D. Increased carbon dioxide concentration in the gas
Correct Answer: C - Increased nitrogen concentration in the gas
RATIONALE
Air intrusion introduces atmospheric nitrogen, raising N2 levels in
extracted gas. Methane and CO2 are generated by waste
decomposition, while oxygen is consumed. Thus, increased nitrogen is
the key indicator of air intrusion.
Question 4
In Virginia, a landfill operator must demonstrate financial assurance for
closure. Which instrument is NOT acceptable under 9VAC20-70?
A. Trust fund
B. Surety bond
C. Letter of credit
D. Corporate guarantee without financial test
Correct Answer: D - Corporate guarantee without financial test
Page 3
, RATIONALE
A corporate guarantee is acceptable only if the owner/operator passes
a financial test demonstrating financial strength. A bare corporate
guarantee without the financial test is not compliant. Trust funds,
surety bonds, and letters of credit are explicitly allowed.
Question 5
A landfill operator is planning to place a final cover over a closed cell. Which
sequence of layers is required by Virginia regulations for a composite final
cover?
A. Vegetative layer, drainage layer, geomembrane, compacted clay
B. Compacted clay, geomembrane, drainage layer, vegetative layer
C. Geomembrane, compacted clay, vegetative layer, drainage layer
D. Drainage layer, vegetative layer, compacted clay, geomembrane
Correct Answer: B - Compacted clay, geomembrane, drainage
layer, vegetative layer
RATIONALE
The typical composite final cover from bottom to top is: compacted
clay (low permeability), geomembrane (synthetic liner), drainage
layer, and vegetative layer. This sequence minimizes infiltration and
promotes lateral drainage.
Question 6
Which of the following best describes the purpose of a leachate collection
system's sump and riser?
A. To provide aeration for aerobic decomposition
B. To allow removal of leachate and inspection of the collection system
C. To recirculate leachate for enhanced methane generation
D. To store leachate for off-site disposal
Correct Answer: B - To allow removal of leachate and inspection
Page 4
