SWANA Landfill Gas Management 3

Question 1

What is the lower explosive limit (LEL) of methane in air, above which methane-air mixtures become potentially explosive?

Accepted Answer

5% by volume

Answer

1% by volume

Answer

15% by volume

Answer

25% by volume

Question 2

LFG-to-energy projects that generate electricity at the landfill most commonly use which prime mover technology?

Accepted Answer

Internal combustion engines or combustion turbines fueled by LFG

Answer

Steam turbines powered by LFG combustion

Answer

Solar photovoltaic panels co-located at the landfill

Answer

Hydroelectric turbines installed at leachate ponds

Question 3

What parameter is typically adjusted at individual LFG wellheads to balance gas collection evenly across a landfill wellfield?

Accepted Answer

Vacuum (negative pressure) applied to each well

Answer

Temperature of the well casing

Answer

Moisture content in the extracted gas

Answer

pH of the gas stream

Question 4

What is the primary purpose of a landfill wellfield monitoring program?

Accepted Answer

Assess gas collection system efficiency and overall wellfield performance

Answer

Track daily waste tonnage received at the facility

Answer

Monitor groundwater contamination beneath the liner

Answer

Measure leachate head levels above the liner

Question 5

Which EPA voluntary program assists landfill owners and operators in developing LFG energy projects by providing technical and financial guidance?

Accepted Answer

Landfill Methane Outreach Program (LMOP)

Answer

Clean Water State Revolving Fund (CWSRF)

Answer

RCRA Section 3005 permitting program

Answer

OSHA Process Safety Management (PSM) program

Question 6

Off-site LFG migration from a landfill into adjacent buildings or structures poses what primary safety hazard?

Accepted Answer

Methane accumulation creating an explosion and fire risk in enclosed spaces

Answer

Groundwater contamination from dissolved methane

Answer

Formation of acid rain from CO2 emissions

Answer

Soil erosion from gas venting pressure

Question 7

During LFG wellfield monitoring, elevated nitrogen or oxygen concentrations measured in extracted gas typically indicate what condition?

Accepted Answer

Air intrusion into the gas collection system or waste mass

Answer

Peak methane generation phase in the waste mass

Answer

Increased carbon dioxide production from aerobic decomposition

Answer

Optimal gas collection and balanced wellfield pressure