Which of the following components is part of a landfill gas collection system?

The correct choice identifies trenches or vertical wells as essential components of a landfill gas collection system. These features serve a critical function by creating pathways for the gas generated within the landfill to be effectively collected and directed to a treatment or flare system.

Landfills produce gas primarily from the decomposition of organic materials, predominantly methane and carbon dioxide. The design of trenches or vertical wells enables the efficient capturing of this gas, helping to prevent its escape into the atmosphere, which can pose environmental risks. Properly designed gas collection systems not only help in managing hazardous gases but can also harness this gas for energy production, contributing to a landfill's operational efficiency and sustainability.

The other components mentioned, such as stormwater management ducts, regular monitoring wells, and access roads, do not have a direct role in collecting landfill gas. Stormwater management systems are intended for handling rainwater and preventing runoff issues. Monitoring wells are used to assess groundwater conditions and the potential impact of landfill operations on surrounding water sources. Access roads facilitate maintenance and operational logistics but are not designed for gas collection.