What material is considered the least desirable for landfill cover?

In the context of landfill operations, the use of cover materials is critical for several reasons, including odor control, preventing disease vectors, and minimizing windblown litter. Among the materials listed, clay is often considered a less desirable option for landfill cover.

Clay has low permeability, which can lead to various issues in landfill management. While its ability to minimize water infiltration might seem beneficial at first glance, it can also trap moisture within the landfill site. This not only creates a breeding ground for anaerobic bacteria but may also result in leachate issues and increased gas production, complicating waste management efforts. Furthermore, clay can be challenging to work with, often requiring more effort to apply and maintain compared to other materials.

In contrast, materials such as sand and gravel can offer better drainage properties and ease of handling. Sand, for instance, allows for better air circulation and evaporation of moisture, helping to keep the landfill drier and reducing the likelihood of odor and other related issues. Overall, while clay has specific uses in landfill operations, its drawbacks make it less desirable compared to other materials for effective landfill cover.