When using the valley or ravine method in a sanitary landfill, how deep are the lifts typically placed?

The valley or ravine method of landfilling typically involves depositing waste into a pre-existing depression in the land, which allows for efficient land use and minimizes the spread of waste. In this method, the depth of the lifts is crucial for effective compaction and containment.

Placing the lifts at a depth of 8-10 feet is common practice as it ensures the waste is sufficiently compacted, while also allowing for proper cover and stabilization of the material. This lift depth is manageable for equipment and facilitates the necessary layers of cover to be applied effectively, which is vital for minimizing odor, controlling pests, and protecting surface and groundwater.

Depths that are too shallow may not provide adequate compaction or may increase the risk of slope failure. Conversely, placing lifts significantly deeper, such as at 12-15 feet or more, may complicate operations and exceed necessary compaction requirements, leading to inefficiencies. Therefore, the selected depth of 8-10 feet strikes a balance between operational feasibility and environmental management in landfill design and practice.