Trench method
In the trench method of sanitary landfilling, the collection transfer vehicle deposits its load into an excavated trench where the solid waste is spread and compacted. At the end of the day, daily cover is applied and the basic cell structure is completed (see Figure IV-33). In this method, cover material is readily available as a result of excavation. Soil material not needed for daily cover can be stockpiled and used later as a cover for an areas fill operation on top of the completed trench fill. Top soil should be stockpiled for placement in the final layer of cover on the completed site.
With the ever increasing requirements for liner and leachate collection systems, the trench method is passing out of use. The reasons are obvious;
-Inability to line
-Leachate containment and collection difficulties
Cohesive soils such as glacial till or clayey silt are ideal for trench operation because the walls between the trenches can be thin and nearly vertical, and the trenches, can be spaced vary close. Weather and the length of time the trench remains open will affect soil stability and must be considered when the slope of the trench walls is determined. If trenches are aligned perpendicularly to the prevailing winds, This can greatly reduce the amount of blowing litter. The bottom of the trench should be slightly sloped for drainage and any surface water run-on must be removed by drainage or pumping. Excavated soil can be used to form a temporary berm on the sides of the trench to divert surface water.