Landfill: Difference between revisions
| Line 123: | Line 123: | ||
As the waste mass decomposes, the fill material settles under its own weight to occupy less volume. This process is known as '''settlement'''.<br> | As the waste mass decomposes, the fill material settles under its own weight to occupy less volume. This process is known as '''settlement'''.<br> | ||
Settlement in landfilled waste occurs due to loading and other processes including chemical and microbial actions. These processes | Settlement in landfilled waste occurs due to loading and other processes including chemical and microbial actions. These processes are time-dependent, and are controlled by factors such as leachate composition, pH, temperature and moisture. As a result, settlement in landfilled waste, especially long-term settlement, is complex and difficult to predict in both magnitude and timing. Notwithstanding that, reasonably accurate estimates are commonly used. | ||
Landfill sites operate under the terms of a Planning Permission. Amongst the matters controlled by the permission will be the final levels to which the site must be restored. As the waste ages and decomposes the final level will settle to a lower level. In order to ensure that the agreed final levels are achieved after the majority of the decomposition and related settlement have finished, it is common to agree that the final levels can be exceeded initially - known as surcharging.<br> | Landfill sites operate under the terms of a Planning Permission. Amongst the matters controlled by the permission will be the final levels to which the site must be restored. As the waste ages and decomposes the final level will settle to a lower level. In order to ensure that the agreed final levels are achieved after the majority of the decomposition and related settlement have finished, it is common to agree that the final levels can be exceeded initially - known as surcharging.<br> | ||