Landfill: Difference between revisions

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==Landfill Restoration and Closure==

Landfill sites are generally restored (finished) to green space, such as agriculture, forestry or (less often) public open space.

The final engineering structure constructed is a capping layer on top of the final layer of waste. Sub-soil and then top soil is placed on to the engineered capping layer. Landfill sites are usually restored progressively in phases as the waste mass reached final levels. The final restoration is usually defined in the Planning Permission for the site.

The engineered cap can be constructed in several ways and the design selected is evaluated in the same way as the landfill lining system, taking account of the various engineering constraints and impacts to be avoided at each site. The design also undergoes similar risk assessment to the lining system.

Commonly, the capping layer will consist of a compacted clay layer of 1 metre thickness. This can be replaced or supplemented by flexible membranes such as LLDPE (Linear Low Density Polyethylene) or GCL (Geo-synthetic Clay) in varying combinations. Membranes can be laid in an over-lapped but unjoined fashion or can be overlapped and welded similar to lining systems.

Soil thickness will depend upon the proposed afteruse of the site; uses involving deep-rooted plants will require thicker soils to protect the engineered capping layer from root-penetration.

Gas and leachate extraction and monitoring equipment (such as monitoring well and pipework) commonly penetrates the capping and soil layers in order to afford access for maintenance and monitoring. Sometimes this equipment is progressivly buried with suitable access points remaining at the surface; this is done principally for aesthetic reasons to improve the appearance of the final restored surface.

Landfill sites where all tipping has ceased and the all infrastructure for post-closure management has been installed are deemed "closed" following agreement with the EA.

The landfill operator is required to continue to maintain monitoring and management of the site post-closure until it can be shown to the satisfaction of the EA that the active management of the site by the operator is no longer required. Assessment of such a state is measured against criteria identified in WMP 26A and subsequent EA guidance. It is generally accepted for non-hazardous landfill sites that this is unlikely to be able to shown for at least 60 years post-closure, probably somewhat longer.

==Landfill Monitoring==

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 ==Landfill Restoration and Closure==
+Landfill sites are generally restored (finished) to green space, such as agriculture, forestry or (less often) public open space.
+The final engineering structure constructed is a capping layer on top of the final layer of waste. Sub-soil and then top soil is placed on to the engineered capping layer. Landfill sites are usually restored progressively in phases as the waste mass reached final levels. The final restoration is usually defined in the Planning Permission for the site.
+The engineered cap can be constructed in several ways and the design selected is evaluated in the same way as the landfill lining system, taking account of the various engineering constraints and impacts to be avoided at each site. The design also undergoes similar risk assessment to the lining system.
+Commonly, the capping layer will consist of a compacted clay layer of 1 metre thickness. This can be replaced or supplemented by flexible membranes such as LLDPE (Linear Low Density Polyethylene) or GCL (Geo-synthetic Clay) in varying combinations. Membranes can be laid in an over-lapped but unjoined fashion or can be overlapped and welded similar to lining systems.
+Soil thickness will depend upon the proposed afteruse of the site; uses involving deep-rooted plants will require thicker soils to protect the engineered capping layer from root-penetration.
+Gas and leachate extraction and monitoring equipment (such as monitoring well and pipework) commonly penetrates the capping and soil layers in order to afford access for maintenance and monitoring. Sometimes this equipment is progressivly buried with suitable access points remaining at the surface; this is done principally for aesthetic reasons to improve the appearance of the final restored surface.
+Landfill sites where all tipping has ceased and the all infrastructure for post-closure management has been installed are deemed "closed" following agreement with the EA.
+The landfill operator is required to continue to maintain monitoring and management of the site post-closure until it can be shown to the satisfaction of the EA that the active management of the site by the operator is no longer required. Assessment of such a state is measured against criteria identified in WMP 26A and subsequent EA guidance. It is generally accepted for non-hazardous landfill sites that this is unlikely to be able to shown for at least 60 years post-closure, probably somewhat longer.
 ==Landfill Monitoring==