Landfill: Difference between revisions

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

===Overview===

The final engineering structure is an '''engineered capping layer''' on top of the final layer of waste. Sub-soil and then top soil is placed on to the engineered capping layer, often termed the restoration levels or horizon. 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.

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*To contain landfill gas within the waste

*To repel/shed rainwater and surface water to reduce the production of Leachate

*To provide a barrier ~~to root growth~~ in the soils ~~from the waste~~

*To provide a barrier between the waste and the roots of vegetation growing in the soils

*To provide an effective growing medium and afteruse for the site

Commonly, the capping layer will consist of a compacted clay layer of 1 metre thickness, placed on the last levels of the waste (which is often a thicker layer of final cover to provide a uniform level for placement of the material). 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 with no fused joints or can be overlapped and welded together similar to lining systems.

Commonly, the capping layer will consist of a compacted clay layer of 1 metre thickness, placed on the last levels of the waste (which is often a thicker layer of final cover to provide a uniform level for placement of the material). This capping layer can be replaced or supplemented by '''flexible membranes''' such as LLDPE (Linear Low Density Polyethylene) or GCL (Geo-synthetic Clay) in varying combinations. Flexible membranes can be laid over-lapped with no fused joints or can be overlapped and welded together similar to engineering 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.

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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 progressively 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.

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. This period is known as the '''aftercare''' period.

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 WMP26A<ref name="refA" /> 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. This period is known as the '''aftercare''' period.

There is published guidance on landfill permit surrender available~~, notably "~~Additional guidance for Landfill (EPR 5.02) and other permanent deposits of waste - How to surrender your environmental permit"<br>

There is published guidance on landfill permit surrender available from the [[EA]]<ref>Additional guidance for Landfill (EPR 5.02) and other permanent deposits of waste - How to surrender your environmental permit</ref>.

=== Settlement and Surcharge ===

===Settlement and Surcharge===

As the waste mass decomposes, the ~~fill~~ material settles under its own weight to occupy less volume. This process is known as '''settlement'''.

As the waste mass decomposes, the waste infill material settles under its own weight to occupy less volume. This process is known as '''settlement'''.

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'''.

The degree of surcharging permitted is agreed as a [[Landfill Surcharge Allowance]]. This figure is usually quoted as a percentage which relates to the depth of the site at each point. The percentage agreed between the planning authority and the developer will vary according to the nature of the waste accepted, the depth of fill and the morphology of the landfill void.~~<br>~~

The degree of surcharging permitted is agreed as a [[Landfill Surcharge Allowance]]. This figure is usually quoted as a percentage which relates to the depth of the site at each point. The percentage agreed between the planning authority and the developer will vary according to the nature of the waste accepted, the depth of fill and the morphology of the landfill void.

It is conventional to have two sets of contours agreed with the planning authority - pre-settlement and post-settlement. The ~~latter~~ represent the level to which the site can be surcharged, the latter represent the levels to which the site will settle. The post-settlement contours are sometimes also known as final levels.

It is conventional to have two sets of contours agreed with the planning authority - '''pre-settlement contours''' and '''post-settlement contours'''. The former represent the level to which the site can be surcharged, the latter represent the levels to which the site will settle. The post-settlement contours are sometimes also known as final levels.

~~[[Landfill Settlement Contours]] are the levels to which a surcharged landfill can filled~~.

== Landfill Monitoring ==

Landfill sites are monitored to ensure that all activities are being undertaken in compliance with permit and other regulatory requirements. Furthermore, monitoring is undertaken to ensure that the site is performing as designed (such that if it is not performing remedial action can be considered) and other day to day impacts are managed to ensure that they are not unacceptable nor cause nuisance.

Landfill sites are monitored to ensure that all activities are being undertaken in compliance with permit and other regulatory requirements. Furthermore, monitoring is undertaken to ensure that any impacts derived from the site are not unacceptable nor cause nuisance.

===General Monitoring Requirements===

Various aspects of the landfill are monitored, such as:

* Quantity and type of waste received including any assessments of ~~suitablity~~ for acceptance at the site

* Quantity and type of waste received including any assessments of suitability for acceptance at the site

* Daily activity and waste placement log

* Leachate volume and quality within the waste mass

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* Complaint records held at the site

==== Leachate, groundwater and surface water monitoring ====

===Reasons for Leachate, groundwater and surface water monitoring===

The specific reasons for leachate, groundwater and surface water monitoring at landfills are:

* to demonstrate that the landfill is performing as designed;

@@ Line 147: / Line 147: @@
 Landfill sites are generally restored (finished) to green space, such as agriculture, forestry or (less often) public open space.
+===Overview===
 The final engineering structure is an '''engineered capping layer''' on top of the final layer of waste. Sub-soil and then top soil is placed on to the engineered capping layer, often termed the restoration levels or horizon. 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.
@@ Line 152: / Line 153: @@
 *To contain landfill gas within the waste
 *To repel/shed rainwater and surface water to reduce the production of Leachate
-*To provide a barrier to root growth in the soils from the waste
+*To provide a barrier between the waste and the roots of vegetation growing in the soils
 *To provide an effective growing medium and afteruse for the site
-Commonly, the capping layer will consist of a compacted clay layer of 1 metre thickness, placed on the last levels of the waste (which is often a thicker layer of final cover to provide a uniform level for placement of the material). 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 with no fused joints or can be overlapped and welded together similar to lining systems.
+Commonly, the capping layer will consist of a compacted clay layer of 1 metre thickness, placed on the last levels of the waste (which is often a thicker layer of final cover to provide a uniform level for placement of the material). This capping layer can be replaced or supplemented by '''flexible membranes''' such as LLDPE (Linear Low Density Polyethylene) or GCL (Geo-synthetic Clay) in varying combinations. Flexible membranes can be laid over-lapped with no fused joints or can be overlapped and welded together similar to engineering 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.
@@ Line 161: / Line 162: @@
 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 progressively 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.
+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. This period is known as the '''aftercare''' period.
+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 WMP26A<ref name="refA" /> 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. This period is known as the '''aftercare''' period.
-There is published guidance on landfill permit surrender available, notably "Additional guidance for Landfill (EPR 5.02) and other permanent deposits of waste - How to surrender your environmental permit"<br>
+There is published guidance on landfill permit surrender available from the [[EA]]<ref>Additional guidance for Landfill (EPR 5.02) and other permanent deposits of waste - How to surrender your environmental permit</ref>.
-=== Settlement and Surcharge ===
+===Settlement and Surcharge===
-As the waste mass decomposes, the fill material settles under its own weight to occupy less volume. This process is known as '''settlement'''.
+As the waste mass decomposes, the waste infill material settles under its own weight to occupy less volume. This process is known as '''settlement'''.
 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'''.
-The degree of surcharging permitted is agreed as a [[Landfill Surcharge Allowance]]. This figure is usually quoted as a percentage which relates to the depth of the site at each point. The percentage agreed between the planning authority and the developer will vary according to the nature of the waste accepted, the depth of fill and the morphology of the landfill void.<br>
+The degree of surcharging permitted is agreed as a [[Landfill Surcharge Allowance]]. This figure is usually quoted as a percentage which relates to the depth of the site at each point. The percentage agreed between the planning authority and the developer will vary according to the nature of the waste accepted, the depth of fill and the morphology of the landfill void.
-It is conventional to have two sets of contours agreed with the planning authority - pre-settlement and post-settlement. The latter represent the level to which the site can be surcharged, the latter represent the levels to which the site will settle. The post-settlement contours are sometimes also known as final levels.
+It is conventional to have two sets of contours agreed with the planning authority - '''pre-settlement contours''' and '''post-settlement contours'''. The former represent the level to which the site can be surcharged, the latter represent the levels to which the site will settle. The post-settlement contours are sometimes also known as final levels.
-[[Landfill Settlement Contours]] are the levels to which a surcharged landfill can filled.
 == Landfill Monitoring ==
+Landfill sites are monitored to ensure that all activities are being undertaken in compliance with permit and other regulatory requirements. Furthermore, monitoring is undertaken to ensure that the site is performing as designed (such that if it is not performing remedial action can be considered) and other day to day impacts are managed to ensure that they are not unacceptable nor cause nuisance.
-Landfill sites are monitored to ensure that all activities are being undertaken in compliance with permit and other regulatory requirements. Furthermore, monitoring is undertaken to ensure that any impacts derived from the site are not unacceptable nor cause nuisance.
+===General Monitoring Requirements===
 Various aspects of the landfill are monitored, such as:
-* Quantity and type of waste received including any assessments of suitablity for acceptance at the site
+* Quantity and type of waste received including any assessments of suitability for acceptance at the site
 * Daily activity and waste placement log
 * Leachate volume and quality within the waste mass
@@ Line 201: / Line 200: @@
 * Complaint records held at the site
-==== Leachate, groundwater and surface water monitoring ====
+===Reasons for Leachate, groundwater and surface water monitoring===
 The specific reasons for leachate, groundwater and surface water monitoring at landfills are:
 * to demonstrate that the landfill is performing as designed;