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Landfill: Difference between revisions
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Landfill sites that incorporate engineered barriers are known as “'''containment facilities'''”. The design of such facilities has more than one form and can incorporate different numbers of layers and different designs. These layers are conventionally known as the “'''landfill lining system'''”.<br> | Landfill sites that incorporate engineered barriers are known as “'''containment facilities'''”. The design of such facilities has more than one form and can incorporate different numbers of layers and different designs. These layers are conventionally known as the “'''landfill lining system'''”.<br> | ||
The Landfill Directive sets out minimum requirements for site engineering. In simple terms, all sites require a "geological barrier" and some sites are additionally required to have an "artificial sealing liner". The most common manner in which these requirements are deal with is by having a clay liner of 1m metre thickness of low permeability engineered clay (permeability of less than 1x10-9 metres per second) overlain with 2mm thick welded HDPE (High Density PolyEthylene)lining membrane. Typically, this would be further overlain with a geotextile protection layer and then a drainage layer of aggregate and pipework. | |||
The Department of the Environment produced a series of Waste Management Papers (WMP)<ref name="refB" /><ref name="refA" /><ref name="ref27" /> over the period from the late 1970s to 1997. WMP 26B contains a review of the types of designs. The design employed at any particular design would be informed by the outcome of the HRA which would assess the likely impact of a site upon the environment taking account of the design proposed. In general terms, the most sensitive sites would require the greatest degree of engineering. | The Department of the Environment produced a series of Waste Management Papers (WMP)<ref name="refB" /><ref name="refA" /><ref name="ref27" /> over the period from the late 1970s to 1997. WMP 26B contains a review of the types of designs. The design employed at any particular design would be informed by the outcome of the HRA which would assess the likely impact of a site upon the environment taking account of the design proposed. In general terms, the most sensitive sites would require the greatest degree of engineering. | ||
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Landfills are constructed in discrete parts known as “[[Landfill Cell|landfill cells]]”. The sub-division into cells is undertaken so as to minimise the operating area and consequently minimise leachate generation and make the site more manageable in terms of odour and litter control. Sub-division also enables the site engineering to be constructed progressively as the site fills. | Landfills are constructed in discrete parts known as “[[Landfill Cell|landfill cells]]”. The sub-division into cells is undertaken so as to minimise the operating area and consequently minimise leachate generation and make the site more manageable in terms of odour and litter control. Sub-division also enables the site engineering to be constructed progressively as the site fills. | ||
[[File:Landfill-gas-flare.jpg|300px|left|Landfill gas flare - source Hoffsetter]] | [[File:Landfill-gas-flare.jpg|300px|left|Landfill gas flare - source Hoffsetter]] | ||
===Landfill Gas=== | ===Landfill Gas=== | ||
Another product of waste decomposition is landfill gas. This is a mixture of various components, principally methane and is a [[Biogas]] not dissimilar to that generated in an [[Anaerobic Digestion]] facility. WMP27B<ref name="refB" /> also contains a useful review of the generation and evolution of landfill gas. | Another product of waste decomposition is landfill gas. This is a mixture of various components, principally methane and is a [[Biogas]] not dissimilar to that generated in an [[Anaerobic Digestion]] facility. WMP27B<ref name="refB" /> also contains a useful review of the generation and evolution of landfill gas. | ||