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[[Category:Technologies & Solutions]]
[[Category:Technologies & Solutions]]
[[Energy from Waste]] is commonly referred to by it's acronym [[EfW]] and is the [[treatment|thermal treatment]] of [[waste]] for [[disposal]] or [[recovery]]
[[File:Coventry.png|250px|left|CSWDC Coventry]]__TOC__
<br clear='left'/>
==Context and Definition==
In legal terms, a '''‘waste [[incineration]] plant’''' means any stationary or mobile technical unit and equipment dedicated to the [[treatment|thermal treatment]] of waste, with or without [[recovery]] of any energy generated, or whether the gases resulting from the thermal [[treatment]] are subsequently incinerated <ref>As an example, a [[Pyrolysis]] facility that burnt the produced [[Syngas]] to generate electricity would be Incineration, whereas a [[Pyrolysis]] facility that processed [[Syngas]] for vehicle fuel would not be classed as an incinerator</ref><ref name='ref01'>European Commission, 2010 Industrial Emissions Directive 2010/75/EU of the European Parliament and of the Council of 24 November 2010 on industrial emissions (integrated pollution prevention and control). Official Journal of the European Union.</ref>. If the Incinerator can be shown to meet the energy efficiency measurement of [[R1]] it can be classified as a [[recovery]] facility, if it cannot it is classified as a [[disposal]] facility<ref>https://data.gov.uk/dataset/8287c81b-2288-4f14-9068-52bfda396402/r1-status-of-incinerators-in-england</ref>. This means that an [[Incineration|incinerator]] that generates power, and is a net exporter of power, can be described as an '''[[Energy from Waste]]''' ([[EfW]]) facility. An incinerator that is an [[EfW]] facility that meets the [[R1]] criteria is the only type of incinerator under the legislation that can legitimately describe itself as an '''[[Energy Recovery Facility]]''' ([[ERF]]).
The most recent recent [[BAT|BREF]] guidance<ref name="Inc">[https://ec.europa.eu/jrc/en/news/new-eu-environmental-standards-waste-incineration BAT and BREF for Waste incineration]</ref> also sets out how [[Incineration|incinerators]] can be described by:
* waste origin (e.g. Municipal Incinerators), '''and in WikiWaste includes [[Residual Waste EFW]] and [[Biomass Waste EFW]]''',
* the nature of the waste (e.g. Hazardous Waste Incinerators),
* the method/type of incineration (e.g. High Temperature Incinerators)
In WikiWaste these last two bullet points are covered in '''[[High Temperature and Clinical Waste Incineration]]'''.
However, there are a range of other terms used in the sector to describe different types of incineration and [[Energy from Waste]], the kiln/furnace used, and the [[subsidy]] that may apply to them, and these are captured in the table below:
{|class="wikitable"
!colspan=2|Definitions in Legislation!!rowspan=7 style="padding: 50px"|&nbsp;!!Types!!Temp. Range °C!!Category!!rowspan=7 style="padding: 50px"|&nbsp; !!Kiln/Furnace/Reactor
|-
|rowspan=6|[[Incineration]]||rowspan=3|[[Incineration with Energy Recovery|With Energy Recovery]]||rowspan=2|[[Combustion]]|| rowspan=2|800 - 1450||rowspan=2|[[Treatment|Thermal Treatment]]|| [[Grate]]
|-
|[[Fluidised Bed]]
|-
|rowspan=2|[[Gasification]]||rowspan=2|500 - 1600||rowspan=2| [[Advanced Thermal Treatment]] ([[ATT]] and [[ACT]])||[[Rotary Kiln]]
|-
|rowspan=3|[[Incineration without Energy Recovery|Without Energy Recovery]]||[[Plasma]]
|-
|rowspan=2|[[Pyrolysis]]||rowspan=2|250 - 700||rowspan=2|[[Advanced Thermal Treatment]] ([[ATT]] and [[ACT]]) ||[[Heated Tube]]
|-
|[[Surface contact]]
|}
The large majority of [[Incineration|incinerators]] built and operating to date in the UK are based on 'conventional' [[Combustion]] type incineration, with some development of [[Gasification]] and [[Pyrolysis]] types over the last 10 to 15 years in the UK, with varying degrees of success. These [[ATT]]/[[ACT]] types of technology were encouraged by the [[subsidy]] available for power generation under the [[Renewables Obligation]].
The three types of [[Incineration|incineration]]/[[EfW]] can have a variety of different furnaces (also termed kilns and reactors) and associated systems to ensure the uniform treatment and residence time of the waste in the kiln/reactor. The most common kilns/furnaces are [[Grate]] based (there are at least five different type of [[Grate]]), with [[Fluidised Bed]] kilns/furnaces more commonly used in [[Gasification]].
==Overview==
==Overview==
EfW is the name often given to the thermal treatment of waste under controlled conditions in which energy is produced. This energy can either be converted to electricity to boost the National Grid and/or, at times when the EfW plant is a [[Combined Heat and Power]] facility, to provide heat in the form of hot water or steam for use by nearby developments. A plant facilitating the generation of electrical power and recovery of usable heat from a combustion process is termed a [[Combined Heat and Power]] ([[CHP]]) plant and it is more efficient than conventional power generation that is focused on power generation alone.
The energy produced by an [[EfW]] facility can either be converted to electricity to boost the National Grid and/or provide heat in the form of hot water or steam for use by nearby developments. A plant facilitating the generation of electrical power and recovery of usable heat from a combustion process is termed a [[Combined Heat and Power]] ([[CHP]]) plant and it is more efficient than [[EfW]] that is focused on power generation alone.  [[Energy from Waste]] facilities can be used to generate [[Baseload Technologies | base load power]] as they produce a steady, reliable amount of energy but generally cannot be adjusted to meet peak demands. The development of an [[EfW]] plant is complex, with many inter-locking requirements for successful delivery<ref> WRAP, 2012. [http://www.wrap.org.uk/sites/files/wrap/O_And_EFW_Guidance_FULL.pdf EfW Development Guidance. Waste and Resources Action Programme.] </ref>.


In the most widely used EfW process, waste is burned on a moving grate. Air is introduced above and beneath the grate in carefully controlled amounts to ensure proper combustion. Good combustion means fewer emissions. The hot gases released are directed to a boiler to recover the heat. The combustion gases are then cleaned in several stages to a strict standard set by the [[Waste Incineration Directive]] ([[WID]]), which are monitored by the [[Environment Agency]] ([[EA]]) in England.
In the most widely used [[EfW]] process, [[waste]] is [[treatment|treated]] via [[Combustion]] on a moving [[Grate]]. Air is introduced above and beneath the [[Grate]] in carefully controlled amounts to ensure proper [[Combustion]]. Good combustion is needed to manage the emissions from an [[EfW]] facility. The hot gases which are released are then directed to a boiler to recover the heat. The combustion gases are then cleaned in several stages to strict standards set by the [[Industrial Emissions Directive]], which are monitored by the relevant regulatory authorities including the [[Environment Agency]] ([[EA]]) in England.
 
[[File:Solid waste energy plant.v3.jpg|800px|center|Adapted from the National Energy Educational Development program by SERC]]


Of the material received into the EfW facility only around 3% will not be recovered and will require specialist treatment. This is residual material created as part of ensuring the gases are clean.
Energy from Waste is generally a catch all term for three broad types of technology (with a range of different technology providers within each broad type of technology type):
*[[Incineration]] or Conventional Combustion
*[[Gasification]]
*[[Pyrolysis]]
==Efficiency==
Where an EFW facility meets the standards of efficiency set out in the Europeans Commissions Guidelines on the [[R1]] energy efficiency formula in Annex II of Directive 2008/98/EC, it can be considered an [[Energy Recovery Facility]] or [[R1]] facility and to achieve this a plant may need [[CHP]] as part of its solution.
==Inputs==
==Inputs==
Often, but not in all cases, before waste is inputted into the EfW process a pre-treatment of this waste is needed. This can include a sorting process that extracts the recyclable material, is able to manipulate the properties of the feedstock such as [[Calorific Value]], [[Biomass]] content, [[Moisture Content]] and the size of the feedstock particles through processes like shredding. Different types of pre-treatment include subjecting waste to a [[Mechanical Sorting Plant]], [[Mechanical Biological Treatment]] (MBT), or [[Mechanical Heat Treatment]] (MHT)<ref name='ref2'>Defra, 2014. [https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/284612/pb14130-energy-waste-201402.pdf Energy from Waste: A guide to the debate February 2014 (revised edition).] London.</ref>.  
Often, but not in all cases, before waste is inputted into the [[EfW]] process a pre-treatment of this waste is undertaken at the [[EfW]] plant or in a separate facility that feeds the plant. This can include sorting and preparation processes to produce a [[Waste Derived Fuel]] that extracts the recyclable material, is able to manipulate the properties of the feedstock such as [[Calorific Value]], [[Biomass]] content, [[Moisture Content]] and the size of the feedstock particles through processes like shredding. Different types of pre-treatment include subjecting waste to a [[MRF|Waste to Fuel MRF]], [[Mechanical Biological Treatment]] (MBT), or [[Mechanical Heat Treatment]] (MHT)<ref name='ref2'>Defra, 2014. [https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/284612/pb14130-energy-waste-201402.pdf Energy from Waste: A guide to the debate February 2014 (revised edition).] London.</ref>.  


The application of EfW and the associated technology is slightly different according to the types of waste fuel that are to be thermally treated. The approaches and the market can be broadly split into:
The application of [[EfW]] in the market is captured in WikiWaste based on [[Residual Waste EFW]] (comprising both untreated and treated [[Residual Waste |Black Bag]] waste) and [[Biomass Waste EFW]] (comprising primarily [[Wood Waste]] EFW but including [[Sewage Sludge EFW]] and [[Agricultural Waste EFW]]).
 
*[[Residual Waste EFW]] (comprising both untreated and treated [[Residual |Black Bag]] waste)
The biogenic portion of the feedstock entering an [[EfW]] facility is considered to be [[Biomass]] and is classified as renewable for that proportion of the waste (and therefore eligible for [[subsidy|subsidies]] e.g. [[ROC]], [[RHI]])<ref name='ref1'>LCCC, 2019. [https://www.lowcarboncontracts.uk/sites/default/files/publications/Contracts%20for%20Difference%20-%20Generator%20Guide%20Feb%202019.pdf Contracts for Difference Generator Guide. Low Carbon Contracts Company.] London.</ref>.
*[[Biomass Waste EFW]] (comprising primarily [[Wood Waste]] EFW but including [[Sewage Sludge EFW]] and [[Agricultural Waste EFW]])


The [[Biomass]] content of the feedstock is an important parameter as the heat/electricity produced from an EfW plant that can be classified as renewable (and therefore eligible for subsidies e.g. [[ROC]], [[RHI]]) is derived from the biogenic portion of the feedstock <ref name='ref1'>LCCC, 2019. [https://www.lowcarboncontracts.uk/sites/default/files/publications/Contracts%20for%20Difference%20-%20Generator%20Guide%20Feb%202019.pdf Contracts for Difference Generator Guide. Low Carbon Contracts Company.] London.</ref>.
==Outputs==
==Outputs==
Aside from the desired electricity, heat, or chemicals (including fuels) generated from the Energy from Waste process; a range of by-products are also produced.
Aside from the desired electricity, heat, steam or chemicals (including fuels) generated from the Energy from Waste process; a range of by-products are also produced.The by-products produced from [[EfW]] processes vary in composition and quantity depending on the type of waste used as a feedstock, and the technology implemented<ref name='ref3' />.
 
The residual [[Incinerator Bottom Ash]] or [[IBA]] left after the combustion process is generally around 20% of the input tonnage by weight for a [[Residual Waste EFW]] plant, but will vary in quantity and chemical composition depending on the composition of the waste feedstock. This often contains minerals and metals along with non-combustible ash, which is increasingly being recycled into [[Secondary Aggregates]], with some being used for the building of roads once processed (after processing [[IBA]] is termed [[IBBA]])<ref name='ref3'>WRAP, 2019. [http://www.wrap.org.uk/sites/files/wrap/6_O_And_EFW_Guidance_Outputs.pdf EfW Outputs and Residues Guidance on the management of energy outputs and residues including air pollution control residues and incinerator bottom ash. EfW Development Guidance.] [online] [Accessed 30 Oct. 2019].</ref>.


The residual Bottom Ash or [[IBA]] left after the combustion process is generally around 20% of the input tonnage by weight but will vary in quantity and chemical composition depending on the composition of the waste feedstock (i.e. bottom ash from Waste Wood EFW will be different to Residual Waste EFW in composition and in percentage terms) . This often contains minerals and metals along with non-combustible ash, which is increasingly being recycled into [[Secondary Aggregates]], with some currently being accepted by The Highways Agency in a processed form <ref name='ref3'>WRAP, 2019. [http://www.wrap.org.uk/sites/files/wrap/6_O_And_EFW_Guidance_Outputs.pdf EfW Outputs and Residues Guidance on the management of energy outputs and residues including air pollution control residues and incinerator bottom ash. EfW Development Guidance.] [online] [Accessed 30 Oct. 2019].</ref> known as [[IBBA]].
The combustion gases from [[EfW]] are cleaned in several stages to a strict standard set by the [[Industrial Emissions Directive]] ([[IED]]), which are monitored by the Environment Agency (EA) in England. This gas cleaning results in a residual [[Flue Ash]] which is around 3% of the overall input to the plant by weight depending on the level of gas cleaning required. [[Fly Ash]] and [[Air Pollution Control]] (APC) residues are often combined. [[APC]] residues contain ash, carbon and lime in varying quantities and is considered a [[Hazardous Waste]] to be disposed of in a [[Hazardous Landfill]], or sometimes to be further processed through washing or stabilisation in order to make it a non-hazardous waste and allow it to be disposed of in a [[Non-hazardous Landfill]]<ref name='ref3' />.


The combustion gases from EFW are cleaned in several stages to a strict standard set by the [[Waste Incineration Directive]] ([[WID]]), which are monitored by the Environment Agency (EA) in England. This gas cleaning results in a residual [[Flue Ash]] which is around 3% of the overall input to the plant by weight depending on the level of gas cleaning required.
The [[Syngas]] produced from [[Advanced Conversion Technology | Advanced Conversion Technologies]] is comprised of hydrogen, carbon monoxide and methane. This is often combusted in order to generate electricity or in [[Waste to Chemicals]] processes it can be turned into a fuel<ref name='ref3' />.


[[Fly Ash]] and [[Air Pollution Control]] (APC) residues are often combined. APC residues contain ash, carbon and lime in varying quantities and is considered a [[Hazardous Waste]] to be disposed of in a [[Hazardous Landfill]], or sometimes to be further processed through washing or stabilisation in order to make it a non-hazardous waste and allow it to be disposed of in a [[Non-hazardous Landfill]]<ref name='ref3' />.
==Emissions==
The standards for emissions limits, monitoring, waste reception and treatment standards that are acceptable for waste incineration plants were set in the [[Waste Incineration Directive]] (2000/76/EC) and updated in the [[Industrial Emissions Directive]] (2010/75/EU)<ref name='ref01' />. The [[Industrial Emissions Directive]] provides the regulatory framework across the EU and requires such installations to hold a [[Environmental Permit|Permit]] based on the use of [[Best Available Technique]] ([[BAT]]).


The [[Syngas]] produced from [[Advanced Conversion Technologies]] is comprised of hydrogen, carbon monoxide and methane. This is often combusted in order to generate electricity or in [[Waste to chemicals]] processes it can be turned into a fuel<ref name='ref3' />.
On the 3rd December 2019 new EU standards were published for waste incineration <ref name="Inc" /> for new emissions, monitoring and efficiency standards. The new specifications stem from a review of [[Best Available Technique]] ([[BAT]]) Reference Document ([[BAT|BREF]]) for Waste Incineration.


The by-products produced from EfW processes vary in composition and quantity depending on the type of waste used as a feedstock, and the technology implemented<ref name='ref3' />.
==Conclusion==
Energy from Waste processes play a vital role in diverting waste from landfill and in generating energy. EfW is the preferred technique for managing waste over [[Landfill]] providing there is sufficient renewable content in the feedstock and the EfW plant is operating at an energy-efficient state (guide to the debate)<ref name='ref2' />. Recycling is higher up in the [[Waste Hierarchy]] and therefore EfW processes should not in principle take feedstocks that include recyclable materials. However, often a synergy exists between EfW and [[Recycling]] where the two waste management techniques can complement each other and work together to reduce waste sent to [[Landfill]]<ref name='ref2' />.
==References==
==References==
<references />
<references />
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