Excerpt
Table of Contents
Abstract
Table of Contents
Index of Figures
Index of Tables
Abbreviations
1 Introduction
1.1 Objectives
1.2 Aim
2 Literature Review
3 Life Cycle Assessment
3.1 Technologies
3.1.1 Material Recovery Facilities
3.1.2 Biological Treatment
3.1.3 Thermal Treatment
3.1.4 Landfilling
3.1.5 Recycling
3.2 Actual Situation
3.2.1 England
3.2.2 Germany
3.2.3 Bulgaria
3.3 Scenarios
3.3.1 England
3.3.2 Germany
3.3.3 Bulgaria
3.4 EU Legislation
3.4.1 Council Directive 1999/31/EC
3.4.1.1 England
3.4.1.2 Germany
3.4.1.3 Bulgaria
3.4.2 Directive 2004/12/EC
3.4.2.1 England
3.4.2.2 Germany
3.4.2.3 Bulgaria
3.5 National Legislation
3.5.1 England
3.5.2 Germany
3.5.3 Bulgaria
4 Results and Discussion
4.1 England
4.2 Germany
4.3 Bulgaria
5 Conclusions
6 References
Appendix I: Energy related input values (IWM-2)
Appendix II: Material Bank Site Collection
Appendix III: Transport Distances
Appendix IV: Packaging Waste
Abstract
Since the pre-industrial era the concentration of carbon dioxide in the atmosphere has increased by nearly 30 per cent, methane concentrations have more than doubled. The resulting climate change will lead to major environmental changes such as rising sea levels (that may flood coastal and river delta communities), shrinking mountain glaciers (that may diminish fresh water resources), the spread of infectious diseases and increased heat related mortality, impacts to ecosystems and loss in biodiversity, and agricultural shifts such as impacts on crop yields (Ackerman, Barlaz, Boguski and others 1998).
As this increase is at least partly caused by human activity, the effort to confront anthropogenic greenhouse gas emissions has increased over the last years. Probably the most important measure implemented is the Framework Convention on Climate Change.
In the EU about one third of manmade methane emissions, with a global warming potential 21 times greater than that of carbon dioxide, can be attributed to solid waste disposal. With some 60% of municipal solid waste still being disposed of to landfill without any form of pre-treatment and extensive reliance on incineration for treatment of most of the remainder, it is clear that there is considerable scope for improvement (Smith, Brown, Ogilvie and others 2001).
In this report the capability of either European or national legislation to improve the actual situation on greenhouse gas emissions related to the management of municipal solid waste was investigated by using England, Germany and Bulgaria as representatives.
From the results obtained by applying a Life Cycle Assessment it becomes obvious that European legislation will improve the actual situation on the management of municipal solid waste. The greenhouse gas emissions generated in England will be reduced by more than 75% and thus result in a negative greenhouse gas flux. In Bulgaria the emissions will decline by more than 82%.
With regard to the waste management hierarchy the greatest improvements will be reached by reducing the amount of biodegradable municipal solid waste from landfilling and meanwhile focusing on material recycling. To deal with the putrescible fraction biological treatment options should be preferred to thermal treatment methods.
All improvements achieved by the different scenarios are based on effective source segregated collection schemes. This measure could be justified by the fact that most treatment options rely significantly on the quality of the input materials and that in comparison with the whole municipal solid waste management emissions based on collection and transportation could be neglected.
Index of Figures
Figure 1: Waste Hierarchy
Figure 2: Methodology of the Life Cycle Assessment
Figure 3: Composition of MSW in England
Figure 4: Global Warming Potential of England's actual situation
Figure 5: Composition of MSW in Germany
Figure 6: Global Warming Potential of Germany's actual situation
Figure 7: Composition of MSW in Bulgaria
Figure 8: Global Warming Potential of Bulgaria's actual situation
Figure 9: Applied MSW Treatment in the English Scenarios
Figure 10: Applied MSW Treatment in the German Scenario
Figure 11: Applied MSW Treatment in the Bulgarian Scenarios
Figure 12 English Scenarios and the Council Directive 1999/31/EC
Figure 13: German Scenarios and the Council Directive 1999/31/EC
Figure 14: Bulgarian Scenarios and the Council Directive 1999/31/EC
Figure 15: England's actual Packaging Waste Management
Figure 16: Packaging Waste Management in the English Scenarios
Figure 17: Composition of Packaging Waste in England
Figure 18: Packaging Waste Management in the German Scenarios
Figure 19: Composition of Packaging Waste in Germany
Figure 20: Packaging Waste Management in the Bulgarian Scenarios
Figure 21: UK Packaging Waste Legislation and Scenario IV Eng
Figure 22: Packaging Waste Management in Germany - national legislation and performance
Figure 23: Global Warming Potential of the English Scenarios
Figure 24: Global Warming Potential of the German Scenarios
Figure 25: Global Warming Potential of the Bulgarian Scenarios
Figure 26: Global Warming Potential of the Scenarios [kg per ton waste]
Index of Tables
Table 1: EU GHG emissions generated during the management of waste
Table 2: System Boundaries of IWM-2
Table 3: Collection of Recyclables (Eng actual situation)
Table 4: Recovery of Commercial MSW (Eng actual situation)
Table 5: Deviation of Input to Landfill - English Scenarios
Table 6: Collection of Recyclables (De actual situation)
Table 7: Recovery of Commercial MSW (De actual situation)
Table 8: Collection of Recyclables (Scenario I Eng)
Table 9: Recovery of Commercial MSW (Scenario I Eng)
Table 10: Collection of Recyclables (Scenario II Eng)
Table 11: Recovery of Commercial MSW (Scenario II Eng)
Table 12: Collection of Recyclables (Scenario III Eng)
Table 13: Collection of Recyclables (Scenario IV Eng)
Table 14: Performance of Biological Treatment (English Scenarios)
Table 15 :Performance of Thermal Treatment (English Scenarios)
Table 16: Landfill Management (English Scenarios)
Table 17: Collection of Recyclables (Scenario I Bul)
Table 18: Collection of Recyclables (Scenario II Bul)
Table 19: Collection of Recyclables (Scenario III Bul)
Table 20: Performance of Biological Treatment (Bulgarian Scenarios)
Table 21: Landfill Management (Bulgarian Scenarios)
Table 22: Recycling Targets of The Producer Responsibility Obligations (England and Wales) (Amendment) Regulations 2003 [%]
Table 23: Energy Related Input Values
Table 24: Material Bring Site Collection System (actual situation Eng)
Abbreviations
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1 Introduction
Relative to the year 1990 global average surface temperature has already increased by 0.6°C (+/- 0.2) and as projected by diverse models will rise further by 1.4 to 5.8°C until the end of the 21st century. In consequence globally averaged sea level will rise 0.09 to 0.88 m by the year 2100.
Natural systems can be especially vulnerable to climate change because of limited adaptive capacity, and some of these systems may undergo significant and irreversible damage. Natural systems at risk include glaciers, coral reefs and atolls, mangroves, boreal and tropical forests, polar and alpine ecosystems, prairie wetlands, and remnant native grasslands. While some species may increase in abundance or range, climate change will increase existing risks of extinction of some more vulnerable species and loss of biodiversity. It is well-established that the geographical extent of the damage or loss, and the number of systems affected, will increase with the magnitude and rate of climate change.
Human systems that are sensitive to climate change include mainly water resources; agriculture (especially food security) and forestry; coastal zones and marine systems (fisheries); human settlements, energy, and industry; insurance and other financial services; and human health. Projected adverse impacts based on models and other studies include:
- A general reduction in potential crop yields in most tropical and sub-tropical regions for most projected increases in temperature.
- A general reduction, with some variation, in potential crop yields in most regions in mid-latitudes for increases in annual-average temperature of more than a few degree centigrade.
- Decreased water availability for populations in many water-scarce regions, particularly in the sub-tropics.
- An increase in the number of people exposed to vectorborne (e.g. malaria) and water-borne diseases (e.g. cholera), and an increase in heat stress mortality.
- A widespread increase in the risk of flooding for many human settlements (tens of millions of inhabitants in settlements studied) from both increased heavy precipitation events and sea-level rise.
- Increased energy demand for space cooling due to higher summer temperatures (McCarthy, Canziani, Leiry and others 2001).
To confront the global ecological concerns, world leaders and citizens from some 200 countries met in Rio de Janeiro, Brazil in 1992. At this "Earth Summit," 154 nations signed the Framework Convention on Climate Change, an international agreement to address the danger of global climate change. The objective of the Convention is to stabilize greenhouse gas (GHG) concentrations in the atmosphere at a level, and over a time frame, that will minimize manmade climate disruptions. By signing the Convention, countries make a voluntary commitment to reduce GHGs or take other actions to stabilize emissions of GHGs at 1990 levels. All parties to the Convention are also required to develop, and periodically update, national inventories of their GHG emissions.
Countries that ratified the Framework Convention on Climate Change met in Kyoto, Japan in December 1997, where they agreed to reduce global GHG emissions and set binding targets for developed nations (Ackerman, Barlaz, Boguski and others 1998).
The so called Kyoto Protocol requires a 5 % reduction in developed countries’ emissions from 1990 levels by 2008-12 of six GHGs (carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulphur hexafluoride (SF6)).
The EU-15 agreed to reduce its GHG emissions by 8 % from 1990 levels by 2008-12. According to Council Decision 2002/358/EC, the EU-15 and its Member States agreed in 2002 on different emission limitation and/or reduction targets for each Member State according to economic circumstances, called the burden-sharing agreement (European Environment Agency (EEA) 2005).
The GHGs that are making the largest contribution to global warming are carbon dioxide, methane and nitrous oxide. All three for instance are produced during the management and disposal of wastes, what will be the subject of this report. Estimated total emissions of these gases from the European Union (EU) are shown in Table 1, which also shows the contributions from solid waste disposal (Smith, Brown, Ogilvie and others 2001).
Table 1: EU GHG emissions generated during the management of waste Source: Smith, Brown, Ogilvie and others (2001)
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The impact of solid waste management on the global warming equivalence of European GHG emissions comes mostly from methane released as biodegradable wastes decay under anaerobic conditions in landfills. About a third of anthropogenic emissions of methane in the EU can be attributed to this source. In contrast, only 1% of nitrous oxide emissions and less than 0.5% of carbon dioxide emissions are associated with solid waste disposal.
For this reason it is often assumed that reducing the amount of methane emitted from landfills would have the greatest potential for reducing the overall climate change impacts of solid waste management. Furthermore, because the atmospheric lifetime of methane is relatively short (only 12 years), it is estimated that overall emissions would need to be reduced by about 8 % from current levels to stabilise methane concentrations at today’s levels. This is a much smaller percentage reduction than those needed to stabilise the concentrations of the other two major GHGs, carbon dioxide and nitrous oxide (Smith, Brown, Ogilvie and others 2001).
These correlations will be further investigated within this report by assessing the climate change impact associated with the management of municipal solid waste (MSW), using England, Germany and Bulgaria as representatives for the EU.
Waste management policy in the EU enshrines the principles of sustainable development in the familiar waste management hierarchy (cp. Figure 1). The hierarchy of waste management options places the greatest preference on waste prevention. Where wastes cannot be prevented, the order of preference decreases re-use, recycling, recovery of energy and finally (as the least preferred option) the disposal in landfills of stabilised wastes from which no further value can be recovered. With some 60% of MSW within the EU still being disposed of to landfill without any form of pre-treatment and extensive reliance on incineration for treatment of most of the remainder, it is clear that there is considerable scope for improvement (Smith, Brown, Ogilvie and others 2001).
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Figure 1: Waste Hierarchy
To evaluate the global warming potential (GWP) related to the management of MSW a Life Cycle Assessment (LCA) of the actual waste management policies and of different scenarios based on either European or national legislation were performed. For the purpose of calculating the GHG emissions the computer model IWM-2 (McDougall, White, Franke and others 2001) was applied.
In line with the LCA the following treatment options capable for MSW management were investigated:
- collection/transportation,
- sorting,
- biological treatment:
- composting,
- mechanical biological treatment (MBT),
- anaerobic digestion (AD),
- thermal treatment:
- Refused Derived Fuel (RDF),
- incineration with energy recovery,
- incineration without energy recovery,
- landfilling, and
- recycling.
Whereas within all treatment options a certain amount of GHGs will be generated, anaerobic digestion, the use of refuse derived fuel and incineration with energy recovery will additionally due to the generation of energy and thus the avoidance of energy from fossil fuels lead to some negative GHG fluxes. This applies also to composting, where peat or inorganic fertilisers could be substituted and to material recycling as a replacement of 'virgin' materials.
MSW as the investigated media was chosen, because it is amongst the most heterogeneous waste streams and is subjected by current legislation measures.
1.1 Objectives
The main objectives of this report were:
- to identify the actual situation for the three investigated countries by evaluating national and European statistics,
- to evaluate GHG emissions generated or avoided by present MSW management strategies,
- to assess European and national legislation, which could be applied on MSW with regard to GHG emissions,
- to create scenarios based on the individual actual MSW management policies to comply with respective environmental legislation,
- to assess changes in GHG generation achieved by measures set in legislation,
- and to compare the scenarios in order to draw conclusions on the performance of different MSW management strategies.
1.2 Aim
The overall aim of this report was to examine in how far either European or national legislation is capable to improve the actual environmental situation with regard to GHG emissions released by the management of MSW and to draw conclusions on which waste management options should be preferred.
2 Literature Review
With regard to the LCA established in the subsequent chapters, a tremendous number of papers was reviewed. The most relevant conclusions could be summarised as follows:
Finnveden, Johannson, Lind and others as well as McDougall, White, Franke and others (2001) draw the conclusion that the waste hierarchy should be only applied as a rule of thumb.
The main source of GHG emissions from the waste sector is methane generated in landfill sites (Hendriks, de Jager, Blok and others 2001).
Crowe, Nolan, Collins and others (2002) declare that biological treatment options rely significantly on the purification of the treated waste fraction and thus should be collected separately.
By Sundqvist it is mentioned that the GHG emissions based on the transport effort is of very low importance in comparison to the whole waste management system. This applies to MSW collection by Local Authorities and to subsequent transport measures. Only the energy consumption of private transport by the use of source segregated collection via material bank site collection schemes must be considered.
Sundqvist further concludes that if there is any possibility to incinerate, material recycle, anaerobically digest or compost waste, it should not be landfilled. This is valid even, if the generated landfill gas is collected and used for energy recovery, and the leachate is collected and treated appropriate.
Smith, Brown, Ogilvie and others (2001) note that the treatment of source segregated MSW followed by recycling for paper, metals, textiles and plastics; and by composting / anaerobic digestion of putrescible wastes gives the lowest net flux of GHGs, compared with other options for the treatment of bulk MSW.
The conclusions from Ackerman, Barlaz, Boguski and others (1998) are that source reduction represents the best option for treating MSW with regard to the generation of GHGs. Recycling generally has the second lowest GHG emissions. The net GHG emissions from incineration with energy recovery and landfilling are similar for mixed MSW.
Finnveden, Johannson, Lind and others (2005) state that recycling of paper and plastics is favourable and that incineration should be preferred for landfilling.
By Finnveden and Björklund (2004) it is mentioned that producing material from recycled resources is less energy intensive than from virgin raw materials.
If the above mentioned statements were justified by the LCA applied within this report will be discussed in the Results and Discussion chapter.
3 Life Cycle Assessment
A sustainable development of waste management schemes needs to consider all related economic, social and environmental aspects to achieve the greatest possible synergies. The environmental impacts and burdens of such a system can be assessed by the use of Life Cycle Assessment.
LCA represents a process to assess the potential environmental burdens associated with a product, a process or an activity. Characteristic parts in a LCA are identifying and quantifying energy and material flows, and evaluating the environmental impacts associated with these flows. The assessment should encompass the entire life cycle of the studied system, including material and energy raw ware acquisition, manufacturing, usage and waste treatment (Sundqvist).
For the purpose of this report different waste management strategies and systems were investigated by the use of the Life Cycle Inventory (LCI) tool IWM-2 created by McDougall, White, Franke and others.
The aim of the analysis was to evaluate the respective impacts on climate change associated with the MSW management policies implemented by the three investigated countries (England, Germany and Bulgaria). Subsequently, using the actual situations as baseline scenarios, the influence of legislation, either national or European, was appraised (cp. Figure 2). To enable comparisons the results were expressed in terms of kg CO2-equivalent per tonne waste managed, which forms the functional unit of the LCA. The system boundaries were defined as follows. The 'cradle' or starting point of the LCA is where the product loses its inherent value or function and therefore becomes waste. The 'grave', where the LCA ends, is described as the stage when the actual waste becomes inert and does no longer form any source of further emissions. The entire system boundaries can be seen from Table 2.
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Figure 2: Methodology of the Life Cycle Assessment
The considered waste stream, the scope of the LCA, was MSW, which includes household waste and any other wastes collected by a Waste Collection Authority, or its agents, such as municipal parks and garden waste, beach cleansing waste, commercial or industrial waste and waste resulting from the clearance of fly-tipped materials (Department for Environment, Food and Rural Affairs (Defra) 2004). Because the IWM-2 model does not provide a platform for the management and recycling of Waste Electrical and Electronic Equipment (WEEE), these were added to the 'others fraction'.
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The available treatment and disposal options investigated in line with the LCA and their likely GHG emissions are described subsequently.
3.1 Technologies
MSW is treated in different ways in different countries in the EU and the Accession States. The variation across countries reflects a combination of:
- differing levels of emphasis on source separation, enabling different approaches to treatment of waste; and
- different approaches, relating to historical, economic, geological and cultural factors, to waste treatment (Hogg, Favoino, Nielsen and others).
The main waste management options available for the treatment and disposal of MSW and their likely GHG emissions can be summarised as follows.
3.1.1 Material Recovery Facilities
To recover valuables inherent in waste and to facilitate subsequent treatment options, waste has to be sorted. This applies in particular to municipal solid waste and especially to household waste, which is amongst the most heterogeneous waste streams in terms of material composition. Beside home sorting via kerbside collection schemes or by the use of bring sites, sorting can also occur as a primal stage of many waste treatment processes.
A centralised approach to deal with pre-sorted or commingled collected waste are Material Recovery Facilities (MRFs) and Refuse Derived Fuel (RDF) manufacturing plants. Common techniques used to separate the recyclables are screening, air classification, air knife, sink/float separation, flotation, magnetic separation, electromagnetic separation, electrostatic separation, detect and route systems and others (McDougall, White, Franke and others 2001).
3.1.2 Biological Treatment
The treatment of biodegradable MSW is performed mainly by applying one of the following three options:
- Composting:
Composting represents the oxidisation of putrescibles by aerobic micro-organism to CO2 and water vapour. The residue is a humic substance that can be used as fertiliser or soil conditioner. Centralised composting can be undertaken in open heaps that are turned and mixed mechanically (windrows), or alternatively in closed vessels with internal mixing, irrigation and aeration (Smith, Brown, Ogilvie and others 2001).
- Anaerobic Digestion:
Like composting AD is based on microbial decomposition, but it takes place in sealed vessels in the complete absence of air (anaerobic conditions). The process converts biodegradable waste to biogas containing mainly methane and CO2. The biogas can be used as fuel, potentially displacing fossil-fuels. The volume-reduced solid residue can be used like compost, but usually requires a period of maturation by composting (Smith, Brown, Ogilvie and others 2001).
To guarantee the later use in agriculture or horticulture the composting and AD rely significantly on the quality of the input (no contaminants such as plastics, metals,…). Thus, source segregated collection of garden and food waste is essential for these processes.
The use of compost from waste may have beneficial effects on greenhouse gas fluxes by replacing other products like fertiliser and peat and may also lead to an increased storage of carbon in the soil (carbon sequestration) (Smith, Brown, Ogilvie and others 2001).
- Mechanical Biological Treatment:
Bulk MSW, or residual wastes enriched in putrescible materials after the removal of dry recyclables, is subjected to a prolonged composting or digestion process which reduces the biodegradable materials to an inert, stabilised compost residue. By the mechanical pre-treatment metals, plastics and other materials are recovered for recycling or either are directed to landfill or incineration (Smith, Brown, Ogilvie and others 2001).
The compost, which, because of its poor quality, is not marketable, is landfilled. Compared with untreated waste, MBT results in a significant reduction in the methane forming potential in the landfill.
Within the biological treatment as a whole GHG emissions (CO2) occur through biodegradation of putrescible material and through energy consumption for process control. Because the generated methane from the biogasification process is used for energy recovery, it can be neglected.
3.1.3 Thermal Treatment
Thermal treatment of solid waste consists of at least three processes:
- Incineration with Energy-Recovery
MSW incineration processes are dominated by the so-called "mass-burn" technologies. These systems accept solid waste with little pre-processing treatment other than the removal of recyclable material and bulky items. A typical mass-burn incinerator uses a single large furnace with an inclined moving or roller grate system (McDougall, White, Franke and others 2001). Each grate design aims to move the waste through the combustion chamber with maximum exposure to oxygen at a high temperature. The residues are ash and flue gases to be quenched prior to cleaning and emission to atmosphere. Energy recovery is obtained by the combustion gases, transferring their heat to refractory-lined water tube sections as well as convective heat exchangers - both of which feed a boiler. Steam from the boiler can be used for district heating or in a turbine for power production to an electricity grid (Hogg, Favoino, Nielsen and others).
- Incineration without Energy-Recovery
Similar to above without the usage of thermal energy.
- Refuse Derived Fuels:
Refuse Derived Fuel (RDF) is manufactured by sorting wastes to remove wet putrescibles and heavy inerts (stones, glass,…) so as to leave combustible material. The remaining waste is then shredded and either burned directly as coarse RDF (cRDF), or pelletised prior to combustion, dense RDF (dRDF). RDF may be incinerated in dedicated facilities or in co-incineration plants such as kilns of the cement industry.
The manufacture of RDF is often an objective of MBT plants (Hogg, Favoino, Nielsen and others).
The main advantages of the thermal treatment options are the volume reduction of up to 90%, the stabilisation (no putrescibles are left to form CH4 within the landfill), the recovery of energy – where this is applied – and the sterilisation of the waste (McDougall, White, Franke and others 2001).
Disadvantages are the emissions of CO2 due to the combustion of fossil-derived wastes for example plastics and the generation of N2O (Smith, Brown, Ogilvie and others 2001).
3.1.4 Landfilling
Whereas landfilling is the only waste disposal method that can deal with all materials present in solid waste streams, it is also causing the greatest impact on climate change.
Within the landfill decaying wastes use up the oxygen entrained within the waste mass. Thus, the waste continues to degrade under anaerobic conditions, what results in the production of landfill gas, which contains roughly 50% methane and 50% carbon dioxide. In sites with no gas control, the gas migrates to the surface of the landfill site and is released to atmosphere. In sites with gas control, a low permeability cover prevents gas releases and a system of wells and pumps is used to extract the gas. The collected gas is either flared or combusted for energy recovery. But even at landfill sites equipped with gas collection measures some gas may escape uncontrolled through cracks or imperfections in the surface layers (Smith, Brown, Ogilvie and others 2001).
3.1.5 Recycling
Recycling saves energy, hence emissions of GHGs and other pollutants, prolongs reserves of fossil raw material sources and avoids impacts associated with the extraction of virgin feedstock.
Recycling of materials from the municipal solid waste stream generally involves the following steps:
- separate collecting of recyclables from individual households and transporting to a place for further treatment,
- sorting, baling and bulking for onward transfer to re-processors (e.g. at a Materials Recycling Facility,
- reprocessing to produce marketable materials and products.
The Life Cycle Inventory Analysis performed for the need of this report considered recycling of paper and cardboard, glass, ferrous and non-ferrous metals, film and rigid plastics, textiles and bottom ash.
3.2 Actual Situation
The assessment of the actual situations for MSW management is mainly based on statistical data provided by European and national administration bodies responsible for environmental protection or statistics. The most topical presented data are available for the period of 2002 / 2003, which were used to create the baseline scenarios.
The energy related input values as well as the calculations for material bank collection, transport distances and packaging waste can be found in the Appendices.
3.2.1 England
Because of the federal system of the United Kingdom with varying environmental legislation for England Wales, Scotland and Northern Ireland, this report focus entirely on England. Although, England and Wales are subjected to the same legislation, only England was utilised for this report. This approach can be justified by the fact that the provided statistics for England and Wales differ decisively in the use of units and in the depth of survey. But because the amount of MSW arising in Wales (1.79 million tonnes) represents only 5.8% of the total MSW generated in England and Wales altogether (31.1 million tonnes), this measure seems to be acceptable (National Assembly for Wales 2004; Department for Environment, Food and Rural Affairs (Defra) 2004).
- Waste Inputs:
England posses 49,753,000 inhabitants (National Statistics 2000) and an average household size of 2.4 people per household (United Nations Economic Commission for Europe (UK) 2005). Consequently, 20,730,417 households has to be served by local waste collection authorities.
The quantity of collected household waste equals 434.1 kg per person and year. In addition about 4,216,567 tonnes are delivered by the producers and 3,490,000 tonnes of commercial waste are collected separately (Department for Environment, Food and Rural Affairs (Defra) 2004). The overall composition of the MSW can be seen from Figure 3.
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Figure 3: Composition of MSW in England
- Waste Collection:
Collection is an important subject of MSW management systems as it determines, which further treatment options can be applied (McDougall, White, Franke and others 2001).
The materials collected separately via kerbside or bank collection schemes as well as the percentage of connected households are shown in Table 3
Table 3: Collection of Recyclables (Eng actual situation)
illustration not visible in this excerpt The fact that the Kerbside Collection System #1 was used as restwaste ton, is not permitted by the inventers of the model, but due to the fact that in Bulgaria not all households are served by waste collection schemes, this approach was used to deal with that problem.
In England recovery of materials from delivered bulky waste does only occur in some model regions (Reeve 2004). Therefore, in the LCA no recovery of bulky waste was applied. For the residue treatment it was assumed that 17% are incinerated and 83% are going to landfill. These figures describe the overall proportion of theses two treatment processes applied for MSW management in England (Department for Environment Food and Rural Affairs (Defra) 2004).
Assuming that 90% of non-household waste is construction waste, the material recovered from commercial waste were calculated by multiplying the total amount with 0.1 times the recycling rate of the different materials, provided in the Municipal Waste Management Survey 2003/04 (Department for Environment Food and Rural Affairs (Defra) 2004). The results can be found in Table 4.
Table 4: Recovery of Commercial MSW (Eng actual situation)
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- Material Recovery Facilities:
MRF:
Applying the best case, for all scenarios it was assumed that 100% of the paper and plastic outputs are used for recycling. The residue treatment was performed as for bulky waste (17% incineration and 83% landfill).
RDF:
87,000 tonnes of MSW are used for RDF manufacturing (Department for Environment Food and Rural Affairs (Defra) 2004), this represents 0.4% of the restwaste. The fines generated within this treatment step were added to the biological stream.
- Biological Treatment:
To comply with the Municipal Waste Management Survey 2003/04 (1,187 thousand tonnes), 96.5% of the separately collected biowaste was assumed to be composted, the residue 3.5% were sent to landfill. No additional household waste was added at this stage. Because the biowaste fraction used was source segregated 100% of the compost residue is marketable.
- Thermal Treatment:
In total 2,614 thousand tonnes of MSW are incinerated. This correspond to 8.9% of restwaste added to the thermal treatment processes. 7,000 tonnes (0.3%) are incinerated without energy recovery, which enter incineration process #2.
Ferrous metal recovery from incinerator bottom ash was assumed at 90%. Because of the pronounced public offence against incineration, the re-use of bottom-ash was limited to 10% (The National Society for Clean Air and Environmental Protection (NSCA) 2005).
- Landfill:
The applied landfill gas collection performance is 33.3%, of which 7.1% recover energy (Environment Agency - 1 2005; Select Committee on Environment and Food and Rural Affairs 2005; the wasteguide 2005). For the collection of leachate 90% for non-hazardous and 99% of hazardous landfills were assumed (Aprili, Bergonzoni, Buttol and others 2005).
Due to the fact that about 2,966,109,920 Nm3 of landfill gas is produced and that the IWM-2 cannot deal with landfill gas amounts greater than 999,999,999 Nm3, for all English scenarios modified scenarios were applied. In the modified scenarios all mass and volume related figures were reduced to 10% of the actual values. The modified scenarios were only used to calculate the GHG emissions produced from landfill sites. The deviation on the landfill inputs can be seen from Table 5.
Table 5: Deviation of Input to Landfill - English Scenarios
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- Recycling:
For recycling the default values of the IWM-2 model were used.
The determined GHG emissions released from the individual treatment steps can be seen from Figure 4. The figure justifies the significance of methane for the calculation of the GWP, because though 'only' 5.8 million tonnes of CO2 and 0.7 million tonnes of CH4 were generated the GWP is about four times greater.
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Figure 4: Global Warming Potential of England's actual situation
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