Environmental benefits of recycling

Environmental benefits of recycling

Environmental benefits of recycling

255 Pages ·2010·2.1 MB ·English

Environmental benefits of recycling


Final report


Environmental benefits of


recycling – 2010 update



An update to the 2006 WRAP report Environmental Benefits of Recycling, reviewing


high quality Life Cycle Assessments from around the world to assess the impact of


alternative waste management options for a range of materials, and discuss the


findings for each material in the context of the UK.





Project code: SAP097


Research date: March- December 2009 Date: March 2010



WRAP’s vision is a world without waste,


where resources are used sustainably.



We work with businesses and individuals


to help them reap the benefits of reducing


waste, developing sustainable products


and using resources in an efficient way.



Find out more at www.wrap.org.uk






























Written by: Jean-Charles Michaud, Laura Farrant and Olivier Jan from Bio Intelligence Service


Birgitte Kjær and Ioannis Bakas, from the Copenhagen Resource Institute






Front cover photography:



WRAP, Bio Intelligence Service, and Copenhagen Resource Institute believe the content of this report to be correct as at the date of writing. However, factors such as


prices, levels of recycled content and regulatory requirements are subject to change and users of the report should check with their suppliers to confirm the current


situation. In addition, care should be taken in using any of the cost information provided as it is based upon numerous project-specific assumptions (such as scale,


location, tender context, etc.). The report does not claim to be exhaustive, nor does it claim to cover all relevant products and specifications available on the market.


While steps have been taken to ensure accuracy, WRAP cannot accept responsibility or be held liable to any person for any loss or damage arising out of or in connection


with this information being inaccurate, incomplete or misleading. It is the responsibility of the potential user of a material or product to consult with the supplier or


manufacturer and ascertain whether a particular product will satisfy their specific requirements. The listing or featuring of a particular product or company does not


constitute an endorsement by WRAP and WRAP cannot guarantee the performance of individual products or materials. This material is copyrighted. It may be reproduced


free of charge subject to the material being accurate and not used in a misleading context. The source of the material must be identified and the copyright status


acknowledged. This material must not be used to endorse or used to suggest WRAP’s endorsement of a commercial product or service. For more detail, please refer to


WRAP’s Terms & Conditions on its web site: www.wrap.org.uk




Executive summary


Context



In 2006, WRAP (Waste & Resources Action Programme) published a major research report, Environmental


Benefits of Recycling, based on an international review of life cycle analyses (LCA) that evaluated the impact on


the environment of recycling, landfilling or incineration of key materials in UK waste streams. The review


assessed 55 ‘state of the art’ LCAs on paper and cardboard, glass, plastics, aluminium, steel, wood and


aggregates. The conclusion was clear – most studies show that recycling offers more environmental benefits and


lower environmental impacts than the other waste management options.



With the emergence of new waste management options and new waste streams in the last three years, WRAP


has decided to update this report and ensure that policy makers and stakeholders are aware of the latest


conclusions from LCA data on waste management options. The methodology behind the new report remains the


same1 – careful screening of over 200 LCAs published worldwide since 2006 against strict criteria to focus on only


the highest quality analyses. However, the scope of the review was changed in several ways:



uf06e New waste management technologies were added: composting and energy from waste (EfW) technologies


such as anaerobic digestion, pyrolysis and gasification.


uf06e New waste streams/materials were added: food waste, garden waste, textiles and biopolymers.


uf06e Some materials were excluded from further analyses – aluminium, steel, glass and aggregates – as the results


of the first study (that recycling is the preferred waste management option for these materials) are not


impacted by the new technologies.



In summary, the material / technology combinations of this study are shown in the following table (those


included in the first report are highlighted in grey)



Anaerobicxa0


Recycling Composting Incinerationxa0 Landfill Pyrolysis Gasification


digestion


Paperxa0andxa0card x x x


Plastics x x x x


Biopolymers x x x x x


Foodxa0andxa0gardenxa0waste x x x x


Woodxa0 x x x


Textiles x x x



The key impact categories used for the assessment of the different waste management options were:



uf06e depletion of natural resources


uf06e climate change potential


uf06e cumulative energy demand


uf06e water consumption








1 The criteria used for the selection were: (i) the study had to be an LCA or LCA-like; (ii) includes a comparison of two or


more end-of-life scenarios for the material fraction under study; (iii) representation of recycling or composting among the


waste management options assessed; (iv) robustness of the publication, either peer reviewed or published in a scientific


journal; (v) transparency in the assumptions made; (vi) primary research and not a review of previous work; (vii) no


ambiguity in the way impacts are ascribed to materials; (viii) plausibility of the waste management options.



Environmental benefits of recycling – 2010 update 1


Key conclusions from the LCA studies



Because of the international nature of the study, the review has attempted to interpret the results in terms of UK


impact. The key parameter in this respect in the energy mix used in the scope of a specific LCA, which might be


quite different from that in the UK. The key conclusions are outlined below by material/waste type.



Paper and cardboard



uf06e The results of the first study are confirmed in that landfilling of paper and cardboard is the least preferable


option, particularly from a climate change potential and energy demand perspective.


uf06e The comparison between recycling and incineration appears more complex, as better energy recovery


efficiencies have been built into the more recent LCAs. In general, the data shows that recycling is preferable


for energy demand and water consumption, but they are comparable for climate change.


uf06e The key parameter affecting the comparison between these two alternatives is the energy mix used in


recycling and virgin paper manufacture. Where the energy recovered through incineration replaces the use of


fossil fuels (as in the UK), the environmental benefits are augmented, especially with regard to climate


change potential and depletion of natural resources.


uf06e The type of paper and card also has a significant influence. For example, it is more beneficial from an


environmental point of view to recycle high quality products such as office paper.


uf06e Looking to the future, as the UK moves to a lower-carbon energy mix, collection quality improves and


recycling technology develops, then recycling will become increasingly favoured over energy recovery for all


impact categories



Plastics



uf06e The results confirm that mechanical recycling is the best waste management option in respect of the climate


change potential, depletion of natural resources and energy demand impacts. The analysis highlights again


that these benefits of recycling are mainly achieved by avoiding production of virgin plastics.


uf06e The environmental benefits are maximised by collection of good quality material (to limit the rejected fraction)


and by replacement of virgin plastics on a high ratio (1 to 1).


uf06e Incineration with energy recovery performs poorly with respect to climate change impact, but pyrolysis


appears to be an emerging option regarding all indicators assessed, though this was only analysed in two LCA


studies.


uf06e Landfill is confirmed as having the worst environmental impacts in the majority of cases.


uf06e As the UK moves to a lower-carbon energy mix, recycling will become increasingly favoured.



Biopolymers



uf06e Although biopolymers are only just emerging in the various waste streams, the limited data shows the good


environmental performances of mechanical and chemical recycling regarding energy demand, depletion of


natural resources and climate change potential.


uf06e However, for LCA studies that did not consider recycling as an option in the analysis, the data shows that


incineration is a preferred option.


uf06e A main advantage of biopolymers that is often highlighted is the fact that some of them are degradable or


compostable. Nevertheless, the analysis pointed out that composting does not appear to be advantageous for


energy demand and depletion of natural resources compared to the other alternatives.


uf06e Two studies also assessed anaerobic digestion. The results for these scenarios showed that anaerobic


digestion performs better than composting regarding both indicators analysed: climate change potential and


energy demand. The advantage of anaerobic digestion over composting comes from the recovery of the


biogas produced via electricity and heat production.



Food & garden waste



uf06e Anaerobic digestion probably qualifies as the most preferable option, especially for climate change potential


and depletion of natural resources. However, this conclusion should be qualified by the fact that this option


was included in less than half of the selected studies.


uf06e Composting brings benefits as a result of the compost that can be used as a substitute for products such as


peat or fertilisers. However, as composting is not associated with energy recovery, it generally does not


perform well compared to the other options for depletion of natural resources and energy demand.


Environmental benefits of recycling – 2010 update 2


uf06e Following anaerobic digestion; composting and energy recovery are generally comparable in their contribution


to climate change potential.


uf06e The analysis also highlighted that home compost bins should be properly managed (aerated and with a mix of


input materials) to avoid anaerobic conditions forming, leading to methane emissions.


uf06e Incineration with energy recovery presents another good environmental performance for the four indicators,


despite the relatively low heating value. The key parameter, especially regarding climate change potential, is


the energy mix. The benefits brought by incineration are greater if the energy produced substitutes fossil


energies.



Wood



uf06e Based on the lack of published LCAs, recycling of wood waste has been given little attention by LCA


practitioners. As a result, a comparative analysis between the waste management options for wood waste


could not be conducted.


uf06e However, from the data available, the key conclusion is that incineration with energy recovery is preferable


for energy demand while recycling is preferable for climate change potential. On the other hand, landfill is to


be avoided due to the associated methane emissions. Analysis of a larger set of indicators would be required


in order to be able to come up with reliable evidence of the benefits of wood recycling.



Textiles



uf06e There is a large gap in terms of LCAs conducted over the waste management options for textiles. Of interest


is that no study has been found assessing ‘closed-loop’ recycling, whereby recycled fibres are used in the


manufacture of new clothing.


uf06e Despite this lack of data, four studies were reviewed to provide a qualitative comparison of the environmental


impacts of different options. The overall conclusion is that textile recycling brings substantial environmental


benefits. The scale of the benefits mainly depends on the recovery routes and the material production that is


avoided.



General conclusion and recommendations



This report reinforces the key conclusion of the first report that recycling of paper/cardboard, plastics and


biopolymers for most indicators assessed provides more environmental benefits than other waste management


options. For wood and textiles, more studies are needed to be able to make firmer conclusions regarding the


environmental benefits of recycling for these materials.



It is disappointing to note that there are very few LCAs which include an assessment of more innovative


technologies such as gasification, pyrolysis and anaerobic digestion. This probably reflects the requirement for a


lot of process data to model a particular option, which can be sparse in the case of the newer technologies.


However, the results of the few selected studies that included anaerobic digestion and pyrolysis are very


encouraging.



There needs to be a stronger evidence base on certain materials (textiles, biopolymers and wood) and the more


innovative EfW technologies. LCA studies need to focus on a larger set of indicators rather than only on climate


change potential or energy demand. There are also LCA methodological issues that need clarification, such as the


treatment of biogenic carbon and the time period considered for landfill impacts; greater clarity on these matters


will help in the comparison of waste management options.



Environmental benefits of recycling – 2010 update 3



Contents


1.0xa0 Introduction.............................................................................................................................6xa0


2.0xa0 Methodology for the selection and assessment of LCA studies...............................................7xa0


2.1xa0 Literature review...................................................................................................................7xa0


2.2xa0 Publications selection criteria..................................................................................................7xa0


2.2.1xa0 The study was an LCA or LCA-like study.....................................................................7xa0


2.2.2xa0 The study included a comparison of two or more end-of-life scenarios for the material


under study...........................................................................................................................8xa0


2.2.3xa0 Transparency in the assumptions made......................................................................8xa0


2.2.4xa0 No ambiguity in the way impacts are ascribed to materials..........................................8xa0


2.2.5xa0 Plausibility of the waste management options.............................................................9xa0


2.3xa0 Analysis of the selected studies..............................................................................................9xa0


3.0xa0 Results of the comparative analysis of the selected publications.........................................11xa0


3.1xa0 Introduction to the methodology used for results comparison................................................11xa0


3.2xa0 Paper and carboard.............................................................................................................12xa0


3.2.1xa0 Presentation...........................................................................................................12xa0


3.2.2xa0 Comparison between the various end-of-life options.................................................13xa0


3.2.3xa0 Detailed comparison between the various treatment options.....................................17xa0


3.2.4xa0 Conclusion..............................................................................................................29xa0


3.2.5xa0 Comparison with the results from the previous report edition....................................30xa0


3.2.6xa0 Data gaps/further research......................................................................................31xa0


3.3xa0 Plastics...............................................................................................................................32xa0


3.3.1xa0 Presentation...........................................................................................................32xa0


3.3.2xa0 Comparison between the various end-of-life options.................................................33xa0


3.3.3xa0 Detailed comparison between the various treatment options.....................................38xa0


3.3.4xa0 Conclusion..............................................................................................................53xa0


3.3.5xa0 Comparison with the results from the previous report edition....................................54xa0


3.3.6xa0 Data gaps/further research......................................................................................54xa0


3.4xa0 Biopolymers........................................................................................................................55xa0


3.4.1xa0 Presentation...........................................................................................................55xa0


3.4.2xa0 Comparison between the various end-of-life options.................................................57xa0


3.4.3xa0 Detailed comparison between the various treatment options.....................................60xa0


3.4.4xa0 Conclusion..............................................................................................................73xa0


3.4.5xa0 Data gaps/further research......................................................................................73xa0


3.5xa0 Food and garden waste.......................................................................................................74xa0


3.5.1xa0 Presentation...........................................................................................................74xa0


3.5.2xa0 Comparison between the various end-of-life options.................................................76xa0


3.5.3xa0 Detailed comparison between the various treatment options.....................................78xa0


3.5.4xa0 Conclusion..............................................................................................................90xa0


3.5.5xa0 Data gaps/further research......................................................................................91xa0


3.6xa0 Wood..................................................................................................................................92xa0


3.6.1xa0 Presentation...........................................................................................................92xa0


3.6.2xa0 Comparison between the various end-of-life options.................................................93xa0


3.6.3xa0 Comparison with the results from the previous report edition....................................94xa0


3.6.4xa0 Data gaps/further research......................................................................................94xa0


3.7xa0 Textiles...............................................................................................................................96xa0


3.7.1xa0 Presentation...........................................................................................................96xa0


3.7.2xa0 Comparison between the various end-of-life options.................................................97xa0


3.7.3xa0 Data gaps/further research......................................................................................99xa0


4.0xa0 Relevance of the findings in the UK context........................................................................100xa0


4.1xa0 The UK context.................................................................................................................100xa0


4.1.1xa0 Waste management..............................................................................................100xa0


4.1.2xa0 Environmental challenges in relation to waste management....................................100xa0


4.1.3xa0 Waste strategy.....................................................................................................102xa0


4.1.4xa0 Summing up: influence of the UK policy on end-of-life options.................................103xa0


4.2xa0 Relevance of findings in the UK context for paper and cardboard.........................................103xa0


4.3xa0 Relevance of findings in the UK context for plastics.............................................................107xa0


Environmental benefits of recycling – 2010 update 4


4.4xa0 Relevance of findings in the UK context for biopolymers......................................................110xa0


4.5xa0 Relevance of findings in the UK context for food and garden waste......................................112xa0


4.6xa0 Relevance of findings in the UK context for wood................................................................115xa0


4.7xa0 Relevance of findings in the UK context for textiles..............................................................118xa0



Appendix 1 Description of the selected environmental indicators................................................... 126


Appendix 2 Summary of key elements from the studies on paper & cardboard...............................127


Appendix 3 Summary of key elements from the studies on plastics.................................................158


Appendix 4 Summary of key elements from the studies on biopolymers.........................................199


Appendix 5 Summary of key elements from the studies on food & garden waste...........................224


Appendix 6 List of selected studies...................................................................................................238


Appendix 7 List of rejected studies...................................................................................................241








Environmental benefits of recycling – 2010 update 5



1.0 Introduction



From the point of view of sustainable development, improving waste management is essential if society’s


environmental impacts are to be reduced. Identifying waste management channels with lower environmental


impacts is thus a key issue. The waste hierarchy illustrated in Figure 1 is often used as a rule of thumb followed


by public policies. However, a recurring theme in the debates that surround waste and resources management is


the extent to which the recycling of materials offers genuine benefits to the environment. Often, critics of the


policy drive towards greater recycling assert that the act of recycling may in fact have little or no benefit to the


environment, suggesting that more energy may be used in getting materials to the recycling facility than is saved


by the process of recycling.



Figure 1 Schematic diagram showing the waste hierarchy



In order to compare waste management routes in environmental terms, the Life Cycle Assessment (LCA)


methodology is currently seen as the best approach to use. The strength of LCA is that the methodology allows


comparison of two or more different products or processes by quantifying the service given by the products or


processes. The weakness of LCA is that the results of the assessment are very sensitive to the scope of the study,


to the hypothesis made, etc. To compare environmental impacts of numerous waste management routes, one


solution is to review and compare existing Life Cycle Assessment (LCA) studies on waste management and to


analyse the impacts of each hypothesis.



To analyse the different burdens or benefits of each waste management option, WRAP (Waste & Resources


Action Programme) reviews and commissions relevant LCAs. The purpose of this study is to update the


Environmental Benefits of Recycling published by the WRAP in 2006. This study reviews LCA studies and


compares the various possible options for waste management. This study was undertaken by Bio Intelligence


Service (BIOIS) and the Copenhagen Resource Institute (CRI, former Danish Topic Centre on Waste and


Resources). Collaboration with WRAP took place throughout the study.



Materials covered by this study are paper and cardboard, plastics, biopolymers, food and garden waste, wood


and textiles. The waste management options that are studied are composting, energy recovery (incineration,


anaerobic digestion, pyrolysis and gasification), landfill and recycling. Table 1 shows the combinations of


materials and treatment options covered in the study (the combinations materials/disposal options included in the


previous edition are highlighted in grey). Some options, such as gasification or pyrolysis, could in theory be used


for most of the fractions but the literature review has pointed out large data gaps, therefore these options could


not be assessed.











Environmental benefits of recycling – 2010 update 6




Table 1 Overview of the materials and treatment options under study


Anaerobicxa0


Recycling Composting Incinerationxa0 Landfill Pyrolysis Gasification


digestion


Paperxa0andxa0card x x x


Plastics x x x x


Biopolymers x x x x x


Foodxa0andxa0gardenxa0waste x x x x


Woodxa0 x x x


Textiles x x x





2.0 Methodology for the selection and assessment of LCA studies



2.1 Literature review



The main objective of this step was to identify all published LCA studies that compare two or more waste


management options for one or more fractions included in the field of this review.



An exhaustive review of LCA publications was carried out using the following sources of information:


uf06e International scientific journals and databases: International Journal of LCA, Science Direct, Springer


uf06e Publications by relevant worldwide organisations in waste management and life cycle assessment:


National Environment Protection Agencies, European Joint Research Center (JRC), DEFRA, WRAP


uf06e BIOIS and CRI’s own databases


uf06e BIOIS and CRI’s contact network


The extensive literature review led to the identification of around 220 studies.



2.2 Publications selection criteria



In order to be able to choose the publications suitable and relevant for analysis, a list of selection criteria was


established. The objective was to narrow the selection to transparent and high-quality studies.



The criteria used for the selection were:


uf06e the study was an LCA or LCA-like study


uf06e the study included a comparison of one or more end-of-life scenarios for the material fraction under


study


uf06e representation of recycling or composting among the waste management options assessed,


uf06e robustness of the publication: the publication should have been either peer reviewed or published in


a scientific journal


uf06e transparency in the assumptions made


uf06e primary research and not a review of previous work


uf06e no ambiguity in the way impacts are ascribed to materials


uf06e plausibility of the waste management options


Further details regarding these selection criteria are given below.




2.2.1 The study was an LCA or LCA-like study



The choice was made to focus on LCA studies because LCA is currently considered as the most reliable method


for analysing the environmental impacts of products and services. One of the main advantages of LCA is that it


enables a quantitative evaluation of potential environmental impacts on several indicators. The LCA methodology


has been standardised by the International Standards Organization (ISO) (ISO 14040 and 14044 standards).


Environmental benefits of recycling – 2010 update 7



Within the requirements of ISO 14040 and 14044, the LCA must consist of the following steps:



uf06e Goal and scope definition which defines the goal and intended use of the LCA, and scopes the


assessment concerning system boundaries, function and flow, required data quality, technology and


assessment parameters,


uf06e Inventory analysis which consists in collecting data on inputs (resources and intermediate


products) and outputs (emissions, wastes) for all the processes in the product system.


uf06e Impact assessment, phase during which inventory data on inputs and outputs are translated into


indicators of potential impacts on the environment, on human health, and on the availability of


natural resources.


uf06e Interpretation of results where the results of the LCI and LCIA are interpreted according to the


goal of the study and where sensitivity and uncertainty analysis are performed to qualify the results


and the conclusions.


In addition, the ISO standards require that LCAs disclosed to the public are submitted to a critical review


performed by independent LCA experts to ensure that the methods and results are scientifically and technically


valid. The fulfilment of the ISO standards is thus a guarantee for quality and transparency. Except for some


studies published by recognised organisations (US EPA for example), the fulfilment of the ISO 14040-series was


required for the publication selection.




2.2.2 The study included a comparison of two or more end-of-life scenarios for the material


under study



In order to be able to conduct a comparison between various end-of-life scenarios, the systems compared must


have the same functional unit and equivalent system boundaries, data quality and impact assessment


methodologies. In practice, it is thus very difficult to compare LCA results for scenarios from different studies. In


the present study, the choice has thus been made to conduct numerical comparisons only for scenarios analysed


in a single publication. This implies that each selected study must include a comparison between at least two


end-of-life options for a given fraction. This criterion was the most restrictive one and some studies of


high quality and interest had to be excluded with respect to this criterion. Nevertheless, it ensured


the overall coherence of the study.




2.2.3 Transparency in the assumptions made



The variability of the results from one LCA study to another is often very high since results are highly dependent


on the assumptions made. It is also common for studies on similar systems to lead to different conclusions. When


conducting comparisons across various studies, it is therefore essential to be able to identify the key parameters


that can explain why conclusions differ from one study to another. The transparency of the assumptions made


was thus considered as an important criterion for the publications selection step. Most identified studies satisfied


this criterion fully but a lack of information in this area was sometimes observed when the study was only


reported in a journal article without an associated report. Requests were made to authors for further information


but this was very difficult obtain, in particular for studies over two years old.




2.2.4 No ambiguity in the way impacts are ascribed to materials



The objective of the study was to come up with an evaluation of the environmentally preferable end-of-life


options for the range of considered fractions. The selected LCAs were thus required to present material-specific


results. High quality LCAs comparing end-of-life options for municipal solid waste as a whole were therefore not


suitable for selection.







Environmental benefits of recycling – 2010 update 8




Final report


Environmental benefits of


recycling – 2010 update



An update to the 2006 WRAP report Environmental Benefits of Recycling, reviewing


high quality Life Cycle Assessments from around the world to assess the impact of


alternative waste management options for a range of materials, and discuss the


findings for each material in the context of the UK.





Project code: SAP097


Research date: March- December 2009 Date: March 2010



WRAP’s vision is a world without waste,


where resources are used sustainably.



We work with businesses and individuals


to help them reap the benefits of reducing


waste, developing sustainable products


and using resources in an efficient way.



Find out more at www.wrap.org.uk






























Written by: Jean-Charles Michaud, Laura Farrant and Olivier Jan from Bio Intelligence Service


Birgitte Kjær and Ioannis Bakas, from the Copenhagen Resource Institute






Front cover photography:



WRAP, Bio Intelligence Service, and Copenhagen Resource Institute believe the content of this report to be correct as at the date of writing. However, factors such as


prices, levels of recycled content and regulatory requirements are subject to change and users of the report should check with their suppliers to confirm the current


situation. In addition, care should be taken in using any of the cost information provided as it is based upon numerous project-specific assumptions (such as scale,


location, tender context, etc.). The report does not claim to be exhaustive, nor does it claim to cover all relevant products and specifications available on the market.


While steps have been taken to ensure accuracy, WRAP cannot accept responsibility or be held liable to any person for any loss or damage arising out of or in connection


with this information being inaccurate, incomplete or misleading. It is the responsibility of the potential user of a material or product to consult with the supplier or


manufacturer and ascertain whether a particular product will satisfy their specific requirements. The listing or featuring of a particular product or company does not


constitute an endorsement by WRAP and WRAP cannot guarantee the performance of individual products or materials. This material is copyrighted. It may be reproduced


free of charge subject to the material being accurate and not used in a misleading context. The source of the material must be identified and the copyright status


acknowledged. This material must not be used to endorse or used to suggest WRAP’s endorsement of a commercial product or service. For more detail, please refer to


WRAP’s Terms & Conditions on its web site: www.wrap.org.uk




Executive summary


Context



In 2006, WRAP (Waste & Resources Action Programme) published a major research report, Environmental


Benefits of Recycling, based on an international review of life cycle analyses (LCA) that evaluated the impact on


the environment of recycling, landfilling or incineration of key materials in UK waste streams. The review


assessed 55 ‘state of the art’ LCAs on paper and cardboard, glass, plastics, aluminium, steel, wood and


aggregates. The conclusion was clear – most studies show that recycling offers more environmental benefits and


lower environmental impacts than the other waste management options.



With the emergence of new waste management options and new waste streams in the last three years, WRAP


has decided to update this report and ensure that policy makers and stakeholders are aware of the latest


conclusions from LCA data on waste management options. The methodology behind the new report remains the


same1 – careful screening of over 200 LCAs published worldwide since 2006 against strict criteria to focus on only


the highest quality analyses. However, the scope of the review was changed in several ways:



uf06e New waste management technologies were added: composting and energy from waste (EfW) technologies


such as anaerobic digestion, pyrolysis and gasification.


uf06e New waste streams/materials were added: food waste, garden waste, textiles and biopolymers.


uf06e Some materials were excluded from further analyses – aluminium, steel, glass and aggregates – as the results


of the first study (that recycling is the preferred waste management option for these materials) are not


impacted by the new technologies.



In summary, the material / technology combinations of this study are shown in the following table (those


included in the first report are highlighted in grey)



Anaerobicxa0


Recycling Composting Incinerationxa0 Landfill Pyrolysis Gasification


digestion


Paperxa0andxa0card x x x


Plastics x x x x


Biopolymers x x x x x


Foodxa0andxa0gardenxa0waste x x x x


Woodxa0 x x x


Textiles x x x



The key impact categories used for the assessment of the different waste management options were:



uf06e depletion of natural resources


uf06e climate change potential


uf06e cumulative energy demand


uf06e water consumption








1 The criteria used for the selection were: (i) the study had to be an LCA or LCA-like; (ii) includes a comparison of two or


more end-of-life scenarios for the material fraction under study; (iii) representation of recycling or composting among the


waste management options assessed; (iv) robustness of the publication, either peer reviewed or published in a scientific


journal; (v) transparency in the assumptions made; (vi) primary research and not a review of previous work; (vii) no


ambiguity in the way impacts are ascribed to materials; (viii) plausibility of the waste management options.



Environmental benefits of recycling – 2010 update 1


Key conclusions from the LCA studies



Because of the international nature of the study, the review has attempted to interpret the results in terms of UK


impact. The key parameter in this respect in the energy mix used in the scope of a specific LCA, which might be


quite different from that in the UK. The key conclusions are outlined below by material/waste type.



Paper and cardboard



uf06e The results of the first study are confirmed in that landfilling of paper and cardboard is the least preferable


option, particularly from a climate change potential and energy demand perspective.


uf06e The comparison between recycling and incineration appears more complex, as better energy recovery


efficiencies have been built into the more recent LCAs. In general, the data shows that recycling is preferable


for energy demand and water consumption, but they are comparable for climate change.


uf06e The key parameter affecting the comparison between these two alternatives is the energy mix used in


recycling and virgin paper manufacture. Where the energy recovered through incineration replaces the use of


fossil fuels (as in the UK), the environmental benefits are augmented, especially with regard to climate


change potential and depletion of natural resources.


uf06e The type of paper and card also has a significant influence. For example, it is more beneficial from an


environmental point of view to recycle high quality products such as office paper.


uf06e Looking to the future, as the UK moves to a lower-carbon energy mix, collection quality improves and


recycling technology develops, then recycling will become increasingly favoured over energy recovery for all


impact categories



Plastics



uf06e The results confirm that mechanical recycling is the best waste management option in respect of the climate


change potential, depletion of natural resources and energy demand impacts. The analysis highlights again


that these benefits of recycling are mainly achieved by avoiding production of virgin plastics.


uf06e The environmental benefits are maximised by collection of good quality material (to limit the rejected fraction)


and by replacement of virgin plastics on a high ratio (1 to 1).


uf06e Incineration with energy recovery performs poorly with respect to climate change impact, but pyrolysis


appears to be an emerging option regarding all indicators assessed, though this was only analysed in two LCA


studies.


uf06e Landfill is confirmed as having the worst environmental impacts in the majority of cases.


uf06e As the UK moves to a lower-carbon energy mix, recycling will become increasingly favoured.



Biopolymers



uf06e Although biopolymers are only just emerging in the various waste streams, the limited data shows the good


environmental performances of mechanical and chemical recycling regarding energy demand, depletion of


natural resources and climate change potential.


uf06e However, for LCA studies that did not consider recycling as an option in the analysis, the data shows that


incineration is a preferred option.


uf06e A main advantage of biopolymers that is often highlighted is the fact that some of them are degradable or


compostable. Nevertheless, the analysis pointed out that composting does not appear to be advantageous for


energy demand and depletion of natural resources compared to the other alternatives.


uf06e Two studies also assessed anaerobic digestion. The results for these scenarios showed that anaerobic


digestion performs better than composting regarding both indicators analysed: climate change potential and


energy demand. The advantage of anaerobic digestion over composting comes from the recovery of the


biogas produced via electricity and heat production.



Food & garden waste



uf06e Anaerobic digestion probably qualifies as the most preferable option, especially for climate change potential


and depletion of natural resources. However, this conclusion should be qualified by the fact that this option


was included in less than half of the selected studies.


uf06e Composting brings benefits as a result of the compost that can be used as a substitute for products such as


peat or fertilisers. However, as composting is not associated with energy recovery, it generally does not


perform well compared to the other options for depletion of natural resources and energy demand.


Environmental benefits of recycling – 2010 update 2


uf06e Following anaerobic digestion; composting and energy recovery are generally comparable in their contribution


to climate change potential.


uf06e The analysis also highlighted that home compost bins should be properly managed (aerated and with a mix of


input materials) to avoid anaerobic conditions forming, leading to methane emissions.


uf06e Incineration with energy recovery presents another good environmental performance for the four indicators,


despite the relatively low heating value. The key parameter, especially regarding climate change potential, is


the energy mix. The benefits brought by incineration are greater if the energy produced substitutes fossil


energies.



Wood



uf06e Based on the lack of published LCAs, recycling of wood waste has been given little attention by LCA


practitioners. As a result, a comparative analysis between the waste management options for wood waste


could not be conducted.


uf06e However, from the data available, the key conclusion is that incineration with energy recovery is preferable


for energy demand while recycling is preferable for climate change potential. On the other hand, landfill is to


be avoided due to the associated methane emissions. Analysis of a larger set of indicators would be required


in order to be able to come up with reliable evidence of the benefits of wood recycling.



Textiles



uf06e There is a large gap in terms of LCAs conducted over the waste management options for textiles. Of interest


is that no study has been found assessing ‘closed-loop’ recycling, whereby recycled fibres are used in the


manufacture of new clothing.


uf06e Despite this lack of data, four studies were reviewed to provide a qualitative comparison of the environmental


impacts of different options. The overall conclusion is that textile recycling brings substantial environmental


benefits. The scale of the benefits mainly depends on the recovery routes and the material production that is


avoided.



General conclusion and recommendations



This report reinforces the key conclusion of the first report that recycling of paper/cardboard, plastics and


biopolymers for most indicators assessed provides more environmental benefits than other waste management


options. For wood and textiles, more studies are needed to be able to make firmer conclusions regarding the


environmental benefits of recycling for these materials.



It is disappointing to note that there are very few LCAs which include an assessment of more innovative


technologies such as gasification, pyrolysis and anaerobic digestion. This probably reflects the requirement for a


lot of process data to model a particular option, which can be sparse in the case of the newer technologies.


However, the results of the few selected studies that included anaerobic digestion and pyrolysis are very


encouraging.



There needs to be a stronger evidence base on certain materials (textiles, biopolymers and wood) and the more


innovative EfW technologies. LCA studies need to focus on a larger set of indicators rather than only on climate


change potential or energy demand. There are also LCA methodological issues that need clarification, such as the


treatment of biogenic carbon and the time period considered for landfill impacts; greater clarity on these matters


will help in the comparison of waste management options.



Environmental benefits of recycling – 2010 update 3



Contents


1.0xa0 Introduction.............................................................................................................................6xa0


2.0xa0 Methodology for the selection and assessment of LCA studies...............................................7xa0


2.1xa0 Literature review...................................................................................................................7xa0


2.2xa0 Publications selection criteria..................................................................................................7xa0


2.2.1xa0 The study was an LCA or LCA-like study.....................................................................7xa0


2.2.2xa0 The study included a comparison of two or more end-of-life scenarios for the material


under study...........................................................................................................................8xa0


2.2.3xa0 Transparency in the assumptions made......................................................................8xa0


2.2.4xa0 No ambiguity in the way impacts are ascribed to materials..........................................8xa0


2.2.5xa0 Plausibility of the waste management options.............................................................9xa0


2.3xa0 Analysis of the selected studies..............................................................................................9xa0


3.0xa0 Results of the comparative analysis of the selected publications.........................................11xa0


3.1xa0 Introduction to the methodology used for results comparison................................................11xa0


3.2xa0 Paper and carboard.............................................................................................................12xa0


3.2.1xa0 Presentation...........................................................................................................12xa0


3.2.2xa0 Comparison between the various end-of-life options.................................................13xa0


3.2.3xa0 Detailed comparison between the various treatment options.....................................17xa0


3.2.4xa0 Conclusion..............................................................................................................29xa0


3.2.5xa0 Comparison with the results from the previous report edition....................................30xa0


3.2.6xa0 Data gaps/further research......................................................................................31xa0


3.3xa0 Plastics...............................................................................................................................32xa0


3.3.1xa0 Presentation...........................................................................................................32xa0


3.3.2xa0 Comparison between the various end-of-life options.................................................33xa0


3.3.3xa0 Detailed comparison between the various treatment options.....................................38xa0


3.3.4xa0 Conclusion..............................................................................................................53xa0


3.3.5xa0 Comparison with the results from the previous report edition....................................54xa0


3.3.6xa0 Data gaps/further research......................................................................................54xa0


3.4xa0 Biopolymers........................................................................................................................55xa0


3.4.1xa0 Presentation...........................................................................................................55xa0


3.4.2xa0 Comparison between the various end-of-life options.................................................57xa0


3.4.3xa0 Detailed comparison between the various treatment options.....................................60xa0


3.4.4xa0 Conclusion..............................................................................................................73xa0


3.4.5xa0 Data gaps/further research......................................................................................73xa0


3.5xa0 Food and garden waste.......................................................................................................74xa0


3.5.1xa0 Presentation...........................................................................................................74xa0


3.5.2xa0 Comparison between the various end-of-life options.................................................76xa0


3.5.3xa0 Detailed comparison between the various treatment options.....................................78xa0


3.5.4xa0 Conclusion..............................................................................................................90xa0


3.5.5xa0 Data gaps/further research......................................................................................91xa0


3.6xa0 Wood..................................................................................................................................92xa0


3.6.1xa0 Presentation...........................................................................................................92xa0


3.6.2xa0 Comparison between the various end-of-life options.................................................93xa0


3.6.3xa0 Comparison with the results from the previous report edition....................................94xa0


3.6.4xa0 Data gaps/further research......................................................................................94xa0


3.7xa0 Textiles...............................................................................................................................96xa0


3.7.1xa0 Presentation...........................................................................................................96xa0


3.7.2xa0 Comparison between the various end-of-life options.................................................97xa0


3.7.3xa0 Data gaps/further research......................................................................................99xa0


4.0xa0 Relevance of the findings in the UK context........................................................................100xa0


4.1xa0 The UK context.................................................................................................................100xa0


4.1.1xa0 Waste management..............................................................................................100xa0


4.1.2xa0 Environmental challenges in relation to waste management....................................100xa0


4.1.3xa0 Waste strategy.....................................................................................................102xa0


4.1.4xa0 Summing up: influence of the UK policy on end-of-life options.................................103xa0


4.2xa0 Relevance of findings in the UK context for paper and cardboard.........................................103xa0


4.3xa0 Relevance of findings in the UK context for plastics.............................................................107xa0


Environmental benefits of recycling – 2010 update 4


4.4xa0 Relevance of findings in the UK context for biopolymers......................................................110xa0


4.5xa0 Relevance of findings in the UK context for food and garden waste......................................112xa0


4.6xa0 Relevance of findings in the UK context for wood................................................................115xa0


4.7xa0 Relevance of findings in the UK context for textiles..............................................................118xa0



Appendix 1 Description of the selected environmental indicators................................................... 126


Appendix 2 Summary of key elements from the studies on paper & cardboard...............................127


Appendix 3 Summary of key elements from the studies on plastics.................................................158


Appendix 4 Summary of key elements from the studies on biopolymers.........................................199


Appendix 5 Summary of key elements from the studies on food & garden waste...........................224


Appendix 6 List of selected studies...................................................................................................238


Appendix 7 List of rejected studies...................................................................................................241








Environmental benefits of recycling – 2010 update 5



1.0 Introduction



From the point of view of sustainable development, improving waste management is essential if society’s


environmental impacts are to be reduced. Identifying waste management channels with lower environmental


impacts is thus a key issue. The waste hierarchy illustrated in Figure 1 is often used as a rule of thumb followed


by public policies. However, a recurring theme in the debates that surround waste and resources management is


the extent to which the recycling of materials offers genuine benefits to the environment. Often, critics of the


policy drive towards greater recycling assert that the act of recycling may in fact have little or no benefit to the


environment, suggesting that more energy may be used in getting materials to the recycling facility than is saved


by the process of recycling.



Figure 1 Schematic diagram showing the waste hierarchy



In order to compare waste management routes in environmental terms, the Life Cycle Assessment (LCA)


methodology is currently seen as the best approach to use. The strength of LCA is that the methodology allows


comparison of two or more different products or processes by quantifying the service given by the products or


processes. The weakness of LCA is that the results of the assessment are very sensitive to the scope of the study,


to the hypothesis made, etc. To compare environmental impacts of numerous waste management routes, one


solution is to review and compare existing Life Cycle Assessment (LCA) studies on waste management and to


analyse the impacts of each hypothesis.



To analyse the different burdens or benefits of each waste management option, WRAP (Waste & Resources


Action Programme) reviews and commissions relevant LCAs. The purpose of this study is to update the


Environmental Benefits of Recycling published by the WRAP in 2006. This study reviews LCA studies and


compares the various possible options for waste management. This study was undertaken by Bio Intelligence


Service (BIOIS) and the Copenhagen Resource Institute (CRI, former Danish Topic Centre on Waste and


Resources). Collaboration with WRAP took place throughout the study.



Materials covered by this study are paper and cardboard, plastics, biopolymers, food and garden waste, wood


and textiles. The waste management options that are studied are composting, energy recovery (incineration,


anaerobic digestion, pyrolysis and gasification), landfill and recycling. Table 1 shows the combinations of


materials and treatment options covered in the study (the combinations materials/disposal options included in the


previous edition are highlighted in grey). Some options, such as gasification or pyrolysis, could in theory be used


for most of the fractions but the literature review has pointed out large data gaps, therefore these options could


not be assessed.











Environmental benefits of recycling – 2010 update 6




Table 1 Overview of the materials and treatment options under study


Anaerobicxa0


Recycling Composting Incinerationxa0 Landfill Pyrolysis Gasification


digestion


Paperxa0andxa0card x x x


Plastics x x x x


Biopolymers x x x x x


Foodxa0andxa0gardenxa0waste x x x x


Woodxa0 x x x


Textiles x x x





2.0 Methodology for the selection and assessment of LCA studies



2.1 Literature review



The main objective of this step was to identify all published LCA studies that compare two or more waste


management options for one or more fractions included in the field of this review.



An exhaustive review of LCA publications was carried out using the following sources of information:


uf06e International scientific journals and databases: International Journal of LCA, Science Direct, Springer


uf06e Publications by relevant worldwide organisations in waste management and life cycle assessment:


National Environment Protection Agencies, European Joint Research Center (JRC), DEFRA, WRAP


uf06e BIOIS and CRI’s own databases


uf06e BIOIS and CRI’s contact network


The extensive literature review led to the identification of around 220 studies.



2.2 Publications selection criteria



In order to be able to choose the publications suitable and relevant for analysis, a list of selection criteria was


established. The objective was to narrow the selection to transparent and high-quality studies.



The criteria used for the selection were:


uf06e the study was an LCA or LCA-like study


uf06e the study included a comparison of one or more end-of-life scenarios for the material fraction under


study


uf06e representation of recycling or composting among the waste management options assessed,


uf06e robustness of the publication: the publication should have been either peer reviewed or published in


a scientific journal


uf06e transparency in the assumptions made


uf06e primary research and not a review of previous work


uf06e no ambiguity in the way impacts are ascribed to materials


uf06e plausibility of the waste management options


Further details regarding these selection criteria are given below.




2.2.1 The study was an LCA or LCA-like study



The choice was made to focus on LCA studies because LCA is currently considered as the most reliable method


for analysing the environmental impacts of products and services. One of the main advantages of LCA is that it


enables a quantitative evaluation of potential environmental impacts on several indicators. The LCA methodology


has been standardised by the International Standards Organization (ISO) (ISO 14040 and 14044 standards).


Environmental benefits of recycling – 2010 update 7



Within the requirements of ISO 14040 and 14044, the LCA must consist of the following steps:



uf06e Goal and scope definition which defines the goal and intended use of the LCA, and scopes the


assessment concerning system boundaries, function and flow, required data quality, technology and


assessment parameters,


uf06e Inventory analysis which consists in collecting data on inputs (resources and intermediate


products) and outputs (emissions, wastes) for all the processes in the product system.


uf06e Impact assessment, phase during which inventory data on inputs and outputs are translated into


indicators of potential impacts on the environment, on human health, and on the availability of


natural resources.


uf06e Interpretation of results where the results of the LCI and LCIA are interpreted according to the


goal of the study and where sensitivity and uncertainty analysis are performed to qualify the results


and the conclusions.


In addition, the ISO standards require that LCAs disclosed to the public are submitted to a critical review


performed by independent LCA experts to ensure that the methods and results are scientifically and technically


valid. The fulfilment of the ISO standards is thus a guarantee for quality and transparency. Except for some


studies published by recognised organisations (US EPA for example), the fulfilment of the ISO 14040-series was


required for the publication selection.




2.2.2 The study included a comparison of two or more end-of-life scenarios for the material


under study



In order to be able to conduct a comparison between various end-of-life scenarios, the systems compared must


have the same functional unit and equivalent system boundaries, data quality and impact assessment


methodologies. In practice, it is thus very difficult to compare LCA results for scenarios from different studies. In


the present study, the choice has thus been made to conduct numerical comparisons only for scenarios analysed


in a single publication. This implies that each selected study must include a comparison between at least two


end-of-life options for a given fraction. This criterion was the most restrictive one and some studies of


high quality and interest had to be excluded with respect to this criterion. Nevertheless, it ensured


the overall coherence of the study.




2.2.3 Transparency in the assumptions made



The variability of the results from one LCA study to another is often very high since results are highly dependent


on the assumptions made. It is also common for studies on similar systems to lead to different conclusions. When


conducting comparisons across various studies, it is therefore essential to be able to identify the key parameters


that can explain why conclusions differ from one study to another. The transparency of the assumptions made


was thus considered as an important criterion for the publications selection step. Most identified studies satisfied


this criterion fully but a lack of information in this area was sometimes observed when the study was only


reported in a journal article without an associated report. Requests were made to authors for further information


but this was very difficult obtain, in particular for studies over two years old.




2.2.4 No ambiguity in the way impacts are ascribed to materials



The objective of the study was to come up with an evaluation of the environmentally preferable end-of-life


options for the range of considered fractions. The selected LCAs were thus required to present material-specific


results. High quality LCAs comparing end-of-life options for municipal solid waste as a whole were therefore not


suitable for selection.







Environmental benefits of recycling – 2010 update 8



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