Relevance of biodegradable and compostable consumer plastic products and packaging in a circular economy.
Date: 2020-04-03
Institutions: Directorate-General for Environment
Subjects: European standard, biodegradability, circular economy, organic fertiliser, packaging product, plastic waste, plastics, recycling technology, waste recycling

Relevance of Biodegradable 
and Compostable Consumer 
Plastic Products and 
Packaging in a Circular 
Economy 
For the European Commission DG 

Environment. Project conducted 

under Framework Contract No 

ENV.B.3/FRA/2017/005

March – 2020 

LEGAL NOTICE 

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responsible for the use which may be made of the information contained therein.  

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Luxembourg: Publications Office of the European Union, 2020 

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Relevance of Biodegradable and 
Compostable Consumer Plastic 
Products and Packaging in a 
Circular Economy 

Final Report 

Simon Hann 

Rosy Scholes 

Star Molteno 

Mark Hilton 

Enzo Favoino 

Line Geest Jakobsen 

23rd March 2020 

Report for European Commission, DG Environment 

Prepared by Simon Hann 

Approved by 

…………………………………………………. 

Mark Hilton 

(Project Director) 

Eunomia Research & Consulting Ltd 
37 Queen Square 
Bristol 
BS1 4QS 

United Kingdom 

Tel: +44 (0)117 9172250 
Fax: +44 (0)8717 142942 

Web: www.eunomia.co.uk 

Disclaimer 

Eunomia Research & Consulting has taken due care in the preparation of this report to 
ensure that all facts and analysis presented are as accurate as possible within the 
scope of the project. However no guarantee is provided in respect of the information 
presented, and Eunomia Research & Consulting is not responsible for decisions or 
actions taken on the basis of the content of this report. 

Abstract 

In 2015 the Commission adopted an EU action plan for the Circular Economy to help stimulate 
Europe’s transition towards a circular economy. The growing number of plastic products and 
packaging marketed as ‘biodegradable’ or ‘(home) compostable’ raises the question of the 
extent to which biodegradability and (home) compostability of plastic is beneficial in the context 
of the transition towards a circular economy. This study assesses possible implications of the use 
of such products and identifies conditions/applications in which industrial or home 
compostability of products or packaging could be of added value when compared to reuse and 
other forms of recovery.  

The results indicate that the evidence is weak in favour of any particular agronomic benefit 
associated with compostable plastic material in compost or digestate and therefore material 
choices for products and packaging should prioritise recyclability over compostability. Exceptions 
to this are where the use of compostable plastic have proven ’added benefits’ such as increasing 
the collection of organic waste and its diversion from residual waste or reduction in plastic 
contamination of compost. Industrial composting and anaerobic digestion infrastructure differ 
considerably across the EU and effectiveness at treating compostable plastic varies even if 
materials comply with harmonised standard EN 13432 on requirements for packaging 
recoverable through composting and biodegradation. Resulting undegraded compostable plastic 
residues is a significant risk that cannot be quantified at present. 

Executive Summary 

The Biodegradable Plastics Market 

The global production capacity for all biodegradable plastics in 2016 was reported to be 964,000 
tonnes and it is estimated that 175,000-200,000 tonnes was produced for the European market 
in 2016 with around half of all the biodegradable plastic products in the EU being sold in Italy. 
This means that biodegradable plastics make up approximately 0.6% of the total (35 million 
tonnes) plastics market in Europe for products in scope of this study.  

The key applications are carrier bags and biowaste bags, which combined make up almost 60% of 
the certified product market by number of certifications in 2019, and 68% of the mass of 
biodegradable plastics product found on the market in 2015. Other flexible packaging, rigid 
packaging and single use items such as trays, cups and cutlery range from 2 to 12% of the 
market. 

The global biodegradable plastics market is currently dominated by three different groups of 
polymers; polyesters, PLA and starch blends. These polymers hold approximately 27%, 24% and 
42% of the market respectively. 

Nature and Quality of Compost Resulting from Compostable Plastics 

Direct evidence of ecological improvement from compostable plastics is sparse and 
inconclusive. There appears to be consensus around the lack of nutritional benefit and therefore 
this leads towards investigating more in-depth the potential physical benefits of incorporating 
carbon directly into the soil as biomass. However, the evidence for the extent to which 
assimilation of the carbon into the compost takes place is also limited. Only recently has the 

i 

carbon in the polymer been tracked into biomass, but this is difficult to quantify at this stage. 
Existing research suggests that at least half of compostable plastic is ‘lost’ to CO2 air emissions as 
it biodegrades in composting. The remaining material is incorporated into biomass in the 
compost. Given scarce evidence further research is required. 

This study explores the types of organic waste infrastructure that exists in Europe and the 
implications of processing compostable plastics within these systems. Anaerobic digestion (AD) 
is increasingly considered the preferred method for processing food waste from an 
environmental perspective. The acceptability of compostable plastics at AD sites varies 
depending on the operational scheme of the site which varies, even within countries. With 
regard to incomplete biodegradation, several stakeholders report this happening in AD and 
composting plants, with the problem being more pronounced in AD plants. The same issues have 
been highlighted in several countries. 

In-vessel Composting (IVC) is a controlled composting process exposed to oxygen rather than a 
digestion process in the absence of oxygen. Some sites have primary screens that may send 
plastics and compostable plastics into rejects. This is a common practice in Germany where 
conventional plastic bags—which are often used by households to deliver biowaste—are 
removed. Germany also uses ‘fresh compost’ which is typically applied directly to agricultural 
land but can be composted for as little as 6-8 weeks which is typically not enough time for 
biodegradation of compostable plastics to fully occur. Conversely, Italy has a general minimum 
requirement that compost should be matured for at least 90 days, which is in line with 
assumptions on which the requirements in the Standard EN 13432 (for treatment in aerobic 
conditions) appear to be based.   

Importantly, none of the Member State or EU level Regulations on compost or digestate quality 
(resulting from any of the above processes) take into account the impacts of microplastics on 
the terrestrial environment or seeks to reduce these. Currently plastic contaminants under 
2mm in size is allowable, which is larger than the definition of microplastics (typically <1mm). 
This is potentially problematic for all types of plastic, but in the context of this report, incomplete 
biodegradation or fragmentation may create plastic particles that fall below these limit values 
and are therefore not targeted for removal. 

Effects of Contamination of Plastics Separately Collected for Material 
Recycling 

With regard to compostable plastics in conventional mechanical plastics recycling, reports 
indicate that the final levels of contamination are acceptable to subsequent recycling 
processes. However, this refers to a scenario in which compostable plastics are only used in 
very small quantities in niche applications. More widespread use in packaging, particularly if 
more rigid packaging is used, may require adaptation of the sorting lines, or generate levels of 
contamination that may cause problems for mechanical recycling. In Italy, where there is already 
widespread use of compostable plastics (with a concentration relative to conventional plastics of 
at least five times greater than any other EU country) the overall contamination rate is below the 
levels considered to be of concern for mechanical recycling before sorting. 

Environmental Performance of Alternative Non-plastic Biodegradable 
Products Compared with Compostable Plastic 

Non-plastic biodegradable alternative products such as paper can be used to fulfil the same 
function as compostable plastics. However, there is limited literature comparing compostable 
plastic products to non-plastic biodegradable products. 

Three carrier bag studies show different results when comparing paper and compostable plastic 
carrier bags. Two out of the three studies find that the compostable plastic bag has generally 

ii 

 
 
 
 
lower or very similar environmental burdens compared to a paper bag, however the overall 
assumptions of the studies, including how reuse is incorporated has a greater bearing on the 
result overall. 

Another study on packaging film was generally inconclusive as some environmental impact 
categories showed the non-plastic alternative has a lower environmental impact and in other 
impact categories the compostable plastic performs better therefore it is difficult to draw 
specific conclusions and there appears to be no clear evidence that non-plastic biodegradable 
alternatives are environmentally preferable to compostable plastics. 

The main take away points are; compared to production, the end of life stage often has low 
contribution to the overall impacts but that landfilling of compostable plastics should be 
avoided in order to reduce climate change impacts from methane release. In regards to the 
production side, feedstock and energy use have the largest influence and, bio-based, 
compostable products can offer benefits in some impact categories, especially climate change, 
but show higher impacts in other categories compared to fossil-based plastics considering an 
average EU end of life treatment.  

The Risk of Littering Biodegradable Plastics 

There is a lack of recent conclusive empirical evidence that clearly correlates the marketing of 
plastics packaging or products as biodegradable/compostable with an increase in the tendency 
to litter these - further research is needed. However, several studies point towards a perception 
amongst consumers that ‘biodegradable’ or ‘compostable’ is an inherently virtuous aspect of a 
product and that littering such an item would be less impactful. There is also evidence 
suggesting that perceptions of the time for such plastics to biodegrade are not likely to be in 
line with reality. 

Reviewing Standards for Industrial Compostability - EN 13432 

There are currently two harmonised standards for biodegradation in industrial composting and 
anaerobic digestion: EN 13432 has been in place since 2000 and is linked to the European 
Directive on Packaging and Packaging Waste (94/62/EC) where meeting the standard presumes 
conformity with the essential requirements in the Directive. EN 14995 contains identical criteria, 
but its scope is for other non-packaging plastic products. Through the research conducted for 
this report, two main criticisms of the standards have been identified: 

•  The aerobic biodegradation and disintegration test durations are too long. 
•  The assumptions in the anaerobic biodegradation test do not reflect reality. 

It is recommended that the standard EN 13432 (and consequently EN 14995) be updated to 
reflect the latest scientific understanding and approaches. This includes a requirement to 
separately test and meet the criteria for biodegradation of all organic constituents which are 
present in the material at a concentration between 1% and 15% and to introduce a nitrification 
inhibition test and an earthworm toxicity test. There may be merit in introducing a test to 
validate the biodegradation performance in soil 

There are also several other potential weaknesses—particularly around the testing time 
threshold and how this relates to reality. It is recommended that Member States conduct their 
own trials to determine whether the Standard is fit for the purpose of verifying that 
compostable plastics perform as required (noting that ‘performance’ is a relative term that will 
be dictated by the local process and compost quality requirements). This will help in determining 
whether they should accept compostable plastics or not in their biowaste treatment facilities. 

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Criteria in Which the Use of Compostable Products and Packaging Could 
Be Beneficial 

Based the preceding findings the following points summarise the basis for the criteria setting: 

•  At this stage the evidence is weak in favour of any particular agronomic benefit 

associated with compostable plastic material in compost or digestate. Some carbon from 
the biodegradable plastics appears to be incorporated into the biomass but at least half 
is ‘lost’ to CO2 air emissions. This leads to the conclusion that material choices for 
products and packaging should prioritise recyclability over compostability. 

•  Exceptions to this are where the use of compostable plastic have proven ’added benefits’ 
such as increasing the collection of organic waste and its diversion from residual waste 
or helping to reduce plastic contamination of compost, thus facilitating circularity in the 
bioeconomy. 
Industrial composting and anaerobic digestion infrastructure as well as organic waste 
collection practices differ considerably across the EU and are not all effective at treating 
compostable plastic. 

• 

•  Material compliance with EN 14432 does not automatically lead to effective treatment 
of compostable plastics and the Standard may require amending to increase its relevant 
and effectiveness. 

•  Undegraded compostable plastic residues in compost or digestate is a significant risk 
that cannot be quantified at present. This is not mitigated under fertiliser quality 
protocols at Member State or EU level (Fertiliser Regulation) which currently do not 
require the absence of microplastics (<2mm). 

It is appropriate to define the prerequisites that need to be achieved for the disposal of 
compostable packaging alongside biowaste to be considered an option. This is in order to make 
sure that;  

• 

• 
• 

the organic waste treatment infrastructure is capable of dealing with these 
materials/products with no negative effects;  
the material/product performs as expected in industrial composting; and,  
the waste treatment method and the appropriate disposal actions required by the end 
user to facilitate this is effectively communicated. 

Without these three elements above in place, the likelihood of negative consequences is high i.e. 
consumer confusion leading to improper disposal and/or situations where organic waste 
treatment is hampered. Following on from establishing the prerequisites, it is possible to 
develop criteria that can be used to define applications for which design for composting may be 
of added value—these are shown in Table 1. 

Table 1: Proposed Criteria for Identifying Applications for Which Design for 
Composting May Be of Added Value 

1 

The use of compostable plastic brings ‘environmental benefits’ over alternative materials 

Criteria 

This application could not have been designed for reuse or recycling or would not undergo 
material recycling even if designed for recycling 

The use of compostable plastic for this specific application can be expected to significantly 
increase the capture of bio-waste compared to non-compostable alternatives 

1a 

1b 

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1c 

2 

2a 

2b 

Through the use of LCA or similar environmental assessment tool, it can be demonstrated that 
compostable plastic is the preferred material for this particular application 

The use of compostable plastic does not directly or indirectly result in a reduction of the quality 
of the resulting compost 

The use of compostable plastic for this application does not lead to consumer confusion and 
subsequent increase in contamination from non-compostable plastics. 

The use of compostable plastic for this application can be expected to significantly reduce the 
contamination of compost with non-compostable plastics (from this application) compared with 
current practice. 

As seen in Figure 1, the study concludes that some of the most potentially beneficial applications 
are biowaste bags, teabags and fruit labels whereas applications such as single use bottles or 
clothing packaging bags constitute detrimental uses. 

Figure 1: Compostable Plastics Beneficial Use Continuum  

Compostable Plastics in Home Composting 

This study assessed the evidence base for how plastic marketed as home compostable behave in 
home composting situations. It identifies the conditions that are found in different types of 
home composting systems used across the EU and compares them with the criteria set in 
existing standards. Based on this analysis, a set of recommendations have been formulated for 
approaches to address the discrepancies between existing frameworks and conditions to be 
found in practice.  

Evidence for the Behaviour of Plastics Under Home Composting Conditions 

Best practice in compost management includes: 

•  Selecting a container suitable for the climate, i.e. that helps to manage temperature and 

air access   

v 

 
 
 
 
•  Ensuring that the balance of ‘greens’ (nitrogen) and ‘browns’ (carbon) is correct – the 

right (C:N) ratio 

•  Ensuring moisture levels are correct (around 50%) using a squeeze test and adjusted  
•  Ensuring sufficient aeration and mix of C/N materials through regular turning of the pile 

The practices of six Member States (Belgium, France, Finland, Portugal, Spain and the UK) were 
analysed, informed from interviews and an analysis of publicly available information. These were 
selected to present a range of maturity in biowaste management along with a range of climatic 
conditions. 

The following observations were made: 

•  National level composting advice is not always clear in terms of the method it is 

describing.  

•  Half the countries considered recommend including meat and fish waste in home 

composting, the other half strongly suggest not to.   

•  There are wide and varying sources of advice in each country and there is little reason to 

believe that the advice of the national organisations necessarily represents actual 
practice in the country concerned.  

•  Overall, the national differences in composting advice do not seem to be significant 

enough to lead to poor practices in some countries. If followed, the advice given should 
lead to a well-managed pile in all cases.  

Only one of the sources of advice (from France) gave guidance to consumers on what to expect 
from composting plastics labelled as ‘compostable’, by indicating that there is likely to be a 
difference in ‘theoretical performance’ of the materials with actual performance.  

There is a lack of robust studies that test how plastics marketed as home-compostable behave 
under home composting conditions. This report identified six studies that attempted to measure 
biodegradation of plastics marketed as home-compostable in home composting conditions. Of 
particular note is a study by ADEME in France took place in 2019 which found; 

• 

incomplete biodegradation for both bags, with visible fragments in the compost after 18 
months;  

•  no ecotoxicity concerns from the resulting compost, but neither were there any 

agronomic benefits from including the plastic material; and 

•  paper bag equivalents were shown to biodegrade in a much shorter timeframe with no 

visible residues. 

Behavioural factors were also found to be a significant factor in the speed of the biodegradation 
process with the following found to speed up the process: 

•  Depositing the biowaste bag full of food waste, rather than empty; 
•  Regular mixing of the pile; and 
•  Starting the pile in springtime not winter.   

Overall, this study and the others preceding it, show that home composting of plastics marketed 
as home-compostable is a process which can present varied results and it is unclear how 
closely these meet consumer expectations. The external influences, particularly behavioural 
ones, are likely to have a high influence on the final outcome. 

Comparison Between Standards and Actual Home Composting Conditions 

The main ways that home composting conditions differ to standard test conditions are:  

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1)  Duration – The results of the ADEME study show that that fragments of plastic material 
can remain in the compost after 12 months, even when the rest of the organic material 
becomes compost.  

2)  Temperature – It is clear that the testing temperatures do not reflect actual real life 
conditions. Lower ambient temperatures (i.e. <20oC) will see slower biodegradation 
taking place. Its effects should be explored by changing the testing temperature to 
something that mirrors the conditions in a temperate climate, but still allowing for 
microbial activity to occur, i.e. not lower than 10oC. 

3)  Inoculum- The tests use a mature compost that is likely to be less biologically active than 
fresh waste that a householder will use—i.e. the test is harder to pass. However, the test 
inoculum is sieved, which increases surface area and may speed up the biodegradation 
process in comparison to a home environment. 

4)  Form of the testing material – materials tested in the form of smaller samples may 

perform differently when composted in their final product form.  

There is also some disparity between standard testing regimes, real-life studies and the actual 
practice conducted by home composters. The latter has not been studied in any great detail and 
Standards assume that a ‘well-managed’ process is being undertaken. Given that individual 
practices have a large bearing on the effectiveness of composting, this is an assumption that will 
likely mean that at least some of the home compostable plastics will not perform in real-life as 
intended. 

Recommendations for Plastics Home Composting Standards 

As a way of strengthening the validity of the tests, some products that currently pass existing 
tests may need to be further tested under less optimal conditions to see how this affects the 
biodegradation and disintegration processes. 

This report recommends that the draft CEN standard describes more clearly the add-as-you-go 
composting method whilst making explicit that this is likely to be a ‘cold composting’ process. 
This should include both a description of the range of abiotic conditions for which the test is 
deemed reliable (temperature, duration, pH, moisture), and related to this a set of practices 
which will ensure these conditions.  
Inevitably, however the testing and labelling is refined, there will be a need for effective 
communication with the consumer. Labelling should give the consumer an expectation of a time 
frame for the composting of the plastic material and it should be made clear that novel indoor 
composting practices are not suitable. For a home composting labelling to function well it will 
need to be accompanied by a strong, possibly region specific, communications programme. 

Home Composting of Plastics as Part of the Circular Economy 

There appears to be no evidence to suggest that home compostable plastic material itself 
provides any specific benefits to the home compost and in the context of the circular economy, 
the material is essentially lost. 

Because of this, the applications are considerably narrowed compared with industrial 
composting, in order to avoid consumer confusion. In this case only biowaste bags, fruit labels 
and tea bags (heat sealed with plastic) are recommended. The last two of these are likely to 
end up in home composting anyway, as attention has only recently been drawn towards the 
hidden plastic content of teabags.  

Reusing carrier bags or vegetable bags as caddy liners for collecting biowaste for home 
composting may be a viable option, but there is still a danger of confusion leading to 
conventional (e.g. PE) bags being used; increased use of industrially compostable bags creates 

vii 

 
 
 
another layer of confusion. The recently declared approach in France mandates that all products 
marked as (industrially) compostable are also required to be home compostable, therefore the 
consumer does not need to make this distinction and confusion is potentially lessened.  

viii   

 
 
 
 
Résumé – Français 

En 2015, la Commission a adopté un plan d'action de l'UE pour l'économie circulaire afin de 
stimuler la transition de l'Europe vers une économie circulaire. Le nombre croissant de produits 
et d'emballages en plastique commercialisés comme étant «biodégradables» ou «compostables 
(à domicile)» soulève la question de savoir dans quelle mesure la biodégradabilité et la 
compostabilité (à domicile) du plastique sont bénéfiques dans le contexte de la transition vers 
une économie circulaire. Cette étude évalue les implications possibles de l'utilisation de ces 
produits et identifie les conditions / applications dans lesquelles la compostabilité industrielle ou 
domestique des produits ou des emballages pourrait apporter une valeur ajoutée par rapport à 
la réutilisation et et aux autres formes de valorisation. 

Les résultats indiquent que les preuves sont faibles en faveur de tout avantage agronomique 
particulier associé à la matière plastique compostable dans le compost ou le digestat et que, par 
conséquent, les choix de matériaux pour les produits et les emballages devraient privilégier la 
recyclabilité par rapport à la compostabilité. Les exceptions à cette règle sont les cas où 
l’utilisation de plastique compostable a démontré des «avantages supplémentaires» tels que 
l’augmentation de la collecte des déchets organiques et leur détournement des déchets 
résiduels ou la réduction de la contamination du compost par le plastique. Les infrastructures de 
compostage industriel et de digestion anaérobie diffèrent considérablement dans l'UE et 
l'efficacité du traitement du plastique compostable varie même si les matériaux sont conformes 
à la norme harmonisée EN 13432 sur les exigences relatives aux emballages valorisables par 
compostage et biodégradation. Les résidus de plastique compostable non dégradés qui en 
résultent constituent un risque important qui ne peut être quantifié à l'heure actuelle. 

Résumé Analytique - Français 

Le marché des plastiques biodégradables 

La capacité de production mondiale de tous les plastiques biodégradables en 2016 serait de 
964.000 tonnes et on estime que 175.000 à 200.000 tonnes ont été produites pour le marché 
européen en 2016, environ la moitié de tous les produits plastiques biodégradables de l'UE étant 
vendus en Italie. Cela signifie que les plastiques biodégradables représentent environ 0,6% du 
marché total (35 millions de tonnes) des plastiques en Europe pour les produits visés par cette 
étude. 

Les principales applications sont les sacs de transport et les sacs pour déchets biologiques, qui 
représentent ensemble près de 60% du marché des produits certifiés en nombre de certifications 
en 2019, et 68% de la masse des produits en plastique biodégradable trouvés sur le marché en 
2015. Les autres emballages souples, les emballages rigides et les articles à usage unique tels que 
les plateaux, les tasses et les couverts représentent entre 2 et 12% du marché. 

Le marché mondial des plastiques biodégradables est actuellement dominé par trois groupes 
différents de polymères : les polyesters, le PLA et les mélanges d'amidon. Ces polymères 
détiennent respectivement environ 27%, 24% et 42% du marché. 

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Nature et qualité du compost résultant des plastiques compostables 

Les preuves directes d'une amélioration écologique grâce aux plastiques compostables sont 
rares et peu concluantes. Il semble y avoir un consensus sur l’absence du bénéfice nutritionnel 
et cela conduit donc à étudier plus en profondeur les avantages physiques potentiels de 
l'incorporation directe du carbone dans le sol sous forme de biomasse. Cependant, les preuves 
de l'ampleur de l'assimilation du carbone dans le compost sont également limitées. Ce n'est que 
récemment que le carbone du polymère a été suivi dans la biomasse, mais cela est difficile à 
quantifier à ce stade. Les recherches existantes suggèrent qu’au moins la moitié du plastique 
compostable est «perdue» en émissions atmosphériques de CO2 lors de sa biodégradation dans 
le compostage. Le reste de la matière est incorporé à la biomasse dans le compost. Étant donné 
le peu de preuves disponibles, des recherches supplémentaires sont nécessaires. 

Cette étude explore les types d'infrastructures de gestion des déchets organiques qui existent en 
Europe et les implications du traitement des plastiques compostables dans ces systèmes. La 
digestion anaérobie (DA) est de plus en plus considérée comme la méthode privilégiée pour 
traiter les déchets alimentaires d'un point de vue environnemental. L'acceptabilité des plastiques 
compostables sur les sites DA varie en fonction du schéma opérationnel du site qui varie, même 
au sein des pays. En ce qui concerne la biodégradation incomplète, plusieurs parties prenantes 
signalent qu’elle se produit dans les usines de DA et de compostage, le problème étant plus 
prononcé dans les usines de DA. Les mêmes problèmes ont été mis en évidence dans plusieurs 
pays. 

Le compostage en cuve est un processus de compostage contrôlé exposé à l'oxygène plutôt 
qu'un processus de digestion en l'absence d'oxygène. Certains sites disposent de tamis primaires 
qui peuvent envoyer les plastiques et les plastiques compostables dans les rejets. C’est une 
pratique courante en Allemagne où les sacs en plastique classiques - qui sont souvent utilisés par 
les ménages pour livrer les biodéchets - sont retirés. L’Allemagne utilise également du 
«compost frais» qui est généralement appliqué directement sur les terres agricoles, mais qui 
peut être composté pendant seulement 6 à 8 semaines, ce qui n’est généralement pas 
suffisant pour que la biodégradation des plastiques compostables se fasse complètement. À 
l'inverse, l'Italie a une exigence minimale générale selon laquelle le compost doit être mûri 
pendant au moins 90 jours, ce qui est conforme aux hypothèses sur lesquelles semblent reposer 
les exigences de la norme EN 13432 (pour le traitement en conditions aérobies.   

Il est important de noter qu'aucune des règlementations des États Membres ou de l'UE sur la 
qualité du compost ou du digestat (résultant de l'un des processus ci-dessus) ne prend en 
compte les impacts des microplastiques sur l'environnement terrestre ou ne cherche à les 
réduire. Actuellement, les contaminants plastiques d'une taille inférieure à 2 mm sont autorisés, 
ce qui dépasse la définition des microplastiques (généralement <1 mm). Cette situation est 
potentiellement problématique pour tous les types de plastique, mais dans le contexte du 
présent rapport, une biodégradation ou une fragmentation incomplète peut créer des particules 
de plastique qui tombent en dessous de ces valeurs limites et ne sont donc pas ciblées pour être 
éliminées. 

Effets de la contamination des plastiques collectés séparément pour le 
recyclage des matériaux 
En ce qui concerne les plastiques compostables dans le recyclage des plastiques mécaniques 
conventionnels, les rapports indiquent que les niveaux finaux de contamination sont 
acceptables pour les processus de recyclage ultérieurs. Toutefois, cela fait référence à un 
scénario dans lequel les plastiques compostables ne sont utilisés qu'en très petites quantités 
dans des applications de niche. Une utilisation plus répandue dans les emballages, en particulier 
si des emballages plus rigides sont utilisés, peut nécessiter une adaptation des lignes de tri, ou 

ii 

 
 
 
 
générer des niveaux de contamination susceptibles de poser des problèmes pour le recyclage 
mécanique. En Italie, où l’utilisation des plastiques compostables est déjà très répandue (avec 
une concentration par rapport aux plastiques conventionnels au moins cinq fois supérieure à 
celle de tout autre pays de l'UE), le taux de contamination global est inférieur aux niveaux 
considérés comme préoccupants pour le recyclage mécanique avant le tri. 

Performance environnementale des produits alternatifs non plastiques 
biodégradables par rapport au plastique compostable 

Les produits de substitution biodégradables non plastiques tels que le papier peuvent être 
utilisés pour remplir la même fonction que les plastiques compostables. Cependant, il existe peu 
de littérature comparant les produits en plastique compostables aux produits biodégradables 
non plastiques. 

Trois études sur les sacs de transport montrent des résultats différents lorsqu'on compare des 
sacs de transport en papier et en plastique compostable. Deux des trois études constatent que le 
sac en plastique compostable a généralement une charge environnementale plus faible ou très 
similaire à celle d'un sac en papier, mais les hypothèses générales des études, y compris la 
manière dont la réutilisation est incorporée, ont une plus grande incidence sur le résultat global. 

Une autre étude sur le film d'emballage n'a généralement pas été concluante, car certaines 
catégories d'impact environnemental ont montré que l'alternative non plastique a un impact 
environnemental plus faible et dans d'autres catégories d'impact, le plastique compostable est 
plus performant ; il est donc difficile de tirer des conclusions spécifiques et il ne semble pas y 
avoir de preuve claire que les alternatives biodégradables non plastiques sont préférables aux 
plastiques compostables sur le plan environnemental. 

Les principaux points à retenir sont les suivants : par rapport à la production, la phase de fin de 
vie contribue souvent peu aux impacts globaux, mais la mise en décharge des plastiques 
compostables devrait être évitée afin de réduire les impacts du changement climatique dus au 
dégagement de méthane. En ce qui concerne la production, les matières premières et 
l’utilisation d'énergie ont la plus grande influence et les produits biologiques compostables 
peuvent offrir des avantages dans certaines catégories d'impact, en particulier le changement 
climatique, mais présentent des impacts plus élevés dans d'autres catégories que les plastiques à 
base de fossiles si l'on considère un traitement de fin de vie moyen dans l'UE. 

Le risque de jeter des déchets de plastiques biodégradables 
Il n'y a pas de preuves empiriques récentes et concluantes qui établissent clairement une 
corrélation entre la commercialisation d'emballages ou de produits en plastique comme étant 
biodégradables/compostables et une augmentation de la tendance à les jeter dans la nature - 
des recherches supplémentaires sont nécessaires. Toutefois, plusieurs études indiquent que les 
consommateurs ont l’impression que les termes «biodégradable» ou «compostable» sont un 
aspect intrinsèquement vertueux d’un produit et que le fait de jeter un tel article aurait moins 
d’impact. Certains éléments indiquent également que la perception du temps nécessaire à la 
biodégradation de ces plastiques n’est probablement pas conforme à la réalité. 

Révision des normes de compostabilité industrielle - EN 13432 

Il existe actuellement deux normes harmonisées pour la biodégradation dans le compostage 
industriel et la digestion anaérobie : la norme EN 13432 est en place depuis 2000 et est liée à la 
directive européenne sur les emballages et les déchets d'emballages (94/62/CE), où le respect de 
la norme présuppose la conformité aux exigences essentielles de la directive. La norme EN 14995 
contient des critères identiques, mais son champ d'application s’étend à d’autres produits en 

iii 

 
 
 
plastique sans emballage. Les recherches menées pour ce rapport ont permis d’identifier deux 
critiques principales des normes: 

•  Les durées des tests de biodégradation et de désintégration aérobie sont trop longues. 
•  Les hypothèses du test de biodégradation anaérobie ne reflètent pas la réalité. 

Il est recommandé que la norme EN 13432 (et par conséquent EN 14995) soit mise à jour pour 
refléter les dernières connaissances et approches scientifiques. Cela comprend l'obligation 
de tester séparément et de satisfaire aux critères de biodégradation de tous les constituants 
organiques présents dans la matière à une concentration comprise entre 1% et 15% et 
d’introduire un test d'inhibition de la nitrification et un test de toxicité pour les vers de 
terre. Il pourrait être utile d’introduire un test pour valider la performance de biodégradation 
dans le sol. 

Il existe également plusieurs autres faiblesses potentielles, en particulier en ce qui concerne le 
seuil de temps de test et son lien avec la réalité. Il est recommandé aux États membres de 
mener leurs propres essais pour déterminer si la norme est adaptée à la vérification de la 
performance des plastiques compostables (en notant que le terme performance est un terme 
relatif qui sera dicté par les exigences locales en matière de processus et de qualité du 
compost). Cela aidera à déterminer s'ils doivent accepter ou non les plastiques compostables 
dans leurs installations de traitement des biodéchets. 

Critères pour lesquels l'utilisation de produits et d'emballages 
compostables pourrait être bénéfique 

Sur la base des résultats précédents, les points suivants résument la base de la fixation des 
critères: 

•  À ce stade, les preuves sont faibles en faveur de tout avantage agronomique particulier 

associé à la matière plastique compostable dans le compost ou le digestat. Une partie du 
carbone des plastiques biodégradables semble être incorporée dans la biomasse, mais 
au moins la moitié est «perdue» en raison des émissions atmosphériques de CO2. Cela 
conduit à la conclusion que les choix de matériaux pour les produits et les emballages 
devraient privilégier la recyclabilité par rapport à la compostabilité. 
Les exceptions à cette règle sont les cas où l’utilisation de plastique compostable a 
démontré des «avantages supplémentaires» tels que l’augmentation de la collecte des 
déchets organiques et leur détournement des déchets résiduels ou la réduction de la 
contamination plastique du compost, facilitant ainsi la circularité dans la bioéconomie. 
Les infrastructures industrielles de compostage et de digestion anaérobie ainsi que les 
pratiques de collecte des déchets organiques diffèrent considérablement dans l'UE et ne 
sont pas toutes efficaces pour traiter le plastique compostable. 
La conformité des matériaux à la norme EN 14432 ne conduit pas automatiquement à un 
traitement efficace des plastiques compostables et la norme peut nécessiter une 
modification pour en accroître la pertinence et l’efficacité. 
Les résidus de plastique compostable non dégradés dans le compost ou le digestat 
constituent un risque important qui ne peut être quantifié à l'heure actuelle. Ce risque 
n'est pas atténué par les protocoles sur la qualité des engrais au niveau des États 
membres ou de l'UE (règlement sur les engrais), qui n’exigent pas actuellement l'absence 
de microplastiques (<2 mm). 

• 

• 

• 

• 

Il convient de définir les conditions préalables à remplir pour que l'élimination des emballages 
compostables en même temps que les biodéchets soit considérée comme une option. Il s’agit de 
s'assurer que; 

iv 

 
 
 
 
•  L’infrastructure de traitement des déchets organiques est capable de traiter ces 

matériaux / produits sans effets négatifs;  

•  Le matériau / produit fonctionne comme prévu dans le compostage industriel; et, 
•  La méthode de traitement des déchets et les mesures d'élimination appropriées requises 
par l'utilisateur final pour faciliter cette opération sont communiquées efficacement. 

Sans ces trois éléments ci-dessus, la probabilité de conséquences négatives est élevée, c'est-à-
dire que la confusion des consommateurs entraîne une élimination incorrecte et / ou des 
situations où le traitement des déchets organiques est entravé. Après avoir établi les conditions 
préalables, il est possible de développer des critères qui peuvent être utilisés pour définir les 
applications pour lesquelles la conception pour le compostage peut apporter une valeur ajoutée 
– ceux-ci sont présentés dans le Tableau 1. 

Tableau 1: Critères proposés pour identifier les applications pour lesquelles la 
conception pour le compostage peut être une valeur ajoutée 

Critères 

1 

L'utilisation de plastique compostable apporte des «avantages environnementaux» par rapport 
aux matériaux alternatifs 

1a  Cette application ne peut pas avoir été conçue pour la réutilisation ou le recyclage ou ne serait 

pas soumise au recyclage des matériaux même si elle était conçue pour le recyclage. 

1b 

L'utilisation de plastique compostable pour cette application spécifique devrait permettre 
d'augmenter considérablement le captage des biodéchets par rapport aux solutions de 
remplacement non compostables 

1c  Grâce à l'utilisation de l'ACV ou d'un outil d'évaluation environnementale similaire, il peut être 

démontré que le plastique compostable est le matériau préféré pour cette application particulière 

2 

2a 

2b 

L'utilisation de plastique compostable n'entraîne pas, directement ou indirectement, une 
réduction de la qualité du compost obtenu 

L'utilisation de plastique compostable pour cette application n’entraine pas de confusion pour le 
consommateur et n’augmente pas la contamination par des plastiques non compostables. 

L'utilisation de plastique compostable pour cette application devrait permettre de réduire 
considérablement la contamination du compost par des plastiques non compostables (à partir de 
cette application) par rapport à la pratique actuelle. 

Comme le montre la Figure 1, l'étude conclut que certaines des applications les plus bénéfiques 
sont les sacs de biodéchets, les sachets de thé et les étiquettes de fruits, tandis que les 
applications telles que les bouteilles à usage unique ou les sacs d'emballage de vêtements 
constituent des utilisations préjudiciables. 

v 

 
 
 
  
 
 
 
 
 
Figure 1 : Continuum des utilisations bénéfiques des plastiques compostables 

Plastiques compostables dans le compostage domestique 

Cette étude a évalué la base de données sur la façon dont le plastique commercialisé comme 
compostable à domicile se comporte dans les situations de compostage domestique. Elle 
identifie les conditions rencontrées dans les différents types de systèmes de compostage 
domestique utilisés dans l'UE et les compare aux critères définis dans les normes existantes. Sur 
la base de cette analyse, un ensemble de recommandations a été formulé concernant les 
approches à adopter pour remédier aux écarts entre les cadres existants et les conditions que 
l’on trouve dans la pratique. 

Données probantes sur le comportement des plastiques dans les 
conditions de compostage domestique 
Les meilleures pratiques de gestion du compost comprennent: 

• 

La sélection d’un conteneur adapté au climat, c'est-à-dire qui aide à gérer la température 
et l'accès à l'air  

•  Veiller à ce que l'équilibre entre les «verts» (azote) et les «bruns» (carbone) soit correct - 

le bon rapport ( C: N ) 

•  S'assurer que les niveaux d'humidité sont corrects (environ 50%) en utilisant un test de 

compression et ajusté 

•  Assurer une aération suffisante et un mélange des matériaux C/N par un retournement 

régulier de la pile 

Les pratiques de six États membres (Belgique, France, Finlande, Portugal, Espagne et Royaume-
Uni) ont été analysées, fondées sur des entretiens et une analyse des informations accessibles au 
public. Ils ont été sélectionnés pour présenter une gamme de maturité dans la gestion des 
biodéchets ainsi qu'une gamme de conditions climatiques. 
Les observations suivantes ont été faites: 

• 

Les conseils de compostage au niveau national ne sont pas toujours clairs en termes de 
méthode qu'ils décrivent. 

vi 

 
 
 
 
 
 
• 

• 

La moitié des pays considérés recommandent d'inclure les déchets de viande et de 
poisson dans le compostage domestique, l'autre moitié suggère fortement de ne pas le 
faire.  
Les sources de conseils sont nombreuses et variées dans chaque pays et il y a peu de 
raisons de croire que les conseils des organisations nationales représentent 
nécessairement la pratique réelle dans le pays concerné. Dans l'ensemble, les 
différences nationales en matière de conseils sur le compostage ne semblent pas 
suffisamment importantes pour conduire à de mauvaises pratiques dans certains 
pays. S'ils sont suivis, les conseils donnés devraient dans tous les cas conduire à une pile 
bien gérée. 

Seule une des sources de conseil (en France) a donné des conseils aux consommateurs sur ce 
qu’ils peuvent attendre du compostage de plastiques étiquetés comme «compostables», en 
indiquant qu'il y a probablement une différence entre la «performance théorique» des 
matériaux et leurs performances réelles. 

Il y a un manque d'études robustes qui testent comment les plastiques commercialisés comme 
compostables à domicile se comportent dans des conditions de compostage domestique. Ce 
rapport a identifié six études qui ont tenté de mesurer la biodégradation des plastiques 
commercialisés comme compostables à domicile dans des conditions de 
compostage domestique. Il convient de noter en particulier une étude réalisée par l'ADEME en 
France en 2019, qui a constaté; 

•  Une biodégradation incomplète pour les deux sacs, avec des fragments visibles dans le 

compost après 18 mois; 

•  Qu’il n’y a pas de problème d'écotoxicité du compost résultant, mais il n'y a pas non plus 

• 

d'avantages agronomiques à inclure la matière plastique; et 
Il a été démontré que les équivalents de sacs en papier se biodégradent dans un délai 
beaucoup plus court, sans résidus visibles. 

Les facteurs comportementaux se sont également révélés être un facteur important dans la 
rapidité du processus de biodégradation, les éléments suivants ayant accéléré le processus: 

•  Déposer le sac de biodéchets rempli de déchets alimentaires, plutôt que vide; 
•  Mélange régulier de la pile; et 
•  Démarrage de la pile au printemps et non en hiver.  

Dans l'ensemble, cette étude et les précédentes montrent que le compostage domestique des 
plastiques commercialisés comme compostables à domicile est un processus qui peut 
présenter des résultats variés et il n’est pas clair dans quelle mesure ceux-ci répondent aux 
attentes des consommateurs. Les influences externes, notamment comportementales, sont 
susceptibles d'avoir une forte influence sur le résultat final. 

Comparaison entre les normes et les conditions réelles de compostage à 
domicile 

Les principales différences entre les conditions de compostage domestique et les conditions 
d’essai standard sont les suivantes: 

1)  Durée - Les résultats de l'étude ADEME montrent que des fragments de matière 

plastique peuvent rester dans le compost après 12 mois, même lorsque le reste de la 
matière organique devient du compost.      

2)  Température - Il est clair que les températures d'essai ne reflètent pas 

les conditions réelles de la vie quotidienne. Des températures ambiantes plus basses (c.-
à-d. <20 oC) entraîneront une biodégradation plus lente. Il convient d'étudier ses effets 

vii 

 
 
 
en modifiant la température de test de manière à ce qu'elle reflète les conditions d'un 
climat tempéré, tout en permettant à l'activité microbienne de se produire, c'est-à-dire 
en ne descendant pas en dessous de 10oC. 

3)  Inoculum - Les tests utilisent un compost mature qui est probablement moins actif 

biologiquement que les déchets frais qu'un ménage utilisera — c'est-à-dire que le test 
est plus difficile à réussir. Cependant, l'inoculum de test est tamisé, ce qui augmente la 
surface et peut accélérer le processus de biodégradation par rapport à un 
environnement domestique.      

4)  Forme du matériel d'essai - les matériaux testés sous forme d'échantillons plus petits 
peuvent se comporter différemment lorsqu'ils sont compostés dans leur forme de 
produit final.      

Il existe également une certaine disparité entre les régimes de test standard, les études en 
situation réelle et la pratique réelle des composteurs à domicile. Cette dernière n'a pas été 
étudié en détail et les normes supposent qu'un processus «bien géré» est en cours. Étant donné 
que les pratiques individuelles ont une grande influence sur l'efficacité du compostage, cette 
hypothèse signifie qu'au moins une partie des plastiques compostables a domicile ne se 
comporteront pas comme prévu dans la vie réelle. 

Recommandations pour les normes de compostage domestique des 
plastiques 

Afin de renforcer la validité des tests, certains produits qui réussissent actuellement les tests 
existants pourraient devoir être testés davantage dans des conditions moins optimales pour voir 
comment cela affecte les processus de biodégradation et de désintégration. 

Ce rapport recommande que le projet de norme CEN décrive plus clairement la méthode de 
compostage à la demande tout en précisant qu'il s'agit probablement d'un processus de 
«compostage à froid». Cela devrait inclure à la fois une description de la gamme des conditions 
abiotiques pour lesquelles le test est jugé fiable (température, durée, pH, humidité) et, en 
relation avec cela un ensemble de pratiques qui garantiront ces conditions. 
Inévitablement, quelle que soit la précision des tests et de l'étiquetage, il sera nécessaire de 
communiquer efficacement avec le consommateur. L'étiquetage devrait donner au 
consommateur un délai pour le compostage de la matière plastique et il devrait être clairement 
indiqué que les nouvelles pratiques de compostage en intérieur ne sont pas adaptés. Pour qu'un 
étiquetage de compostage domestique fonctionne bien, il devra être accompagné d'un 
programme de communication solide, éventuellement spécifique à la région. 

Le compostage domestique des matières plastiques dans le cadre de 
l'économie circulaire 

Rien ne semble indiquer que la matière plastique compostable à domicile apporte en soi des 
avantages spécifiques au compost domestique et, dans le contexte de l'économie circulaire, la 
matière est essentiellement perdue. 

De ce fait, les applications sont considérablement réduites par rapport au compostage 
industriel, afin d'éviter toute confusion chez le consommateur. Dans ce cas, seuls les sacs de 
biodéchets, les étiquettes de fruits et les sachets de thé (thermoscellés avec du plastique) sont 
recommandés. Les deux derniers sont de toute façon susceptibles de se retrouver dans le 
compostage domestique, car l'attention n'a été attirée que récemment sur le contenu plastique 
caché des sachets de thé. 

La réutilisation des sacs de transport ou des sacs de légumes comme sacs de caddie pour la 
collecte des biodéchets en vue du compostage domestique peut être une option viable, mais il 
existe toujours un risque de confusion conduisant à l'utilisation de sacs conventionnels (par 

viii   

 
 
 
exemple PE); l'utilisation accrue de sacs compostables industriellement crée une autre couche de 
confusion. L'approche récemment déclarée en France exige que tous les produits marqués 
comme étant compostables (industriellement) soient également compostables à domicile, le 
consommateur n'a donc pas besoin de faire cette distinction et la confusion est potentiellement 
atténuée.  

ix 

 
 
 
 
 
Contents 

Abstract ....................................................................................................................... i 

Executive Summary ..................................................................................................... i 

Résumé – Français ....................................................................................................... i 

Résumé Analytique - Français ...................................................................................... i 

Glossary.................................................................................................................... xiv 

Material Abbreviations .............................................................................................. xv 

1.0 Introduction .......................................................................................................... 1 

2.0 Key Definitions ...................................................................................................... 4 

2.1  Biodegradable and Compostable ............................................................................. 4 

2.2  The Biodegradation Process ..................................................................................... 7 

2.3  Home Compostable .................................................................................................. 8 

2.4  Bio-based and Fossil-based Compostable Plastics ................................................... 8 

2.5  Oxo-(bio)degradable Materials .............................................................................. 10 

2.6  Standards and Certifications .................................................................................. 10 

2.6.1 

Controlled Environments ................................................................................ 10 

2.6.2 

Industrial Composting .................................................................................... 10 

2.6.3  Uncontrolled Environments ............................................................................ 12 

2.6.4 

Certifications .................................................................................................. 13 

3.0 The EU Biodegradable Plastics Market .................................................................. 15 

3.1  Scope ...................................................................................................................... 15 

3.2  Common Biodegradable Polymers ......................................................................... 15 

3.2.1 

Polylactic Acid (PLA) ....................................................................................... 17 

3.2.2 

Polyesters ....................................................................................................... 17 

3.2.3 

Polyhydroxyalkanoates (PHA) ........................................................................ 18 

3.2.4 

Starch Blends .................................................................................................. 18 

3.3  Applications ............................................................................................................ 19 

3.3.1 

Common Market Segments ............................................................................ 19 

3.3.2  Most Common Applications ........................................................................... 24 

3.4  Certified Biodegradable Products .......................................................................... 25 

x 

 
 
 
 
3.5  Past and Current Quantity of Products on the Market .......................................... 27 

3.5.1 

Past Global Production Capacity .................................................................... 28 

3.5.2 

Estimate of quantity on European Market ..................................................... 30 

3.5.3 

Comparisons with the Conventional Plastics Market ..................................... 32 

3.5.4  Market by Geography within Europe ............................................................. 33 

3.5.5  Market Size by Plastic Type ............................................................................ 34 

3.6  Future Quantity of Products on the Market .......................................................... 35 

3.6.1  Market Drivers ................................................................................................ 35 

3.7  Labelling and Communication Assessment ............................................................ 39 

3.7.1  Methodology .................................................................................................. 39 

3.7.2  Results ............................................................................................................ 39 

3.8  Key Conclusions ...................................................................................................... 42 

4.0 Impacts of an Increase in the Market for Compostable Consumer Plastic Products 
and Packaging ............................................................................................................ 44 

4.1  Establishing the Nature and Quality of Compost Resulting from Compostable 
Plastics ............................................................................................................................. 44 

4.1.1 

Compostable Packaging Contributing to Recycling Targets .......................... 44 

4.1.2 

Key Conclusions .............................................................................................. 50 

4.2 

Implications of Compostable Plastics in Organic Waste Processing ...................... 51 

4.2.1 

Common Organic Waste Treatment Methods ............................................... 51 

4.2.2 

Effects of Contamination of Biowaste and Compost Quality ......................... 57 

Cost implications of biodegradable/compostable plastics in organic waste 

4.2.3 
processing .................................................................................................................... 61 

Case Study: Effects of Compostable Bags on Separate Collection of Biowaste

4.2.4 
62 

4.2.5 

Key Conclusions .............................................................................................. 65 

4.3  Establishing the Effect of Biodegradable/Compostable Plastics Entering Plastics 
Recycling Streams ........................................................................................................... 67 

Problems Related to Contamination of Compostable Plastics in Plastics 
4.3.1 
Recycling ...................................................................................................................... 68 

4.3.2  Occurrence of Compostable Plastics in Plastics Recycling ............................. 74 

4.3.3 

Key Conclusions .............................................................................................. 76 

4.4  The Risk of Littering Biodegradable Plastics .......................................................... 77 

4.4.1 

Key Conclusions .............................................................................................. 79 

xi 

 
 
 
 
5.0 Review of EN 13432 .............................................................................................. 81 

5.1  Recommendations for an EN 13432 Update ......................................................... 85 

6.0 Environmental Performance of Compostable Plastics ........................................... 87 

6.1  Environmental performance of alternative non-plastic biodegradable products 
compared with compostable plastic ............................................................................... 87 

6.1.1 

Paper Carrier Bags .......................................................................................... 87 

6.1.2 

Packaging Film from Wheat Gluten ............................................................... 89 

6.1.3 

Key Conclusions .............................................................................................. 90 

6.2  Environmental performance of compostable plastics from an LCA perspective .. 90 

6.2.1 

Packaging Film ............................................................................................... 91 

6.2.2  Beverage Bottles............................................................................................. 92 

6.2.3 

Packaging Films .............................................................................................. 92 

6.2.4 

End Of life ....................................................................................................... 93 

6.2.5 

Key Conclusions .............................................................................................. 95 

7.0 Criteria Setting ..................................................................................................... 97 

7.1  Methodology .......................................................................................................... 97 

7.2  Proposed Prerequisites .......................................................................................... 97 

7.3  Recommendations for Communication ................................................................. 98 

7.4  Recommendations for Waste Treatment ............................................................ 100 

7.5  Proposed Criteria for Beneficial Use .................................................................... 101 

7.6  Criteria Testing ..................................................................................................... 103 

8.0 Compostable Plastics in Home Composting ......................................................... 107 

8.1  Systems and Practices of Home Composting ....................................................... 107 

8.1.1 

System Design – Containers for Home Composting ..................................... 108 

8.1.2 

Effective Management of the Compost Pile ................................................. 112 

8.1.3  Defining Best Practice in Compost Management ........................................ 114 

8.1.4 

Key Conclusions ............................................................................................ 116 

8.2  Comparing Home Composting Across Six EU Countries ...................................... 118 

8.2.1 

Existing Biowaste Management ................................................................... 118 

8.2.2 

Support for Home and Community Composting .......................................... 120 

8.2.3 

Comparing National Advice on Compost Management .............................. 124 

8.2.4 

Key Conclusions ............................................................................................ 125 

xii 

 
 
 
 
8.3  Studying the Conditions Found in Home Composting and their Effect on the 
Biodegradation of Plastics ............................................................................................ 126 

8.3.1  Biotic Exposure Conditions in Home Composting ......................................... 127 

8.3.2  Abiotic Conditions in Home Composting ...................................................... 128 

8.3.3 

Evidence of Range of Conditions in Home Composting ............................... 129 

8.3.4 

Evidence for the Behaviour of Plastics Under Home Composting Conditions

131 

8.3.5 

Key Conclusions ............................................................................................ 137 

8.4  Standards and Certifications for Home Composting of Plastics .......................... 139 

8.4.1 

Specifications of Test Methods ..................................................................... 139 

8.4.2 

Country Level Standards ............................................................................... 141 

8.4.3  Draft European CEN Standard for Home Composting of Plastic Carrier Bags

145 

8.4.4 

Certifications ................................................................................................ 146 

8.4.5 

Key Conclusions ............................................................................................ 147 

8.5  Comparison Between Standards and Actual Home Composting Conditions ...... 148 

8.5.1  Differences Between Home Composting Conditions and Test Conditions ... 148 

8.5.2  Defining the Scope of Home Composting Practices for which Standards are 
Valid 

150 

8.5.3 

Key Conclusions ............................................................................................ 151 

8.6  Recommendations to Reconcile Theory and Practice ......................................... 152 

8.6.1  Home Composting of Plastics as Part of the Circular Economy ................... 154 

8.6.2 

Key Conclusions ............................................................................................ 156 

xiii 

 
 
 
 
 
 
 
 
Glossary 

The following are some of the key terms that are used throughout this report.  

Anaerobic Digestion 

The breakdown of organic material by micro-organisms in the absence of 
oxygen which produces biogas, which can be burned for energy onsite or 
upgraded for injection into the gas network, and digestate, which can be used 
as a fertiliser.  

Conventional Plastic  Plastic derived from fossil-based feedstocks that is not considered to be 

biodegradable or compostable in any reasonable timeframe 

Bio-based plastics 

Bio-based plastics are those with building blocks that are derived partly or 
wholly from plant-based feedstocks. These are often also known as 
bioplastics. 

Biodegradable 
(Biodegradation) 

The breakdown of an organic chemical compound by micro-organisms in the 
presence of oxygen to carbon dioxide, water and mineral salts of any other 
elements present (mineralization) and new biomass or in the absence of 
oxygen to carbon dioxide, methane, mineral salts and new biomass. 

Compostable Plastic  Plastic that biodegrades in industrial composting and is compliant with EN 

13432 or equivalent national standard. 

EN 13432 

The European standard “Requirements for packaging recoverable through 
composting and biodegradation.” This is the standard used to test that a 
plastic material is compostable in industrial composting, but it applies to 
packaging irrespectively of the material they are made of. 

Industrial 
Composting 

A blanket term which includes all forms of centralised organic waste 
treatment that is characterised by high levels of control and results in various 
forms of soil improver. 

Plastic that biodegrades in home compost within a reasonable timeframe.  

Third party testing to an established test method or standard. Often including 
a labelling scheme. Also includes certifications that do not have international 
standards associated with them such as the marine and fresh water 
environments. 

Incineration of residual waste where energy is recovered as electricity and/or 
heat 

A plant that receives, separates and prepares recyclable materials for sale to 
material manufacturers 

Macro-nutrients in fertilisers: nitrogen (N), phosphorus (P) and potassium (K) 
or NPK. 

Home Compostable 
Plastic 

Certifications 

Energy from Waste 
(EfW) 

Materials recycling 
Facility (MRF) 

NPK 

xiv   

 
 
 
 
 
Material Abbreviations 

The following is a list of the material acronyms and abbreviations that are used in this 
report 

PLA 

PHA 

PHB 

PET 

Polylactic acid 

Polyhydroxyalkanoate  

Polyhydroxybutyrate 

Polyethylene Terephthalate 

Bio-PET 

Bio-based Polyethylene Terephthalate 

(HD) (LD) PE 

(High density) (Low Density) Polyethylene 

Bio-PE 

PEF 

PP 

Bio-PP 

PA 

Bio-PA 

PCL 

PVA 

MEG 

Bio-based Polyethylene 

Polyethylenefuranoate 

Polypropylene 

Bio-based polypropylene 

Polyamides 

Bio-based Polyamides 

Polycaprolactone 

Polyvinyl Alcohol 

Monoethylene Glycol 

LA (D-LA and (L-LA) 

Lactic Acid 

xv 

 
 
 
 
 
 
1.0 

Introduction 

In 2015 the Commission committed itself to promoting a circular economy with its EU 
action plan for the circular economy setting out the actions that will be taken to drive 
“the transition to a more circular economy1, where the value of products, materials and 
resources is maintained in the economy for as long as possible, and the generation of 
waste minimised”. More recently, in January 2018, the Commission adopted a Strategy 
for Plastics in a Circular Economy2 which laid the foundation for a new plastics economy 
where the design and production of plastics and plastic products fully respect reuse, 
repair and recycling needs, and more sustainable materials are developed and 
promoted. The Plastics Strategy, inter alia, sets out that, “by 2030, all plastic packaging 
placed on the market should be reusable or recyclable in a cost-effective manner”. As 
regards the increasing market shares of plastics with biodegradable properties, the 
Strategy takes a cautious approach and states that it brings new opportunities as well as 
risks and adds that “in the absence of clear labelling or marking for consumers, and 
without adequate waste collection and treatment, it could aggravate plastics leakage 
and create problems for mechanical recycling”. 
The growing number of plastic products and packaging being marketed as 
‘biodegradable’ or ‘(home) compostable’ however raises the question of the extent to 
which biodegradability and (home) compostability of plastic is a beneficial feature in the 
context of the broader circular economy agenda. The Plastic Strategy recognised this, 
pointing to the need to identify the applications where biodegradable plastics have clear 
environmental benefits and clarifying how they should be handled after use. It also 
identifies specific challenges stressing that “most currently available plastics labelled as 
biodegradable generally degrade under specific conditions which may not always be 
easy to find in the natural environment, and can thus still cause harm to ecosystems”. A 
number of questions as to the broader implications are as yet unanswered, including the 
implications of the increase in biodegradable plastics on the reuse and recycling of non-
biodegradable plastic products and packaging, the feasibility of generally applicable 
criteria or standards for biodegradation in home-composting in an EU context, effects on 
the quality of the compost, the form of their potential contribution to litter prevention4, 
and related consumer information and incentives.  
Identifying “the conditions where the use of compostable and biodegradable plastics is 
beneficial” requires, inter alia, to clarify the conditions under which using biodegradable 
and (home) compostable plastics for products and packaging can be of added value 
when compared to reuse or other end-of life treatment options. 

1 https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:52015DC0614  
2 https://ec.europa.eu/environment/waste/plastic_waste.htm 

1 

 
 
 
 
 
Regarding challenges relating to consumer information the Plastic Strategy points out 
that “plastics labelled ‘compostable’ are not necessarily suitable for home composting” 
and that “it is important to ensure that consumers are provided with clear and correct 
information, and to make sure that biodegradable plastics are not put forward as a 
solution to littering”. The Strategy announces that the Commission will “start work to 
develop harmonised rules on defining and labelling compostable and biodegradable 
plastics”. The Staff Working Document accompanying the Strategy5 stresses that “it is of 
utmost importance that consumers are properly informed and aware of the meaning of 
the different concepts and of the proper handling or end-of-life treatment, the risk being 
that plastic items are incorrectly handled or disposed of at the end of their useful life”. 

In light of the above the European Commission, DG Environment, has commissioned a 
study in the context of its ongoing work related to a framework for plastics with 
biodegradable properties. The overall objectives of this study were to:  

•  provide an overview of the market and regulatory situation with regard to 

biodegradable/ compostable plastic products and packaging;  

•  assess possible implications of the use of such products in a circular economy 
context, in particular on waste management and in light of conditions found in 
practice in home composting systems across the EU (in terms of leakage of 
compostable plastics into the open environment and for the quality of the 
compost); and,  
identify conditions/ applications in which biodegradability/ (home) 
compostability of products or packaging could be of added value when compared 
to reuse and other forms of recovery and clarify the basis for establishing such 
conditions/ applications. Identification of relevant benchmarks in relation to the 
“added value”.  

• 

•  provide an overview of biodegradability criteria set in existing home-

compostability frameworks (standards, legislation, certification schemes)  

•  assess the practical relevance and limitations of such criteria in light of conditions 

found in practice in home-composting systems across the EU and identify 
possible measures for addressing discrepancies. 

•  develop related recommendations. 

The report is laid out in the following sections:  

•  Section 2.0  Key Definitions 

This section discusses some of the key definitions that need to be understood as 
a prerequisite for reading the rest of the report. This includes terms such as 
‘compostable’ and ‘biodegradable’, what these mean in practice and in European 
law. 

•  Section 3.0  The EU Biodegradable Plastics Market 

The section look sat the EU market for biodegradable and compostable plastics; 
what the key materials are, the key applications, the extent of certification of 

2 

 
 
 
 
 
 
such products, consumer information provided, and provides and outlook for the 
future market. 

•  Section 4.0  Impacts of an Increase in the Market for Compostable Consumer 

Plastic Products and Packaging 
This section looks at developing a better understanding of the role of 
biodegradability in the context of circular economy and possible trade-offs 
associated with making products or packaging biodegradable/compostable rather 
than reusable or recyclable.  

In order to achieve this, the following aspects are discussed in subsequent 
sections: 

o  Establishing the nature and quality of compost resulting from the 

composting of biodegradable/compostable plastics 

o 

Implications of Compostable Plastics in Organic Waste Processing 

o  Establishing the effect of biodegradable/compostable plastics entering 

plastics recycling streams 

o  Analysing the evidence base for the littering risks associated with 

biodegradable/compostable plastics 

•  Section 5.0  Review of EN 13432  

This section addresses the key criticisms that have been aimed at EN 13432 and 
evaluates how these may be included in any future update and sets out 
recommendations for this. 

•  Section 6.0  Environmental Performance of Compostable Plastics 

An overview of some of the issues around determining and comparing 
environmental performance of compostable plastics compared with alternatives. 

•  Section 7.0  Criteria Setting 

This section of the report brings together the knowledge of previous sections to 
assess the possible conditions in which the use of compostable products and 
packaging is beneficial. Criteria are derived that specific applications can be 
tested to. 

•  Section 8.0  Compostable Plastics in Home Composting   

This section of the report looks at the systems and practices of home composting 
in example Member States. It then looks at the conditions in home composting 
and the evidence base for what happens to compostable plastics in practice. This 
is then compared with the current Standards and recommendations are made.  

An Appendix with supporting information is available as a separate document 

3 

 
 
 
 
 
 
 
 
 
 
 
2.0  Key Definitions 

2.1 

Biodegradable and Compostable 

When discussing biodegradability, it is important to note that almost all materials 
ultimately biodegrade, even in the open environment. However, conventional, fossil-
based plastic items are predicted to take many hundreds of years; this is not a 
meaningful timeframe in human terms and can cause many problems to ecosystems 
over this time. Larger conventional plastic items will also progressively break down into 
microplastics which are known to be ingested by both aquatic and terrestrial organisms3 
—the use of biodegradable plastics for some applications is often thought to reduce the 
risk of this.   

The biodegradability of a plastic is also influenced heavily by the environmental 
conditions that it is in, for example one plastic may biodegrade relatively quickly in one 
environment but take hundreds of years in a different environment. The rate of 
decomposition is affected by the presence of bacteria, fungi and oxygen, hence why a 
‘biodegradable’ material may decompose in industrial composting but not (or at a 
considerably slower rate) on land or in a marine environment. It is therefore necessary 
to define both the environment and the timeframe when talking about biodegradation. 

There are many definitions for biodegradation, which generally do not specify a 
particular environment or timeframe. It should be emphasised that the term 
biodegradable, when referring to plastics, has little or no meaning in a policy context 
without a clear specification of the exact environmental conditions that this process is 
expected to occur in and the required maximum timeframe.  

EN 13432 and EN14995 on the compostability of packaging and non-packaging plastics 
respectively define (ultimate) biodegradation as the following: 

“[The] breakdown of an organic chemical compound by micro-organisms in the 
presence of oxygen to carbon dioxide, water and mineral salts of any other 
elements present (mineralization) and new biomass or in the absence of oxygen to 
carbon dioxide, methane, mineral salts and new biomass”. 

This definition is similar to ones provided by other standards organisations and helps to 
explain the process of biodegradation from a basic scientific perspective. Definitions can 
become more meaningful when talking about specific environments, for example 
industrial or home composting. The Directive on the reduction of the impact of certain 

3 Eunomia Research & Consulting (2018) Investigating options for reducing releases in the aquatic 
environment of microplastics emitted by (but not intentionally added in) products, Report for European 
Commission, February 2018 

4 

 
 
 
 
 
 
plastic products on the environment (commonly known and henceforth in this report 
referred to as the single use plastics (SUP) Directive) was enacted in July 2019;4 It 
includes Article 3(16) which states that: 

‘biodegradable plastic’ means a plastic capable of undergoing physical, biological 
decomposition, such that it ultimately decomposes into carbon dioxide (CO2), biomass 
and water, and is, in accordance with European standards for packaging, recoverable 
through composting and anaerobic digestion; 

This is the first time that the term biodegradable is linked explicitly with composting and 
anaerobic digestion (AD) in European law and the first time that biodegradable plastic 
has been defined. While the SUP provides for a definition it does not in its scope 
distinguish conventional from biodegradable plastics – both are covered by the Directive 
in the same way. The Directive requires an evaluation by 3 July 2027 of the technical 
progress concerning criteria or a standard for biodegradability in the marine 
environment. 

The Packaging and Packaging Waste Directive (PPWD) refers to biodegradable and 
compostable packaging in its ‘Essential Requirements’ (which all packaging needs to 
comply with to be allowed on the EU market). The two relevant requirements are:5 

Annex II (3c): 

“Packaging recoverable in the form of composting 
Packaging waste processed for the purpose of composting shall be of such a 
biodegradable nature that it does not 6hinder the separate collection and the 
composting process or activity into which it is introduced.” 

Annex II (3d): 

“Biodegradable packaging 
Biodegradable packaging waste shall be of such a nature that it is capable of 
undergoing physical, chemical, thermal or biological decomposition such that most of 
the finished compost ultimately decomposes into carbon dioxide, biomass and water. 
Oxo-degradable plastic packaging shall not be considered as biodegradable.” 

For Member States one of the key issues is whether biodegradable plastic that are 
separately collected with organic waste and that enters aerobic or anaerobic treatment 
can be counted towards packaging recycling rates and in some cases may have 
implication in the achievement of the plastics packaging recycling targets of 50% by 2025 
and 55% by 2030. To that end, Article 6a (4) of the Packaging and Packaging Waste 
Directive 94/62/EC states that; 

4 European Commission (2019) Directive (EU) 2019/904 on the reduction of the impact of certain plastic 
products on the environment 
5 European Parliament and the Council (2018) Directive (EU) 2018/852 of the European Parliament and of 
the Council of 30 May 2018 amending Directive 94/62/EC on packaging and packaging waste 
6 Until a 2018 amendment these words were ‘should not’ 

5 

 
 
 
 
 
“For the purposes of calculating whether the [recycling] targets… have been 
attained, the amount of biodegradable packaging waste that enters aerobic or 
anaerobic treatment may be counted as recycled where that treatment 
generates compost, digestate, or other output with a similar quantity of recycled 
content in relation to input, which is to be used as a recycled product, material or 
substance. Where the output is used on land, Member States may count it as 
recycled only if this use results in benefits to agriculture or ecological 
improvement.” 

The final phrase “benefits to agriculture or ecological improvement” is key and is 
discussed further in Section 4.1. 

The current situation in EU law therefore leads us to two conclusions: 

1)  Industrial composting or AD are the only acceptable waste disposal methods for 
biodegradable plastics that may potentially contribute to the recycling rate of a 
Member State.  

2)  EN 13432 is the de facto method for verifying that compostable plastics meet the 
essential requirements for packaging recoverable in the form of composting. 

Therefore, for the purposes of this study the definition of compostable plastics is the 
following: 

Any packaging product that is certified to conform to EN 13432 – Requirements for 
packaging recoverable through composting and biodegradation – or any equivalent 
national standard. 

Any non-packaging product that is certified to conform to EN 14995 - Plastics - 
Evaluation of compostability - Test scheme and specifications – or any equivalent 
national standard. 

Industrial composting attempts to create exactly the right balance of all the important 
factors to make the process as fast as possible. The types and concentration of micro-
organisms that metabolise the materials are highly controlled. All other environments 
such as in soil, fresh or marine water, are not controlled in any way and therefore the 
time for a material to biodegrade will vary massively.  

There is a general hierarchy of ‘aggressiveness’ for environments, with industrial 
composting being the most aggressive and the oceans being one of the least aggressive – 
see Figure 2.  

6 

 
 
 
 
 
 
 
Figure 2: Hierarchy of aggressiveness for biodegradation environments 

Source: Adapted from- Degradable Polymers and Materials – Principles & Practice,33-43, 2012. Editors: 
Khemani, K. and Scholz, C 

2.2 

The Biodegradation Process 

As biodegradation is the degradation caused by biological activity the material must 
therefore be capable of being assimilated by microorganisms (primarily bacteria and 
fungi). The aerobic process shown in the simplified equation below shows how the 
microorganisms use oxygen to metabolise (biodegrade) the carbon in the polymer which 
is then mineralised into CO2 and water. The microorganisms secrete enzymes which 
break down (cleave) the polymer chains to a size which makes them bioavailable. This 
biodegradation process takes place on the surface as the enzymes cannot penetrate the 
polymer which means that the carbon in the core of the plastic is unavailable until the 
outer is metabolised. This is the primary reason why thicker material biodegrades 
slower. 

7 

 
 
 
 
 
Source: Adapted from Chinaglia et al7 

The way to gauge the progress of this process is to measure the consumption of oxygen 
or the production of CO2. Biodegradation percentage is most often calculated as the 
ratio between the CO2 produced and the theoretical CO2 if all of the carbon in the 
material were oxidised.  A proportion of the carbon will always be converted to biomass 
and therefore 100% biodegradation will not result in 100% mineralisation (i.e. 100% of 
the available carbon converted to CO2).8 There is yet to be a developed a reliable 
method to measure the transfer of carbon into biomass although this has recently been 
achieved on a small scale by labelling the carbon in the polymer and tracking it through 
the process.9 

2.3 

Home Compostable 

A material may be termed ‘home compostable’ if it can biodegrade in a home 
composting environment. The practice and attitude of home composters, however, vary 
widely from household to household, and with different temperatures and 
microorganisms depending on both material input and geography. These highly variable 
conditions mean that it can be hard to define if a material is ‘home-compostable’, and at 
the time of writing no European standard for defining home compostability exists. 
However there are independent certifications and some Member States including France 
and Belgium have their own local standards/decrees—this and all further discussion on 
home composting can be found in more detail in Section 5.0. 

2.4 

Bio-based and Fossil-based Compostable Plastics 

The terms bio-based and fossil-based relate to the raw material feedstocks that are used 
to produce plastics. This is entirely separate from the way in which the material behaves 

7 Chinaglia, S., Tosin, M., and Degli-Innocenti, F. (2018) Biodegradation rate of biodegradable plastics at 
molecular level, Polymer Degradation and Stability, Vol.147, pp.237–244 
8 Bettas Ardisson, G., Tosin, M., Barbale, M., and Degli-Innocenti, F. (2014) Biodegradation of plastics in soil 
and effects on nitrification activity. A laboratory approach, Frontiers in Microbiology, Vol.5 

9 Zumstein et al. (2018) Biodegradation of synthetic polymers in soils: Tracking carbon into CO2 and 
microbial biomass, Sci. Adv. 2018;4: eaas9024 

8 

 
 
 
 
 
 
 
 
in a composting (or any other) environment; not all bio-based plastics are compostable 
or biodegradable; and not all compostable or biodegradable plastics are bio-based. The 
terms bio-based and biodegradable are therefore not synonyms. The term ‘bioplastic’ is 
also often used but the more precise term of bio-based helps to remove some of the 
ambiguity. 

It is possible and becoming increasingly common for conventional plastics such as 
polyethylene (PE) and polyethylene terephthalate (PET) to be made, at least in part, 
from a bio-based feedstock. This has no noticeable effect on the end product and is 
chemically identical to its fossil-based counterpart and can therefore be recycled in the 
same way and is not biodegradable. 

Equally, for a plastic material to be compostable it is not required to be made from bio-
based materials. There are several compostable plastics that can be made from fossil-
based material. It is therefore important not to confuse what the material is made from 
with its possible end of life options. That being said, a large proportion of compostable 
plastics used in packaging are from a bio-based source and the trend is to move 
increasingly towards this. There are several definitions for the term ‘bio-based plastic’ 
however most are similar to the one used by the International Union of Pure and Applied 
Chemistry10: 

“a polymer composted or derived in whole or in part of biological products issued 
from biomass (including plant, animal, and marine or forestry materials).” 

It is important to note that under most definitions, a product can be referred to as bio-
based even if it has mostly fossil-based content – see Figure 3 for one such example, 
although there’s no agreed definition for this at present. As such, when looking at the 
feedstock for each polymer type it is important to look at bio-based content. The bio-
based content is the amount of biomass used by percentage of weight to create the final 
product. It is measured in accordance with EN 16640 or EN 16785. No environmental 
benefits are claimed by these types of labels or certifications although the perception of 
consumers may be that there is an implied ‘greenness’. The provenance of the feedstock 
is usually not a criterion that is assessed and therefore a higher bio-based content is no 
guarantee of improved environmental credentials (and vice-versa). 

Figure 3: TUV Austria Certification for Bio-based Plastics 

20-40% Bio-based 

40-50% bio-based 

60-80% Bio-based 

>80% bio-based 

10 Vert, M., Doi, Y., Hellwich, K.-H., et al. (2012) Terminology for biorelated polymers and applications 
(IUPAC Recommendations 2012), Pure and Applied Chemistry, Vol.84, No.2, pp.377–410 

9 

 
 
 
 
 
 
2.5 

Oxo-(bio)degradable Materials 

There are many kinds of material that claim to be biodegradable, or even just 
degradable, but the reality of such assertions is questionable. ‘Oxo-degradable’, ‘oxy-
degradable’ or ‘oxo-biodegradable’ plastics are a key example, and they should not be 
confused with the biodegradable plastics discussed in this report. They are conventional 
plastics such as polyethylene (PE) which contain an additive designed to help them 
fragment.  
Manufacturers claim that these materials fragment and degrade in the presence of 
oxygen. This leads to fragmentation, making the material more bioavailable for 
microorganisms to supposedly aid degradation. There is little evidence in practice for full 
biodegradation of these materials.11 
In 2018 the European Commission announced that “a process to restrict the use of oxo-
plastics in the EU will be started” and have officially stated that oxo-biodegradable 
plastic packaging shall not be considered as biodegradable. The Single-Use Plastics 
Directive also explicitly places a ban on all products made from oxo-degradable plastic 
and Member States are required to comply with this by 3rd July 2021. These materials 
will therefore not be included in the scope of this report. 

2.6 

Standards and Certifications 

The following provides a brief overview of how definitions are tested and certified in 
practice.  

2.6.1 

Controlled Environments  

For the purposes of testing and standardisation it is important to distinguish between 
controlled and uncontrolled environments. Industrial compositing can be considered a 
controlled environment as all of the key parameters that encourage biodegradation can 
kept at strict levels and it is a recognised form of waste management. Home composting 
can be, to a lesser extent, considered controlled as the key parameters can also be 
influenced – the systems and practice in home composting is discussed further in Section 
8.1 

2.6.2 

Industrial Composting 

There are currently two European standards for biodegradation in industrial composting 
and anaerobic digestion: EN 13432 has been in place since 2000 and is linked to the 
European Directive on Packaging and Packaging Waste (94/62/EC) where meeting the 
standard presumes conformity with the essential requirements in the Directive. EN 

11 Eunomia Research & Consulting (2016) The impact of the use of ‘oxo-degradable’ plastic on the 
environment : final report., September 2016, https://publications.europa.eu/en/publication-detail/-
/publication/bb3ec82e-9a9f-11e6-9bca-01aa75ed71a1 

10   

 
 
 
 
 
14995 contains identical criteria, but its scope is for other non-packaging plastic 
products.  

The EN 13432 standard outlines both specifications for industrial composting and 
anaerobic digestion. The standard has three primary requirements: 

1)  Disintegration: the sample must contain no more than 10% of material 

fragments larger than 2mm after 12 weeks (5 weeks in anaerobic digestion) of 
being maintained under test composting conditions with other organic wastes. 
2)  Biodegradability: the sample must biodegrade to carbon dioxide by at least 90% 
compared to a control or reference material (often cellulose) within 6 months 
under test composting conditions (50% after two months in anaerobic digestion) 

3)  Quality compost: the sample must not have any negative effect on the 

composting process. 

The requirement for 50% biodegradation in AD reflects the shorter processing time of 
AD, however, this is caveated with the following requirement: 

“The lower percentage of biodegradation is justified because in all commercially 
available biogasification plants the process scheme provides a short second aerobic 
stabilization phase in which the biodegradation can further continue.” 

The relevance and importance of this is discussed further in Section 4.1 and the standard 
itself is discussed in detail in Section 5.0. 

The most commonly used certifications for industrial composting within the EU are OK 
compost from TUV Austria, the seedling logo which is licenced by European Bioplastics 
and the DIN Geprüft from Din Certco. These also certify compliance with EN 13432. 
Occasionally the logo from the Biodegradable Plastics Institute (BPI) is found on products 
in the EU, but this is primarily for the US market and signifies conformity with ASTM 
D6400 – the American equivalent of EN 13432 which has almost identical requirements. 
The labels associated with each of the certifications are as shown in Figure 4. 

More comprehensive discussion of EN 13432 including some of the limitations and 
criticism that have been levelled at it can be found in Section 5.0 

Figure 4 - Industrial Composting Certifications Associated with EN 13432 

Source: TUV Austria, European Bioplastics, Din Certco 

11 

 
 
 
 
 
 
2.6.2.1  Home Composting 

The standards and certifications for home composting are discussed in detail in Section 
8.0 where this study investigates the validity of this as a waste treatment method for 
plastics. 

2.6.3 

Uncontrolled Environments  

Uncontrolled environments are those where the there is no waste management system 
in place and the item ends up there either through littering or as an inherent part of the 
product use. These environments should ideally not be considered legitimate end 
destinations for any material regardless of whether it will biodegrade—there may be 
some instance where this is unavoidable or alternatives result in worse environmental 
impacts. This is why there is a great deal of work ongoing to validate standards in these 
environments.  

2.6.3.1  Marine Environment 

The marine environment is a particularly difficult environment to develop standards for.  

An American standard – ASTM D7081 – previously existed for biodegradation in the 
marine environment, however this standard was withdrawn in 2014 and has yet to be 
replaced12. Work has been ongoing for several years to develop a new marine standard, 
however the marine environment is actually a whole host of different environments with 
varying temperatures and organic life so it is very difficult to create the large number of 
test methods that can accurately imitate these environments— it is almost impossible to 
determine a standard test method that works at the same time for surface waters, 
coastal sediments and the deep sea, for example. ASTM D7081 only focused on surface 
waters, but plastics are likely to move throughout the depths of the oceans and into 
sediments—testing and certification to this standard is still being carried out despite it 
not being representative of reality. 

A further complication when trying to develop a standard for the marine environment is 
deciding a time frame in which it is suitable for a plastic to reside in the ocean. The level 
of risk to wildlife, from either entanglement or ingestion, would relate specifically to this 
timeframe. A method for qualifying this risk has yet to be determined and therefore 
there is no way to arrive at a suitable timeframe. This is in marked contrast to industrial 
composting standards which do not use a time threshold based on environmental risk, 
but are tuned to the composting/AD process. The concept of ‘inherent biodegradability’ 
that is used in composting standards to verify that is will eventually biodegrade is likely 
to be insufficient in the open environment. 

12 ASTM D7081-05: Standard Specification for Non-Floating Biodegradable Plastics in the Marine 
Environment, accessed 9 November 2018, 
https://www.astm.org/DATABASE.CART/WITHDRAWN/D7081.htm  

12   

 
 
 
 
 
2.6.3.2 

Soil and Mulch Films 

In 2018 a standard for biodegradable mulch films was introduced – EN 1703313. The 
standard requires a minimum of 90% biodegradation within two years at a test 
temperature of 25°C, and includes various eco-toxicity tests and a restriction on the use 
of hazardous substances. Although the standard supposedly confirms biodegradation in 
soil, it would be incorrect to use it for anything other than mulch films as it is product 
specific. It is, however, identical to the criteria specified in TUV Austria’s OK 
Biodegradable Soil certification which is aimed at any products. 

There is currently no European wide standard for the biodegradation of other plastic 
products in soil, however the Belgian “product standards for compostable and 
biodegradable materials” and the French NF U 52-00114 standard include specifications 
for these types of products. These align with TUV Austria’s OK Biodegradable Soil 
certification with the primary condition being 90% biodegradation over 2 years at a 
temperature of 18°C – 30°C. 

2.6.4 

Certifications 

Despite a lack of European standards for many environments, there are several 
independent certification bodies who certify for biodegradation in different 
environments. The two most common certification bodies within Europe are TUV Austria 
and Din Certco; these are shown in Figure 5. TUV Austria provide certifications for 
industrial composting, home composting, soil, marine and fresh water environments. Din 
Certco provide certifications for industrial and home composting and soil.  

As described previously the marine certification is based on the now withdrawn ASTM 
D7081 standard (there has never been a European equivalent). The test requires 
biodegradation within 6 months at a temperature of 30 ± 2°C—and whilst this is a lab 
test and thus not designed to directly replicate the marine environment, this 
temperature is far higher than the majority of the sea surface waters and this becomes 
even more so with increased depth. It is unclear what the time threshold would have to 
be if the temperature were reduced to a level that is more representative. The 
certification does, however, recognise the risk of using this functionality as a marketing 
tool that might promote littering; it has therefore prohibited the use and marketing of 
this label on products unless the product has “…a function in the same environment (sea 
water) where they are meant to biodegrade” (fishing gear for example). It is not a 
certification that should be used as a way of mitigating the impact of land-based litter 
than may find its way into the marine environment. Several material suppliers openly 

13 BS EN 17033:2018 – Plastics. Biodegradable mulch films for use in agriculture and horticulture. 
Requirements and test methods.  
14 https://www.boutique.afnor.org/standard/nf-u52-001/biodegradable-materials-for-use-in-agriculture-
and-horticulture-mulching-products-requirements-and-test-methods/article/633557/fa136042 

13 

 
 
 
 
 
promote that their material has passed this certification (including Lenzing15 and 
Kaneka16 which both show it adjacent to products which would not be suitable for 
promotion i.e. clothing and bags respectively) although there is no evidence to suggest 
that any products themselves display this label in contravention of rules and TUV Austria 
devote resources to police conformance. 

Figure 5: European Certifications for Biodegradable Plastics 

Labels 

Reference 
Standard 

Test Conditions  

(if different from 
ref std.) 

Biodeg Test 
Threshold 

EN 13432 

ISO 175561 

ASTM D7081 
(withdrawn) 

Ambient 
temperature  

(20°C – 30°C) 

90% in 12 
months 

90% in 2 
years4 

90% in 6 
months 

90% in 56 
days 

EN 149872 

20°C and 25°C 

Notes: 
1. 
2. 

3. 
4. 

This is the test method for aerobic biodegradability of plastics in soil. 
This is the test method for biodegradability of plastics in waste water treatment plants—used as a proxy for fresh water 
environments. 
Test threshold the same as EN 13432 
Test threshold the same as EN 17033 

15 https://sustainability.lenzing.com/issue-03-2018/ 
16 https://www.kaneka.co.jp/en/business/material/nbd_001.html 

14   

 
 
 
     
 
 
 
 
 
 
 
 
 
3.0  The EU Biodegradable Plastics Market 

The following section summarises the current knowledge around the most common 
applications and market in the EU for biodegradable plastics. It is fair to say that overall 
the data is limited, often conflicting and lacking in detail. This is a result of the market 
being relatively new and small compared with the overall plastics market. The raw 
biodegradable polymer market is dominated by a few larger manufactures, so data on 
production and sales is commercially sensitive. Identifying exact quantities of specific 
products on the market is even more challenging. This is because some applications may 
account for a few hundred or thousand tonnes per year which could easily fluctuate as a 
result of small changes, such as a factory closing, a feedstock shortage or even a 
customer buying more or less product in a particular year. It is clear, however, that the 
biodegradable market for packaging, and in particular single use bags, is the strongest 
and most likely to increase over the coming years. 

It is important to highlight that the market is usually characterised under the term 
biodegradable plastics rather than compostable plastics. These terms are used in the 
report where the original data source refers to them as such. In reality, the vast majority 
of the biodegradable plastic market is likely to also be classed as compostable plastic, 
and would be marketed as such. From the perspective of certifications, 99% of certified 
biodegradable products are either industrial or home compostable. 

3.1 

Scope 

The scope of this overview is restricted to consumer plastic products and packaging. This 
is a broad category that is best characterised by identifying products that are not 
included; these are any industrial or building products and other commercial products 
such as fishing equipment.  

The only exception to this is in this section of the report addressing the market, as 
agricultural mulch films are included. They are expected to be a relatively large market 
sector, but these are not included throughout the rest of the report. 

3.2 

Common Biodegradable Polymers 

There are many types of biodegradable polymers on the market, with varying degrees of 
biodegradability. They each have their own unique properties, such as appearance, 
water and oxygen barrier properties, heat resistance and sealability. Polymers are often 
combined to produce composite materials with improved properties. Some of the 
properties of common biodegradable plastics are as outlined in Table 2, as well as their 
level of biodegradability.  

Most commercially available compostable plastics are thermoplastics, which mean they 
could, in theory, be melted and reused. Although they can theoretically be recycled, it is 

15 

 
 
 
necessary to get a completely pure waste stream which is very challenging with current 
waste infrastructure. 

Table 2: Properties of Biodegradable Plastics17 

Plastic type 

Properties 

PLA 

Starch blends 

•  Brittle 
•  Clear 
•  Generally suitable for food contact applications 
•  Can also be used as a foam 
• 

Industrially compostable. Needs high temperatures to degrade 
therefore not biodegradable in other environments.18 

•  Wide range of different properties 
•  Can be used as a foam 
•  Difficult to get food contact approved, however some are, e.g. 

Mater-Bi19 

•  Often industrially and home compostable, dependent on the 

blend 

Cellulose 
Acetate 

•  Rigid 
•  Some types certified according to EN 1343220, although it is not all 

Cellulose 
(regenerated) 

•  Clear 
•  Thin flexible films (cellophane) and non-wovens 
•  Thought to be biodegradable in water, and industrially 

Polyesters 
(PBAT, PBS(A), 
PCL) 

PHAs 

Composites 

compostable 
•  Various properties 
•  Can replace PP or LDPE 
•  Some flexible and very tough 
•  Some grades food contact approved 
•  Normally found in blends 
•  Various properties 
•  Not used often commercially, normally in blends 
• 

Industrially and home compostable, thought to be biodegradable 
in soil and marine environments. 

•  Two or more materials (normally resin and fibre) 
• 
Improved mechanical and physical properties 
•  Biodegradability depends on the constituent products 

17 CE Delft (2017) Biobased Plastics in a Circular Economy: Policy Suggestions 
18 Food Standards Agency (2010) Biobased materials used in food contact applications: an assessment of 
the migration potential, December 2010, 
https://www.food.gov.uk/sites/default/files/media/document/a03070.pdf 
19 Mater-Bi Packaging Solutions: Biodegradable and Compostable for Food and Non-food Applications, 
http://materbi.com/en/wp-content/uploads/sites/2/2016/05/scheda-packaging_EN_TUV_LR-.pdf 
20 Biograde® › FKuR 

16   

 
 
 
 
 
3.2.1 

Polylactic Acid (PLA) 

Polylactic acid (PLA) is 100% bio-based21 and is one of the most common biodegradable 
plastics on the market22. It is industrially compostable, but does not conventionally 
biodegrade in other environments, due to the high temperatures required.23 PLA has 
many mechanical and optical properties that make it a good substitute to conventional 
plastic, and make it suitable for food packaging applications. It has been proven to be 
‘Generally Recognized As Safe’ by scientists following guidelines from the US Food and 
Drug Administration.24 Also, many brands of PLA have specifically been approved for 
food contact applications within Europe; for example, Natureworks PLA has been 
approved for direct contact with all aqueous, acidic and fatty foods below 60°C, and for 
acidic drinks served under 90°C.25 It is used as both a rigid plastic product and as a film, 
however the films are relatively stiff compared to conventional films such as LDPE. It has 
low water barrier properties, which means that as a mono-layer material it is not well 
suited to products that require a long shelf life.26 

3.2.2 

Polyesters 

After PLA, the most common biodegradable polyesters on the European market are 
polyesters, including polybutylene adipate terephthalate (PBAT), polycaprolactone (PCL) 
and polybutylene succinate (PBS).27 These are primarily fossil-based, however bio-based 
PBS is also commercially available with up to 50% bio-based content.28 They are often 
blended with other biodegradable plastics to improve their properties. For example, 
polyesters are often combined with PLA films to reduce the PLA’s stiffness, or with 

21 FBR BP Biorefinery & Sustainable Value Chains, FBR Sustainable Chemistry & Technology, Biobased 
Products, van den Oever, M., Molenveld, K., van der Zee, M., and Bos, H. (2017) Bio-based and 
biodegradable plastics : facts and figures : focus on food packaging in the Netherlands, Report for 
Wageningen, 2017, http://library.wur.nl/WebQuery/wurpubs/519929 
22 European Bioplastics (2018) Bioplastics Facts and Figures 2018 
23 Food Standards Agency (2010) Biobased materials used in food contact applications: an assessment of 
the migration potential, December 2010, 
https://www.food.gov.uk/sites/default/files/media/document/a03070.pdf 
24 Conn, R.E., Kolstad, J.J., Borzelleca, J.F., Dixler, D.S., Filer, L.J., Ladu, B.N., and Pariza, M.W. (1995) Safety 
assessment of polylactide (PLA) for use as a food-contact polymer, Food and Chemical Toxicology, Vol.33, 
No.4, pp.273–283 
25 Food Standards Agency (2010) Biobased materials used in food contact applications: an assessment of 
the migration potential, December 2010, 
https://www.food.gov.uk/sites/default/files/media/document/a03070.pdf 
26 FBR BP Biorefinery & Sustainable Value Chains, FBR Sustainable Chemistry & Technology, Biobased 
Products, van den Oever, M., Molenveld, K., van der Zee, M., and Bos, H. (2017) Bio-based and 
biodegradable plastics : facts and figures : focus on food packaging in the Netherlands, Report for 
Wageningen, 2017, http://library.wur.nl/WebQuery/wurpubs/519929 
27 FBR BP Biorefinery & Sustainable Value Chains, FBR Sustainable Chemistry & Technology, Biobased 
Products, van den Oever, M., Molenveld, K., van der Zee, M., and Bos, H. (2017) Bio-based and 
biodegradable plastics : facts and figures : focus on food packaging in the Netherlands, Report for 
Wageningen, 2017, http://library.wur.nl/WebQuery/wurpubs/519929 
28 Molenveld, K. (2015) Biobased Packaging Catalogue, 2015 

17 

 
 
 
 
 
starch-based films to improve water resistance and tear strength. Polyesters are also 
often used as a coating for paperboard.29 

3.2.3 

Polyhydroxyalkanoates (PHA) 

Polyhydroxyalkanoates (PHAs) are a wide range of polymers - including 
polyhydroxybutyrate (PHB), polyhydroxyvalerate (PHV) and polyhydroxyhecanoate 
(PHH) - that are all very new to the commercial market. They are 100% bio-based and 
show potential to degrade in environments less aggressive than industrial composters, 
for example in soil or marine water.30 They have many promising properties, for example 
they are hydrophobic, can be used at a high temperature and are extremely versatile.31 
Some PHAs are food contact approved, however this is on a product specific basis.32 It is 
thought that PHAs haven’t broken into the packaging market due to their high cost. 

3.2.4 

Starch Blends 

Starch blends are complex mixtures of starch with other biodegradable polymers (often 
fossil-based biodegradables, e.g. BASF’s Ecoflex®). The blending of the starch with these 
other polymers can improve properties such as water resistance and flexibility.33 There is 
a very wide variety of different starch blends on the market that all lend themselves well 
to different applications, and different levels of compostability. Due to their high 
flexibility and translucence, they are well suited to carrier bags and fruit and vegetable 
bags. They are also often used in food waste caddy liners34. It is generally difficult to get 
food contact approval for starch blends, however there are some exceptions to this rule, 
for example Mater-Bi.35 Rigid or foamed starch-based plastics also exist, and can be 
used, for example, as fruit trays, service ware or loose fill foam packaging.36 

29 Molenveld, K. (2015) Biobased Packaging Catalogue, 2015 
30 ibid 
31 Food Standards Agency (2010) Biobased materials used in food contact applications: an assessment of 
the migration potential, December 2010, 
https://www.food.gov.uk/sites/default/files/media/document/a03070.pdf 
32 Molenveld, K. (2015) Biobased Packaging Catalogue, 2015 
33 Food Standards Agency (2010) Biobased materials used in food contact applications: an assessment of 
the migration potential, December 2010, 
https://www.food.gov.uk/sites/default/files/media/document/a03070.pdf 
34 FBR BP Biorefinery & Sustainable Value Chains, FBR Sustainable Chemistry & Technology, Biobased 
Products, van den Oever, M., Molenveld, K., van der Zee, M., and Bos, H. (2017) Bio-based and 
biodegradable plastics : facts and figures : focus on food packaging in the Netherlands, Report for 
Wageningen, 2017, http://library.wur.nl/WebQuery/wurpubs/519929 
35 Mater-Bi Packaging Solutions: Biodegradable and Compostable for Food and Non-food Applications, 
http://materbi.com/en/wp-content/uploads/sites/2/2016/05/scheda-packaging_EN_TUV_LR-.pdf 
36 ibid 

18   

 
 
 
 
 
3.3 

Applications 

3.3.1 

Common Market Segments 

Biodegradable plastics are found in many different market segments, including 
packaging, textiles, automotive, consumer goods, agriculture, horticulture, construction 
and electronics. There is data published on the amount of biodegradable plastic within 
each market segment. This data, however, does not state the environment in which this 
plastic is expected to biodegrade in, instead it refers to all biodegradable plastics. For the 
market segments that are of relevance to this project - packaging, consumer good and 
agriculture - it almost all consists of either compostable or soil biodegradable plastics 
(for mulch films), as shown in Appendix A.1.0. 

As shown in Figure 6, packaging is the leading sector for biodegradable plastics. This is 
also the dominant section within Europe for the conventional plastics market. 
Biodegradable plastics are also used frequently as consumer goods and in agriculture – 
often as mulch films. 

Figure 6: Applications by market segment for biodegradable plastics, 201837 

37 European Bioplastics (2018) Bioplastics Facts and Figures 2018 

19 

Flexible Packaging44%Rigid Packaging15%Agriculture & Horticulture13%Consumer goods9%Other19% 
 
 
 
 
 
3.3.1.1 

Packaging 

As shown, packaging takes 59% of the market share of biodegradable plastics. This 
includes both flexible and rigid types, with flexible packaging being the most common, 
taking over 44% of the market. Biodegradable plastics are predominantly used in 
packaging as the products often have a short functional life, i.e. are single-use.  

It should be noted that in this report, packaging includes carrier bags and biowaste bags, 
which are not packaging according to the definition under Article 3 of the Packaging and 
Packaging Waste Directive. Where data for these products is available separately it will 
be clearly stated. 

The product with the largest share of the European biodegradable plastics market is the 
biobags used to collect organic waste from households. Many of these are industrially 
compostable in accordance with EN 13432, as well as being certified as home 
compostable.  

There has also been an increasing trend in recent years to move towards industrially 
compostable bags for fruit and vegetables, both self-service and prepacked. It has been 
shown that for some compostable plastics, when used as fruit and vegetable bags, they 
can offer advantages over conventional plastics; for example, PLA’s high breathability 
can extend shelf life of perishable food, thus minimising food waste.38 These 
characteristics, however, can be disadvantageous in other circumstances, for example 
the breathability of PLA reduces its suitability as a beverage bottle (although coatings 
could be used to improve this).  

The most common compostable plastics that are used for packaging are PLA and starch-
based plastics, and their share of the market is discussed further in Section 3.5.4. Shown 
in Table 3 is an outline of the alternatives to conventional plastic used in packaging, and 
their most commonly associated applications. 

38 FBR BP Biorefinery & Sustainable Value Chains, FBR Sustainable Chemistry & Technology, Biobased 
Products, van den Oever, M., Molenveld, K., van der Zee, M., and Bos, H. (2017) Bio-based and 
biodegradable plastics : facts and figures : focus on food packaging in the Netherlands, Report for 
Wageningen, 2017, http://library.wur.nl/WebQuery/wurpubs/519929 

20   

 
 
 
 
 
 
 
 
 
 
Table 3: Compostable alternatives to conventional plastics including their 
applications39 

Conventional Plastic 

Application 

Biodegradable alternative 

Polyethylene (PE) 

Films and bottles 

Polypropylene (PP) 

Films, bottles and 
thermoformed 
products 

Starch blends 

PLA blends 

PHA  

PHA blends 

PHA  

PHA blends 

PLA blends 

Polystyrene (PS) 

Hard thermoformed 
packaging and foam 

Polyethylene terephthalate 
(PET) 

Bottles, trays and 
blister packs 

PLA (foam, films and hard 
packaging) 

Cellulose (pulp trays) 

Starch blends 

PLA 

The Directive on the reduction of the impact of certain plastic products on the 
environment (commonly referred to as the Single Use Plastics (SUP) Directive) 40 will 
have a large impact on plastic packaging in the EU. It includes specific measures to 
reduce the consumption of some products such as takeaway cups and single use bottles, 
and ban other products, such as single use cutlery. The intent is that biodegradable and 
bio-based plastics are considered to be ‘plastic’ under the SUP Directive and fully 
covered by its provisions. The issue of (marine) biodegradable plastics will be looked at 
again in the context of the 2027 evaluation of the Directive.  

Although under the Directive compostable plastics are currently treated the same way as 
conventional plastics, in some countries have taken an alternative approach by banning 
certain types of plastic packaging, but with compostable plastics as an exemption – 
vegetable bags in France for example (see section 3.6.1.1 for more detail). Given that the 
Directive targets plastics that are being littered – specifically those that end up in the 

39 Molenveld, K. (2015) Biobased Packaging Catalogue, 2015 
40 (2019) Directive (EU) 2019/904 of the European Parliament and of the Council of 5 June 2019 on the 
reduction of the impact of certain plastic products on the environment (Text with EEA relevance), 155 

21 

 
 
 
 
 
 
marine environment, compostable plastic products are unlikely to be considered a 
suitable alternative in future revisions. 

Food Packaging 

Compostable plastics are most often used in food contact applications, as these can 
easily become contaminated with food and therefore can make traditional dry recycling 
challenging. If the packaging is compostable, it can theoretically be processed alongside 
this organic contamination in a composting facility. This may have particular relevance 
for on-the-go products, and for packaging where cleaning prior to collection isn’t an 
option. 

One example that accounts for a large proportion of the compostable plastic market 
share is on-the-go packaging such as deli containers, drinks cups and sandwich boxes. As 
outlined above, these can, when waste collection operators instruct households to do 
so, be disposed of with food-/ biowaste in organic collections. However, it should be 
kept in mind that the appropriate waste stream may not be available outside of the 
household, as organic collections are not widespread in workplaces or public spaces. 
However, in the EU, following the 2018 revision of waste legislation, Member States will 
have the obligation to put separate collection of bio-waste in place by 2023.  

Through discussion with experts, it has been established that there is one particular 
situation where there is the potential to use compostable packaging: closed systems, for 
example at events or within hospitality (e.g. in a fast food outlet), where it has been 
prearranged that all packaging will be compostable and there is a suitable waste 
collector in place.41 However, where using reusable products or packaging is feasible, 
this will generally be preferable over the use of single use/ disposable packaging. 

There are strict EU regulations regarding the safety requirements for materials in contact 
with food42 which set out the general principles of safety and inertness for all Food 
Contact Materials (FCMs) These standards are the same for conventional and 
biodegradable plastics. 

Non-food packaging 

There are fewer examples of non-food applications from compostable plastics. Through 
discussions with stakeholders, one application that was identified where compostable 
plastics could be appropriate was in pallet wrap plastic.43 If this plastic was replaced with 
a compostable alternative there would be an opportunity to collect the packaging in a 
segregated manner. Some stakeholders are sceptical of using compostable plastics for 
this purpose, as several additional labels are added along the supply chain which would 
potentially render the product non-compostable. 

41 European Bioplastics (2018) Biodegradable Plastics in the Single-Use Context 
42 Regulation (EC) No 1935/2004 of the European Parliament and of the Council of 27 October 2004 on 
materials and articles intended to come into contact with food 
43 Interview with Charlie Trousdell, Independent Consultant 

22   

 
 
 
 
 
Another non-food packaging application is mailshot packaging, which are traditionally 
made from polyethylene. These bags could be replaced with a compostable plastic 
alternative, and subsequently used in the household as food caddy liners.44 

Loose fill starch packaging is another example where biodegradable or compostable 
plastics are used. This packaging is traditionally polystyrene, due to its physical 
properties and low price, which is difficult to recycle.  

It is also arguable that unless these types of packaging were food contaminated (which is 
unlikely) then it could easily be aggregated together and recycled—this is regularly 
undertaken for other plastic films at industrial sites that can collect enough clean films 
together to make recycling viable.  

3.3.1.2  Consumer Goods 

As biodegradable plastics have a wide range of properties they can, in theory, replace a 
wide range of consumer goods that would typically be made with conventional plastic. 
Some have particular properties that lend themselves well to specific applications, such 
as improved breathability; a function particularly important in personal hygiene products 
such as female sanitary products, nappies and disposable gloves.  

It is important to note that biodegradable plastics are not necessarily beneficial for 
products that require a long functional life. 

3.3.1.3  Agriculture and Horticulture 

Biodegradable plastics are often used in agriculture as mulch film and bale wrap. They 
can potentially offer advantages over other conventional plastics; however, this depends 
largely on the biodegradability of the product.  

Traditionally, mulch films have to be retrieved from the field separately from organic 
matter; a task that is both laborious and costly. The theory behind biodegradable mulch 
films, however, is that they do not need to be separated from organic matter but can 
simply be ploughed back into the soil after use, and will biodegrade in the soil 
environment. They are often thin, and have a corresponding standard for their 
biodegradation – see section 2.6.3.2.  

The biodegradable mulch film market has grown significantly in the past five years – it 
was reported to take 3% of the total global market for mulch films in 2016 and 13% in 
2018. It is thought that this is due to the savings that farmers can make by not having to 
remove it. In Norway, for example, it is expected that 75-80% of mulch films are 
biodegradable.45 

44 Material concerns: what can take the place of polywrap? | PrintWeek, accessed 24 June 2019, 
https://www.printweek.com/print-week/feature/1165797/material-concerns-what-can-take-the-place-of-
polywrap 
45 Torfinn Belbo (2018) ZERO-notat: Fornybar landbruksplast, Report for ZERO, August 2018, 
https://zero.no/wp-content/uploads/2018/08/ZERO-notat-fornybar-landbruksplast.pdf 

23 

 
 
 
 
 
Biodegradable plastics are also used in horticulture, for example as pots that can be 
planted directly into the soil. It is not clear how widespread this use is, however it is 
expected to be a very small proportion of the market. 

3.3.2 

Most Common Applications 

Little data is available on the quantity of each end product on the market, as the data is 
often commercially sensitive. As such, it is not possible to determine a completely 
accurate and up to date, ordered list of the most common applications and the 
quantities on the market.  

The Nova Institute reported in 2015 that the top applications by weight sold, in order, 
were shopping bags, biowaste bags, disposable tableware, rigid packaging, other flexible 
packaging (not including shopping or biowaste bags), consumer goods, fibre products 
and agricultural and horticultural applications.46 This is the only data available on EU 
sales by application, but due to the nature of the market—several niche applications—
there is a lack of specific detail. 

Through analysing both data on the products that are certified (from 2019) and the 
proportion of product groups on the market (from 2015), the ten most common 
applications on the European market have been identified - outlined in Table 4. 

For carrier bags, biowaste bags, rigid packaging, other flexible packaging and agricultural 
films, data was available on the proportion of these products on the EU market in 
2015.47 This allowed calculation of an indicative quantity on the market - using the total 
market size, as calculated in this report.  

The other applications listed in the table were determined through analysing the share 
of the individual product certifications. This is as a proportion of product certifications 
put on the market, rather than as a proportion of financial value or actual tonnes on the 
market. The indicative values have been calculated by looking at the share of product 
certifications from TUV Austria – see Section 3.4 for more details. It should be 
recognised that this only represents certified products; it is expected, however, that this 
is largely representative of the market as a whole as none of the major manufactures sell 
uncertified material even if the end product is not certified (which it should be). 

The list of ten most common applications has also been verified through discussions with 
industry stakeholders and a review of the limited literature available. 

As shown, carrier bags and biowaste bags combined make up almost 60% of the certified 
product market by number of certifications in 2019, and 68% of the mass of product 
found on the market in 2015. The main disparity between certification and quality is in 

46 Nova Institute (2016) Market study on the consumption of biodegradable and compostable plastic 
products in Europe 2015 and 2020 
47 Nova Institute (2016) Market study on the consumption of biodegradable and compostable plastic 
products in Europe 2015 and 2020 

24   

 
 
 
 
 
rigid packaging compared with flexible packaging whose relative proportions are 
reversed. It is unclear why this is the case other than the likelihood that there are fewer 
manufactures of rigid packaging and therefore fewer individual products overall. 

There is also a large number of certified compostable single use cutlery items and plates 
on the European market. These products will be banned under the SUP Directive and 
therefore the quantity on the market is expected to decrease to near-nothing once the 
restrictions on placing on the market enter into force from July 2021 

Table 4: Most common applications of certified compostable plastics on the 
European market 

Application 

Carrier bags 
Biowaste bags 
Rigid packaging (food and non-
food) 
Other flexible packaging (food 
and non-food, not incl. carrier 
or biowaste bags) 
Agricultural films 
Single use trays and plates1 
Single use cups2 

Single use cutlery3 
Bags for loose products 
(vegetables and other) 
Coffee pads, filters and capsules 
Notes:  

Indicative quantity on EU 
market in 2015, ktonnes4 
65 – 74 
54 – 62 

Share of product 
certifications5 
29% 
28% 

16 – 18 

8 – 9 

7 - 8 
Data not disaggregated: 
Disposable tableware (incl. 
trays, plates, cups and 
cutlery) 10 - 12 

Unknown 

Unknown   

4% 

12% 

2% 
6% 

4% 

2% 

3% 

3% 

1.  Plates will be banned across Europe under the SUP Directive Article 5 
2.  May be subject to national bans or restrictions under SUP Directive Article 4 
3.  Will be banned across Europe under the SUP Directive Article 5 
4.  Calculated using total quantity on EU market as calculated within this report, plus proportion of EU 

market data in 2015 – where available - from Nova Institute (2016) Market study on the 
consumption of biodegradable and compostable plastic products in Europe 2015 and 2020 
5.  TUV Austria: Certified Products, as of 25 June 2019, http://www.tuv-at.be/certified-products/  

3.4 

Certified Biodegradable Products 

It has not been possible thus far to determine absolute quantities of products that are 
certified, or to subsequently work out how much of the biodegradable plastic said to be 
on the European market holds a certification. Both TUV Austria and DIN Certco carry out 
regular auditing of their certifications to ensure the integrity of their labelling systems. 
Neither, however, are able or willing to provide any data around the extent to which 
they discover non-conformances.  

25 

 
 
 
 
When looking at certified products it is important to note that a particular raw material 
can be certified at production level, but once incorporated into a product it may not 
have the same compostable properties and cannot be certified—the final product in 
itself must be certified which can be implied if all component parts have also been 
certified. One example on the market within Europe is a storage unit made from Bio-on® 
PHA (a certified compostable material for some applications), however in order to create 
a durable product the material thickness requirement48 means that it is unlikely that it 
could be certified as compostable (and arguably shouldn’t be, as a supposedly durable 
product).49 Despite this, it is still marketed as ‘biodegradable’. This example 
demonstrates not only the need for certifications, but also how it is easy to—
deliberately or otherwise—make claims that are not scientifically credible. It also shows 
the difficulty in accurately quantifying the proportion of certified products and there is 
no way of knowing how many products with these sorts of unverified claims exist on the 
EU market.  

Through discussions with European Bioplastics it has been established that all raw 
material sold by their members is certified according to EN 13432. This accounts for a 
large share the market, with an estimated 84% of material (by mass) being produced by 
European Bioplastics members.50 As outlined above this does not necessarily mean that 
products made from these materials are eligible for certification. 

It has been possible to analyse the number of products that are certified by TUV Austria 
by product type (as described in Section 3.3.2). Further details on the methodology used 
to gather this data, as well as further data, is provided in Appendix A.1.0. 

As shown in Figure 7, 60% of the certifications given by TUV Austria are for bags, with 
49% of those bags shopping bags, and 46% bags for the collection of organic waste. 17% 
of certifications are for catering products, including trays, plates, cups, cutlery and coffee 
pods, filters and capsules amongst others. 17% of certified products are other packaging 
(i.e. not including bags), including food and non-food and rigid and flexible packaging. 
Agricultural, horticultural and garden products make up 3% of certified products, which 
includes mulch films, plant pots, clippers and landscaping covers. There are also 3% of 
products that are classed as miscellaneous items.  

48 The thickness or gauge of a material plays a very important part in whether a product can be certified as 
compostable. This is because of the required time limit that may be exceeded for thicker material despite 
the material being ‘inherently biodegradable’. 
49 Storage Componibili Bio by Kartell - Pink | Made In Design UK, accessed 30 August 2019, 
https://www.madeindesign.co.uk/prod-componibili-bio-storage-3-drawers-natural-biodegradable-
material-by-kartell-ref5970-ro.html 
50 Discussion with European Bioplastics 

26   

 
 
 
 
 
 
Figure 7: Share of TUV Austria certifications, by market area of the product 

With regard to packaging, as highlighted in Section 2.0, the Packaging and Packaging 
Waste Directive (PPWD) necessitates that the Essential Requirements must be met. EN 
13432 is the de facto standard used to prove conformity (compliance with the standard 
presumes compliance with the essential requirements)—certification is the best route to 
independently verifying compliance. However, the Essential Requirements are not well 
enforced and are currently subject to review in order to strengthen them. 

3.5 

Past and Current Quantity of Products on the Market 

Due to commercial sensitivities; data is not readily available on the actual quantities of 
biodegradable products on the market. It was estimated in 2015 that 84% of the 
European raw polymer market is dominated by five key players: BASF, BIOTEC, FKuR, 
NatureWorks and Novamont.51 Gathering data from end users is also challenging, as the 
end user market is made up of many small businesses, as well as larger organisations. 
The typical volume that converters deal with is 100-1,000 tonnes, and the typical volume 

51 Nova Institute (2016) Market study on the consumption of biodegradable and compostable plastic 
products in Europe 2015 and 2020 

27 

Bags60%Catering17%Packaging17%Garden, horticultural & agricultural products3%Other3%Bags for collection of biodegradable refuse46%Shopping bags49%Bags for loose products (fruit and vegetables and others)5% 
 
 
 
 
 
 
 
of people selling at consumer level is 10-100 tonnes.52 This makes the market extremely 
difficult to trace. 

Data is available, however, on the capacity of plastic production facilities. This gives an 
indication of the amount of biodegradable plastics on the global market. Although this 
data is currently considered the best source of market data for the biodegradable 
plastics industry, there are limitations to the data. The data has been reported annually 
by European Bioplastics for the past ten years, however the scope and data collecting 
methods have been refined over the years. Data prior to 2017 is not comparable with 
the current production capacity data reported for 2018.   

There are two key reasons that production capacity may not be reached. The demand 
for biodegradable polymers has a significant influence on the quantity of polymer 
produced, and as such the production relies on the end market for biodegradable 
products. The production also depends heavily on the availability of feedstocks. For 
example, it was expected that large quantities of succinic acid – a feedstock used to 
produce PBS - would be available on the market in 2017, however the predicted amount 
has not been available for PBS production.53 

3.5.1 

Past Global Production Capacity 

As outlined above, the production capacity data has been reported by European 
Bioplastics54,55,56,57,58 for the past ten years, but each year is not wholly comparable. The 
annually reported predictions are as shown in Figure 8. 

The source of data was changed to improve accuracy, so it is expected that the most 
recent data for 2017 and 2018 is the most reliable. This most recent comparable data 
shows there was a 3.05% increase in production capacity from 2017 to 2018. Through 
discussions with key stakeholders it has been determined that this increase has been 
fairly consistent since 2008, with an average annual increase of 3-4%. 

52 Nova Institute (2016) Market study on the consumption of biodegradable and compostable plastic 
products in Europe 2015 and 2020 
53 (2019) Discussion with European Bioplastics 
54 European Bioplastics (2010) Bioplastics Facts and Figures 2010, accessed 15 May 2019, 
http://www.plastemart.com/upload/literature/bioplastic-capacity-to-surpass-one-mln-ton-2011-
biodegradable-polymers.asp 
55 European Bioplastics (2011) Bioplastics Facts and Figures 2011, accessed 15 May 2019, 
http://www.plastemart.com/upload/literature/europe-strong-bioplastic-growth-led-by-bio-polyethylene-
terephthalate-pet.asp 
56 European Bioplastics (2013) Bioplastics Facts and Figures 2013 
57 European Bioplastics (2014) Bioplastics Facts and Figures 2014 
58 European Bioplastics (2017) Bioplastics facts and figures 2017 

28   

 
 
 
 
 
Figure 8: Reported global production capacity of biodegradable plastics, 
2008 to 2018  

Note that change in data sources and methodologies mean that no trend can be inferred between 
2014 and 2017 

3.5.1.1 

European Share 

The European share of the market is hard to predict due to commercial sensitivities. The 
Nova Institute estimated the quantity of polymers sold on the EU market in 2015 to be 
between 115-140kt, and the quantity of end products sold to be 100kt.59  

There is little data available on how the European share of the market may have 
changed over the past ten years, it has been reported that Europe held 35-40% of the 
market value in 201660 and another source reported the share to be 55% in 201861, 
however it is not clear if these estimates are comparable, and indeed whether this 
reflects a real market share increase.  

59 Nova Institute (2016) Market study on the consumption of biodegradable and compostable plastic 
products in Europe 2015 and 2020 
60 Biodegradable plastics - Global Market Outlook (2016-2022), accessed 17 May 2019, 
https://www.strategymrc.com/report/biodegradable-plastics-market 
61 (2018) Demand For Biodegradable Plastics Expected To Surge, accessed 18 June 2019, 
https://cleantechnica.com/2018/07/31/demand-for-biodegradable-plastics-expected-to-surge/ 

29 

 
 
 
 
 
 
It is expected, however, that the European market has been growing more rapidly than 
other markets due to some legislative support and also growing environmental 
awareness amongst consumers. 

One policy that is thought to have had an impact is the standardisation of recoverable 
mulch films. The standard – EN 13655 – was updated to include a minimum material 
thickness of 25µm to help prevent the films breaking up as they are removed from the 
field. Previous to this standard, conventional mulch films were often as low as 5 – 10µm, 
so to become compliant many film producers have had to increase their thickness 
significantly. As thickness increases so does cost, so it is expected that many producers 
have turned to biodegradables as they could be used at a lower thickness and were 
therefore more competitive. 

Other national policies have also influenced the market, such as the banning of non-
compostable plastic carrier bags in Italy and France. In 2017 the French Government 
enacted a ban on single-use conventional plastic bags, including those for fruit, 
vegetables and deli goods. Compostable plastic bags with an increasing proportion of 
bio-based feedstock were excluded from the ban and therefore there was a large scale 
move to compostable bags.  

Prior to 2017, roughly 17 billion single-use bags were consumed each year in France. It is 
not clear at this stage how many of these bags have been replaced by compostable bags 
or simply prevented. 

It is reported that in Italy, only 61% of single use bags were compostable in 2018, despite 
legislation requiring them all to be.62 

3.5.2 

Estimate of quantity on European Market 

The global production capacity for all biodegradable plastics in 2018 was reported to be 
912,000 tonnes63. Although this data is the most recent, and also expected to be the 
most accurate due to refined data collection methods and sources, there is no further 
data for this year that can be used to calculate European production capacity. The most 
recent data available was from 2016. 

An estimation of the actual production tonnage as a proportion of global production 
capacity is calculated to be 70% in 2016. This was calculated by comparing the reported 
value of the global market to the value of the market that would be reached if facilities 
were producing at full capacity. The value of the market if facilities were running at full 

62 Arcelli, P. La ﬁliera dei polimeri compostabili Dati 2018 – Evoluzioni attese 
63 European Bioplastics (2018) Bioplastics Facts and Figures 2018 

30   

 
 
 
 
 
capacity was calculated using the price of biodegradable plastics per tonne in 201664, 
and the percentage of global production capacity by plastic type in 201665.  

It was reported that globally, in 2018, 59% of the end products made are packaging, 9% 
consumer goods and a further 13% for agricultural and horticultural purposes66. 
Although there are reported estimates for 2016, this proportional split is expected to be 
much more reliable and thus has been used rather than the 2016 data. This is a 
limitation to this analysis; however, literature suggests there have been no significant 
relative increases in the proportion of scope or non-scope products. It has also been 
assumed that the product share on the market within Europe is the same as the product 
share globally. 

In this work it is assumed that the majority of biodegradable products within the 
agriculture and horticulture market area are in scope, either as they are mulch films or 
consumer goods. As such, it is estimated that 81% of biodegradable polymers produced 
are used for products within scope of this report.  

Europe held 35-40% of the biodegradable plastics market in 201667.  

The global production capacity for all biodegradable plastics in 2016 was reported to be 
964,000 tonnes68. This suggests that there were up to 175,000-200,000 tonnes of scope 
products on the European market in 2016. The methodology for producing this estimate 
is as shown in Figure 9. 

To verify this result, the total market value in Europe was used alongside the quantity of 
each plastic type expected to be on the market to calculate a “price per tonne” value for 
2016. This was compared with the known prices for polymers, as published by 
Wageningen Food and Bio-based Research69. It was found that this methodology gives 
an appropriate price per tonne value, and thus gives a reasonable estimate of the 
market value in Europe. 

The figure is also in agreement with other information quoted from stakeholders. 

64 FBR BP Biorefinery & Sustainable Value Chains, FBR Sustainable Chemistry & Technology, Biobased 
Products, van den Oever, M., Molenveld, K., van der Zee, M., and Bos, H. (2017) Bio-based and 
biodegradable plastics : facts and figures : focus on food packaging in the Netherlands, Report for 
Wageningen, 2017, http://library.wur.nl/WebQuery/wurpubs/519929 
65 European Bioplastics (2017) Bioplastics facts and figures 2017 
66 European Bioplastics (2018) Bioplastics Facts and Figures 2018 
67 Biodegradable plastics - Global Market Outlook (2016-2022), accessed 17 May 2019, 
https://www.strategymrc.com/report/biodegradable-plastics-market 
68 European Bioplastics (2017) Bioplastics facts and figures 2017 
69 FBR BP Biorefinery & Sustainable Value Chains, FBR Sustainable Chemistry & Technology, Biobased 
Products, van den Oever, M., Molenveld, K., van der Zee, M., and Bos, H. (2017) Bio-based and 
biodegradable plastics : facts and figures : focus on food packaging in the Netherlands, Report for 
Wageningen, 2017, http://library.wur.nl/WebQuery/wurpubs/519929 

31 

 
 
 
 
 
Figure 9: Tonnes of scope biodegradable plastic products on the European 
market in 2016 

3.5.3 

Comparisons with the Conventional Plastics Market 

The quantity of in-scope end products sold in Europe, including both conventional and 
biodegradable plastics, was reported to be 35 million tonnes in 201670. This means that 
biodegradable plastics make up approximately 0.6% of the in-scope plastics market in 
Europe; a relatively small market share. 

Studies at nation-level are not common, however a study was recently carried out 
focussing on biodegradable and/or bio-based products on the Norwegian market. It was 
expected that 3% of all plastic packaging was either bio-based or biodegradable. 
Assuming a similar split in Norway to Europe as a whole71, this indicates that 
approximately 1.3% of all plastic packaging is biodegradable. The report also states that 
between 0.8 - 1.2% of plastic products in agriculture and horticulture in Norway were 
biodegradable72.  

There has also been a study carried out within the UK for the Biomass Biorefinery 
Network, predicting that approximately 8,000 tonnes of biodegradable, bio-based 
plastics are currently on the UK market. It is unclear exactly how much plastic is on the 
UK market; however, it is predicted that there were approximately 5.2 million tonnes of 
plastic waste arisings in the UK in 201873. This indicates that biodegradable plastics 
account for less than 1% of the market.  

70 Plastics Europe (2016) Plastics – the Facts 2016: An analysis of European plastics production, demand 
and waste data, October 2016 
71 European Bioplastics (2018) Bioplastics Facts and Figures 2018 
72 Eunomia Research & Consulting (2018) Bio-Based and Biodegradable Plastics, forthcoming 2018 
73 Eunomia Research & Consulting (2018) A Plastic Future – Plastics Consumption and Waste Management 
in the UK, Report for WWF - UK, March 2018 

32   

 
 
 
 
 
 
 
3.5.4 

Market by Geography within Europe 

The Nova Institute reported on the end products sold on the market by application 
within several key companies in Europe. The proportional split of the market by country 
is as shown in Table 5.  

As shown, some markets within Europe are much more advanced than others, primarily 
the Italian market, with 48% of all the biodegradable plastic products in the EU in 2015 
being sold in Italy. This is likely to have shifted to some degree since 2015, due to other 
countries such as France introducing plastic bag legislation and thereby driving increased 
demand - as outlined in section 3.5.2. Discussions with the original author of the report 
from which this data has come from suggests that it is their view that the market has not 
shifted hugely over this time, however. 

For context, whilst biodegradable plastics make up 0.6% of the European plastic market, 
in Italy this is around 1.6% in France and Germany it is around 0.3%.74 This means that 
the concentration of biodegrade plastics was at least five times greater than any other 
EU country in 2015/16. 

Table 5: EU sales proportion of biodegradable end products by geography 
and application, 201575 

Biowaste bags 
Shopping bags 
Flexible packaging 
(excl. bio/shopping 
bags) 
Rigid packaging 
Disposable 
tableware 
Coated paper 
packaging 
Agricultural and 
horticultural 
Consumer goods 
Fibres 

 Total 

AT-DE-
CH 
26% 
3% 

BE-NL 

16% 
5% 

FR 

10% 
3% 

IT 

26% 
84% 

SP 

2% 
- 

N-EU 

UK-IE 

10% 
3% 

11% 
1% 

22% 

22% 

22% 

22% 

56% 

33% 

11% 

17% 

- 

- 

25% 

25% 
33% 
20% 

25% 

25% 
33% 
13% 

- 

- 

- 

25% 

25% 
0% 
7% 

22% 

33% 

67% 

25% 

25% 
33% 
48% 

- 

- 

- 

- 

- 

- 
- 
1% 

- 

11% 

11% 

17% 

33% 

- 

- 
- 
7% 

- 

- 

- 

- 

- 
- 
5% 

74 Based on approx. 6m tonnes plastic market in Italy, 4m tonnes in France and 12m tonnes in Germany 
and total biodegradable plastics market of 200,000 tonnes in 2015/16. 
75 Nova Institute (2016) Market study on the consumption of biodegradable and compostable plastic 
products in Europe 2015 and 2020 

33 

 
 
 
 
  
 
 
 
3.5.5 

Market Size by Plastic Type 

The global market is currently dominated by three different groups of polymers; 
polyesters, PLA and starch blends. These polymers hold 27%, 24% and 42% of the market 
respectively – as shown in - with the remaining 7% split between PHA and other 
polymers. 

Again, as previous studies have varied in source and scope, it is difficult to quantify how 
this has changed over the past ten years. It should be noted that production capacities of 
each polymer can fluctuate significantly if one production facility ceases or suspends 
production, which is not necessarily representative of what is being consumed. 

Figure 10: Split of the global production capacity by polymer type, 201876 

The proportion of materials on the market that are bio or fossil based has been looked 
at, as shown in Figure 11. 

As shown, for the majority of materials on the market it has not been possible to 
determine the amount of bio-based feedstock in the material. This is largely due to the 
fact that there is no lower limit on the quantity of bio-based material in a polymer for it 

76 European Bioplastics (2018) Bioplastics Facts and Figures 2018 

34   

Polyesters27%PLA24%Starch blends42%PHA3%Other3% 
 
 
 
 
 
 
 
to be labelled as such, therefore even products that refer to themselves as bio-based can 
be upwards of 80% fossil-based content. 

Typically, starch blends include between 25-100% of bio-based material. PBS – a 
common polyester – can be 50-100% fossil-based, whereby PBAT is currently 100% 
fossil-based. Bio-PBS is relatively new to the market, so it is expected that it’s share is 
relatively small compared to the more established fossil-based PBS. 

Figure 11: Proportion of products made from fossil or bio-based building 
blocks 

3.6 

Future Quantity of Products on the Market 

3.6.1 

Market Drivers 

There are many potential market drivers, such as increased consumer pressure for 
materials to be ‘environmentally friendly’, policy measures and voluntary agreements. In 
the following section the political landscape in several focus countries will be detailed, in 
regards to compostable and biodegradable plastics. These countries have been identified 
as those that have, or are about to, enact policy that will heavily influence the 
biodegradable plastics market. 

35 

Bio-based27%Partly bio-based53%Fossil based17%Unknown3% 
 
 
 
It should also be noted that there are targets and directives across the EU that will 
influence the market. The EU’s Plastic Strategy77 has the objective for all packaging 
placed on the EU market to be reusable or recyclable by 2030, although the term 
recyclable has not yet been defined. The Packaging and Packaging Waste Directive 
requires Members States to achieve a recycling target for plastics of 50% in 2025 and 
55% by 2030.  Plastics packaging that is composted may, under certain circumstances 
specified under article 6a of the Directive, and further specified in an implementing act 
on the calculation rules78, be counted towards the recycling target. 

The new Single-Use Plastics (SUP) Directive79 commits the Commission to investigating 
the issues around biodegradability of plastics to determine whether they have a place in 
a circular economy. There is currently no exception for such materials in the SUP 
Directive. As stated previously, the Directive bans all products made from oxo-
degradable plastic. 

Appendix A.1.2 also provides an indicative scenario of what a business as usual growth 
may look like. However, it is clear that there are also many additional variables that will 
affect the market and therefore, this scenario should not be considered a forecast of the 
likely market. 

3.6.1.1 

France 

Under the Energy Transition for Green Growth Act single use plastic bags thinner than 50 
microns have been banned in France80. Home compostable bags are an exception to this 
decree and therefore a large-scale switch to home compostable plastics has been made. 
This applies to supermarket checkout bags, loose fruit and vegetable bags and packaging 
for mailshots, amongst others. The home compostable bags must meet the French 
standard for home composting – see section 2.6.2.1. They must also feature a bio-based 
content of at least 30%, with this planned to increase progressively to 60% in 2025. 

This may have resulted in a significant increase to the compostable plastic market in 
France, however data is not available on how this has influenced the market, and as the 
transition has taken place it is unlikely to drive the market within France further.  

Single use carrier bags have been gaining a lot of attention within Europe, with many 
countries enacting policies regarding their use. Some countries have enacted similar 
policies to France, for example Austria, who have also exempted compostable bags.81 
Other countries, however, have enacted policies to prevent single use bags altogether, 

77 http://europa.eu/rapid/press-release_IP-18-5_en.htm   
78 Commission Implementing Decision (EU) 2019/665 of 17 April 2019 amending Decision 2005/270/EC 
establishing the formats relating to the database system pursuant to European Parliament and Council 
Directive 94/62/EC on packaging and packaging waste, (http://data.europa.eu/eli/dec_impl/2019/665/oj) 
79 https://eur-lex.europa.eu/legal-content/EN/TXT/?qid=1562859783264&uri=CELEX:32019L0904 
80 https://www.legifrance.gouv.fr/affichTexte.do?cidTexte=JORFTEXT000031044385&categorieLien=id  
81 The Paper Bag Regulations in EU, accessed 25 June 2019, https://www.thepaperbag.org/for-compliance-
with-the-law/regulations-in-eu/ 

36   

 
 
 
 
 
for example by charging a fee for any single use carrier bag and encouraging reusable 
bags. 

3.6.1.2  Germany 

Between 2005 and 2012 plastic packaging producers who made certified compostable 
packaging were exempt from the cost of collecting and recycling these wastes. 
Stakeholders raised concerns about the end-of-life treatment of this waste, with fears 
that it could contaminate recycling. In German regulations, biodegradable plastic 
packaging is not considered to be organic waste and, as a consequence, it is frequently 
incorrectly collected with recyclable waste – disrupting the recycling process.82 As such, 
stakeholders were strongly opposed to the fee exemptions and they were subsequently 
removed. 

The VerpackG Act does, however, stipulate that the systems collecting the waste fees 
are obliged to create incentives that encourage the use of recycled material or material 
from renewable sources for the production of packaging. This signals that bio-based and 
recycled materials may be recognised as equally feasible solutions to making packaging 
more sustainable. Germany already supports the use of certified bio-based and 
compostable bio-waste plastic bags for the collection of bio-waste in the Bio-waste 
Ordinance83.  

3.6.1.3 

Italy 

In 2011 the National Budget Law, and the National Environmental Law, ruled that thin 
single-use bags had to be certified industrially compostable in Italy. This includes 
checkout bags, as well as bags for fruit, vegetables and baked goods. Since 2018, 
customers have also been expected to pay for the compostable bags.84 It is reported that 
only 61% of bags were certified as industrially compostable in 2018, despite this 
legislation. 85  

3.6.1.4  Netherlands 

The Dutch EPR scheme – “The Packaging Waste Fund” – was established in 2013. 
Companies that place more than 50 tonnes of packaging on the market are liable for a 
charge that then contributes to the disposal of such waste. There are different tariffs 
associated with different materials, for example the charge for plastic per tonne is 
significantly higher than materials that are easier to recycle such as paper. The EPR 
scheme previously offered advantages to compostable plastics that comply with EN 
13432. They had significant savings, as the fee was 2 cents per kg rather than the 64 

82 International benchmark of support measures for bio-based products and their applicability in France, 
SYNTHESIS REPORT, Study undertaken for ADEME by: BIO BY DELOITTE and NOMADÉIS. (June 2015) 
83 https://www.european-bioplastics.org/germany-takes-important-step-to-support-bio-based-packaging/  
84 Povoledo, E. (2018) Biodegradable Bags Cause Outrage in Italy. (It’s Not Really About Bags.), The New 
York Times 
85 Arcelli, P. La ﬁliera dei polimeri compostabili Dati 2018 – Evoluzioni attese 

37 

 
 
 
 
 
cents per kg for conventional plastic. This exemption, however, is due to end in 2019, 
with the fee for compostable plastics being increased to match those of conventional 
plastics. The decision to end the exemption was made as industrial composting facilities 
did not want the additional plastic material, and monitoring of the biowaste chain was 
not sufficient to ensure the plastic was actually recycled.86 

The impact that these reduced fees previously had on the compostable plastic industry 
was not quantified.  

3.6.1.5  UK 

The Resources and Waste Strategy outlines how the British government intend to 
minimise waste, promote resource efficiency and move towards a circular economy. Key 
targets of the strategy that may influence the compostable plastic market include: 

•  Extended Producer Responsibility for packaging by 2023; 
•  Mandatory weekly separate food waste collections; and 
•  Beverage Deposit Return Scheme by 2023 (subject to consultation). 

An Extended Producer Responsibility (EPR) scheme may result in increases in cost for 
producers, however there are also opportunities for money from these schemes to be 
put towards the bio-economy. It is unknown at this stage what form the EPR schemes 
will be in, and whether they will include compostable plastic.  

Mandatory weekly food waste collections will likely make the labelling of compostable 
plastic simpler. It is not yet clear on whether the treatment methods will be 
standardised, but this could, in theory, make the treatment of compostable plastic 
consistent within the UK, and thus a consistent message could be used on labelling 
making it easier for consumers to understand. 

There are currently consultations ongoing, at various stages for each of the four nations, 
regarding the implementation of a Deposit Return Scheme (DRS) in the UK. It is unclear 
at this stage how this will affect the biodegradable or compostable plastics market. It will 
be important for any legislation to clearly define how compostable plastics fall into these 
schemes, to avoid contamination of mechanical recycling streams.  

The UK Plastics Pact (UKPP) is a voluntary commitment from businesses across the 
plastic value chain aiming to tackle plastic waste. One of the targets of the UKPP is for 
100% of plastic packaging within the UK to be reusable, recyclable or compostable by 
2025 – five years earlier than the European target. If this target is reached, it is possible 
that the UK compostable packaging market could see a significant boost until 2025, 
however then growth is likely to level off as the full market potential is reached. 

86 Afvalfonds verpakkingen, accessed 25 June 2019, https://afvalfondsverpakkingen.nl/en/ 

38   

 
 
 
 
 
 
3.7 

Labelling and Communication Assessment 

Labelling of compostable and biodegradable products on the market can generally be 
very confusing to consumers. One common example of bad practice is when a product is 
described as ‘100% compostable’ – with no explanation of what this means, or guidance 
on which waste stream is appropriate. It is also often used when a product has not been 
certified to be home compostable. This can be very misleading, and the layperson could 
even think that this means the item can be littered and degrade in a short timeframe 
(this is discussed further in Section 4.4). 

It is important to understand the extent to which bad labelling is used on the market, 
and to look at how the disposal of these products could be communicated more 
effectively. Eunomia have carried out an analysis on the labelling of products across 
Europe, and the methodology and results are described in this section. 

3.7.1 

Methodology 

The key challenge in the assessment was to achieve a representative sample. Initially 
biodegradable or compostable packaging and products was gathered by the project 
team from the market within Europe. Stakeholders with a cross section of existing views 
with regard to compostable plastics from across the European market were also asked to 
send images of products from their own countries. Examples from the UK, Italy, 
Germany and France were found. 

For further details on the representativeness of the sample, see Appendix A.2.0.  

3.7.2 

Results 

The results from the assessment are shown in Table 6 where the majority of the product 
labels assessed have certifications, however they often do not distinguish clearly 
between home and industrial composting. The majority of labels also do not clearly state 
which waste stream the product should go in.  Potentially the most problematic category 
is items which claim to be biodegradable but without specifying the environment which 
it degrades in, as with no further information, this is the category which consumers may 
consider acceptable to litter. 

Table 6: Clarity of labelling assessment results 

Does the product clearly state that it is 
biodegradable/compostable? 

Does the product state compliance with EN 13432? 

Does the product display a certification? 

Yes 

No 

31 

30 

25 

3 

4 

9 

39 

 
 
 
 
 
If claimed to be compostable, does the product clearly distinguish 
between home and industrial composting? 

11 

23 

If stated to be ‘biodegradable’, does the product clearly define the 
environments in which it biodegrades in? 

1 

Does the product clearly state which waste stream it should go in? 

13 

18 

21 

Some examples of bad practice that encourage irresponsible behaviour were also 
present, for example packaging foam chips and carrier bags that claimed to be able to 
dissolve in water – shown in Figure 12—whilst made from PVA and thus would dissolve, 
the suggestion that this is a viable disposal method is questionable. There were also 
several examples of mistranslated messaging, for example a plastic film which was said 
should be disposed of in own garden compost, otherwise disposed of as ‘standard foil’ – 
a mistranslation from German to English – see Figure 13—but suggesting the material 
could be recycled with conventional plastics. Figure 14 shows a bottle label from Italy – 
one of the few ridged packaging examples. It is described as both compostable and 
biodegradable and whilst it instructs that it should be placed with biowaste, the graphics 
heavily imply that biodegradation in soil or in the open environment is also possible. It 
does, however include the Italian Composting and Biogas Association (CIC) logo for local 
compliance with EN 13432 although it is displayed somewhat less prominently on the 
reverse of the product. 

Figure 12: An example of bad labelling practice – unclear message on 
where a consumer should dispose a product 

40   

 
 
 
 
 
Figure 13: An example of bad labelling practice – mistranslation from 
German to English causing confusion 

Figure 14: Italian Compostable Plastic Bottle Label 

Figure 15 shows an example of what may be considered better practice considering the 
current availability of appropriate disposal options for these materials. It suggests 
specific waste streams and where not to dispose of it and displays certification logos. 
However, it is still vague in language by being non-specific about ‘compost’ which could 
mean either household collected or home composting – the certification is for home 
composting, but this might be confusing for those who do not have this. This 
demonstrates how complex the messaging is and the difficulty in conveying this even on 
a larger item such as this plastic bag. The messaging is also likely to be very region 
specific which is problematic for products sold across Europe as in the example in Figure 
13. 

41 

 
 
 
 
 
 
Figure 15: An example of good labelling practice – clear instruction on re-
use/disposal and accompanying certifications. 

Through discussions with stakeholders it was found that product manufacturers are 
becoming increasingly aware of the need for clearer messaging on products, however 
there is not always sufficient space to write clear instruction. Vegware are a key example 
of a company who are looking to improve their on-pack messaging as they have decided 
to modify their current messaging which contains the terms ‘completely compostable’ 
and ‘made from plants, not plastic’. The former statement does not provide any specific 
instruction to consumers and whilst the latter is an attempt to separate the act of 
composting from plastics recycling in the mind of the consumer, it is factually incorrect 
to state that PLA is not a plastic.  

In future, their products will now have two statements: ‘packaging made from plants’ 
and ‘commercially compostable where accepted’. Both of these statements are factually 
correct and will help to make the disposal options clearer. 

Vegware have also introduced a green band on some of their products that is intended 
to be easily identifiable by consumers and composters alike. This is coupled with training 
for composters in order to recognise this green band and visually identify that the 
product is not contamination (only for composters that are willing and capable of 
processing these materials). Whether this has or will be a successful method of 
identification—particularly for composters—remains to be seen at this time. 

3.8 

Key Conclusions 

Key Conclusions – The EU Biodegradable Plastics Market 

The available data on the amount of biodegradable plastic produced is limited, often 
conflicting, lacking in detail and outdated. This is a result of the structure of the 
market which is dominated by a few larger manufactures; if one facility closes then 
the size of the market can change dramatically in a short space of time. As it is a 
relatively small market compared with conventional plastics, less research is carried 
out and thus reporting is not as frequent. Identifying exact quantities of specific 
products on the market is even more challenging. This is because some applications 
may account for a few hundred tonnes per year which could easily fluctuate as a result 

42   

 
 
 
 
  
 
of small changes such as a feedstock shortage or even a single customer buying more 
or less product in a particular year. It is clear, however, that the strongest 
biodegradable plastics market application is flexible packaging, and in particular, the 
various types of compostable or biodegradable bags. 

The key applications have been identified by using data for production and from 
numbers of certified products to determine a top ten list: 

•  Carrier bags 
•  Biowaste bags 
•  Rigid packaging (food and non-food) 
•  Other flexible packaging (food and non-food, not incl. carrier or biowaste bags) 
•  Agricultural films 
•  Single use trays and plates 
•  Single use cups 
•  Single use cutlery 
•  Bags for loose products (vegetables and other) 
•  Coffee pads, filters and capsules 

Determining the share of the above-mentioned products which are certified 
compostable vs. the share which aren’t, be it for the overall market for biodegradable 
plastics or for specific applications, has not been possible. All European Bioplastics 
Members (80% of the market) certify their material, but this does not prevent it begin 
used in applications that might hinder composting (e.g. using thicker material or using 
it alongside non-compostable materials)  

Carrier bags and biowaste bags combined make up almost 60% of the certified 
product market by number of certifications in 2019, and 68% of the mass of 
biodegradable plastics product found on the market in 2015.  

The global biodegradable plastics market is currently dominated by three different 
groups of polymers; polyesters, PLA and starch blends. These polymers hold 27%, 24% 
and 42% of the market respectively. 

The labelling of compostable products often is not clear for the consumer, and 
sometimes incites irresponsible behaviour such as littering of plastics that do not 
biodegrade in the open environment. Examples of good and bad practice have been 
highlighted in this section. 

43 

 
 
 
 
 
4.0 

Impacts of an Increase in the Market for 
Compostable Consumer Plastic 
Products and Packaging 

Whereas the market assessment in Section 3.0 includes mulch films within its scope the 
scope of this section is restricted to ‘consumer plastic packaging and products’. It also 
focuses specifically on compostable plastic products. This is because this is the only type 
of biodegradable plastic that in principle has a waste management route and a 
European standard associated with it.  

The overall objective of this section of the report is to develop a better understanding of 
the role of compostable plastics in the context of circular economy and possible trade-
offs associated with making products or packaging biodegradable/compostable rather 
than reusable or recyclable.  

In order to achieve this, the following aspects are discussed in subsequent sections: 

•  Establishing the nature and quality of compost resulting from the composting of 

biodegradable/compostable plastics 
Implications of Compostable Plastics in Organic Waste Processing  

• 
•  Establishing the effect of biodegradable/compostable plastics entering plastics 

recycling streams 

•  Analysing the evidence base for the littering risks associated with 

biodegradable/compostable plastics 

4.1 

Establishing the Nature and Quality of Compost 
Resulting from Compostable Plastics 

In this section the evidence was analysed to evaluate the nature and quality of the 
compost resulting from composting biodegradable plastics. This includes analysis of 
Article 6a (4) of Directive 94/62/EC and the evidence for compostable plastics meeting 
the criteria for contributing to packaging recycling targets. 

4.1.1 

Compostable Packaging Contributing to Recycling Targets 

Article 6a (4) of the Packaging and Packaging Waste Directive (PPWD) 94/62/EC states 
that;  

“For the purposes of calculating whether the targets laid down in points (f) to (i) of 
Article 6(1) have been attained, the amount of biodegradable packaging waste that 
enters aerobic or anaerobic treatment may be counted as recycled where that 
treatment generates compost, digestate, or other output with a similar quantity of 
recycled content in relation to input, which is to be used as a recycled product, 
material or substance. Where the output is used on land, Member States may count 

44   

 
 
 
it as recycled only if this use results in benefits to agriculture or ecological 
improvement.”  

In other words, the key requirement to establish whether or not packaging can be 
counted towards the recycling target is whether or not the output from the aerobic or 
anaerobic treatment of this packaging “results in benefits to agriculture or ecological 
improvement” where the output is used on land. It is also clear that this implies that any 
negative effects from the output being used on land would lead to not fulfilling this 
criterion. 

The extent to which compostable plastics will fulfil this requirement is partially down to 
the way in which ecological improvement is defined. The spirit of Article 6(1) is that 
compostable plastic provides the same, or at least broadly similar, benefits to 
agricultural soil as the other composted organic matter. This goes beyond the 
requirements of the current EN 13432 which states that the compost is “not negatively 
affected by the addition of that packaging material or packaging component” according 
to plant growth test OECD 208. The implication of this is that conformance with this 
standard does not necessarily imply that the requirements of Article 6(1) are also met. 

The Commission Implementing Decision EU 2019/665 of 17 April 2019 was introduced to 
ensure a common calculation methodology in the PPWD. Article 6C (1d) states that: 

“Where biodegradable packaging that is subject to aerobic or anaerobic treatment is 
included in the recycled amounts for the respective packaging material, the amount 
of biodegradable packaging in biodegradable waste shall be determined by 
performing regular composition analyses of the biodegradable waste entering those 
operations. Biodegradable packaging waste that is removed before, during or after 
the recycling operation shall not be included in the recycled amounts.” 

The wording of the article excludes packaging which is rejected through pre-treatment 
(primary screens, hydropulpers, etc.), and at any other point in the aerobic or anaerobic 
treatment operation. This means that compostable plastics that are placed on the 
market cannot be assumed to be counted towards packaging recycling targets even in 
municipalities that use organic treatment facilities that accept these materials. 

4.1.1.1 

Evidence on the Nature of the “Compost” From Compostable 
Plastics and the Potential Related Qualitative Benefits 

The scientific evidence surrounding the nature of compostable plastic after the 
composting process (beyond determining any ecotoxicological effects) is distinctly 
lacking at present. This is likely to be because the focus has been determining that there 
are no negative effects (e.g. toxic elements introduced into soil) rather than ensuring 
positive effects (benefits). It is possible that compostable plastic will improve soil 

45 

 
 
 
structure and stabilise aggregates, but the yields will be very difficult to quantify, which 
is also the case for ‘normal’ types of organic material.87 

A 2008 study comparing using life cycle assessment (LCA) to compare different event 
drinks cups by the Austrian Institute of Ecology concluded that “since PLA material does 
not contain any plant-available nutrients (structural formula) and does not contribute to 
the built-up of the soil structure, composting is purely a disposal alternative.”88 

The assertion that it does not contribute to soil structure is contentious. Indeed, the 
problem of attempting to quantify the direct benefits from the composting of plastics is 
often problematic within LCA—this is especially true when one must make assumptions 
as to how much material becomes incorporated into the final compost. Several such 
studies were analysed by the German Federal Environment Agency89 which concluded 
that nutrient benefit was negligible and therefore the main benefit would be from 
providing soil structure, but suggests that if 90% degradation was to occur then soil-
structure building would also be negligible. However, the study also noted that 
manufactures claim that a real-life degradation rate would be closer to 50% (similar to 
bio-waste) with the reminder enhancing soil structure (in the form of biomass)—this 
claim is common place, but it is difficult to find substantive evidence for it other than 
older chemical testing protocols from the OECD only requiring a 60% pass level for 
biodegradation (this is discussed further in Section 4.1.1.2). 

In 2019 the Norwegian Composting facility SIMAS IKS conducted a study by composting 
4.2 tons of PLA cups from a festival.90 The PLA cup was certified to composting standard 
EN 13432. The PLA cups were shredded to a size of 0-10 mm and composted in windrow 
composting for 12 weeks together with garden and food waste, in proportions of 10% 
PLA, 45% garden waste and 45% food waste. The PLA plastic was not visible in the 
compost  after 12 weeks of composting. The final compost product was analysed in a 
laboratory and classified as the highest quality. SIMAS concluded that the PLA did not 
have a negative effect on the compost. However, the study did not observe or look for 
evidence that the PLA had ecological improvements in the compost and studies such as 
this will find it impossible to do so as there are many interconnected variables that 
prohibit assigning ’benefit’ to one particular input. 

87 Sander Brun., (2019). Personal communication on ecological improvements to soil from biodegradable 
plastics.  
88 Christian Pladerer, and et al. (2008) Comparative Life Cycle Assessment of various Cup Systems for the 
Selling of Drinks at Events, Report for Austrian Federal Ministry of Agriculture and Forestry, Environment 
and Water Management, 2008 
89 Systemadmin_Umwelt (2013) Study of the Environmental Impacts of Packagings Made of Biodegradable 
Plastics, March 2013, https://www.umweltbundesamt.de/publikationen/study-of-environmental-impacts-
of-packagings-made 
90 SIMAS IKS - Dagny Karin Ugulsvik Alvik. (2019) Erfaringer med kompostering af PLA. 
https://www.grontpunkt.no/nyhet/vellykket-kompostering-av-pla-glass/   

46   

 
 
 
 
 
An ADEME study from 201891 introduced compostable plastic bags into a composting 
process and found that this did not lead to differences in agronomic and sanitary quality 
or pose any ecotoxicological risk to the environment for compost compared to compost 
without bags added. It met all of the agronomic criteria of standard NF U 44-051 (the 
French compost quality standard). Again, there was no evidence of any additional 
benefits compared with compost. 

For further evidence of the ecological benefit from compostable plastic we can also look 
at studies for mulch films—these are often the same or similar types of materials that 
film packaging is made from. Soil health from the use of any kind of mulch film is a 
much-debated topic—and has been subject to far more research—which may also aid in 
the current discussion. A recent meta study summarised the current literature on 
impacts of biodegradable plastic mulch films on soil biological and biogeochemical 
processes.92 The important element to focus on is when the films are incorporated into 
the soil after their purpose has been fulfilled. The study concluded: 

•  Mulch films incorporated into the soil are generally considered to be safe 
•  However, ecotoxicity tests focus on one stage of plant growth i.e. gemination. 

Other (later) effects are less well understood. 

•  Mulch films can have some effect on microbial activity with increased microbial 

abundances, respiration, and enzyme activities. 

•  Mulch films had no measurable impact on nitrification potential of soils but 

effects on other nutrients remain unknown. 

Taken together this suggests there may be long terms effects, but whether these provide 
net benefits is unclear. Mulch films are also likely to be applied to land in higher 
concentrations compared to compostable plastics within compost therefore the 
magnitude of these effects in the latter situation is even less clear. 
Finally, there is also recent evidence93 to suggest that it is possible to modify the 
compostable plastic to enhance soil quality through adjusting the C/N ratio of the 
materials and the number of added nutritional compounds. These sorts of innovations 
are far from being mainstream as yet, but may demonstrate a potential opportunity to 
improve overall compost quality, although the practicalities of this are unclear at 
present. 

91 Déportes I.Z, Le Ravallec V., Mortas N., Thévenin N., and Machinet G. (2018) Biodégradabilité En 
Compostage Des Sacs Plastiques Biodégradables (Norme Nf T 51-800) Et Des Sacs En Papier, Report for 
ADEME, September 2018 
92 Bandopadhyay, S., Martin-Closas, L., Pelacho, A.M., and DeBruyn, J.M. (2018) Biodegradable Plastic 
Mulch Films: Impacts on Soil Microbial Communities and Ecosystem Functions, Frontiers in Microbiology, 
Vol.9 
93 Moreira, A.A., Mali, S., Yamashita, F., Bilck, A.P., de Paula, M.T., Merci, A., and Oliveira, A.L.M. de (2018) 
Biodegradable plastic designed to improve the soil quality and microbiological activity, Polymer 
Degradation and Stability, Vol.158, pp.52–63 

47 

 
 
 
 
 
4.1.1.2 

Implications for Interpretation of “Ecological Improvement” 

From the qualitative side, the key element to be considered is “ecological improvement” 
(and the similar one, “benefit to agriculture”, mentioned in the Commission Decision 
2011/753/EU). This may require, in the future, a unified definition at EU level, given its 
pivotal role in assessing whether a material may be counted as “recycled”. In the 
absence of such EU-wide definition, the subject may be somewhat informed by 
considering the agricultural purpose of using compost or digestate, which refers to the 
nature of composted products, their intended role in fertilisation, and related required 
properties.  

A useful definition for “soil improvers” to frame the intended benefits of using compost, 
is indicated in the Commission Decision (EU) 2015/2099 for the EU Ecolabel for growing 
media, soil improvers and mulch states that a soil improver: 

“…means a material added to soil in situ whose main function is to maintain or 
improve its physical and/or chemical and/or biological properties (...)” 

Similarly, the Fertiliser Regulation (EU) 2019/1009 states that a soil improver: 

“… shall be an EU fertilising product the function of which is to maintain, improve or 
protect the physical or chemical properties, the structure or the biological activity of 
the soil to which it is added.” 

Both of these definitions align well and allow for soil improvement to be classified as 
either physical or chemical. From the agronomic angle, compost is considered a “soil 
improver”. Arguably, possible “ecological improvement” related to compostable plastics 
might not necessarily have to be considered in terms of nutrient capacity, but could be 
considered in terms of the physical soil improving effects related to organic matter. 
There is currently no evidence to suggest that compostable plastics contribute any 
chemical benefit—assumed to include the provision of nutrients. The physical benefit 
gained from compostable plastic—in the form of converted biomass contributing carbon 
into the soil— is supported by some evidence (as described previously in Section 
4.1.1.1.)  

Therefore, the nature of compost/digestate as “soil improvers” could be seen as of 
relevance in relation to the issue of “ecological improvement” to the extent that it, at 
least in part, indirectly links to various agronomic benefits such as:  

Improved structure and tilth94 

• 
•  Reduced resistance to ploughing and tilling95  
• 
•  Reduced energetic input to the primary sector from all previous effects 
•  Enhancement of microbial and biochemical activities in soils  

Improved water holding capacity 

94 Soil tilth is its physical condition of soil, especially in relation to its suitability for planting or growing a 
crop 
95 Tilling is the agricultural preparation of soil by mechanical agitation 

48   

 
 
 
 
 
• 

Increased availability of various nutrients to plant roots, preventing them from 
being locked onto mineral particles   

•  Carbon sequestration in soils 

This would in principle call for looking at the question of what compostable plastic might 
biodegrade into from a more quantitative angle. In this context one may note that it is 
implicit in EN 13432 that around 50% of the compostable plastics is mineralised during 
the composting process—the rest being biochemically converted and incorporated into 
the output, i.e. compost. This is because the defining threshold concentrations of heavy 
metals in EN 13432 are 50% of the limits set in the Ecolabel for soil improvers: 

“It is assumed that 50 % of the original weight of the packaging or packaging 
material will remain in compost after biological treatment together with the 
complete original amount of hazardous substances. The limit values are based on 
ecological criteria for the award of the Community eco-label to soil improvers…and 
are set at 50 % of the maximum concentration of those requirements.” 

The implication being that if 50% of the material is incorporated into biomass then this 
effectively doubles the concentration of heavy metals. This has long been considered as 
a reference ‘rule of thumb’ average for mineralisation of polymers occurring during 
composting, but it is difficult to find substantive evidence for it other than older chemical 
testing protocols from the OECD only requiring a 60% pass level for biodegradation. The 
OECD guideline for testing of chemicals for ready biodegradability (301) states that: 96 

 “[Lower thresholds are required] as some of the carbon from the test chemical is 
incorporated into new cells, the percentage of CO2 produced is lower than the 
percentage of carbon being used.” 

The specified OECD tests are required to be undertaken within 28 days which is not 
enough time for the microorganisms to fully metabolise the material and expel CO2 (and 
CO2 is the indicator of biodegradation, not the direct result of it). Later tests such as 
those specified in EN 13432 have adopted 90% as the threshold as the time has been 
extended (180 days) to allow full mineralisation to take place—this provided more 
certainty that the material is inherently biodegradable. 

However, these tests should not be taken as a reference for the fate of compostable 
plastics in real life. In this respect, most of research available so far on actual 
mineralisation of compostable plastics, refers to standard lab conditions as defined in 
ISO 14855, and expresses degradation as a percentage, relative to the reference material 
(cellulose)97. As stated, this does not allow calculation of actual mineralisation (and the 
related conversion rates into final outputs) in real composting conditions, i.e. how much 

96 OECD (1992) OECD Guidelines for the Testing of Chemicals - 301 A-F - Ready Biodegradability 

97 See e.g. Narancic et al. (2018) Biodegradable Plastic Blends Create New Possibilities for End-of-Life 
Management of Plastics but They Are Not a Panacea for Plastic Pollution, Environ. Sci. Technol. 2018, 52, 
10441−10452 

49 

 
 
 
 
 
of the starting polymer has been turned into CO2 and H2O, and how much has been 
incorporated into the output biomass.   

A study setting out to answer this specific question was recently carried out by Zumstein 
et al. (2018)98, who tested biodegradable mulch films (PBAT): using Carbon-13 labelled 
polymers which was incubated for six weeks in soil. This study is directly relevant to 
compostable plastics as the same microbial process takes place albeit at different 
temperatures and inoculum. 

The study found:  

•  Between 8% and 13% of Carbon from the investigated biodegradable polymers 

was turned into CO2 over the six week test period 

•  Extensive surface colonisation of films by both fungi and unicellular organisms 
•  Roughly 6% of Carbon in microbial biomass was made of Carbon-13, taken from 

the Carbon-13 labelled polymers (unfortunately, embodied Carbon was 
expressed as a percentage of the microbial Carbon, and not of the starting 
Carbon in the investigated polymers) 

Importantly this study also confirmed that microorganisms do colonise the material; that 
the secreted enzymes do cause depolymerisation on the surface; and, there is microbial 
uptake of the resulting low molecular weight compounds. 

4.1.2 

Key Conclusions  

Key Conclusions – Establishing the nature and quality of compost resulting from the 
composting of biodegradable/compostable plastics 

To properly interpret Article 6a (4) of the Packaging and Packaging Waste Directive 
(PPWD) 94/62/EC it must be established whether or not the output from the aerobic or 
anaerobic treatment of packaging “results in benefits to agriculture or ecological 
improvement” where the output is used on land. It is also clear that this implies that any 
negative effects from the output being used on land would lead to not fulfilling this 
criterion. 

Direct evidence of ecological improvement from compostable plastics is sparse and 
inconclusive. There appears to be consensus around the lack of nutritional benefit and 
therefore this leads towards investigating more in-depth the potential physical benefits 
of incorporating carbon directly into the soil as biomass. The definition of ‘soil improver’ 
in the Fertiliser Regulation and Ecolabel for Soil Improvers indicates that either physical 
or chemical functions can be considered in this regard. 

98 Zumstein et al. (2018) Biodegradation of synthetic polymers in soils: Tracking carbon into CO2 and 
microbial biomass, Sci. Adv. 2018;4: eaas9024 

50   

 
 
 
 
 
 
However, the evidence for the extent to which assimilation of the carbon into the 
compost takes place is also limited. Only recently has the carbon in the polymer been 
tracked into biomass, but this is difficult to quantify at this stage. 

Further research would be required to have a clearer view of how much organic matter 
becomes mineralised during actual composting conditions and, conversely, how much 
gets incorporated in the final compost product. Tracking the carbon through the process 
is very much in the early stages, but does further the understanding of what is taking 
place (which was largely assumed until this point).  

Until such time as the term ‘ecological improvement’ is further defined it seems 
reasonable that this could be considered in terms of a ‘soil improver’ as defined in the 
Fertiliser Regulation and Ecolabel for soil improvers. In relation to compostable plastic, 
before considering its benefits analogous to those of a soil improver, further specific 
study would be needed to determine the exact nature and quantity of the remaining 
material that does not degrade into CO2 and water and whether this behaves broadly in 
similar ways, from an ecological perspective, as the surrounding compost. At this stage 
the evidence is too weak to arrive at any form conclusions in this regard. 

4.2 

Implications of Compostable Plastics in Organic 
Waste Processing 

The following sections explore the types of organic waste infrastructure that exists in 
Europe and the implications of processing compostable plastics within these systems. 
There is also a particular focus on the countries of Italy and Germany; the former for the 
significant market of compostable plastics and the latter for the reverse. Case studies 
and examples from across Europe are also used to broaden the perspective. 

4.2.1 

Common Organic Waste Treatment Methods 

There are broadly three different kinds of organic waste treatment systems that are 
commonly used throughout the EU: 

•  Anaerobic Digestion (AD) 
• 
•  Open Air Windrow (OAW) or Aerated Static Piles (ASP) 

In Vessel Composters (IVC) 

The following sections describe these processes in high level to provide context for the 
discussion in later sections that looks at some of the issues reported by these types of 
plants. 

4.2.1.1  Anaerobic Digestion (AD) 

AD is increasingly considered the preferred method for processing food waste from an 
environmental perspective. This is because it is an enclosed process that generates 
methane in the form of biogas which is a high value output and can either offset fossil 
gas production or be burned to produce electricity on site resulting in an overall net 
benefit in terms of climate change mitigation.  

51 

 
 
 
Food waste, rather than garden waste from household sources, is generally preferred in 
AD facilities. This is because garden waste has a lot of wood-based (lignin) materials 
which will not break down in AD quickly or produce much biogas and consequently it is 
more cost effective to use open air windrow of IVC for most garden waste. 

The two main variations of the AD process that are relevant to the present discussion are 
wet and dry processes. In a ‘wet’ process there is generally less than 15% dry matter 
which is pumped around the system rather than layered. The UK, Denmark, and Norway 
commonly use this process. The process is also often mesophilic (~37 ° C) rather then the 
higher temperatures in other composting a dry AD processes. Digestate is the primary 
output by weight; this is a slurry-like substance which can be applied to agricultural land, 
but has less nutritional benefit than mature compost— it is very high in mineral nitrogen 
and ammonia with very little carbon content to provide structure to the soil and cannot 
be applied all year round. 

The ‘dry’ AD process which is has a much lower water content (15-45% dry matter) and 
will often be more efficient and cheaper to run as the heat required to accelerate the 
degradation is not wasted on heating water—conversely the set-up costs of dry AD are 
higher than wet AD.99 The dry batch systems, which operate at higher levels of dry 
matter, do not use pumps and pipes—materials are moved through front-end loaders—
and they generally have fewer problems with plastic contamination fed into the process, 
with contaminants removed at the end of the process, during the final refining step.  

This is more common in Italy and Austria and generally also includes a secondary 
composting stage to stabilise the digestate to meet the end of waste status. This can 
increase the value of the digestate, both in economic and agronomic terms as the 
balance of nitrogen and carbon is closer to compost and therefore it can be used for a 
wider array of applications. 

The business model for AD often depends heavily on income from biogas generation, 
particularly in countries where renewable energy subsidies are/were available such as 
the UK and Germany (reduced significantly in 2014). Under these circumstances the 
digestate quality is often of lesser importance as the incentive is to maximise biogas 
production. 

According to the European Biogas Association there are 17,432 biogas plants operating 
in Europe as of 2017 – this includes all types of AD including wastewater sludge as well 
as landfill gas capture.100 10,971 of these are situated in Germany – the vast majority are 
used to process agricultural waste which is also true for most other EU countries. AD 
plants designed specifically for household food waste, represent a much smaller 
proportion of the capacity across Europe and are almost non-existent in Germany 

99 https://www.biogasworld.com/news/dry-wet-anaerobic-digestion-systems/ 
100 https://www.europeanbiogas.eu/wp-content/uploads/2019/05/EBA_Statistical-Report-
2018_AbrigedPublic_web.pdf 

52   

 
 
 
 
 
(although this is beginning to change101). This demonstrates that the technologies have 
not grown up around the requirement to treat food waste and it is often the case that 
plants (or the underlying technology) have been adapted from taking different feed 
stocks. These are even less well equipped to deal with plastic contamination which is 
typically only a problem in food waste. 

In Denmark a senior Danish composting sector representative interviewed in the context 
of this study revealed that one AD site is composed of an anaerobic step with a final 
aerobic maturation stage; as such, the system had no problem in processing 
compostable plastics, and support was expressed for the specific use of compostable 
bags, so as to a) increase captures and b) minimise contamination from conventional 
plastics. Conversely, other sites processing food waste collected from Copenhagen (and 
other bordering municipalities) are co-processing this with manure, which requires prior 
pre-processing that turns food waste into a pulp; the main fate of compostable plastics 
there, is to end up in final rejects (residual waste going to incineration).  

As a consequence, the pre-processing company argues for the use of conventional 
plastics. The City of Copenhagen keep using and supplying compostable plastics, since it 
is argued that small fragments that may end up in the pulp that is sent to anaerobic 
digestion will ultimately biodegrade, which would not be true for conventional plastics. 

This indicates that acceptability may vary depending on the operational scheme of the 
site even within countries.  

An aspect of AD that is less well understood (and certainly poorly communicated and 
managed by EN 13432) is that because the process is anaerobic that not all compostable 
plastics are suitable. Different polymers are degraded by different microorganisms, and 
different microbial communities may be available depending on the composition of the 
waste that is used. A typical wet AD plant operates with a hydraulic retention time102 
(HRT) of 15–30 days, but only certain polymer types are theoretically capable of 
biodegrading within that timeframe where materials such as PCL, PLA and PVA take 
longer.103 This is problematic as all of these materials are known to biodegrade in other 
composting processes and are often certified as such. 

A 2019 study by French waste management company, Suez, tried to determine how PBS, 
PBAT and PLA bags actually perform in mesophilic AD plants by simulating at a lab scale 
and measuring methane production.104 It found that they had weak anaerobic 
biodegradability with limited or no methane production after 21 days of digestion. This is 
in comparison with paper bags which showed “satisfactory biodegradation.” The authors 

101 http://adbioresources.org/news/running-an-ad-plant-lessons-from-germany 
102 A measure of the average length of time that a compound remains in the bioreactor 
103 Bátori, V., Åkesson, D., Zamani, A., Taherzadeh, M.J., and Sárvári Horváth, I. (2018) Anaerobic 
degradation of bioplastics: A review, Waste Management, Vol.80, pp.406–413 
104 Laure Constans, Maxime Rouez, Marion Lespiell, and Justine Auclair (2019) Plastiques compostables : 
biodégradabilité anaérobie et contribution à la production de méthane, Report for Suez, December 2019 

53 

 
 
 
 
 
also comment that the persistence of the physical integrity could pose mechanical 
problems with the AD process, and indeed this is a known problem for some operators. 

4.2.1.2 

In Vessel Composters (IVC) 

In vessel composting is used throughout the EU for treating food and/or garden waste. 
There are several types and variations of the process as well as several stages, but it is in 
essence, primarily a controlled composting process exposed to oxygen rather than a 
digestion process in the absence of oxygen.  

IVC operators still have similar challenges with regard to plastic contamination as AD 
operators, but there are no pipes or pumps to block and disrupt the process. However, 
some sites still have primary screens that may send plastics and compostable plastics 
into rejects. This is a common practice in Germany where conventional plastic bags, 
which are often used by households to deliver biowaste, are removed.  

UK waste contractor Biffa105 state that they do not accept compostable plastics in food 
waste streams as their processing sites as it will merely been screened out. Biffa have 
run trials with PLA items in IVC sites but this showed that the products weren’t 
biodegrading fully after being shredded coarsely and integrated into the biowaste. A 
smaller shred size improves this, but there is a real concern as to how to manage the 
potential cross-contamination in this stream from conventional plastics which would also 
be shredded and therefore impossible to remove later – at the moment there are no 
checks between collecting it, fine shredding it and then going into the compost mix. 
Larger fragments take longer to compost which makes it less economical but are easier 
to remove if not fully composted. Screened material generally goes to energy from 
waste (EfW).   

One of the most important aspects to understand is that the compost output will vary 
dramatically dependently upon how long it is processed for. There are a number of, 
primarily economic and regulatory, drivers for the reasons why a facility may choose to 
produce compost that has not yet fully matured. 

Germany use a voluntary, but well established Rottegrad classification system, 
developed by the Bundesgütegemeinschaft Kompost106 (BGK) which grades compost 
maturity level for certain applications (and certifies to quality standard RAL-GZ 251 of 
which 70% of compost in Germany carries the marque107). The two main examples are 
mature compost (graded IV-V) and fresh compost (graded II-III). The maturity level can 
be determined by measuring the self-sustaining temperature that the compost exhibits 
or the oxygen consumption – either test indicates the activity level in the compost. 
mature compost is generally used for higher value (horticultural) applications, such as 
gardening, landscaping, greenhouses and tree nurseries, whereas fresh compost is 

105 Teleconference call to Eunomia in Spring 2019 
106 Federal Quality Compost Association  
107 https://www.kompost.de/uploads/media/Compost_Course_gesamt_01.pdf 

54   

 
 
 
 
 
typically applied directly to agricultural land — the latter can be composted for as little 
as 6-8 weeks. Figure 16 shows industrial composting process over time where the 
temperature increases with biological activity and decreases as the carbon is 
metabolised. The Rottegrad system is shown for reference which demonstrates that 
there is still a great deal of microbial activity taking place in ‘fresh’ compost, which 
makes it only suitable for a limited set of applications. 

Figure 16: The Industrial Composting Process in the Context of the German 
“Rottegrad” Maturity System  

Source: WRAP (2016) 

The implications for putting compost on agricultural land that has not fully matured are 
that the land should ideally not be planted (especially with more sensitive crops) until 
the maturation has finished —for marketing purposes in Germany this results in a lower 
cost product. The agronomic benefits—or lack thereof—of fresh compost is the subject 
of much debate in Germany and providing conclusions in this regard is out of scope of 
the current study. However, a literature review of the issues around compost stability by 
WRAP from the UK (but looking at literature across Europe especially from Germany 
where much of the research has been conducted) concluded that “Agricultural and field 

55 

 
 
 
 
 
 
horticultural trials have not shown significant agronomic problems when less mature 
composts have been used.”108 

Nevertheless, these particular practices are unlikely to be compatible with the conditions 
that are specified in EN 13432 (see Section 5.0 for the discussion on this aspect) and 
appear to be one of the key barriers to compostable plastics in Germany. 

Conversely, Italy has a general minimum requirement that compost should mature for at 
least 90 days (up to twice as long as German fresh compost) as well as fulfilling other 
minimum quality criteria. Digestate is also still considered a waste (whereas in other 
countries it can be used directly on land , albeit in Germany land spreading is considered 
as an R10 operation, i.e. still dealing with a waste) and requires post-composting in order 
to achieve the status of a product which can be sold — this is in line with assumptions on 
which requirements appear to be based in EN 13432 for treatment in aerobic conditions. 

A study in the Netherlands109 put various compostable plastic items (plant pots, bags, 
teabags and coffee pods all certified to EN 13432) through an industrial composting 
process and analysed the level of disintegration that could be observed. The composting 
cycle of 11 days (on the lower end of practice in the Netherlands) was not sufficient to 
completely disintegrate most of the compostable products (orange peel and banana skin 
reference materials also did not fully disintegrate, however). Facilities that recirculate 
unfragmented plastic through the process would not find this problematic although this 
only happens down to a size of 10 mm. Further degradation is likely to take place during 
a subsequent maturation phase, but the compost is often utilised in the Netherlands 
without this step. The authors focus on ‘visible ‘contamination and note that brightly 
coloured coffee pods showed up more often – no comment was given on actual 
contamination and whether it would then subsequently be applied to land. The main 
focus was on whether the compostable plastic would result in rejection of the compost 
due to visual checks. Plants that have any pre-treatment or separation stage and the 
beginning will remove much of the compostable plastic for residual treatment – this is 
common in the Netherlands. In the context of the present study this further 
demonstrates that considerable variation exists in both products and composting 
processes to not fully guarantee full biodegradation of compostable plastics in the 
Netherlands, although it appears to be possible for processes to be optimised to achieve 
this. 

108 WRAP (2016) Literature review: Compost stability – impact and assessment, July 2016 
109 Maarten van der Zee, and Karin Molenveld (2020) The fate of (compostable) plastic products in a full 
scale industrial organic waste treatment facility, Report for Dutch Ministry of Economic Affairs and Climate 
Policy, February 2020 

56   

 
 
 
 
 
 
4.2.1.3  Open Air Windrow (OAW) and Aerated Static Piles (ASP) 

The open air windrow (OAW) is the most basic form of composting facility and very 
similar to home composting in that the organic material is piled up, usually outside, and 
left to compost naturally. The windrows are turned regularly to aerate and redistribute 
the material (while static piles are usually not turned) and some more sophisticated 
operations use air blown through pipes embedded in the ground underneath. Some 
facilities are under roofs or fully enclosed which blurs the line between this an IVC. 
Higher—thermophilic—temperatures can be achieved due to the overall mass of the 
organic matter generating and maintaining heat throughout the process. These higher 
temperatures set the process apart from home composting and the biodegradation 
process as a whole is very similar to IVC as they both take place in the presence of 
oxygen. 

A 2018 study carrier out by ADME in France110 found that composting time needs to be 
extended in the presence of compostable plastics (in this instance, biowaste bags). At 
least 6 months of composting in an aerated static pile was required to stop observing 
bag fragments plastics in the screened compost. It is unclear whether the lack of visible 
fragments resulted in full biodegradation (although the study found that microbes were 
colonising the material), but this timescale fits with the 6 month requirement in EN 
13432. Any similar process that does not adopt at least this timescale is therefore likely 
to find visible fragments in the compost. 

4.2.2 

Effects of Contamination of Biowaste and Compost Quality  

One may also be concerned about possible detrimental effects of compostable plastics 
on the quality of collected biowaste, which may in turn, negatively affect compost 
quality.     

A higher level of impurities in collected biowaste may be directly detrimental to the 
quality of the composted output (e.g. a higher visual contamination, since the final 
refining steps are never 100% effective) and/or affect composting operations and costs, 
requiring additional separation steps and increasing the percentage of rejects.  

From the European Compost Network (ECN) position paper111, and based on the state of 
discussions at the ECN Working Group on bioplastics (which includes representatives of 

110 Déportes I.Z, Le Ravallec V., Mortas N., Thévenin N., and Machinet G. (2018) Biodégradabilité En 
Compostage Des Sacs Plastiques Biodégradables (Norme Nf T 51-800) Et Des Sacs En Papier, Report for 
ADEME, September 2018 
111 European Compost Network (2019) ECN Position Paper on the Acceptance of Compostable Plastics, 
October 2019 

57 

 
 
 
 
 
 
most EU Countries), according to Ricci112, by and large, there seems to be a certain 
agreement in the composting sector, around the following principles:  

•  Compostable bags may be considered as a tool for separate collection (although 

this may have variations in different countries, as already identified)  
•  The same may be valid, to some extent, for specific items in “closed loop” 
systems as e.g. in event management (e.g. when reusable tableware is not 
suitable for whatever reason) or disaster relief operations (where reusable 
tableware may be inherently problematic)  

•  Use of compostable plastics as a direct replacement for plastic items (including 
packaging), may create various degrees of confusion with conventional plastics, 
since it may increase the degree of confusion amongst the end users, resulting in 
cross-contamination of conventional plastics (going to mechanical recycling) and 
compostable plastics (going to compost sites). 

Concerns about quality may arise from any of the following, or their combined effect:  

•  Specific pollution (e.g. heavy metals) potentially brought into the system by 

compostable plastics.  
Incomplete biodegradation (or incomplete conversion into compost). 

• 

These points are addressed in the following sub-sections.  

4.2.2.1 

Pollution and Physical Contaminants   

The recently published (June 2019) EU fertilisers regulation113, provides a common 
definition of compost standards in the mid-term (the Regulation will entry into force by 
July 2022). In the meantime, national standards are applicable. The last overview on EU 
standards for compost (and digestate) was performed by the JRC in 2013 (published in 
2014)114. As with previous surveys, the JRC report confirms there are two main areas in 
which standards are defined:  

•  pollutants (mostly heavy metals)  
•  physical contaminants (“impurities”: glass, plastics etc.)  

The former is covered by EN 13432, in that it sets a threshold for heavy metals in 
compostable plastics at 50% of maximum allowable concentrations defined by the EU 
Ecolabel for soil improvers (considered as a possible reference for “high quality soil 
improvers”).  

112 Interviews with Marco Ricci, Chair of Working Group on bioplastics at ECN.  

113 Regulation 2019/1009, laying down rules on the making available on the market of EU fertilising 
products, published OJ of the EU, 25 June 2019 

114 JRC, End-of-waste criteria for biodegradable waste subjected to biological treatment (compost & 
digestate): Technical proposals, Luxembourg, 2014 

58   

 
 
 
 
 
On the issue of impurities from physical contaminants, the reported maximum allowable 
concentrations according to the JRC are shown in in Appendix A.3.0 (along with recent 
values adopted in Denmark, not reported by the JRC). This shows that most standards 
limit values for plastics either separately (typically between 0.15% and 0.3%) or as part 
of an overall limit on “physical contaminants” (typically around 0.5%, but with Spain 
requiring a maximum of 3%). Impurities are defined by their size, with anything below 
2mm being acceptable for all countries except France which allows impurities up to 
5mm.  

Similar provisions for setting maximum allowable percentages of physical contaminants 
are included in the EU Regulation on Fertilisers, which, when describing requirements for 
compost and digestate to qualify as a CE marked Fertiliser (therefore allowing for cross 
border movement), requires a maximum of 0.3% impurity from plastics >2mm and from 
2026 this will be reduced to 0.25%. By 2029 this limit value will be further assessed as 
the impacts of separate collection of biowaste become clearer. 

Importantly, none of the Member State or EU level Regulations take into account the 
impacts of microplastics on the terrestrial environment or seeks to reduce these. 
Currently the size limit is 2mm which is larger than the definition of microplastics 
(typically <1mm). This is potentially problematic for all types of plastic, but in the context 
of this report, incomplete biodegradation or fragmentation may create plastic particles 
that fall below these limit values and are therefore not targeted for removal. Under the 
Fertiliser Regulation it is clear that such contaminated fertiliser could by exported and 
used in other EU countries. The risk of this is not entirely clear for fertiliser from 
digestate as the Regulation stipulates several process types that are suitable (including 
an option of secondary maturation), but these are all focused on eliminating pathogens 
in the digestate and not on successful biodegradation of plastics. Further testing under 
each one of the processes identified in the regulation would be required to verify this.    

Removing impurities is a continued problem for composters especially as local quality 
protocols become stricter. A comprehensive joint research programme115 was carried 
out by the Italian composting network (CIC) together with the national Packaging and 
Plastic Packaging Recovery Organisations CONAI and COPREPLA; the programme was 
aimed at monitoring a) fate of plastics and compostable plastics in the composting 
sector, and b) potential issues related to cross-contamination. In that context, CIC 
reported the so-called “dragging effect”. This is the issue of the increased rejects from 
the organic recycling process (including organics unintentionally discarded) caused by 
the need to screen out conventional plastics. 
This “dragging factor” (calculated as the proportion total mass of rejects : amount of 
plastics in impurities) is on the average  400% (with range values from 50 to 1,400 %); in 
other words, each unit weight of plastic that is screened out, results in a four-fold 

115 Centemero, M.: Accordo di Programma tra Assobioplastiche, CIC, CONAI, COREPLA, Resoconnto 
sintetico delle attività di monitoraggio, Proc. of the dedicated event, Milano, 2017 

59 

 
 
 
 
 
increase in the amount of overall rejects. This has negative effects on mass balances 
and total efficacy of the composting strategy as a recovery route for organics. This also 
impinges to some extent on the economics of composting, and is one of the contributing 
factors as to why the Italian composting sector has embraced the use of compostable 
plastics along with the phasing out of primary screens.  

4.2.2.2 

Incomplete Biodegradation/Disintegration  

Concerning incomplete biodegradation, which will also be considered further on the 
issue was investigated in a Report by a specific Working Group established by the Italian 
Packaging Recovery Organisation CONAI116. The report included results of composting 
trials at various blending ratios between separately collected organics and compostable 
plastics added on purpose (PLA and Mater-Bi); blending percentages were ranging from 
1 to 5%, and included both films and rigid plastics such as bottles, trays, cups and 
tableware. All tests showed above 90% disintegration in 12 weeks, thereby meeting the 
requirements of the disintegrability and compostability test stipulated by EN 13432.  

With regard to a potential increase of rejects, and incomplete biodegradation, SUEZ 
(2018)117 based on internal studies, came to the following position:  

“In current industrial methanisation conditions, compostable (...) plastics are sorted 
out before entry into anaerobic digestion facilities. During our study, we confirmed 
that compostable plastics hardly degrade during tests in anaerobic controlled 
conditions. The risk for microplastics in the soil and in digesters is therefore real.”  

A similar position was expressed by a coalition of sectoral German waste management 
associations118, whose position reads:  

“Biodegradable plastics may seriously adversely affect the quality of the end products 
(compost and digestate), as it cannot be guaranteed that they will disintegrate and 
biodegrade adequately during the course of the different biological treatment 
processes; this is particularly important given current biowaste processing timescales. 
Furthermore, it cannot be guaranteed that at the end of a biowaste treatment 
process, particles of biodegradable plastics greater than 1 mm in size (which will be 
classed as physical contaminants/impurities) will not be present” 

The statement was also categoric that outside of the use of bags119, no other plastic 
products should be labelled as compostable. The primary concern is aimed at the lack of 

116 CONAI, WG Biodegradable Packaging Recovery Project, Final Report, 2012 

117 SUEZ (2019)SUEZ recommendations concerning Bio-sourced and Compostable Plastics 
118 German Waste and Biowaste Associations (ANSK, ASA, BDE, BGK, BVSE, DGAW, Fachverband Biogas, 
VHE, VKU, 2019) Position Statement on the disposal of biodegradable plastics through bio-waste treatment   

119 Bags were considered out of scope for the position statement under the premise that they are 
acceptable if approved by the ‘relevant local public authorities for waste management and in close co-
operation with bio-waste treatment companies.” 

60   

 
 
 
 
 
adequate biodegradation in AD plants under current processing times. The same issues 
have been highlighted in several countries—including the UK, Denmark, and Norway that 
use AD extensively to process food waste, but do not operate a secondary composting 
stage (unlike most Italian plants) due to wet processing. 

4.2.3 

Cost implications of biodegradable/compostable plastics in 
organic waste processing 

The previously mentioned recent Commission Implementing Decision EU 2019/665 of 17 
April 2019 sheds additional light on this in Article 6C (1d): 

“Where biodegradable packaging that is subject to aerobic or anaerobic treatment is 
included in the recycled amounts for the respective packaging material, the amount 
of biodegradable packaging in biodegradable waste shall be determined by 
performing regular composition analyses of the biodegradable waste entering 
those operations. Biodegradable packaging waste that is removed before, during or 
after the recycling operation shall not be included in the recycled amounts.” 

The wording of Article 6C (1d) in the Commission Implementing Decision EU 2019/665 
appears to state that the recycling rate of compostable packaging will be determined by 
regular sampling of composting operations, so as to determine amounts that get 
discarded into the rejects, and amounts that gets converted into compost through the 
composting process; this is something that does not take place in respect to 
compostable plastics at most facilities at present and therefore will incur additional cost. 
Currently there is no way for composting facilities to regain those costs until a form of 
EPR is introduced. There is also the additional issue of determining what is and is not 
packaging especially if the majority of compostable plastics are flexible films without 
particularly distinguishing characteristics. 

This is problematic for composters, who may be required to test for the presence of 
compostable plastics. Arguably this requirement may induce composters to refuse to 
accept any organic waste that is likely to contain these materials in order to reduce these 
costs. This may have a considerable impact on the more widespread use of compostable 
plastics if this takes place.  

A potential approach to work around the issue was adopted through the research 
programme120 carried out jointly by the Italian Composting Association CIC and the 
Plastic Packaging Recovery Organisation COREPLA, which surveyed, inter alia,  the 
presence of compostable packaging going to composting and anaerobic digestion sites, 
so as to ascertain the contribution of organic recycling to general recycling rates for 
packaging.  

120 M. Centemero, Accordo di programma tra Assobioplastiche, CIC, CONAI, Corepla, Resoconto sintetico 
delle attività di Monitoraggio, 2017 

61 

 
 
 
 
 
The survey was based on sampling at 27 sites (15 composting sites and 12 combined 
anaerobic digestion + composting sites), representing a total processing capacity of some 
2 Mt/year (out of a national total of 6 Mt).It was set up to determine an average 
percentage of compostable plastics, and compostable packaging, in the input material 
and in the rejects. Once multiplied with the total processed tonnage, this makes it 
possible to calculate the contribution of organic recycling to total packaging recycling 
rates. Such an approach would transfer the monitoring system from each given site, to 
the system as a whole, with the organisational and economic burden born by the 
producer responsibility organisations (PROs). Nevertheless, as the EU calculation rules 
are relatively new, there are no standardised process for tackling this issue at present.  

4.2.4 

Case Study: Effects of Compostable Bags on Separate 
Collection of Biowaste  

To date, one of the main uses of compostable plastics in the EU has been for biowaste 
bags which are used to make collection of food waste more user friendly (when used to 
line a kitchen caddy), thereby maximising participation and capture. Biowaste bags are 
also commonly made from conventional plastic (either formally, or by reusing carrier 
bags) and paper (again, either formally, or with the householder lining the caddy with 
newspaper, for example).  

Compostable bags for collection of source separated food waste are largely used in 
Norway, Italy, Spain (Catalonia, Basque Country), the UK and Ireland. The compostable 
bag is designed to enter an industrial composting facility together with the food waste. 
However not all EU countries have composting facilities suitable for food waste. Food 
waste is also treated in anaerobic digestion (AD) plants, for which the compostable bags 
are not intended  unless a secondary composting phase is used. 

This is also the only compostable plastic product that the European Compost Network 
(ECN) support more widespread use of in a recent position statement121 (assuming that 
the local infrastructure is capable of accepting these materials). The ECN class them as 
‘Type 1 - Tools that are functional to ease the users in the separate collection of bio-
waste’, although much of the evidence cited in the position statement comes from Italy 
where compostable biowaste bags have gained a high level of acceptance already. 

4.2.4.1 

Positive Examples of Comparing Compostable with Conventional 
Plastic Biowaste Bags for Food Waste Collection  

When determining whether compostable bags are beneficial it is important to compare 
these with other materials. There are many studies that have investigated various ways 
in which householder participation in biowaste collection can be maximised, but fewer 
have isolated the effects specifically to material. However, there are indications that 
compostable bags reduce contamination and increase participation. The following 

121 European Compost Network (2019) ECN Position Paper on the Acceptance of Compostable Plastics, 
October 2019 

62   

 
 
 
 
 
examples of this are from two countries that generally have a low acceptance of 
compostable plastic and therefore the results may be more instructive. 

Research for the City of Copenhagen122 and a test study for the Danish Environmental 
Protection Agency123 comparing compostable and fossil-based plastic bags found that 
the compostable plastic bags have the following benefits:  

•  The food waste collected with a compostable bag is less contaminated with other 

• 

materials;  
the compostable bag is likely to biodegrade over time if it is not properly sorted 
out and ends up in the digestate/the field; 

•  compostable bags provide a good signal to citizens to sort the food waste 

correctly; and,  

•  citizens perceive the compostable bag as more environmentally friendly. 

The last two points are difficult to untangle and are primarily related to consumer 
perception. The studies were initialled by Copenhagen City Council after it emerged that 
the compostable bags that were being supplied were made from fossil-based material. 
The Council and the public had a general perception that; compostable = bio-based = 
‘environmentally friendly’. As previously discussed in this report, these three aspects are 
not linked at all. The city is continuing to supply the bags, which may be requested 
through an online Municipal delivery service, but now required to include a minimum 
50% bio-based content.124 This demonstrates that perceptions appear to be just as 
important in driving behaviour as the actual performance of the material in practice. 

A recent study was performed by the Witzenhausen Institut in Germany where 13 cities 
and municipalities were examined for the factors which affect compost quality from 
household organic waste. One of the main conclusions was that:125 

“The widespread fear that the admission of biodegradable bags leads to an increase 
in impurities could not be verified during the analyses. On the contrary, the admission 
of biodegradable bags resulted in fewer impurities in biowaste.” (translated from 
German) 

The difference between municipalities that discourage or ban composable bags and 
those that recommend them is around a 30% decrease in impurities for the later. 
However, as this was a survey of existing practice it is not entirely certain that other 
factors do not contribute to this difference. 

122 COWI. (2018). Opsamling af viden om indsamlingsposer til bioaffald. City of Copenhagen.  
123 COWI. (2017). Posekvalitetens og materialets betydning for indholdet af fysiske urenheder i biopulp. 
Financed by Danish EPA. 

125 M. KERN, H.-J. SIEPENKOTHEN, T. TURK (2018): Erfassung von haushaltsstämmigen Bioabfällen und 
Qualität des Bioguts - Auswertung von Biogut-Sortieranalysen. In: Müll und Abfall 10/2018, S. 526-531 

63 

 
 
 
 
 
 
Overall from the above examples evidence suggests that using compostable plastic 
collection bags compared fossil-based plastic bags can potentially increase the amounts 
collected—through increased participation, albeit potentially due to consumer 
misunderstanding of the environmental benefits of the material itself—and decrease the 
contamination. No evidence or examples were found for the reverse.  

4.2.4.2  Concerns and Issues with the Use of Compostable Bags for Food 

Waste Collection 

A large variability may be detected, across different EU Member States, in the way the 
composting sector accepts or considers the use of compostable biowaste bags.  

The German BGK (the National Composting and Quality Assurance Network) reports low 
acceptance of compostable plastics by operators. Delivery of compostable packaging or 
other materials in a bio-waste bin is not permitted with the exception of bags for 
collection of kitchen waste (in a few Municipalities), and it is generally not desired by the 
plant operators. A survey by BGK from 2018, reports that 88.6% of respondents reject 
the use of compostable plastic bags, while site managers prefer paper (bags or 
newspaper) for collection of biowaste.126 The reasons for this typically refer to; 

• 

• 

the presence of primary screens, which is widespread at German compost sites in 
order to remove impurities (including conventional plastic shopping bags which 
are often used by households to contain biowaste); and, 
the duration of composting is shorter than required by EN 13432 to ensure 
biodegradability and compostability (as described in Section 4.2.1) 

As a consequence of the low acceptance of compostable bags by German compost sites, 
many Municipalities in Germany do not require, and in some cases prohibit, the use of 
compostable bags for separate collection. In data reported by DUH127, in a survey on 
some 400 Municipalities in 2016, 74% prohibited the use of compostable bags, and only 
12% were considering them (the remaining, i.e. 14% of the Municipalities, were not 
running schemes for separation of food waste).  

In the UK, while biowaste bags are used in many local authority areas, they are not 
mandated and since the UK uses wet AD process for food waste (as opposed to dry AD in 
Italy for example), all bags have to be removed as far as possible in the pre-digestion 
maceration and screening. Given that some shredded bag material is still likely to pass 
through to the digester, it is often still preferable for this material to be made from 
compostable plastic rather than conventional plastic, however wet AD plants in the UK 
still report that any plastic material, compostable or otherwise, is a problem as it can 
block pumps, pipes and valves in their wet systems and accumulate.   

126 European Compost Network (ECN), Survey on acceptance of compostable plastics in various Countries, 
personal communication, 2019 
127 Deutsche Umwelthilfe (DUH), Presentation at the stakeholders’ workshop, Brussels, 2019 

64   

 
 
 
 
 
Similarly, in Denmark the food waste is mainly treated in wet mesophilic128 AD plants 
where the collection bags are sorted out in the pre-treatment. In recent years many 
municipalities have chosen to collect food waste with a fossil-based plastic bag. The pre-
treatment plants report that the compostable plastic bags are more prone to causing 
problems with blocking pumps, sticking to screws and other equipment as the 
compostable bag are more easily stretched (lower tensile strength). Moreover, the pre-
treatment plants report that the compostable bags, in some cases, have started 
disintegrate into smaller pieces before reaching the pre-treatment plant making it 
harder to sort out and thereby increasing the potential of plastic contamination in the 
final digestate. Yet another problem pointed out by pre-treatment plants is that the food 
waste sticks to the compostable bag and when the bag is sorted out a larger part of the 
food waste is also sorted out129. 

These experiences from compostable plastic bags for food waste collection are specific 
to this application, but some points can be taken away for compostable plastics in 
general: 

•  When it comes to compostable bags the positive effects primarily relate to the 
purpose of facilitating increased or improved collection of food waste and a 
reduction in contamination, and there is reasonable evidence to suggest this is 
the case. 

•  Despite this there is still no universal acceptance. Other products which cannot 

demonstrate such benefits to composters will have an even harder time 
becoming accepted.  

•  The difference in collection method, processing and the approach to removal of 

conventional plastic contamination all affect acceptance. These vary considerably 
within the EU and even within Member States. 

4.2.5 

Key Conclusions  

Key Conclusions – Implications of Compostable Plastics in Organic Waste Processing 

With regard to the extent to which the use of compostable plastics harms compost 
quality both; 

•  Directly by bringing pollutants in the compost mix: this is addressed by EN 

13432, but there is suggestion that the current ecotoxicity criteria are not strong 
enough to guarantee no negative effects, and;  

128 Mesophilic systems operate at 25-45°C and thermophilic systems operate at 50-60°C or above. 
Thermophilic systems can process organic waste faster and produce more biogas production and there is 
greater pathogen removal.  However, the capital costs of thermophilic systems are higher as more energy 
is required to heat and management is more complex. 
129 COWI. (2018). Opsamling af viden om indsamlingsposer til bioaffald. Københavns Kommune. 

65 

 
 
 
 
 
 
• 

Indirectly by increasing contamination from conventional plastics. This does not 
seem to be evident in surveys that exist on this topic, however such surveys at 
present only refer to use of compostable biowaste bags, which is the most 
widespread application of compostable plastics. Questions may arise, on the 
possible effect of a larger application of compostable plastics for e.g. packaging. 
More research may be needed to foresee (or detect) the effect of a larger use of 
compostable plastics in the packaging sector. 

With regard to incomplete biodegradation, several stakeholder report this taking place 
in AD and composting plants. The primary concern is aimed at the lack of adequate 
biodegradation in AD plants under current processing times. The same issues have been 
highlighted in several countries—including the UK, Denmark, and Norway that use AD 
extensively to process food waste, but do not operate a secondary composting stage 
(unlike most Italian plants) due to wet processing. This is also an issue for German 
composters who use a shorter processing time to produce ‘fresh compost.’ 

Importantly, none of the Member State or EU level Regulations take into account the 
impacts of microplastics on the terrestrial environment or seeks to reduce these. 
Currently the size limit is 2mm which is larger than the definition of microplastics 
(typically <1mm). This is potentially problematic for all types of plastic, but in the 
context of this report, incomplete biodegradation or fragmentation may create plastic 
particles that fall below these limit values and are therefore not targeted for removal. As 
compostable plastics are not routinely tested for biodegradation in soil conditions, the 
implications of this are unclear. 

From existing surveys of composters and direct interviews with several operators the 
following observations can be made: 

•  Concerns are expressed by some national compost networks about use of 

compostable plastics, particularly in Germany. Concerns refer to the increase of 
rejects (which is not, strictly speaking, related to compost quality) or to not fully 
biodegraded compostable plastics in the end product. Other national networks in 
situations with a widespread use of compostable plastics and a long track record, 
such as in Italy, did not report such problems, and show supportive to the use of 
compostable plastics. The disparity between these two countries at either end of 
the acceptance spectrum for compostable plastics can be attributed, in part, to 
the different composting process that take place; Germany with its acceptance 
of a short processing time (6-8 weeks) to produce ‘fresh compost’, compared 
with Italy and its mandatory 12 week process and secondary composting stage 
after aerobic digestion. 

•  At present, the operational design at locally available compost sites is very 

• 

influential on the acceptability of compostable plastics.  
In particular; compost sites with primary screens divert compostable plastics 
(together with non-compostable ones) towards rejects. When considering 
promotion of compostable plastics, primary screens should be concurrently 
phased out, as is typical in those areas where the use of compostable biowaste 

66   

 
 
 
bags is most widespread. Screening of non-compostable plastics can take place 
at the end of the process. 

•  Most AD (anaerobic digestion) systems find it difficult to handle compostable 
plastics (and meet subsequent quality standards for physical contaminants), if 
not followed by a final maturation stage by means of composting—some 
countries use a ‘wet’ AD process which cannot be followed by a composting 
stage. 

Overall from the examples identified in this study, evidence suggests that using 
compostable plastic collection bags compared to conventional plastic bags can 
potentially increase the amount of biowaste collected—through increased participation, 
albeit potentially due to consumer misunderstanding of the environmental benefits of 
the material itself—and decrease the contamination. No evidence or examples were 
found for the reverse.  

4.3 

Establishing the Effect of 
Biodegradable/Compostable Plastics Entering 
Plastics Recycling Streams  

In the view of an increased diffusion of compostable plastics on EU markets, one should 
consider possible cross-implications with the recycling of ordinary plastics. In this 
respect, concerns have been raised, related to increased presence of compostable 
plastics in plastics collected for recycling.  

From this standpoint, one must address concerns on potential negative effects of 
increased biodegradable/compostable plastics entering plastic recycling, which refer to 
any or all of the following:  

•  Higher loss rates of recyclable plastics due to contamination with compostable 

plastic;  

•  Lower efficiency of the recycling facilities due to contamination of compostable 

plastic;  

•  Higher energy consumption required for sorting the recyclable plastic out of the 

collected plastic stream.  

•  Mechanical properties of recycled polymers may be undermined by presence of 

biodegradable/compostable plastics in recycled streams 

This is well mirrored, for instance, in the position paper by SUEZ130, already mentioned, 
which highlights the following: 

130 SUEZ (2019)SUEZ recommendations concerning Bio-sourced and Compostable Plastics 

67 

 
 
 
 
 
 
 
“In general, any compostable plastic mixed with recyclable plastics will reduce the 
mechanical properties of the recyclates. This means that it will degrade the 
quality and reduce the recycling opportunities. (...) An increase in the diversity and 
the mix of plastics only complicates sorting operations”.  

Ultimately, the points above may be addressed by 3 specific questions:  

•  What may be the acceptable presence of compostable plastics in polymers to be 
recycled? — It is worth noting that this more specifically refers to materials ready 
to be converted, hence after sorting at plastic sorting plants (where sorting must 
be performed anyway, so as to separate various types of polymers)  

•  What may be, in the case of increased use of compostable plastics, the likely 

expected percentages of compostable plastics in ordinary plastics collected for 
recycling, and going to sorting plants? — This may be primarily addressed 
through evidence available from those areas with current highest diffusion of 
compostable plastics.  

•  Will increased needs (if any) to sort compostable plastics out of recyclable 
plastics, likely cause an increase in costs (on account of the change in mass 
balances and/or more complex sorting equipment) for the plastic recycling 
sector?   

4.3.1 

Problems Related to Contamination of Compostable Plastics 
in Plastics Recycling 

Concerning the percentage of compostable plastics that may be considered “acceptable” 
without undermining recycling processes and mechanical properties, this is likely to 
differ for various types of plastics, with particular regard to the difference between rigid 
and flexible plastics.  This mirrors also the different fate of various types of plastics at 
sorting platforms.  

The typical sorting scheme at sorting sites, includes;  

•  bag opening (if needed) and primary screening (to remove small impurities);  
•  ballistic separation and/or wind sifting, to separate 2-D and 3-D materials;  
•  optical sorting of 3-D materials; and,  
•  possibly, hand sorting of 2-D materials to collect large plastic films.  

It should be noted that optical sorting targets specific polymers to be valued (i.e. 
positive identification), and not impurities to be rejected. This means the type of 
impurities is irrelevant. Hence, compostable plastics will behave like any other impurity i, 
while if mis-sorted/identified (i.e unintentionally ending up with the target materials) 
they may affect mechanical properties of the sorted materials.  

For 2-D materials, and specifically small films (e.g. bags, packets) the issue of 
contamination may instead be more relevant, since 2-D impurities (e.g. 
compostable/biodegradable bags or flexible packaging) will finally end up in the mixed 
film stream, together with other polymers. However, from evidence that was collected 
(see further on), this is the stream which is able to incorporate higher percentages of 

68   

 
 
 
impurities, before they become detrimental to recycling and mechanical properties of 
recycled materials.  

Concerning rigid plastics, a study from Wageningen University on rPET131 reported that 
contamination of 0.3% PLA (reflecting the contamination of 10 kg of rPET with one tray 
of 30 grams of PLA) in PET caused marginal effects on recycling of PET.  

As stated in the Report, the concentration of PLA (and other contaminants, such as PVC, 
PS, PP, etc.) for the model studies;  

“…were chosen by the industrial board, based on their industrial experience (...) to 
reflect realistic levels”,  

which, incidentally, may be an indication of currently achievable levels of contamination 
in specific polymers after processing at a sorting site, based on operational experience of 
site managers.  

In the already mentioned Report132, the WG from CONAI also included outcomes from 
lab and industrial testing on mechanical, chemical and visual properties of plastic 
polymers blended with PLA and Mater-Bi at various mixing ratios.  

In an industrial spinning test, PLA was tested in blends with rigid plastics (PET), at 
blending percentages (to mimic possible contamination rates) of 0.25 to 2% concluding 
that “a concentration of about 1-2% of PLA in recycled PET can be managed in a common 
short spinning plant”.  

Testing on Mater-Bi (a proprietary PBAT blend from Novamont) was performed at higher 
mixing percentages, to take into consideration the larger contamination that may 
typically be detected in flexible packaging. Mater-Bi granules were mixed with PE at 
mixing rates ranging from 2.5% to 20%, while Mater-Bi bags were mixed with domestic 
packaging films (mainly LDPE). Results showed that it was possible “to reprocess/recycle 
mixtures of up to 10% concentration of Mater-Bi shoppers [bags] with conventional 
plastic shoppers. At higher concentrations (...) problems could arise”.  

During interviews with experts from Plastics Recyclers Europe (PRE)133, the following key 
points were highlighted:  

• 

• 

in general, they recommend staying below an average level of 2% contamination 
(in polymers sent to converters after sorting) to avoid any detrimental effect to 
mechanical recycling  
this should be considered differently for rigid plastics (with lower contamination 
thresholds) and for flexible plastics (where higher contamination thresholds are 
typical and are more acceptable)  

131 E.U. Thoden Van Velzen, M.T. Brouwer and K. Molenveld, Technical quality of rPET, Wageningen 
University 2016 
132 CONAI, WG Biodegradable Packaging Recovery Project, Final Report, 2012 
133 Interviews with Chaim Gabriel Waibel, Advocacy Advisor at PRE  

69 

 
 
 
 
 
Interviewed experts from Plastics Recyclers Europe (PRE) concurred, in general, with the 
vision expressed by the ECN experts, that compostable plastics:  

•  should not pose problems as a tool for separate collection of organics where 

these are tightly connected to collection schemes. In which case they are unlikely 
to contaminate ordinary plastics;  

•  may be acceptable in what may be defined as use in “closed loops” (i.e. specific 
situations with trained managers, and collection planned and run accordingly, as 
e.g. event management when reusable is not suitable); and, 

•  on the contrary, it would be of high concern if there was a widespread adoption, 
asthis may lead to a degree of confusion for end users which can cause increased 
cross-contamination, and adversely impact the quality of ordinary plastics 
separately collected for recycling.  

It may be worth mentioning that PRE also based their positions, on a particularly detailed 
study carried out by TCKT on behalf of EuPC134  

 The Report states that: 

“in general, the recycling process of the different materials worked without major 
complications. However, there were difficulties (unsteady bubble and melt pressure 
varied during the extrusion process) when it came to the extrusion of new blown film 
with materials containing more than 5% DEG (i.e. degradable135) material”.  

With regard to mechanical properties, the report states that:  

“mechanical properties of all mixtures decreased in most cases, except the breaking 
elongation which showed much higher than the breaking elongation of the virgin 
LDPE. (...) mixtures with 50% DEG (i.e. degradable) material had significant lower 
mechanical properties. However, the visual impact and the mechanical properties 
already decreased at the 2 % mixtures”. 

Again on films, another study by the Wageningen University136, more specifically 
covering issues related to bio-based and biodegradable plastics, concluded that “mixing 
up to 10% of a starch based film and up to 10% of a PLA film in a sorted plastic film 
mixture has no significant negative effect on mechanical properties”, as reported in 
Figure 17. The bars show results in terms of percentage, relative to the reference 
material, shown in leftmost bars as 100% for each property. 

134 Transfer Center for Polymer Technology (TCKT) on behalf of EuPC: Impact of Degradable 
and Oxo-fragmentable Plastic Carrier Bags on mechanical recycling, 2013  
135 The report unfortunately does not specify the identity of the tested materials, though in the testing 
scheme, some were described as “biobased and compostable” (one may assume these were complying 
with EN 13432, but this was not stated) and one as “non-biobased and degradable”—the reference to 
“oxo-fragmentable” in the title of the report, may infer that “degradable” refers to oxo-degradable 
plastics. 
136 M. Van den Oever, K. Molenveld, M. Van der Zee, H. Bos,, Bio-based and biodegradable plastics - Facts 
and Figures,  Wageningen University, 2017 

70   

 
 
 
 
 
Figure 17: Effect of increased percentages of compostable plastics on 
mechanical properties of sorted plastic film mixture. Numbers reported as a 
percentage of the reference mixture 

Source: M. Van den Oever et al 

Worth noting that these results refer to the mixture of small-size flexible plastics (films) 
which in traditional operational conditions at sorting platforms is not subject to optical 
sorting, and only comes from mechanical separation (e.g. Wind sift, ballistic separation). 
Such recycling streams are inherently mixed with significant levels of PE, growing 
proportions of PP—which is increasingly used for small size packets— and minor but still 
significant percentages of PET, PVC, PS and others. Mechanical properties are therefore 
already influenced by the heterogeneous nature of such blends. However, this is likely to 
be the recycling stream where most of the compostable plastics would end up (if not 
organically recycled), considering the current dominance in the compostable plastics 
market of film-based applications (e.g. bags and packaging). The picture would change in 
case of increasing uses in rigid packaging, with particular reference to possible use of 
compostable plastics for those items likely to end up in the 3D streams at sorting 
platforms (e.g. trays) 

In another recent and detailed study from Belgium137 a comprehensive investigation was 
carried out around the impacts of the widespread use of bioplastics (therewith focussed 
on  “bio-based”, but basically also falling under the category of 
“biodegradable/compostable”) and the potential problems this may cause in mechanical 
recycling, with particular (although not exclusive) regard to bottle-to-bottle recycling.  

137 L. Alaerts , M. Augustinus, K. Van Acker, Impact of Bio-Based Plastics on Current Recycling of Plastics, in 
Sustainability 2018, 10, 1487 

71 

 
 
 
 
 
 
The study investigated in a particularly detailed way the potential issues with 
contamination of PET bottles (hence, rigid packaging) by PLA bottles. From a 
comprehensive review of previous studies, the authors reported that problems start 
occurring from 2% contamination for degradation and yellowing, while issues with 
respect to transparency and discoloration may show up from a contamination rate of 
0.1% or even lower. As a consequence, they considered 0.1% as the maximum 
acceptable contamination threshold for quality bottle-to-bottle recycling.  

The authors then took into account;  

•  estimates for market increases of PLA bottles; and, 
•  separation efficiencies of optical sorters.  

For proper interpretation of results, it is noteworthy that what seems to be missing from 
the study is the potential influence of dedicated separate collection schemes (in 
particular, co-collection of PLA with biowaste), which would inevitably decrease, to some 
extent, the contamination upfront (the study assumes all the PLA bottles to be found in 
the collected PET bottles).  

The authors inferred a potential contamination rate, after optical sorting at 90% 
separation efficiency, of 0.01-0.08% by 2021; the higher end (which assumes, based on 
international outlooks and own estimations by the authors, a marked increase in the use 
of PLA bottles) is similar to the 0.1% threshold they considered as the safe level to have 
unconstrained rPET recycling, whilst higher levels may allow only some applications (as 
e.g. 5% for bottle-to-fiber). 

With that in mind, the authors considered options for further removal of PLA in the 
recycling chain in order to assure high-quality rPET as; 

•  adjustment of NIR sorting equipment to decrease the number of sorting 

mistakes. In the author’s own words, this may, however, also lead to a larger 
stream of rejected bottles, yields and the financial return of the recycling 
process; 
installation of additional NIR sorting equipment;  

• 
•  separation processes exploiting low softening temperatures of PLA and based on 

• 

a hot conveyor belt or a rotating drum; and,  
labelling of PLA bottles, either for the purpose of communication at the 
consumer level (sorting message, which brings up the potential influence of 
separate collection), or for instance using, chemical markers which can allow 
smooth detection in automatic sorting. 

The authors also inferred that any of these options would lead to an increased cost for 
the overall recycling process, although no specific estimate was reported.  

Other biopolymers that were investigated by the authors (PHA and PEF) did not 
demonstrate any issue of particular concern, given the fields of application (mulch films, 
biodegradable medical and surgical tools) and/or lower foreseen degree of uptake.  

72   

 
 
 
Other authors138 investigated interference of PLA, PHB and TPS on recycling of 
polypropylene (PP). Recycled PP was blended with biodegradables polymers by melt 
extrusion followed by an injection moulding process to simulate the industrial 
conditions. Materials were then evaluated for changes on their thermal and mechanical 
performance. The authors drew the conclusions that less than 5% contamination of 
biodegradable polymers did not affect the overall performance of recycled PP intended 
for applications such as food packaging and agricultural films. 

Also, experts from the Italian plastic packaging recovery organisation COREPLA139 were 
specifically interviewed by the project team on the subject, so as to get more details 
from a situation where adoption of compostable plastics is already more widespread 
compared with the rest of Europe. Experts from COREPLA in particular noted the 
following:  

•  sorting is increasingly often performed in two stages:  

o  a first stage “in positive” mode, aiming at selecting different targeted 

polymers  

o  a second stage “in negative” mode so as to remove and minimise 

impurities from previously selected polymers  

• 

the tendency towards adoption of two-stage sorting is unrelated to the discussed 
issue, but rather caused by long-term evolution of the system to become more 
efficient, including increasing volumes of materials that can be handled (which 
makes it more and more profitable to minimise impurities) and the increased 
quality required by converters  

•  more and more often, optical sorting is applied to 2-D plastics (films); this is 

improving the quality of recovered flexible plastics, although there is an intrinsic 
higher contamination even after optical sorting, on account of;  

o 

o 

films overlapping each other, thereby randomly hiding some items from 
optical sorters;  
films moving around between identification with NIR and being sorted 
out; and, 

o  a structurally higher presence of contaminants, such as coupled materials, 

inks and dyes and food residue. 

Experts from COREPLA also reported on trials performed on recycling of sorted polymers 
at industrial level, with LDPE packaging supplemented on purpose with various 
percentages of starch-based compostable plastic bags. The trials showed that beyond 4-
5% compostable plastics, working with the mix became problematic.  

138 M.D. Samper, D. Bertomeu, M.P.  Arrieta, J.M. Ferri, J. López-Martínez,  Interference of Biodegradable 
Plastics in the Polypropylene Recycling Process, Materials 2018, 11, 1886 

139 Interviews with Marco Alberti  Recovery Manager, and Antonio Furiano, Marketing Manager at 
COREPLA 

73 

 
 
 
 
 
 
Also, the experts said that in general, problems related to the presence of compostable 
plastics in recycled polymers are not detected, although anecdotally such problems are 
reported, which typically may coincide with localised campaigns that include large use of 
compostable plastics, beyond what may be considered an “ordinary use” (e.g. 
compostable bags, closed loops applications).   

One technical solution to problem of correctly identifying and recycling plastics in 
general is ‘tagging’ via chemical tracers or digital watermarks. Diverting compostable 
plastics away from plastics recycling is one of the key areas that is being investigated by 
the Holy Grail Project140—a consortium of brand owners led by Procter & Gamble—
which is looking into these types of technologies. The technical implantation of such 
solutions at scale is still to be developed, but it is a promising solution to the challenge of 
maximising the value from plastic recycling. 

4.3.2 

Occurrence of Compostable Plastics in Plastics Recycling 

The results mentioned above on recycling and mechanical properties may be compared 
with the actual presence of compostable plastics;  

• 

• 

In post consumer plastics targeted by separate collection and going to recycling; 
and, 
In specific streams of sorted plastics after processing at sorting platforms  

With regard to the first point, most informing evidence comes from a comprehensive 
research programme from Italy141 carried out jointly by the Italian Composting 
Association CIC and the Plastic Packaging Recovery Organisation COREPLA, to assess 
cross-contamination of compostable plastics (going to recycling) and ordinary plastics 
(destined to mechanical recycling).  

The survey included two large monitoring campaigns at sorting platforms (19 sites in 
2016 and 17 sites in 2017) and consisted of roughly 1,500 compositional analyses of 
separately collected plastics (before sorting). This is of particular interest since Italy is 
typically the country with most widespread use of compostable plastics primarily as a 
tool for separate collection of organic waste. In Italy, this totals around 100,000 tonnes 
of compostable plastics marketed each year, to be compared with a total of some 2.5Mt 
of packaging plastics.   

Results showed an average contamination rate of 0.84% compostable plastics in 
separately collected conventional plastics in 2016, a number which was confirmed in 
2017 (0.85%). This seems to depict a situation with contamination levels compatible, 
(according to the studies cited in Section 4.3.1) with mechanical recycling, even before 
sorting, which may decrease the percentage further.  

140 https://www.newplasticseconomy.org/assets/doc/Holy-Grail.pdf 
141 M. Centemero, Accordo di programma tra Assobioplastiche, CIC, CONAI, Corepla, Resoconto sintetico 
delle attività di Monitoraggio, 2017 

74   

 
 
 
 
 
The presence of compostable plastics in specific plastic streams after sorting, is 
addressed by the report from Van Velzen et. Al (2016) on rPET already mentioned, which 
reported a typical level of 0.3% PLA in sorted PET from sorting lines. The survey from 
Oever et al. (2017) considered higher percentages for mixed films, and tested up to 10% 
compostable plastics (PLA and starch blends) in such mixtures. As already mentioned, 
both reports already seem to detect no detrimental effect on recycling and mechanical 
properties at the investigated contamination levels, which they consider “typical”.  

Evidence reported from Wageningen seems consistent with info and evidence retrieved 
during interviews with TOMRA, producers of sorting equipment.  According to experts 
from TOMRA142, the following may typically be found after sorting:  

•  There is an increasing adoption of optical sorting also on flexible plastics   
•  Around or below 0.1% contamination by compostable plastics may be detected in 

rigid plastics after sorting  

•  Higher contamination rates ( of around 7-8%) in plastic films, on account of 

primary forms and other contaminants (dies, organics, etc.)  that cause a higher 
incidence of errors by the sorting equipment. Notably, the reported 
contamination is the total contamination by various polymers, with compostable 
plastics contributing to a minor extent (typically 0.1% in the expert’s opinion) 

The study by TKCT for EuPC, though, reported some detrimental effects on plastic films 
at lower percentages (around and above 2%), although the following may be noted:  

•  The trials by TKTC were not comparing mixed films (as the ones coming from real 
operational conditions) with various percentages of compostable plastics, but 
pure LDPE with increasing percentages of compostable plastics, which should 
logically amplify the different properties of tested mixtures  

•  The foregoing is highly informing to give answers to a “what if?” question, 

although it may not be closely related to real operational conditions for mixed 
films after sorting   

In fact, Oever et al. (2017) report that “In general [during our surveys we do] not find 
bio-plastic in (sorted) post-consumer plastics and when they are found, amounts are very 
low”.  

This statement is also supplemented with Table 7 which shows the content of 
compostable plastics in more than 200 (sorted) plastic waste batches collected in the 
Netherlands during more than 5 years. In only 9 out of the over 200 batches bio-based 
plastic was found. Detected percentages in various streams after sorting were ranging 
from 0.008% to 0.3%, which is seemingly consistent with the “no detrimental effect” 
scenarios reported in tests on mechanical properties.   

142 Interviews with Juergen Priesters, Business Development Directoor at TOMRA Sorting GmbH 

75 

 
 
 
 
 
 
Table 7: Bio-plastics found in (sorted) plastic waste in various batches 
analysed over a 5 year period. 

Waste type  

Mix DKR-350 

PLA 

Film DKR-310 

Film DKR-310 

Rigid plastics 

Municipal Solid Waste  

HDPE 

Bioplastic type 

Starch film 

PLA film 

PLA film 

PLA film 

Starch film 

PLA & PUR 

Starch blends 

Share of  ( %wet 
weight) 

0.12% 

0.14% 

0.008% 

0.01% 

0.02% 

0.3% 

0.03% 

4.3.3 

Key Conclusions  

Key Conclusions – Establishing the effect of biodegradable/compostable plastics 
entering plastics recycling streams 

Contamination from compostable plastics in plastics sent for recycling, may vary from 
material to material, and tend to be lower for rigid plastics, higher for flexible plastics. 
The type of end recycled product also effects how detrimental this contamination is—
PET recycling for food grade applications is highly sensitive, whereas plastics destined to 
be recycled into fibres are less affected. 

Processes at sorting platforms tend to reduce the level of contamination in any given 
stream targeted for recycling. This is typically more effective for optical sorting (which 
typically targets rigid plastics) while it shows less effective for mechanical separation 
(mixed films). In both cases, reports indicate that final levels of contamination are 
compatible with subsequent recycling, although this refers to a scenario in which 
compostable plastics are only widespread in niche applications. More widespread use in 
packaging—particularly if more rigid packaging is used— may require adaptation of the 
sorting lines, or generate levels of contamination that may cause problems to 
mechanical recycling. The use of innovate technologies for ‘tagging’ plastics via chemical 
markers or water marks may also be employed for compostable plastics and would 
reduce the risk of contamination should the market increase to a point where these 
materials are deemed problematic.    

In Italy, where there is already widespread use of compostable plastics (~50% of the EU 
market) the overall contamination rate is below the levels considered to be of concern 
for mechanical recycling before sorting. Operational design of sorting platforms are 
effective in ensuring these end up in “rejects” alongside other low-value plastics (e.g. 
from optical sorting of rigid plastics). That being said, Italy still mostly uses compostable 
plastics for niche applications, e.g. compostable bags for separate collection and 

76   

 
 
 
 
tableware in “closed loops”; a more widespread application beyond these boundaries 
may result in different outcomes which has yet to receive any significant research.   

4.4 

The Risk of Littering Biodegradable Plastics 

There has long been concern that littering may be increased where a product claims to 
be ‘biodegradable’ in the open environment due to the assumption that some or all of 
the impacts of littering are avoided.  

There is generally a lack of recent evidence and surveys as it is likely that attitudes may 
have changed in recent years due to an increased awareness of plastic pollution. A focus 
groups from Scotland in 2007 showed that most participants felt that it was acceptable 
to litter ‘biodegradable’ items as these were seen as harmless – although participants 
did not distinguish between organic food waste and biodegradable plastics.143  This study 
appears to suggest that the driver for littering is not apathy, but misinformation. 

However, only 19% surveyed for a US study thought it was understandable to litter if the 
item was biodegradable or could rot away although one group thought it was a 
commonly held view that cigarette butts were biodegradable and acceptable as a form 
of litter.144 Another survey on the reasons why smokers litter cigarette butts, 
documented that some respondents believed that cigarette butts are different to other 
types of litter, for reasons including that it was believed that cigarette butts are 
biodegradable.145 An analysis of tobacco industry focus groups found evidence that 
tobacco companies thought that biodegradable filters might encourage littering.146 
Because the tobacco industry also thought that biodegradable filters ‘may not degrade 
as quickly as smokers really want’; recognising that ‘all discarded filter tips look alike to 
the public’, an increased or static litter rate, and the fact that biodegradable filters would 
highlight the fact that the degradability of filters generally was an issue, would run 
counter the desire of industry to improve their public perception. 

143 Keep Scotland Beautiful (2007) Public attitudes to litter and littering in Scotland, cited in Brook 
Lyndhurst (2013) Rapid Evidence Review of Littering Behaviour and Anti-Litter Policies, Report for Zero 
Waste Scotland, 2013, 
http://www.zerowastescotland.org.uk/sites/files/zws/Rapid%20Evidence%20Review%20of%20Littering%2
0Behaviour%20and%20Anti-Litter%20Policies.pdf 
144 S. Groner Associates (2009) Littering and the iGeneration. City-Wide Intercept Study of Youth Litter 
Behavior in Los Angeles., Report for Keep Los Angeles Beautiful, 2009, http://www.cleanup-
sa.co.za/images/Littering%20and%20the%20iGeneration_Youth%20Litter%20Study%20for%20KLAB%20.p
df 
145 ENCAMS (2008) No Butts. Smoking-Related Litter, 2008 
146 Smith, E.A., and Novotny, T.E. (2011) Whose butt is it? tobacco industry research about smokers and 
cigarette butt waste, Tobacco Control, Vol.20, pp.i2–i9 

77 

 
 
 
 
 
 
This raises the interesting issue of the public’s perception of the timescales for 
biodegradation. In the open environment this would be difficult, if not impossible to 
guarantee. There is also an indication from the tobacco industry study that the 
expectation would be for weeks or months rather than years (which is a more realistic 
timeframe) – if a piece of litter is still present months later, it still creates a visual 
disamenity during that time.  

However whether the belief around the increased or equivalent littering of 
biodegradable cigarette filters can be extended to other types of litter perceived as 
degradable is not known with certainty: as mentioned cigarette butt litter is frequently 
perceived as in a different league to other types of litter such as bottles, cans or 
potentially bags of any type, because cigarette butt litter is relatively small and less 
conspicuous. The deliberate littering of plastic items—whether marked as biodegradable 
or compostable—may also have different connotations when compared to a small 
fibrous product made from bio-based ingredients. 

A more recent focus group from Scotland again revealed similar responses and states 
that 147 

“For some participants, the idea of ‘degradability’ makes litter [of fruit cores and 
skins] feel less unacceptable; a few people also mentioned this characteristic in 
relation to plastic bags or paper.”  

The report concluded that whether something is considered biodegradable was a 
“consistent criterion” for prioritizing litter clear-up. 

In response to the question, “I’m more likely to litter when the item I’m holding is 
biodegradable”, 22.6% of the respondents agreed or strongly agreed, while the 
remainder, 77.4% disagreed or strongly disagreed. Those who agreed to any extent 
scored more highly with regard to self-reported littering behaviour, suggesting that 
perhaps the propensity for biodegradable litter to promote littering behaviour is greater 
amongst those that are already more likely to litter. 

The caveat to any survey or focus group based study is that reported ‘hypothetical’ 
behaviour is difficult to correlate with actual behaviour, for which empirical observations 
are necessary. There is also an issue with the term ‘biodegradable’ which is often used is 
such studies, but it lacks a common agreement on meaning and does not reference a 
particular material or product – for one individual this may mean an apple core and for 
another, a paper bag for example. 

147 Brook Lyndhurst (2015) Public Perceptions and Concerns around Litter, Report for Zero Waste Scotland, 
2015, 
http://www.zerowastescotland.org.uk/sites/files/zws/Litter%20Insights%20final%20web%20March%2015
.pdf 

78   

 
 
 
 
 
More recently a summary of two German focus groups on the perceptions of bioplastics 
found that:148 

“..the actual timeframe a product needs to biodegrade totally differs from what 
consumers assume. Marine littering had been addressed as one of the major concerns 
about petro-based plastics. Some participants hoping bioplastics promised to provide 
a solution to marine littering were shocked and disappointed to learn that not all 
bioplastic products – actually most of them – are biodegradable or biodegrade 
outside of a composting facility.” 

This addressed the wider issue that the term bioplastic is also often synonymous with 
biodegradable or compostable plastic. As none of these terms are standardised it allows 
communication and consequently understanding of these terms to differ vastly. 
As there is a distinct lack of concrete evidence, it is also worth looking more widely to 
studies that investigate the psychology around environmental behaviour in general. A 
meta analysis of such behaviour149 from 2013 suggests that behaviour is influence by a 
large number of factors both internal and external. Existing attitudes, personal and social 
norms, and perceived behavioural control are all considered as drivers for specific 
behaviours – this supports the notion that littering is more likely to take place if 
predisposed to such behaviour. The marketing or a product as ‘biodegradable’ may just 
be the trigger to act accordingly and potentially remove any negative social connotations 
— the lower the perception of responsibility and capability to address an issue, the less 
likely a person is to take (positive) action. 

4.4.1 

Key Conclusions  

Key Conclusions – The Risks of Littering Biodegradable Plastics 

•  There is a lack of recent conclusive empirical evidence that clearly correlates the 

marketing of biodegradable/compostable plastics with an increase in the 
tendency to litter - further research is needed. 

•  Several studies point towards a perception amongst consumers that 

‘biodegradable’ or ‘compostable’ is a virtuous aspect of a product and that 
littering such an item would be less impactful. 

•  Some related empirical evidence—on environmental behaviour in general—
suggests that labelling a product with ‘biodegradable’ may be seen by some 
people as a technological solution removing responsibility from the individual. 
This may increase the tendency for those already predisposed to litter these 
items.  

148 Haider, T., Volker, C., Kramm, J., Landfester, K., and Wurm, F. (2019) Plastics of the future? The Impact 
of Biodegradable Polymers on the Environment and on Society, Angewandte Chemie International Edition, 
No.58, pp.50–62 
149 Klöckner, C.A. (2013) A Comprehensive Model of the Psychology of Environmental Behaviour—A Meta-
Analysis, Global Environmental Change, Vol.23, No.5, pp.1028–1038 

79 

 
 
 
 
 
•  There is also evidence suggesting that perceptions of the time for such plastics to 
biodegrade are likely not in line with reality and overall, actions are not always 
based upon correct information. 

80   

 
 
 
 
5.0  Review of EN 13432  

One of the key issues when discussing compatibility of compostable plastics with the 
composting sector, is codifying their fitness for composting.  

The need for a codified standard, was first addressed after the adoption of the Packaging 
and Packaging Waste Directive (PPWD) 94/62/EC, in that the Directive acknowledged 
composting and anaerobic digestion as “organic recycling”, and introduced the Essential 
Requirements where the concept of “packaging recoverable in the form of composting” 
was included. 

As a consequence, CEN was requested in 1996 to prepare standards to assess suitability 
of packaging for such processes. The standard EN 13432 on compostability in industrial 
composting, was approved and published in 2001. EN 13432 has subsequently 
undergone three reviews (in 2005, 2010 and 2015) with no changes. It is now the 
standard that signifies compliance with the Essential Requirements for compostable 
packaging under the PPWD. 

The standard’s specific requirements are assessed to see whether any issue of reliability 
or any cross implication with operational conditions at processing sites may cause 
problems.  

The standard includes on the following key requirements:  

•  Analysis on chemical composition. The key requirement here is that heavy metal 
content be kept below specific threshold values. Limit values are based on the 
Community Eco-label for soil improvers from 1998150 (although these values are 
still used in the current 2015 version), and are set at 50 % of the maximum 
concentration required by the Eco-label. The rationale for this (already discussed) 
assumes 50 % of the original weight of the material will remain in compost after 
biological treatment together with the complete original amount of hazardous 
substances. This requires that the theoretical final concentration in the 
composted compostable plastics should not exceed the maximum allowable 
concentration defined in the EU Eco-label.  

•  Biodegradability, which must be measured through a lab test method (ISO 

14855: biodegradability under controlled composting conditions). In order to 
show complete (intrinsic) biodegradability, a biodegradation level of at least 90% 
must be reached in fewer than 6 months. A separate test is defined for 
degradability under anaerobic conditions (which is relevant to processing in 
anaerobic digestion sites). The anaerobic test lasts 2 months and the requirement 

150 COMMISSION DECISION (EU) 98/488 of 7 April 1998 establishing the ecological criteria for the award of 
the Community eco-label to soil improvers  

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is 50% biodegradation; the standard also states that that this lower threshold is 
because “in all commercially available biogasification [AD] plants the process 
scheme provides a short second aerobic stabilization phase in which the 
biodegradation can further continue.” Evidently it is not that case that all plants 
undergo the step and, in many countries, the opposite is true. 

•  Disintegration: final compost after 12 weeks is screened with a 2 mm sieve. The 
mass of test material residues with dimensions > 2 mm shall be less than 10% of 
the original input.  

•  Eco-toxicity:  performed on the compost produced with compostable plastics 
inside the input feedstock. The test, performed through germination tests 
according to test method OECD 208, verifies absence of negative effects on plant 
growth.  

With reference to the they key requirements, Table 8 describes some of the important 
issues and criticisms that have been uncovered throughout this study and some of the 
potential solutions to these. These are largely focused on the issues around the 
biodegradation and fragmentation tests not being reflective of all composting/AD 
practice. 

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Table 8: Assessment of EN 13432 Criticisms 

Criticism 

Problem 

Discussion 

Potential 
Remedies 

Problems with Remedies 

Aerobic 
biodegradation 
test duration is 
too long  

(6 months) 

Duration of the 
test on 
disintegration 
is too long  

(12 weeks) 

The 
assumptions in 
the anaerobic 
biodegradation 
test do not 
reflect reality  

Instances of the 
plastic 
remaining 
visible in the 
compost at the 
end of the 
treatment 
process which 
for some 
countries 
means compost 
quality 
standards 
cannot be met 

As the test is to determine ‘inherent 
biodegradability’ under ideal conditions it can be 
argued that the test duration should not be 
directly related to real life. Other inherently 
biodegradable materials, such as lignin (typically 
anything wood-like in garden waste), would show a 
much lower degradation rate in the 6 months and, 
if subject to the test, would not pass it. Hence, the 
duration of the test may be intended to show the 
highest possible biodegradation during the testing 
time. The Presence of visible fragments, in the case 
of shorter composting times, may undermine the 
marketing value of compost. Larger fragments, 
that may still persist after shorter composting 
times, may be screened out, thereby increasing the 
amount of rejects. 

The anaerobic 
biodegradation 
test does not 
reflect real life 
practice and 
assumes a 
secondary 
composting 
stage. 

Effectively the Standard only applies to a compost 
output, not a digestate output. In reality only some 
EU Member States use post-composting of 
digestate where there is a requirement to meet 
the End of Waste criteria (e.g. Italy) while there are 
many sites elsewhere that do not include post-
composting, since national regulations allow direct 
land spreading of digestate (e.g. Germany, UK and 
Scandinavian Countries). Testing under AD 

Reducing the time 
pass threshold  

Potential exclusion of materials in countries that already 
process in line with the standard (e.g. Italy) 

Product quality and specification reduced as thinner 
material is required to pass the test 

Composting 
facilities to meet 
the time 
requirements 

The composting process is driven by the need to process 
organic waste and the output quality governed by 
individual Member States’ agronomic requirements. The 
requirements of compostable plastics should not be the 
driving force.  

Require soil (or low 
temperature) 
biodegradation 
testing for residual 
un-degraded 
material 

Require a specific, 
dedicated post-
composting stage 
for the plastic 
rejects 

There is additional time and cost for verification and it 
would be unclear what state the material should be in 
for testing. Introducing such requirements may restrict 
the use to materials that only biodegrade at high 
temperatures. This may only be helpful for countries 
that do not currently have organic waste treatment 
systems that reflect the requires of the standard.  

This is an operational change that cannot be dictated by 
the Standards and may only be cost effective if a plant is 
receiving high amounts of compostable plastics 

83 

 
 
 
 
Anaerobic 
testing is also 
not a 
requirement  

conditions is also not a strict requirement which is 
problematic for countries that process organic 
waste in this way.  

Adapt testing for 
biodegradation 
requirements 
without the 
assumption of 
secondary 
composting  

This may be questionable on agro-environmental 
grounds — post-composting ensures full stabilisation, 
minimises residual phytotoxicity, avoids release of 
fugitive methane and ammonia, with the latter being a 
precursor for secondary nanoparticulate. It is also 
unclear whether materials would pass such a test 

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5.1 

Recommendations for an EN 13432 Update 

In order for the requirement for EN 13432 compliance be effective it is also 
recommended that the standard (and consequently EN 14995) be updated to reflect the 
latest scientific understanding and approaches. Currently these are best reflected in the 
draft CEN standard for home composting of carrier bags (detailed in the following 
Section 8.4.3) that includes the additional aspects which could also strengthen testing 
and requirements for industrial composting: 

•  A requirement to separately test and meet the criteria for biodegradation of all 
organic constituents151 which are present in the material at a concentration 
between 1% and 15% — thereby removing the potential for non-biodegradable 
constituents to be used in large proportions in the product. 

•  The introduction of a nitrification inhibition test and an earthworm toxicity test 
(these are also requirements specified in the recent EU fertiliser Regulation 
amendments and EN 17033 on biodegradable mulch films, therefore are already 
recognised as important for agriculture applications).152 

•  A requirement that substances of very high concern (SVHC) and those on the 
candidate list shall not exceed a concentration limit of 0.1 % in the material of 
the product.153 

Reducing the time threshold for aerobic composting is potentially problematic and risks 
penalising countries that already successfully work within the Standards. The concept of 
testing for ‘inherent biodegradability’ is also important as the Standards are not 
designed to replicate the process exactly – however they should provide assurance that 
the product will perform as expected. This is the major weakness of Standards that are 
designed to be applied across the EU (and many more countries across the world have 
also adopted), but can never truly reflect every circumstance. Changing the Standards to 
reflect all practises is impractical and therefore it is recommended that Member States 
conduct their own trials to determine whether the Standard is fit for the purpose of 
verifying that compostable plastics perform as required (noting that ‘performance’ is a 
relative term that will be dictated by the local process and compost quality 
requirements). This will help in determining whether they should accept compostable 
plastics or not in their biowaste treatment facilities and what changes need to be made 
to do so in the future (if desirable). Any suggestion to amend the timescale should be 
undertaken in consultation with organic waste processors representing the different 
technologies and techniques which are used throughout the EU. The Standards should 
then provide more guidance of where they are or are not applicable.  

151 Chemical constituent that contains carbon covalently linked to other carbon atoms and to other 
elements, most commonly hydrogen, oxygen or nitrogen. 
152 REGULATION (EU) 2019/1009 https://eur-lex.europa.eu/legal-
content/EN/TXT/HTML/?uri=CELEX:32019R1009&from=EN#d1e40-1-1 
153 This also includes those on the candidate list - https://echa.europa.eu/candidate-list-table  

85 

 
 
 
 
 
It is also not a strict requirement of EN 13432 that biodegradability under anaerobic 
conditions is determined and the assumption that there is always a secondary 
composting stage is also incorrect. This demonstrates that that standards are not a 
reliable way of ensuring that compostable plastics are performing effectively in 
anaerobic organic waste treatment. There is no clear way forward in this regard as the 
solutions are largely operational and cannot be driven by this standard. Making the 
anaerobic biodegradation test an obligatory part of meeting EN 13432/14995 may go 
some way to improving this, but it is unclear how representative the current test is. 
Another option is to create a separate AD standard which Member States could make a 
mandatory requirement for compostable plastics in their country. Creating multiple 
Standards may add to confusion, rather than solve this issue, however. The Standard 
would likely still include an expectation of a secondary composting stage; the current 
issue of the Standard being erroneously applied in situations where this stage is not 
practiced may still, therefore, be a problem. 

There is also still an outstanding question around the issue of residual fragmented 
compostable plastics in the compost/digestate. These are likely to be in the microplastic 
size range as both the disintegration tests and many country compost quality 
requirements have a limit of 2mm. The visual aspect is not so important for farmers, 
who are more concerned with functional performance.154 Introducing stronger toxicity 
tests as described above will help, here. However, there may be merit in introducing a 
test to validate the biodegradation performance in soil. The current tests only validate 
inherent biodegradability at higher temperature and as there are different 
microorganisms present that are active at different (lower) temperatures, this cannot be 
guaranteed in soil. As described later on in this report (Section 8.3.4.2), with regard to 
home composting, not all materials will also biodegrade at low temperatures as they 
require a thermal trigger to start hydrolysing. 

The French government have also recognised this issue with a recent amendment in 
law155 to require any product that wants to be described as ‘compostable’ must also 
conform to the country’s home composting standard. The implications of this 
amendment are yet to be seen (e.g. some product types and compostable materials 
effectively being restricted), but in countries where the organic waste system is not 
capable of guaranteeing the full biodegradation of compostable plastics, these sorts of 
stronger requirements may be necessary. The amendment is also aimed at reducing 
consumer confusion around terminology. 

A further additional proposed requirement stems from the example of a single-use 
coffee pod. It is reported that these products may disintegrate faster in their pure 
material form compared to the product form post use (i.e. including the used coffee and 

154 Perchard D (2005) CEEES workshop, biodegradable polymers-where are the limits, 3 November 2005. 
CEEES-confederation of the environmental engineering societies. 
http://www.ceees.org/auxiliary/biopolymer051103.pdf  
155 http://www.assemblee-nationale.fr/dyn/15/amendements/2454/AN/1181 

86   

 
 
 
 
 
with the lid pierced)—this holds true with the known phenomenon that increasing the 
surface available to the microorganisms speeds up biodegradation. 

Whilst some laboratories that test these items already test in this form, it is 
recommended that this is codified in the standard to ensure this practice is universal. 

6.0  Environmental Performance of 

Compostable Plastics 

6.1 

Environmental performance of alternative non-
plastic biodegradable products compared with 
compostable plastic 

Non-plastic biodegradable products such as paper can often be used to fulfil the same 
function as compostable plastics. The environmental performance of these products 
compared with compostable plastics are investigated in this chapter. There is limited 
literature comparing compostable plastic products to non-plastic biodegradable 
products. 

6.1.1 

Paper Carrier Bags 

One on the most widely used and discussed plastic products, carrier bags, has been 
studied through comparative LCA comparing carrier bags for groceries made from paper 
and compostable plastic.  

Research by Bisnella, Fruegaard Astrup & Damgaard156 compared grocery carrier bags 
made from LDPE, paper, bleached and unbleached, and starch-based plastic among 
others.  The functional unit of this study was:  

“Carrying one-time grocery shopping with an average volume of 22 litres and with an 
average weight of 12 kilograms from Danish supermarkets to homes in 2017 with a 
(newly purchased) carrier bag. The carrier bag is produced in Europe and distributed 
to Danish supermarkets. After use, the carrier bag is collected by the Danish waste 
management system”156.  

In the study one plastic LDPE bag was needed to fulfil the functional unit whilst it 
required two craft paper bags and two compostable plastic bags. The study did not 
consider composting or biological treatment of the compostable plastic bag nor the 
paper bag, since materials other than organic waste are generally not treated with 
biological waste treatments in Denmark. Two end of life scenarios were modelled for the 

156 Bisinella, V. A., Fruergaard Astrup, T., & Damgaard, A. (2018). Life Cycle Asessment of grocery carrier 
bags. The Danish Environmental Protection Agency. 

87 

 
 
 
 
 
starch-based bags; 1) direct incineration and 2) function as a waste bag for municipal 
waste and consequently incinerated. Three EoL scenarios were modelled for the paper 
bags 1) direct incineration and 2) recycled 3) function as a waste bag for municipal waste 
and consequently incinerated. For both bags the best EoL scenario was to function as a 
waste bag and be incinerated with the municipal waste. If the carrier bag is used as a 
waste bag it will avoid the production of a thin fossil plastic waste bag. The results 
showed that the paper bag performed better than the compostable plastic bag in 11 out 
15 impact categories considered, including climate change. Both the paper bag and the 
compostable plastic bag performed better than the fossil LDPE bag in the impact 
category of climate change. In general, LDPE carrier bags, were found to provide  the 
lowest overall environmental impacts when not considering reuse.  

The study of Chivancik-Uslu, Puig, Hauschild, Fullana-i-Palmer157, compares different 
carrier bags by applying both a classic LCA and by assessing the risk of littering of each 
bag. The functional unit of the study was:  

“To facilitate the transportation of purchased food and drinks to an average 
household for one year, from the point of sale to the place of consumption157" 

The number of bags included in the functional unit were 408 per year for both the 
compostable plastic bag and the paper bag, assumed 204 purchases and 2 bags per 
purchase. The waste management distribution represents the generic Spanish waste 
system. The modelled EoL for the paper bag was 57% recycling, 4.4% incineration and 
38% landfill. For the compostable plastic bag, the EoL applied was 17% incineration and 
83% landfilling. The results showed that the compostable plastic bag had lower 
environmental impacts in 7 out of 8 impact categories considered, compared to the 
paper bag. The paper bag had a lower impact for water use. The compostable plastic bag 
had a climate change impact of 145 kg CO₂/FU (functional unit) and the paper bag 295 kg 
CO₂/FU. Comparing the compostable carrier bags (both paper and plastic) to a regular 
LDPE carrier bag, the LDPE carrier bag performed better in most impact categories, 
however, in terms of risk of littering both compostable alternatives showed a lower risk 
of littering.  

Edwards & Fry158 performed an LCA on carrier bags from paper and starch-polyester 
blend that is compostable. The functional unit of the study was:  

"Carrying one month’s shopping (483 items) from the supermarket to the home in the UK 
in 2006/07". 

To fulfil the functional unit a total of 82 starch-based bags were needed compared to 65 
paper bags. The baseline EoL scenario is 14% incineration and 86% landfill, which was 
the average distribution for municipal waste in the UK in 2006. The results showed that 

157 Civancik-Uslu, D., Puig, R., Hauschild, M., & Fullana-i-Palmer, P. (2019). Life cycle assessment of carrier 
bags and development of a littering indicator. Science of the Total Environment, 621-630. 
158 Edwards, C., & Fry, J. M. (2011). Life cycle assessment of su-permarket carrier bags: a review of the bags 
available in 2006. Report: SC030148. UK Environment Agency. 

88   

 
 
 
 
 
the compostable plastic bag had a lower climate change impact compared to the paper 
bag, respectively 4.2 kg CO₂/FU and 5.5 kg CO₂/FU. For other impact categories the 
compostable plastic bag performed better than the paper bag in; abiotic depletion, 
acidification, human toxicity, terrestrial ecotoxicity and photochemical oxidation, but 
worse in fresh water ecotoxicity, eutrophication and marine ecotoxicity.  

The climate change impact of the compostable plastic carrier bag was lowered to 3.3 kg 
CO₂/FU with composting solely as EoL treatment. Composting of the paper bag however 
only lowers the climate change impact to 5.4 kg CO₂/FU. The starch-based bag has higher 
impacts from methane generation in landfilling than the paper bag. The environmental 
impact is dominated by resource use and production stages. Transport, secondary 
packaging and EoL management generally have a minimal influence on the 
environmental performance. Comparing the compostable carrier bags (both plastic and 
paper) to a HDPE carrier bag the results show that the HDPE bag has lower 
environmental impacts in most impact categories. The study therefore concludes that 
the conventional HDPE bag has the least environmental burden.  

6.1.2 

Packaging Film from Wheat Gluten 

Deng et al.159 carried out a comparative LCA for packaging film made from wheat gluten 
powder, PLA and LDPE. Wheat gluten is a co-product from production of wheat flour. 
The bio-based compostable packaging films struggle to achieve a low water vapor 
permeability and are therefore less suitable in packaging were a moisture barrier is 
needed. The functional unit of the study is 1 m² packaging film with 0.15mm thickness.  

The results with incineration as EoL scenario for all packaging films show that the wheat 
gluten film has a much lower climate change impact (2,015 kg CO₂/FU) compared to both 
PLA (584 kg CO₂/FU) and LDPE film (561 kg CO₂/FU). For other impact categories the 
wheat gluten packaging film showed higher impacts compared to the PLA film in 10 out 
of 18 impact categories considered.  

The production of the packaging film is the life cycle phase contributing to most impact 
categories for wheat gluten film and PLA, for LDPE the direct emissions from incineration 
contributes most to the climate change impact. The wheat gluten film uses 75% less non-
renewable energy compared to PLA but gets less benefits from incineration.  

The study reports that windrow composting and incineration with energy recovery are 
comparable for the majority of the impacts assessed. For both PLA and wheat gluten 
packaging film the biological treatment of industrial composting does not offer 
substantial benefits over incineration.   

159 Deng, Y., Achten, W. M., Van Acker, K., & Duflou, J. R. (2013). Life cycle assessment of wheat gluten 
powder and derived packaging film. Biofuels, Bioproducts and Biorefining, 7(4), 429-458. 

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6.1.3 

Key Conclusions  

Key Conclusions – Environmental performance of alternative non-plastic 
biodegradable products compared with compostable plastic 

The three reviewed carrier bag studies show different results when comparing paper 
and compostable plastic carrier bags. Two out of the three studies find that the 
compostable plastic bag has generally lower environmental burdens compared to a 
paper bag. On the other hand, one study concludes the paper bag performs better than 
the compostable plastic bag. However, all three studies concluded that conventional 
non-compostable fossil carrier bags have a lower environmental impact than alternative 
bio-based compostable carrier bags in most impact categories. The three studies 
represent three different EU Member State waste management systems, however none 
of the studies include biological treatment as a baseline scenario for compostable carrier 
bags. This is a particular weakness given that these materials are designed to be 
composted and demonstrates some of the issues with the way in which current LCAs 
have been conducted for these materials—this includes the lack of scenarios for reuse 
as a biowaste bag. 

The study on packaging film shows that in some impact categories the non-plastic 
alternative has a lower environmental impact and in other impact categories the 
compostable plastic performs better.  

It can be concluded that there is no clear evidence that non-plastic biodegradable 
alternatives are environmentally preferable to compostable plastics. 

6.2 

Environmental performance of compostable plastics 
from an LCA perspective 

LCAs are calculated based on a specific scope, methodology, system boundary and data 
quality. These factors vary between LCAs and therefore it can be misleading to compare 
and/or aggregate findings from different LCAs. In this section the results of two JRC 
studies with a number of LCA case studies are briefly described. 

The JRC published a draft report "Environmental sustainability assessment comparing 
through the means of lifecycle assessment the potential environmental impacts of the 
use of alternative feedstock (biomass, recycled plastics, CO2) for plastic articles in 
comparison to using current feedstock." in 2018 with the aim to develop a consistent 
and appropriate methodological approach to better understanding the life-cycle impacts 
of alternative feedstock for plastics production. The first part of the report contains a 
review on the existing literature comparing conventional plastic with plastics from 
alternative feedstocks and proposed methodological requirements. The report identified 
32 studies that met the defined quality criteria and level of detail. These studies were 
scrutinized based on methodological approach and relevant aspect for LCAs on plastics 

90   

 
 
 
 
 
and bio-based plastics, such as EoL, littering, inclusion of land use changes, 
multifunctionality, biodegradation etc. Looking into the types of compostable plastics 
covered, corn as feedstock and PLA as plastic type were the most addressed types in the 
studies. Out of the 32 studies, 14 studies included analysis of different EoL options, and 
13 studies included an in-depth analysis of biodegradation in the EoL phase160. The 
biodegradation of PLA in industrial composting varied between 44% and 95% while for 
starch-based plastics the variation was between 60% and 91%. Regarding the overall 
modelling of biodegradation in biological waste treatments (industrial composting and 
anaerobic digestion (AD)) the focus is mostly on the fate of carbon and nitrogen during 
treatment and subsequent land application of the residual composted or digested 
material. However, the fate and impacts of any non-degradable element or compound in 
the compostable plastics (e.g. metals and additives) is usually not addressed. This might 
be due to lacking information on full product composition and use of additives. 

The second part of the report by the JRC contains LCAs comparing compostable bio-
based plastic with conventional fossil-based plastic carried out with the proposed 
methodology on beverage bottles and packaging films. The results of these LCAs are 
summarized below: 

6.2.1 

Packaging Film 

The materials assessed are starch-based film, PLA film, PP, LDPE and bio-based LDPE. The 
feedstock for the PLA film was corn cultivated in USA. The functional unit is 100 m2 of 
food flexible packaging film with an average thick-ness of 30 μm and ensuring a similar 
overall shelf life of the packaged product. The EoL was based on average EU waste 
management; for the compostable packaging film (PLA and starch-based) 31% was 
landfilled, 39% incinerated, 27% industrial composted and 3% anaerobic digested. For 
the fossil-based packaging films 31% was landfilled, 39% incinerated and 30% recycled. 
The results show that compostable packaging films (starch and PLA) have lower impacts 
than the reference PP film in several impact categories and higher impacts in others. It 
therefore depends on the importance of each impact category if the PLA and starch-
based alternatives can be considered to have lower environmental burden. The starch-
based film had the highest climate change impact due to high emissions from landfilling. 
For all materials types the polymer production (including feedstock cultivation) is the life 
cycle phase contributing to the highest share of emissions, followed by the EoL stage. 
The study shows that the biodegradable film alternatives (PLA and starch-based), show 
no general advantages compared to PP when biological treatment options (industrial 
composting and AD) are considered individually. 

160 Nessi, S., Bulgheroni, C., Konti, A., Sinkko, T., Tonino, D., & Pant, R. (2018). Environmental sustainability 
assessment comparing through the means of lifecycle assessment thepotential environmental impacts of 
the use ofalternative feedstock (biomass, recycled plastics,CO2) for plastic articles in comparison to 
usingcurrent feedstock. The European Commission - Joint Research Centre (JRC). 

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6.2.2 

Beverage Bottles 

A conventional PET beverage bottle is compared with other plastic material, were PLA, 
made from corn from USA, is the only compostable material. For PLA it was assumed 
that the EoL was divided into 30% recycling, 27% industrial composting, 3% AD, 20% 
incinerating and 20% landfilling. The PET bottle was assumed 60% recycled, 20 
incinerated and 20% landfilled. The PLA beverage bottles show an environmental 
advantage in the resource impact categories and the three toxicity related impact 
categories. However, for the other 11 impact categories including climate change the 
PLA bottles perform worse. The polymer production (including feedstock cultivation) is 
the life cy-cle stage were above 50% of the environmental impacts occur, the EoL stage 
only contains 3-14% of the impacts. Focusing on compostable PLA, no overall advantages 
are found when biological treatment options (composting and anaerobic digestion) are 
considered individually and no substantial changes occur in the comparison with fossil-
based non-biodegradable materials. Therefore, when proper waste collection can be 
achieved, the use of compostable materials for beverage bottle production does not 
represent, a solution to achieve an improved environmental performance compared to 
conventional fossil-based materials, especially if these come from recycled feed-stock. 

In 2018 the European commission published another report "Environmental impact 
assessments of innovative bio-based product. Task 1 of Study on Support to R&I Policy in 
the Area of Bio-based Products and Services"161. The report contains several LCAs on bio-
based plastic products (both compostable and not) compared with their fossil 
conventional counterparts. The temporal scope was from 2019 and 5-10 years forward, 
the modelling was based on a cradle-to-grave LCA and the geological scope was Europe. 
The EoL modelling was therefore based on average EU waste technologies but EoL 
scenarios for single different waste treatments were also analysed. Littering was not 
included in the modelling which is one of the uncertainties of this study. The study 
includes six LCA case studies of compostable plastic two of the most relevant case 
studies for this project are highlighted below. 

6.2.3 

Packaging Films 

The three materials assessed in the LCA were PLA, PP and bio-based PP. The feedstock of 
PLA was a market average mix made from corn cultivated in the United States and 
sugarcane from Thailand. The LCA was modelled with the assumption that 15 kg of food 
waste will follow per kg of plastic disposed. The weighted results with toxicity and 
average EU EoL show that the PLA packaging film has a lower weighted score, hence it is 
the preferred choice. The difference in the scores is only 10 % and a small change in the 
prerequisites can influence which product system is environmentally preferable. The EoL 

161 COWI A/S , Directorate-General for Research and Innovation (European Commission) , Utrecht 
University. (2019). Environmental impact assessments of innovative bio-based product. Task 1 of “Study 
on Support to R&I Policy in the Area of Bio-based Products and Services “ - Study. European Commission. 

92   

 
 
 
 
 
phase had a large contribution in most impact categories, mostly due to the additional 
food waste considered. 

6.2.4 

End Of life 

The end of life of compostable/biodegradable products is an area that is generally 
problematic to model in LCA and there is no established methodology for doing so. 
There is little empirical data that can be used for processes such as landfill and 
composting—these are particularly difficult to effectively measure emissions from in a 
reliable way and it is even more difficult to attribute these to specific materials. Results 
are highly dependent upon system boundaries, scope, data limitations and critical 
assumptions, such as EoL and biodegradation162,163,164. 

Table 9 summarises the current understanding of the various end-of-life treatment 
methods for compostable plastics in comparison to conventional plastics. It is possible 
for compostable plastics breaking down in landfills to produce methane, but the specific 
evidence for this is mixed as landfills are heterogeneous, complex environments. A 2011 
study using the relatively obscure material PHBO found that it did emit methane in 
simulated landfill conditions.165  A study conducted on behalf of Natureworks—a global 
PLA producer—found the opposite166, but an independent study focusing on PLA found 
that some methane is produced from PLA when temperatures of 55oC are reached, 
which is common in landfills with a high organic content.167 The composition of the 
landfill will also highly influence this and all three studies are from the USA which has 
less strict rules around what can be landfilled than the EU. 

However, logically if the materials biodegrade in anaerobic digestion, one would expect 
similar in the anaerobic conditions in landfill which will be partly down to whether the 
correct microorganisms are present. As discussed previously in Section 4.2.1.1, the 
ability to biodegrade in anaerobic conditions is also dependent on the material and 
therefore blanket statements cannot be made one way or the other in this regard. 

162 Gironi, F., & Piemonte, V. (2011). Bioplastics and petroleum-based plastics: strengths and weaknesses. 
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 33(21),, 1949-1959. 

163 Hottle, T. A., Bilec, M. M., & Landis, A. E. (2013). (2013). Sustainability assessments of bio-based 
polymers. Polymer Degradation and Stability, 98(9), , 1898-1907. 
164 Yates, M. R., & Barlow, C. Y. (2013). Life cycle assessments of biodegradable, commercial biopolymers—
A critical review. Resources, Conservation and Recycling, 78, 54-66. 
165 Levis JW and Barlaz MA (2011), Is biodegradability a desirable attribute for discarded solid waste? 
Perspectives from a national landfill greenhouse gas inventory model. Environ Sci Technol, 03/05/2019 
https://www.ncbi.nlm.nih.gov/pubmed/21615182  
166 Kolstad, J.J., Vink, E.T.H., De Wilde, B., and Debeer, L. (2012) Assessment of anaerobic degradation of 
IngeoTM polylactides under accelerated landfill conditions, Polymer Degradation and Stability, Vol.97, No.7, 
pp.1131–1141 
167 Max J. Krause, and Timothy G. Townsend (2016) Life-Cycle Assumptions of Landfilled Polylactic Acid 
Underpredict Methane Generation, Environmental Science & Technology Letters, Vol.3, p.166−169 

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Conventional plastics are inert and hence produce no GHG (and arguably act as carbon 
storage). 

Incineration is more straight forward as both compostable and conventional release 
their locked up carbon as CO2 when burned. However, the province of the carbon that is 
released is important in this instance. From a purely end-of-life point of view the short 
cycle biogenic carbon released from bio-based plastics is generally considered to be less 
impactful (even carbon neutral) than releasing older fossil carbon. Of course, the wider 
the full life cycle impacts should be considered before declaring that bio-based material 
is superior from a climate change point of view. 

The comparison between incineration with composting often one the key deciders in 
LCA studies that focus on compostable plastics. A study by Rossi, Dubois, Humbert & 
Jolliet168, on European EoL options for bio-based compostable films of PLA and 
thermoplastic starch (TPS) found that composting did not lead to environmental savings 
compared to incineration, but AD performed similarly—the assumptions around energy 
offsets are key to this as incineration was assumed to produce electricity and heat which 
offsets mostly fossil based sources. Many incinerators do not use the heat and the 
electricity benefits are reduced with the increase in renewable technologies—both these 
factors are region and time specific and can have a large effect on the results. 

The JRC, for their five LCA case studies169, assumed that 90% of the carbon in 
biodegradable plastics is released as carbon dioxide during composting—this is based on 
the threshold testing under EN 13432, but the likelihood is that this is much lower in 
practice (50-70%) with the remainder converted to biomass. The assumptions used for 
anaerobic digestion are more complex. The JRC calculated, for biodegradable beverage 
bottles, 35% of the carbon is released and of that 63% is methane and 37% is CO2 under 
the assumption that the material partly biodegrades in AD and then continues this in a 
secondary composting stage. For both these systems, bio-based compostable plastic is 
likely to perform better in GHG terms compared with fossil based versions as the carbon 
released is short-cycle and considered to be close to neutral.  

Conventional plastics do not have either of these end of life options and if they do end 
up in composting there are known detrimental effects, however these are yet to be 
quantified. No LCA studies have yet included scenarios where the conventional plastic is 
mismanaged into organic waste, despite this being known to be a problem in reality. 

168 Rossi, V. C.-E., Dubois, C., Humbert, S., & Jolliet, O. (2015). Life cycle assessment of end-of-life options 
for two biodegradable packaging materials: sound application of the European waste hierarchy. Journal of 
cleaner production.  
169 Nessi, S., Bulgheroni, C., Konti, A., Sinkko, T., Tonino, D., & Pant, R. (2018). Environmental sustainability 
assessment comparing through the means of lifecycle assessment thepotential environmental impacts of 
the use ofalternative feedstock (biomass, recycled plastics,CO2) for plastic articles in comparison to 
usingcurrent feedstock. The European Commission - Joint Research Centre (JRC). 

94   

 
 
 
 
 
 
Table 9: End of Life Scenarios for Different Plastic Types  

Green = most favourable environmental scenarios; Yellow = mixed or uncertain 
scenarios; Red = least favourable environmental scenarios 

Material 

Landfill 

Incineration 

Composting 

Anaerobic Digestion 

Bio-based 
Compostable 

Fossil-based 
Compostable 

Bio-based 
Conventional 

Fossil-based 
Conventional 

Mixed 
evidence, but 
likely to 
release at 
least a small 
amount of 
methane 

Releases 
biogenic CO2 ; 
offsets energy 
generation 

Releases 
biogenic CO2; 
~1/3 is 
converted to 
biomass 

Mass released as ~1/4 mostly 
methane which is captured and 
offsets energy generation; ~1/3 
is converted to biomass, the 
remining is biogenic CO2

1 

Releases fossil 
CO2; offsets 
energy 
generation 

Releases fossil 
CO2 ~1/3 is 
converted to 
biomass 

Mass released as ~1/4% mostly 
methane which is captured and 
offsets energy generation; ~1/3 
is converted to biomass, the 
remining is fossil CO2

1 

Inert 

Releases 
biogenic CO2 

Releases fossil 
CO2 

Unwanted 
contamination 
but inert – not 
viable waste 
disposal route 

Unwanted contamination but 
inert – not viable waste disposal 
route 

1. 

It is unclear exactly which proportions are converted to methane, CO2 or biomass. This will 
largely depend on the resident time and whether there is a subsequent composting stage – the 
latter is assumed in this instance as described in the JRC feedstock LCA report. 

Source: Adapted from JRC (2018) 

6.2.5 

Key Conclusions  

Key Conclusions – Environmental performance of compostable plastics from an LCA 
perspective 

Results from LCA studies reviewing or conducting comparative LCAs on compostable 
plastics and conventional fossil-based plastic mostly agree that in some impact 
categories the bio-based compostable plastic has lower impacts and vice versa in other 
impact categories, but the results are highly dependent upon system boundaries, scope, 
data limitations and critical assumptions, such as feedstock, end of life treatment and 
biodegradation. 

The main take away points from two comprehensive EU studies are: 

•  Generally, studies are inconclusive and often have conflicting results. 

Methodologies for assessing the end of life for compostable plastics and the 
production impacts of bio-based plastics require further development to enable 
accurate and fair comparisons. 

95 

 
 
 
 
•  The biological treatments of compostable products do not offer general benefits 
compared to recycling or incineration. Both studies emphasize that landfilling of 
compostable plastics should be avoided in order to reduce climate change 
impacts. 

•  Compared to production the EoL stage often has low contribution to the overall 

impacts. 

•  Bio-based, compostable products can offer benefits in some impact categories, 

especially climate change but show higher impacts in other categories compared 
to fossil-based plastics considering an average EU EoL.  

•  Generally, throughout the LCAs case studies the life cycle phase contributing to 

the majority of impacts was the production stage.  

•  The important factors influencing the environmental performance are feedstock 

and energy use during production.  

•  The studies highlight several limitations that alter a full comparison between the 

compostable and the fossil counterparts due to limitations on data on 
compostable products. 

96   

 
 
 
 
7.0  Criteria Setting 

This section of the report brings together the knowledge of previous sections to assess 
the possible conditions in which the use of compostable products and packaging could 
be beneficial. Criteria are derived against which specific applications can be tested. 

7.1 

Methodology 

The methodology for developing the criteria has been twofold: 

•  Requesting and collecting stakeholder position statements and deriving key 

criteria from the statements; and, 

•  After deriving an initial long list, discussing the refining this list during and after a 

stakeholder meeting. 

The full list is shown in Appendix A.4.0 together with which position statements were 
used to derive the criteria. 

7.2 

Proposed Prerequisites  

From the stakeholder engagement process and the preceding research, it has become 
clear that it is appropriate to define the prerequisites that need to be achieved for the 
disposal of compostable packaging alongside biowaste to be considered an option.  

This is in order to make sure that; 

1)  The organic waste treatment infrastructure is capable of dealing with these 

materials/products with no negative effects. 

2)  The material/product performs as expected in industrial composting; and, 
3)  The waste treatment method and the appropriate disposal actions required by 

the end user to facilitate this is effectively communicated. 

Without these three elements above in place, the likelihood of negative consequences is 
high i.e. consumer confusion leading to improper disposal and/or situations where 
organic waste treatment is hampered. Table 10 describes the proposal for these 
prerequisites.  

97 

 
 
 
 
 
 
 
 
 
Table 10: Proposed prerequisites for packaging and products where 
primary disposal is through composting or anaerobic digestion 

1)Waste 
Treatment 

2)Product 
Specification 

3)Communication 

Prerequisite 

1)   Separate collection of organic waste is in place.  

2)  Aerobic composting must be given sufficient time that 

biodegradation can fully occur and anaerobic digestion must 
include an aerobic composting phase. This must not result in 
negative financial, operational or environmental 
consequences. 

3)  Products in their entirety must meet EN Standards for 

composting of packaging or plastic products – i.e. compostable 
products should not be comprised of components that do not 
meet the standards 

4)  The term ’biodegradable’ is not used on the product or any 

marketing communication associated with it. 

5)  The correct waste management route is clearly identifiable for 
the end consumer/user and this is communicated effectively 
on the product/ packaging 

7.3 

Recommendations for Communication 

The word ‘biodegradable’ in the context of compostable plastics is considered by the 
majority of stakeholders to be an unhelpful term when used in marketing claims and 
that at best is confusing and at worst can lead to unwanted behaviour such as littering. It 
is clear that precision in the use of terminology will help with communication and 
therefore it is important to use terminology on the product that only relates directly to 
the preferred waste management practice. This is why it is recommended that the term 
biodegradable is not used to  

Although labelling and communication in itself is not likely to remove all chance of 
negative consequences from some products being made from compostable plastic (i.e. 
confusion leading to more plastic contamination in composting), looking at ways to 
communicate more effectively will be important. 

Currently there are no standardised ways of communicating the correct way for 
consumers to recycle packaging across Europe—largely due to the different ways in 
which systems operate. The same goes for communication for compostable plastics, 
where currently the messaging is often at the discretion of the producer who may also 
chose to display one of the labels from certification schemes such as TUA Austria or Din 
Certco. Neither label helps direct the consumer towards a disposal method—
understandable as the labels are used across Europe. 

98   

 
 
 
 
 
One example from the USA that is worth highlighting is the How2Recyle label which 
introduced a How2Compost label in 2016. Figure 18 shows examples of these labels with 
the original recycling label on the left and two examples of the composting label – 
importantly it also allows for other non-plastic materials to be designated compostable if 
the circumstance dictate. There are three important aspects to this labelling system that 
could be considered good practice: 

•  The composting labelling is consistent with the recycling labelling and therefore is 

a recognised system the consumers look for on packaging. 

•  The label is linked directly with the certification process – in the US this is the 

BPI170 who certify products to the US equivalent of EN 13432. 

•  The website (using the web address on the label) can be used to search whether 
the local waste collection accepts the materials – although the scope of this 
service appears limited in functionality and integration at present. 

Figure 18: The USA ‘How2Recyle/compost’ Logos 

These three aspects could be incorporated into the basis for labelling schemes in the EU 
with the expectation that the execution may be different between different Member 
States. A possible Member State that this could be trialled in is France as the recent 
legislation is likely to lead to a large increase in the use of compostable bags. Under 
France’s Roadmap for the Circular Economy171, a key target is to simplify waste sorting 
processes by having unambiguous sorting instructions and harmonizing the colours of 
waste bins throughout the country (Figure 19) and therefore incorporating a 
compostable label at an early stage would help with consumer recognition and 
acceptance—this may be particularly important given the relatively low level of separate 
organic waste collection in France. 

170 https://bpiworld.org/ 
171 Roadmap for the circular Economy - 50 measures for a 100% circular economy, Ministry for an 
Ecological and Solidary Transition and Ministry for the Economy and Finance. Last accessed 19/02/19  
https://www.ecologique-solidaire.gouv.fr/sites/default/files/FREC%20anglais.pdf 

99 

 
 
 
 
 
 
 
 
Figure 19: CITEO Sorting Labelling 

Translation: Think about sorting! – Tray and plastic film to dispose – Carboard box to recycle 

7.4 

Recommendations for Waste Treatment 

By 2024, separate collection of bio-waste is set to become mandatory in the EU as part 
of revisions Article 22 of the Waste Framework Directive.172 Until then, this practice 
should be expected to still vary between and within Member States. Without separate 
collection in place there is no reliable and consistent way of making sure that 
compostable plastics reach appropriate composting facilities rather than ending up in 
residual waste. 

The current disintegration time specified in EN 13432 is 12 weeks (5 weeks for AD). 
Evidence suggest that this timescale is not always reflected in reality (the product of 
‘fresh compost’ in Germany for example). Adapting timescales to suite the use of 
compostable plastics is likely to be unfeasible at present. Equally, setting a minimum of 
12 weeks may also be unhelpful when some modern and highly controlled processes can 
take less time. 

The wording of the proposed prerequisites in this study does not specifically point to a 
time period but that the process “must be given sufficient time that biodegradation can 
fully occur.” This time period may differ between countries, but the important aspect is 
that products certified to EN 13432/14995 will be treated effectively in the process. The 
only way to test this is to sample and catalogue the outputs of the composting process—
an activity that has been undertaken for many years in Italy. If the minimum composting 
standards in a country have been demonstrated to effectively compost compostable 
plastics there will be opportunities to promote the use of the material in certain 
applications, if this is not the case, the material should not be promoted. 

172 Directive (EU) 2018/851 https://eur-lex.europa.eu/legal-
content/EN/TXT/?uri=uriserv:OJ.L_.2018.150.01.0109.01.ENG  

100  

 
 
 
 
 
 
 
7.5 

Proposed Criteria for Beneficial Use 

Table 11 shows the proposed criteria for identifying potentially beneficial uses of 
compostable plastic. These centre around two key headline criteria:  

1)  there should be environmental benefits to using compostable plastics over 

alternatives – this leads to several sub-criteria that relate to the means or the 
conditions in which such benefits could be realised.  

2)  there should be no (direct or indirect) reduction in the quality of the compost — 
this relates to compost quality, but goes beyond the proposed prerequisites for 
the material itself to focus on the wider consequences. This is supported with 
two sub criteria identifying scenarios where non-compostable plastic 
contamination is not increased or is even reduced. 

A weighting is applied to these sub-criteria in order to recognise that some aspects are 
more important than others – in this regard it is considered that preventing an increase 
in non-compostable plastic contamination is the most important. Secondary to this is a 
net reduction of contamination along with the other environmental benefits gained from 
increasing biowaste capture. Criterion 1c allows for LCA to be used as a tool to prove 
environmental benefits, but is not a definitive criterion. Finally, criterion 1a has the 
lowest weighting in recognition that there may be circumstances where other benefits 
may outweigh those gained from recycling or reuse. The current pledge under the EU 
plastics strategy is to ensure that all plastic packaging is recyclable by 2030. This means 
that this criterion should have less importance over the coming years and that beneficial 
applications of compostable plastics will be most effective where ‘co-benefits’ can be 
achieved (i.e. in a situation where all packaging is ‘recyclable’). 

The criteria rejected for inclusion at this point as detailed in Appendix A.4.0, however it 
is important to directly address one specific criterion that has been suggested primarily 
by the compostable plastics industry, namely for situations where the product is 
contaminated with food waste. In this regard it is important to make the distinction 
between food waste and food residue. The latter is small amounts of food (primarily 
liquids) that remain on the packaging and after use and, in this particular application, 
would be considered unavoidable. Where this might be considered as waste is when 
food that could have been consumed, remains. It is clear that this should be tackled 
through waste prevention measures and is not a reason to use compostable materials. 
The claimed benefit is often that the food waste/residue can be recovered if the 
packaging is compostable and set to organic treatment. Whilst this is true, the benefit 
associated with a relatively small amount of unavoidable residue is likely to be negligible 
and not a sufficient reason in itself. The most likely relationship with food is that it 
increases the likelihood of the packaging ending up in organic waste and therefore if this 
is compostable it will reduce plastic contamination. 

One aspect of compostable plastics which is often discussed is the economic benefit of 
this material in compost compared with the equivalent plastics in recycling. It is implicit 
in the above criteria that on a purely material basis, recycling has the higher value. This is 

101 

 
 
 
where identifying the specific applications is important, as there will be some where the 
material value is less relevant than the added value e.g. increasing food waste capture.  

Table 11: Proposed Criteria for Identifying Applications for Which Design 
for Composting May Be of Added Value 

Criteria 

Wtg 

The use of compostable plastic brings ‘environmental benefits’ over 
alternative materials 

This application could not have been designed for reuse or 
recycling/would not undergo material recycling if designed for recycling 

The use of compostable plastic for this specific application can be 
expected to significantly increase the capture of bio-waste compared to 
non-compostable alternatives 

Through the use of LCA or similar environmental assessment tool it can 
be demonstrated that compostable plastic is the preferred material for 
this particular application 

The use of compostable plastic does not directly or indirectly result in 
a reduction of the quality of the resulting compost 

The use of compostable plastic for this application does not lead to 
consumer confusion and subsequent increasing contamination with 
non-compostable plastics.1  

The use of compostable plastic for this application can be expected to 
significantly reduce the contamination of compost with non-
compostable plastics (from this application) compared with current 
practice 

1 

1a 

1b 

1c 

2 

2a 

2b 

Notes: 

1.  It is possible to require the whole product group to be designed for composting to avoid the 
coexistence of compostable with non-compostable materials within the same application.  

3 

4 

3 

5 

4 

102  

 
 
 
 
 
 
 
 
 
 
7.6 

Criteria Testing 

Table 12 shows the ten most common applications that were identified in the market 
analysis in Section 3.3.2. It should be noted that single use cutlery is due to be banned 
across the EU under the SUP Directive and compostable plastics are not exempt from 
this—these items are therefore no tested against the criteria. Some of the applications 
represent groups of products and therefore to test the criteria, specific examples within 
these product groups have been chosen.  

Table 12: Application Examples 

Application 
Carrier bags 
Biowaste bags 

Other flexible packaging (food and non-food) 

Single use trays  
Rigid packaging (food and non-food) 
Single use cups 
Bags for loose products (vegetables and other) 
Coffee pads, filters and capsules 

Example 
Carrier bags used in supermarkets 
Biowaste bags as liners for indoor caddy 
Clothing bags e.g for shirts   
Pre-packed fresh fruit bags for e.g. 
apples/bananas 
Trays used for fast food 
Rigid fast food Containers 
Single use paper cups with plastic liner 
Supermarket vegetable bags 
Coffee capsules/pods 

As well as key products identified in the market assessment, products that are 
considered to be benchmarks at either end of the spectrum (i.e. 
detrimental>>>beneficial) are also tested; the single use bottle is a product that is 
universally considered by the stakeholders engaged for this study to be an example of a 
packaging product that should not be made from compostable plastic. At the other end 
of the scale, tea bags and fruit labels are considered by the compostable plastics industry 
to be archetypal examples of beneficial use. Two further scenarios are also added;  

• 

trays used for fast food in a ‘closed system’ (i.e. a canteen where all products are 
compostable and are all collected in special bins to be sent to a composter) 
where reuse is and is not possible; and, 

•  a situation where non- compostable coffee pods are banned. 

These are included to demonstrate that the same product may or may not be beneficial 
depending upon the specific circumstances. 

Table 13 shows the results of the criteria testing. Each of the products are rated 1-5 
against the criteria. A rating of five considers the criterion statement to be completely 
true whereas a rating of one is considered completely untrue. A rating of three means 
the evidence is mixed or unconfirmed. The benchmarks performed as expected with 

103 

 
 
 
 
both tea bags173 and fruit labels highlighted as having potential for added value when 
designed for composting – in large part due to the fact that they are never recycled and 
will regularly end up in biowaste (with the conventional plastic elements becoming 
contamination). Conversely, the single use bottle fails in all of the criteria and therefore 
does not represent a beneficial use example. This does not discount the use of 
alternative materials to PET for use in bottles such as PLA, but they should not be 
marketed as compostable. PLA is a special case where it can be composted, but also 
there is evidence of mechanical recycling taking place in one isolated case in Belgium 
(but this is far from widespread or likely to be) – it is clear that both of these waste 
management routes cannot exist in parallel for the same products (especially when they 
look identical) as this can lead to confusion. If PLA is used as an alternative to PET it 
should not be for its compostability. 

The other example products are also situation specific in some instances – the 
assumptions for these are outlined below the table. For example, the carrier bag is 
assumed to be reused as a caddy liner some of the time. If this was not the case, the 
increase in capture of biowaste would be given a lower score and LCA studies (Section 
6.1) generally do not show that this material—compared with conventional plastic— is 
the best option unless reuse is part of the lifecycle. Similarly, it is assumed that both 
compostable and non-compostable versions of carrier and vegetable bags will exist on 
the market and therefore confusion and contamination issues could result. The results 
of this criteria testing example would therefore change depending upon the scenario 
and therefore cannot be universally applied or conclusions drawn that are true in 
every circumstance. 

A further example of this is for trays used for fast food. Whether it is beneficial to make 
the product out of compostable plastic entirely depends upon the circumstances.  The 
three examples given here are; a situation where the packaging ends up in litter bins and 
likely residual waste; a close system where reuse is not possible (likely to be niche 
circumstances) and; a closed system where reuse is possible i.e. a canteen with washing 
facilities. Only the closed system where reuse is not possible is likely to be a beneficial 
application for compostable plastic for this product. Where reuse is available, there are 
no benefits in terms of the criteria being tested against. 

Fast food tubs also do not appear to be a beneficial use of compostable plastic and this is 
likely to be reflected in other rigid fast food applications as well. The same is also true of 
single use paper cups with a plastic liner; both do not help with capturing biowaste, but 
also may be confusing for consumers and lead to more contamination in composting for 
the same reasons as the single use bottle—most likely these items will end up in litter 
bins where they are unlikely to be composted.  

173 Referring to paper teabags that are often heat sealed with polypropylene and therefore contain plastic 
that is not obvious, rather than bags that are entirely polymer based. 

104  

 
 
 
 
 
Biowaste bags and vegetable bags appear to be the most beneficial applications for 
compostable plastic films when the latter is reused as biowaste bag, however the 
relationship between these two products is important and certain local or national 
policies will affect this. For example, if biowaste bags are provided for free to encourage 
collections, the vegetable bags are less likely to be reused and the benefit is lessened. On 
the contrary, if biowaste bags are mandatory, but not provided, the vegetable bag may 
be more beneficial as its reuse is almost guaranteed. 

Coffee capsules provide the most benefit in a situation where alternatives are banned—
this would reduce consumer confusion and capture the coffee biowaste. Several of the 
other applications sit in the middle ground where the benefits may be improved or 
worsened depending upon the circumstances, but should not be particularly promoted 
at this time. 

Figure 20 shows the products on a continuum using the weighted % of maximum scores 
(i.e. 0-100%) in order to visually compare the results. This is based on the general 
assumptions identified in Table 13 and therefore it may look different for each Member 
State depending upon whether these assumptions hold true (or other considerations 
come into play). The cut-off point between which applications are promoted and which 
are discouraged is also a decision process that should be taken at the Member State 
level especially for those items which fall into the grey area in the middle (i.e. neither 
detrimental nor beneficial). 

It should also be recognised that not all of these applications are likely to be covered 
under the Packaging and Packaging Waste Directive primarily due to the Article 3(1)i that 
states that an item should not be considered as packaging if it “is an integral part of a 
product and it is necessary to contain, support or preserve that product throughout its 
lifetime.” Products such as coffee pods and teabags are likely to be described by this 
clause and therefore the mechanisms for promotion or restriction of these items or 
similar may be different. 

Figure 20: Compostable Plastics Beneficial Use Continuum  

105 

 
 
 
 
Table 13: Criteria Testing (5= completely true, 1= completely untrue, lowest weighted score possible = 19, highest = 95) 

Example products 

Not recyclable or 
could not have been 
designed for reuse 

Increases the 
capture of bio-
waste 

Weighting>> 

Carrier bags used in supermarkets1 
Biowaste bags as liners for indoor caddy2 
Clothing packaging bags e.g. for shirts   

Pre-packed fresh fruit bags  
Trays used for fast food3 
Fast food Trays (closed system - reuse 
unavailable)4 
Fast food Trays (closed system – reuse 
available) 
Rigid Fast food Containers3 
Single use paper cups with plastic liner5 
Supermarket vegetable bags6 
Coffee capsules/pods7 
Coffee capsules/pods (alternatives 
banned) 

Single Use Bottle 

Fruit Labels 

Tea Bags (plastic heat sealed) 
Notes: 

3 
2 

5 

2 

4 

2 

4 

1 

2 

2 

2 

2 

2 

1 

5 

5 

4 
3 

5 

1 

2 

1 

5 

1 

1 

1 

3 

5 

5 

Benchmarks 

1 

1 

2 

LCA demonstrates 
preferred option is 
compostable 
plastic 
3 
3 

Reduces the 
contamination of 
compost with non-
compostable plastics 
4 
2 

3 

2 

1 

1 

3 

1 

1 

1 

3 

3 

3 

1 

2 

3 

4 

1 

2 

1 

3 

2 

1 

1 

2 

1 

3 

1 

5 

5 

Does not lead 
to increasing 
contamination  Wtd 
Score 

% of 
Max 
Score 

41% 
80% 
14% 
29% 
11% 
64% 

50 
80 
30 
41 
27 
68 

28 

12% 

27 
27 
45 
49 
72 

19 
65 
72 

11% 
11% 
34% 
39% 
70% 

0% 
61% 
70% 

5 
3 

4 

2 

2 

2 

3 

2 

2 

2 

2 

2 

5 

1 

4 

4 

2.  Carrier bags - Assumes that carrier bags are sometimes used as a caddy liner and that conventional carrier bags are currently a significant source of 

contamination in biowaste. There are also conventional bags on the market at the same time which can cause confusion. 

3.  Biowaste bags - Assumes biowaste bags are provided for free by municipality 
4.  Fast food trays and containers - Assumed that these end up mostly in residual waste, not composted 
5.  Fast food trays used in closed system – All waste is collected and composted together. Only in niche applications where no reuse is possible 
6.  ‘Single use’ is specified as these are still on the market and reusable alternatives may not always be practical 
7.  Supermarket vegetable bags - Assumes that bags are sometimes used as a caddy liner and that conventional bags are currently a significant source of 

contamination in biowaste. There are also conventional bags on the market at the same time which can cause confusion. 

8.  Coffee capsules/pods - Assumes both compostable and non-compostable pods on the market with the potential to confuse consumers 

106  

 
 
 
8.0  Compostable Plastics in Home 

Composting 

Home composting as a means of treating domestically produced biowaste is an 
attractive option because it eliminates collection and transport costs of the waste, it 
offers a means of improving soil quality without the need for chemicals, and also 
encourages local responsibility for waste. However, it has drawbacks when viewed solely 
as a potential means of waste treatment, mostly because it is difficult to monitor the 
quantity of waste being treated, as well as the quality of the output. 

This section of the report seeks to assess the feasibility of establishing criteria for 
labelling plastics as home-compostable for treatment in home composting situations. It 
identifies the conditions to be found in different types of home composting systems 
used across the EU and comparing them with the criteria set in existing standards.   

The following themes are covered:  

•  Systems and practices of home composting  
•  Conditions in home composting affecting biodegradation of plastics 
•  Comparison of compost advice, promotion and practice across six EU countries 
•  Standards and Certifications for Home Composting  
•  Comparison between frameworks and actual home composting conditions 

Based on this analysis a set of recommendations are formulated for approaches to 
address the discrepancies between existing frameworks and conditions to be found in 
practice. These have relevance for any forthcoming EU standards and communication 
towards home composters. 

8.1 

Systems and Practices of Home Composting  

Composting is an age-old practice that is more akin to baking a cake rather than building 
a Lego model. Many different recipes exist, containers come in all shapes and sizes, and 
cultures vary on key ingredients, but with a careful selection and right mixing the end 
product is recognisably similar – a nutrient-rich, dark brown compost that can be used 
beneficially to improve soil condition and plant growth.  

The active process in composting is the action of microbes, bacteria and fungi that 
breakdown organic material. When looking at compost systems and practices the best 
results are found when the ideal conditions are created for the microbial inhabitants. 
They thrive in a dark, warm environment that is humid but not too wet, and with 
sufficient access to oxygen. In designing a compost system these requirements are 
balanced with certain practical factors; the ease of adding organic matter, the removal of 
leachate and the ease of unloading the compost. 

107 

 
 
 
8.1.1 

System Design – Containers for Home Composting  

There are a wide variety of containers on the market for those interested in home 
composting, and home-made containers can function equally as well as commercially 
available items (see Figure 21). 

Figure 21: Range of compost containers for purchase of home construction 

Compost containers should be situated in a shady location, not in direct sunlight or they 
risk drying out. Ideally, a container is raised slightly to allow leachate to drain away and 
allow air to circulate, though they can be placed directly onto earth.  

Open systems are exposed to the elements and the material can be held within a slatted 
container or piled up in a heap. Closed systems use a container with a lid to reduce 
exposure to the elements and ventilation of the compost is achieved through holes or 
louvres. It can be slightly more difficult to control moisture levels in an open system, but 
it’s still a popular choice amongst gardeners; one study of composting in France reports 
that 64% of households that compost at home, use an open pile system.174  

The size of the container affects the biological process; a pile that is too small may not 
facilitate a build-up of temperature and hence support microbial action. It will also lose 

174 Olivier, Stephane, Royne, Veronique, and Rebert, Mylene (2009) Enquête nationale sur la gestion 
domestique des déchets organiques, 2009 

108  

 
 
 
 
 
 
heat more quickly slowing down the process. A larger pile may hold too much water, 
thus inhibiting air flow.  A minimum size of 200 litres is recommended to achieve a 
temperature increase needed for the composting process.175 While smaller bins are 
available, they may require the use of additives to kick start the composting process. A 
variety of ‘compost starter’ products are available containing a mix of nitrogen and 
microbes, though there is considerable debate as to their efficacy. Tumbling composters 
are also typically smaller than 200L to allow for the turning of the bin. This mechanical 
action aerates and mixes the compost with the aim of accelerating the composting 
process.  

In colder climatic conditions an insulated container is required to keep the compost 
warm enough to facilitate microbial activity. Until 2019 Finland only permitted home 
composting in closed and insulated containers, and containers on the market in Finland 
typically have a thermometer built in (see Figure 22).  Similarly, in Sweden, to be 
acceptable the system needs to be insulated, vermin proof and have ventilation holes 
covered with nets176.  These products are more costly than standard compost bins, 
perhaps limiting the number of households for whom this is a viable option.  

Figure 22: Compost containers for cold climates 

In the warmer climates of Southern Europe too much aeration of a compost pile will 
result in the compost drying out and watering the compost is more common practice. 

175 Compost Systems, accessed 27 June 2019, 
http://www.homecompostingmadeeasy.com/compostsystems.html 
176 Ermolaev, E., Sundberg, C., Pell, M., and Jönsson, H. (2014) Greenhouse gas emissions from home 
composting in practice, Bioresource Technology, Vol.151, pp.174–182 

109 

 
 
 
 
 
 
Recommendations in Greece suggest lining the compost container with cardboard to 
help retain moisture.177 Sometimes composters also use holes in the ground to keep the 
compost cooler.  

8.1.1.1  Multi Container Method and Community Composting 

Many composting manuals suggest that best results can be obtained by having more 
than one composting pile, which allows the user to build up a good mix of constituents in 
a pile and then leave it with periodic turning, whilst slowly building up a new pile. This 
requires more space than single unit composting but can be done in a community 
composting setting where several households combine their waste in one location.  

In many European cities, where apartment living is common and households do not have 
their own garden, community composting sites are used (see Figure 23). These range in 
size from multi-household bins serving around 5 households, to community composting 
sites that serve 50-80 households. In Basel, where composting has been promoted since 
1987, 30 such larger sites exist.178  

Where community compost schemes are in operation they rely on a ‘compost master’ 
who is trained to care for the system and takes on the role either as a volunteer or as a 
paid employee of the scheme. This reduces the need for each individual householder to 
understand the composting process. Householders can simply bring their waste to the 
site, often at allotted times when the site is being attended, and the community 
composter regulates the balance of bulking material to household waste.  Multi-
household composting increases the load size and frequency of loading which will 
positively affect the efficiency of the biodegradability process 179.   

177 Mediterranean Garden Society, Greece Compost and how to make it, accessed 8 July 2019, 
http://www.mediterraneangardensociety.org/compost.html 
178 FICHE 4 : BALE (SUISSE) - PDF, accessed 9 July 2019, https://docplayer.fr/18727475-Fiche-4-bale-
suisse.html 
179 Andersen, J., Boldrin, A., Christensen, T., and Scheutz, C. (2010) Greenhouse Gas Emissions from Home 
Compoosting of Organic Household Waste, Waste Management, Vol.30, pp.2475–2482 

110  

 
 
 
 
 
 
 
Figure 23: Community composting (Navarre, Spain, Paris and Digne les 
Bains, France) 

8.1.1.2 

Indoor Composting 

In an urban setting where space is limited, indoor composting is also a viable solution for 
households, though households without a garden are likely to have less need for making 
their own compost. There are two ways of composting indoors. Vermicomposting (worm 
composting) can be done in containers as small as 50L, because the biological process is 
markedly different from outdoor home composting. Red worms digest household food 
waste and excrete worm castings which are rich in minerals useful for plant growth. This 
process can be done within three to six months. Another method for indoor composting 
called Bokashi was developed in Japan in the 1980’s and uses a bran inoculated with 
microbes to ferment kitchen waste in anaerobic conditions, usually a special container 
that allows the waste to be tightly covered. The leachate of this process is beneficial to 
plants.180 It is unlikely that either of these processes will be able to biodegrade plastics as 
we do not know if worms cannot directly consume plastic materials or if the 
fermentation process will breakdown these materials. This could lead to consumer 

180 Bokashi: All You Need to Know, accessed 8 July 2019, //www.planetnatural.com/composting-
101/indoor-composting/bokashi-composting/ 

111 

 
 
 
 
 
 
confusion when labelling products as ‘home compostable’ as increasingly these practices 
are known as composting.  

8.1.2 

Effective Management of the Compost Pile 

Although there are a wide variety of composting systems that a home composter can 
use the more significant factor affecting the compost outcome is how the compost is 
managed as an active process.  

Managing the compost pile comprises the following activities: 

1)  Careful selection of the materials 
2)  Initial construction of the pile 
3)  Addition of further materials 
4)  Regulation of moisture levels 
5)  Regular mixing the pile 

Variations in how composting is practiced can be found in the materials fed into the 
compost (whether meat and fish are included, or what type of bulking material is 
available locally), how often the compost is added to and turned.  These variations in 
practice all affect the composting process by creating different biotic conditions which 
allow the microbial population to thrive. The key abiotic conditions are temperature, 
moisture levels, oxygen availability, pH and carbon/nitrogen balance. In general, what is 
added to the pile is key to affecting the moisture levels and carbon/nitrogen balance, 
while how often the pile is added to and turned affects the build-up of temperature.  

8.1.2.1  Materials to Include 

Compost specialists refer to two types of organic waste; ‘green’ waste – most commonly 
food waste and grass clippings, and ‘brown’ waste – commonly woody garden material 
such as woodchips, leaves or pine needles or shredded paper/cardboard. Table 14 shows 
the different C/N ratios of common composting materials. This simple distinction is 
important because green waste is high in nitrogen and moisture, while brown waste is 
higher in carbon and provides structure within the compost helping the flow of oxygen, 
which bacteria need to function. Brown waste is also referred to as a ‘bulking agent’. The 
ratio of bulking agent to food and other ‘green’ waste is crucial to the composting 
process. An example of an ideal balance would be for every kg of food waste around 
0.25 kg of dry leaves are added to the compost. However, managing the inputs based on 
this sort of scientific approach is far beyond what would be expected of the average 
home composter (and most want to compost what they have available, not search for 
additional correct materials). Because of this, advice generally ranges anywhere from a 
2:1 brown:green ratio by volume to a 1:1 or even 1:2.  

Table 14: Examples of Nitrogen and Carbon Rich Compost Feed 

Nitrogen Rich ‘Greens’ 

Carbon Rich ‘Browns’ 

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Input 

Plants/leaves 

Coffee grounds 

Food Waste – fruit  

C:N Ratio 

10-20:1 

25:1 

16:1 

Input 

C:N Ratio 

Card and paper 

150-200:1 

Fats and oils 

Hay and straw 

250:1 

90:1 

Food Waste- vegetables 

10-15:1 

Autumn fall or evergreen leaves 

60-80:1 

Grass clippings 

Manure 

10-15:1 

20-30:1 

Wood branches/trigs 

Sawdust  

700:1 

500:1 

Source: Jane Gilbert, The composting Trouble-shooter 

8.1.2.2  Ongoing Management of the Pile  

While it is not easy for a home composter to directly monitor the carbon nitrogen 
balance in their pile, moisture levels are a good proxy for this. Adding too many ‘greens’ 
which can occur if food waste is not balanced with bulking agent, will lead to an over-
moist pile.  The moisture can be monitored using the simple ‘squeeze test’ taking a 
handful of compost and squeezing it to see if water drips off, aiming for the moisture 
level of a damp, wrung out sponge. Indeed, monitoring moisture levels is one of the 
main ways that a home composter can judge the overall functioning of their compost 
pile as it is easier to monitor and change than temperature.  

Moisture levels can be adjusted by changing the ratio of bulking agent to food waste or 
watering the compost. In warm climatic conditions the moisture levels will need 
regulating with the addition of water, sometimes daily, so the compost pile should be 
sited near to a water point. In this way differences in climatic conditions can be adapted 
to, and in both dry and wet climates active management of the compost is needed. 

In the colder climatic conditions of Northern Europe, the ambient temperature is suited 
to composting for a much shorter time of the year than in continental Europe. This 
window can be extended through careful management of the compost pile the compost 
process can be kept active by insulating the compost container and continuing to add 
more waste and turn it regularly. However, if the wet compost freezes the composting 
process simply pauses and resumes when the air warms up again. 181 

Given the extra management needed to maintain active compost in colder climates it is 
likely that the numbers of people committing to do this are small. Similarly, in 
Mediterranean Europe the dryness of the summer months will inhibit the composting 
process and in order to sustain this regular watering of the pile is needed. It is likely that 

181 Meillakotona (2019) Komposti – ammattilaisten vinkit käyttöön ja hoitoon, accessed 28 October 2019, 
https://www.meillakotona.fi/artikkelit/ammattilaisen-ohjeet-kompostin-hoito 

113 

 
 
 
 
 
the numbers of people producing successful compost year-round in these climates is 
much lower than in Atlantic/Central/Eastern Europe.  

Sufficient aeration can be achieved by choosing a well-ventilated container, and 
managed with regular turning of the compost pile. Turning the compost improves the 
airflow and has been shown to increase the temperature, so facilitates the build-up of 
high temperatures which can produce compost in just a few months.  

Even with good management different natural materials will vary in how long it takes 
them to compost. Table 15 shows some examples of the different length of time needed 
for natural rotting of different materials. Some of these materials can be shredded to 
speed up the time, others are chosen as bulking agents precisely because they rot more 
slowly so maintain the structure in the compost pile. An experienced home composter 
will not be surprised to find some materials remain intact even when the surrounding 
material has turned into useable compost.  

Materials that would require a full year to biodegrade in an ambient climate may require 
two annual cycles or more in colder climates —this will be the same for the organic 
matter and biodegradable plastics so that although the process is longer than typical it is 
unlikely that the householder will be presented with perfect compost but with the 
plastics still intact.  

Table 15: Typical compost times for different waste materials 

Typical time to rot down 

Examples of waste materials 

within 6 months 

Kitchen food waste, grass, vegetable plants such as carrot 
tops, dead flower heads 

1-2 years 

Flower stems, hedge clippings (but not evergreens) 
shredded woody prunings, autumn leaves 

3 years or more 

Wood shavings, evergreen leaves or conifer needles, egg 
shells, oak and beech leaves, avocado stones, cabbage 
stems 

Source : Allan, D. (2019) The Home Composter, accessed 29 October 2019, 
http://www.askorganic.co.uk/composting/How%20long%20to%20make%20compost.htm 

8.1.3 

Defining Best Practice in Compost Management 

Batch composting is a term used for an efficient composting process that can produce 
useable compost in several months in benign climates. Batch composting involves 
building a complete pile in one go, with a layering of green and brown material and a 
layer of soil can be included.  The pile is kept moist and mixed weekly but no new 
material is added in this time. High temperatures can build up in this pile, supported by 
the regular mixing of material resulting in the fast production of compost.  

114  

 
 
 
 
A more common home composting practice is known as add-as-you-go composting 
which involves regular additions of small quantities of food waste, daily or weekly 
thereby suiting the waste management needs of a household. After an initial layer of 10-
15 cm of soil and brown material, then kitchen waste can be added as it is produced, 
always being covered with another layer of brown material to create the right moisture 
balance. As with batch composting the pile should be mixed periodically and moisture 
levels checked.  

The add-as-you-go composting style creates a compost system that is less likely to 
achieve very high temperatures so the decomposition of material is longer and slower 
than in batch composting, taking between 6-12 months to mature. Sometimes this is 
described as ‘cold composting’. However, if managed well with careful balancing of 
inputs and regular turning, a well-managed add-as-you-go pile can be as successful as a 
batch pile.  

In an attempt to define ‘best practice’ of home composting an artificial distinction can be 
drawn between a ‘well-managed’ pile and a ‘basic’ pile.  This is different from the 
distinction between batch composting and add-as-you-go because an add-as-you-go pile 
can be well-managed and produce hot compost if done carefully. Both approaches can 
produce compost from home waste but a well-managed pile will reach significantly 
higher temperatures in its core, resulting in a faster composting process and one more 
likely to have the conditions needed biodegrade plastics. A basic pile will remain at lower 
temperatures and need a full year to compost organic materials. It is likely to have a 
lower potential to biodegrade plastics. These two methods are both successful at 
producing compost and should be viewed in contrast to the even more minimal practice 
of dumping organic waste and leaving it to rot. Waste dumping is not composting and it 
can be assumed that householders engaging in this practice also do not believe they are 
composting.  

Table 16 shows the key differences between a well-managed pile and a basic pile. In 
8.3.2 Abiotic Conditions in Home Composting, the range of conditions resulting from 
such practices is explored in greater detail.   

Table 16: Features of a well-managed pile and a basic pile 

Well-managed pile 

Basic pile 

(batch or add-as-you-go) 

(add-as-you-go)  

System 

Practices 

Suitable container selected for the climate 

Ensures temp and air regulated for climate  

Careful layering of different materials – bulky 
materials are shredded 

Ensures health C/N ratio 10-40 and aeration 

Any container is used 

Basic layering of materials 

115 

 
 
 
 
 
Balance of ‘greens’ and ‘browns’ is monitored and 
adjusted 

Ensures health C/N ratio and aeration 

Garden waste and food waste 
added in the quantities produced 
by the household 

Moisture levels are checked using squeeze test and 
adjusted  

Ensure moisture levels around 50% 

Low awareness of moisture levels 

Regular turning of the pile 

Ensures sufficient aeration 

Infrequent turning 

Hot composting  

Cold composting 

(temp can reach above 45°C) 

(temps remain under 45°C) 

~3-4 months 

~12 months 

Resulting 
conditions 

Timescale 

Community composting systems demonstrate how an add-as-you-go method can also be 
well managed. Community systems use an add-as-you-go style of feeding which allows 
households to bring their waste on a regular basis when they need to dispose of it. 
However, because they are managed closely by trained individuals, and they also have 
space for several compost vessels they can create and manage several ‘batch’ piles 
whilst still accepting new waste. This can result in a ‘hot composting’ process producing 
compost within several months.  

Without targeted primary research it is very difficult to ascertain what proportion of 
households that engage in composting are knowledgably managing their piles or 
adopting a basic practice. Arguably, the building or purchasing of a container signifies an 
investment that may lead the householder to be more engaged and proactive in 
managing the system, but this cannot be presumed. Furthermore, households that only 
adopt a more basic management practice are more likely to become discouraged, as the 
compost will take longer to become ready and be less appealing in form, potentially 
being too moist or slightly smelly.  

8.1.4 

Key Conclusions  

Key Conclusions – Systems and Practices of Home Composting  

Home composting can be successfully done in a range of ways but requires some 
knowledge and active management. The aim of managing a compost pile is to provide 
the ideal conditions for microbes (bacteria and fungi) to thrive. It is the microbes that 
drive the composting process by consuming carbon in the biowaste.  

Best practice in compost management includes: 

•  Selecting a suitable container selected for the climate 

116  

 
 
 
 
 
o  Ensuring temperature and air regulated for climate  

•  Ensuring the balance of ‘greens’ and ‘browns’ is correct 

o  C/N ratio is adequate for composting to take place efficiently 

•  Moisture levels are checked using squeeze test and adjusted  

o  Ensuring moisture levels of around 50% 

•  Regular turning of the pile 

o  Ensuring sufficient aeration and mix of C/N materials 

Effective management of the compost pile: 

It is possible to produce workable compost without following best practice by adopting a 
more basic practice; infrequent mixing, and infrequent monitoring of moisture levels. As 
long as the mix of materials is within an appropriate range and the compost pile is 
naturally aerated this will still produce compost but will result in low temperature 
composting process, remaining under 45°C and taking at least a year.  
Though it is often recommended to build a compost pile in one go ‘batch composting’, a 
more common practice in home composting is ‘add as you go’ where fresh biowaste is 
added regularly. This latter suits the home composter’s regular production of biowaste 
but is more likely to lead to a low temperature composting process.  
Cold composting is very common in home composting, with temperatures remaining 
under 45°C and needing a full year for maturation. Hot composting is achievable with 
good management but it cannot be assumed to be the norm.  

Without targeted primary research it is very difficult to ascertain what proportion of 
households that engage in composting are actively managing their piles according to this 
best practice or adopting a basic management practice. Arguably, the building or 
purchasing of a container signifies an investment that may lead the householder to be 
more engaged and proactive in managing the system (especially in Nordic countries 
where the initial investment is higher), but this cannot be presumed.  

Other issues with system design 

Composting in different climatic conditions is possible using adapted containers and 
careful management.  Both colder climates and warmer ones require changes in practice 
to overcome the challenges. 
Indoor composting methods such as vermicomposting and Bokashi are increasingly 
being promoted as solutions for urban residents who want to compost their waste. This 
presents an issue when labelling products as ‘home compostable’ as the biological 
process in these indoor solutions is unlikely to be able to biodegrade plastics which 
could lead to consumer confusion. 

117 

 
 
 
 
 
8.2 

Comparing Home Composting Across Six EU 
Countries  

There is little reported data on the extent and practices of home composting across 
different EU countries.  This report seeks to build a picture of the situation in six Member 
States, informed from interviews and an analysis of publicly available information. The 
six countries are Belgium, France, Finland, Portugal, Spain and the UK. These were 
selected to present a range of maturity in biowaste management along with a range of 
climatic conditions.  

8.2.1 

Existing Biowaste Management 

Biowaste forms a significant component of waste across the EU and is increasingly 
viewed as a commodity within the circular economy. Waste that is made from organic 
matter (putrescibles) comprises between 35-40% of Municipal Solid Waste (MSW). 182 
Some countries, e.g. Switzerland, distinguish between biowaste and compost waste as 
not all putrescibles are suitable for composting.183 It is estimated that the amount of 
compostable waste produced by a household in a year is around 45-55kg. 184 Biowaste 
can be transformed into valuable products using anaerobic digestion and industrial scale 
composting facilities and is also part of what is fed into a home composting system.  

There is a patchwork of provision within countries and across the EU with regard to 
separate collection of biowaste. Even those countries that have made this a legal 
requirement are at very different stages in this process. For example, Lisbon is 
introducing a door to door collection of biowaste for the first time, starting in October 
2019 with 6,700 homes covered. 185 Within the capitals of the countries compared 
biowaste capture rates vary from 0.2% to 42.7% indicating the different levels of 
maturity of the waste management systems. Table 17 summarises the biowaste capture 
rates for the six countries in this analysis.  

182 EU Commission (2014) Separate collection_Final Report.pdf, accessed 22 August 2019, 
https://ec.europa.eu/environment/waste/studies/pdf/Separate%20collection_Final%20Report.pdf 
183 Piipo, S, and Pongracz, E (2014) Sustainable_bio-waste_strategy_in_Finlan.docx 
184 Andersen, J., Boldrin, A., Christensen, T., and Scheutz, C. (2010) Greenhouse Gas Emissions from Home 
Compoosting of Organic Household Waste, Waste Management, Vol.30, pp.2475–2482 
185 Portugal Resident (2019) Councils to start ‘composting’ kitchen waste 

118  

 
 
 
 
 
 
 
 
Table 17: Biowaste collection rates 

Ctry 

Is there a household collection of biowaste? 

Biowaste capture rate in 
capital city (%) 

BEL 

ESP 

FIN 

FRA 

UK 

PRT 

Yes: Begun in Flanders in late 1990's 

No – Bring points 

Yes, since late 1990’s – but depends on population 
density 

Is a legal requirement in 108 of 450 municipalities 

No, but started in Paris 2017 

39% of local authorities have a separate collection of 
food waste186 

No, Pilot scheme starting in Lisbon in October 2019. 

Source: EU Commission 2014187 

8.4 

No data 

42.7 

2.3 

27.3 

0.2 

Biowaste collection, when averaged across 28 EU capitals, is reported to be 19.6 kg/cap 
per annum, which is considerably less than the estimated potential diversion of biowaste 
from municipal collection into home composting - 150 kg/hhld/yr. 188 A successful 
community composting scheme in Galicia, Spain collects around 30kg/cap/yr. 189 

All this is likely to change throughout the EU at the end of 2023 when the Waste 
Framework Directive under Article 22(1)(a) mandates that Member States shall 
separately collect organic waste but also under Article 22(2)(b) shall ‘encourage home 
composting’. How strongly Member States will provide this encouragement remains to 
be seen. Some existing home composters may begin to use the new biowaste collection, 
but those that compost to create a soil improver will likely not be influenced to do this. 

A study in 2010 estimated that home and community composting could lower 
management costs of European countries by at least 34% and reduce greenhouse gas 

186 WRAP (2019) WRAP Dry recycling performance benchmarks, accessed 28 October 2019, 
http://laportal.wrap.org.uk/Statistics.aspx 
187 Bio-waste collection rate provides an overview on the amount of bio-waste that is separately collected 
per inhabitant. This indicator allows the comparison between capitals since separate bio-waste collection 
is not yet well established across the EU.  EU Commission (2014) Separate collection_Final Report.pdf, 
accessed 22 August 2019, 
https://ec.europa.eu/environment/waste/studies/pdf/Separate%20collection_Final%20Report.pdf 
188 Davey, A., Clist, S., and Godley, A. WRAP helps individuals, businesses and local authorities to reduce 
waste and recycle more, making better use of resources and helping to tackle climate change., p.54 
189 Global Alliance for Incinerator Alternatives (2012) On-the-Road-to-Zero-Waste.pdf 

119 

 
 
 
 
 
emissions by 40% over current management practices. 190 However, home composting, 
when viewed solely as a potential means of waste treatment, has drawbacks mostly 
because it is difficult to monitor the quantity of waste being treated, as well as the 
quality of the output. Some argue that community composting offers a better means of 
waste management because it can be monitored more closely while offering the same 
ecological benefits as home composting.191 Community composting also has limitations 
though as it requires a larger space, that is located close to households but at a suitable 
distance that residents are not affected by any possible odours. It also requires a suitably 
qualified or experienced person to take overall responsibility for management of the 
compost process and maintain the health of the compost. In some regions of Spain 
community composting sites are handling between 80-100% of biowaste. 192 

Other initiatives seek to fill the gap between industrial scale processing of biowaste and 
home composting by providing small scale decentralised solutions to biowaste 
management through micro-scale anaerobic digestion (AD) and solid-state fermentation 
(SSF) within the urban and peri-urban areas.193,194  

8.2.2 

Support for Home and Community Composting 

Many Member States have been promoting home composting over the past 20 years 
though the current extent of home composting is difficult to ascertain as there is little 
incentive to monitor the practice beyond the impact of particular promotional schemes. 
Table 18 summarises the extent of data on home and community composting across 
these six countries.  

Table 18: Data on the Extent of Home and Community Composting 

Ctry 

Extent of community composting  

Extent of home composting 

BEL 

ESP 

2,500 active ‘master composters’ in Flanders 

34% of population 

Intensive projects in a handful of areas. Some of 
these can treat 80-100% of the biowaste of the 
local community 

unknown 

190 Adhikari, B.K., Trémier, A., Martinez, J., and Barrington, S. (2010) Home and community composting for 
on-site treatment of urban organic waste: perspective for Europe and Canada, Waste Management & 
Research, Vol.28, No.11, pp.1039–1053 
191 Zero Waste Europe (2019) Community Composting: A Practical Guide for Local Management of 
Biowaste Zero Waste Europe Guides/01, 2019, https://zerowasteeurope.eu/wp-
content/uploads/edd/2019/04/zero_waste_europe_fertile_auro_community_composting_guide_april_20
19.pdf 
192 Plana, R. (2019) Personal communication from Ramon Plana.docx 
193 SCOW (2017) Welcome to SCOW | SCOW, accessed 30 August 2019, http://www.biowaste-scow.eu/ 
194 Decisive 2020 (2019) How innovative biowaste management can boost the circular economy, accessed 
30 August 2019, http://www.decisive2020.eu/events-item/how-innovative-biowaste-management-can-
boost-the-local-circular-economy/ 

120  

 
 
 
 
 
Ctry 

Extent of community composting  

Extent of home composting 

FIN 

FRA 

UK 

PRT 

Supported - Need to register their activity.  

40% of households in Helsinki 

Successful project in Paris since 2010 with 350 
sites with waiting lists to join. 207,935 
participants in the Paris scheme 

35-43% of households with garden, 9-
10% of apartments 

121 sites (20,500 tonnes/yr) 

35% of households with a garden 

5 sites in Lisbon in first year 

900 participants in Lisbon project in 
first year 

In order to register as a home composter some countries have certain requirements that 
must be met. For example, the German regulations specify that an applicant needs to 
have land of 25m2, sufficient for the application of resulting compost, whilst in Sweden 
to be registered a household compost system needs to be insulated, vermin proof and 
ventilation holes covered with nets.195 These registration requirements therefore offer a 
way of ensuring that the composting process is tailored to the practices required in a 
particular country. Some countries (e.g. Germany, Poland) have chosen to incentivise 
home composting by allowing self-declared ‘home composters’ to avoid paying waste 
collection fees as they will no longer be served by a biowaste collection service. 
However, this financial incentive has the potential to encourage self-declaration without 
adequately treating household bio waste.  

8.2.2.1  Belgium 

Promoting home composting has been part of the national strategy to reduce waste in 
Belgium since 1991. Tax levies were introduced to incentivise recycling and organic 
materials are one of the highest taxed items. Educational activities have been well 
supported, one example being the establishment of a ‘compost masters’ program in 
Flanders training citizens to volunteer to train others and manage community compost 
sites. In 2008 it was reported that there were 2,500 active master composters and 4000 
citizens had been trained. From this it is estimated that in 2008 about 100,000 tonnes of 
organic materials were kept out of the waste collection system. By 2010, approximately 
34% of the Flemish population—almost two million people—were composting at home. 
196 

195 Ermolaev, E., Sundberg, C., Pell, M., and Jönsson, H. (2014) Greenhouse gas emissions from home 
composting in practice, Bioresource Technology, Vol.151, pp.174–182 
196 Global Alliance for Incinerator Alternatives (2012) On-the-Road-to-Zero-Waste.pdf 

121 

 
 
 
 
 
 
8.2.2.2 

Finland  

Since 2016 there has been a prohibition on landfilling waste with more than 10% of 
organic material.  It is reported that 40% of households in Helsinki compost their own 
waste. 197 Prior to 2019 all householders composting were required to register as home 
composters and had to use a thermally insulated container. The introduction of new 
waste management regulations in March 2019 dropped these requirements and instead 
only properties that are collectively composting with more than five apartments 
cooperating on this need to report this activity. Smaller households no longer need to 
register as home composters. 198 

8.2.2.3 

France 

A national study into the home treatment of organic waste in France found that 35 - 43% 
of households in a house (presumably with a garden) compost their kitchen waste, while 
only 9-10% of those living in collective housing (apartments) do so. 199 

Home composting is promoted nationally through an annual event 'tous au compost' run 
by the Reseau Compost Citoyen and supported by Ademe. Over 1000 educational events 
are organised each year including tours of local composting sites. 200  

An exemplar scheme in France is found at Besancon, where a local waste treatment 
company collaborated with the municipalities under an EU funded project ‘Waste on a 
diet’ from 2012 -2016.  A ‘pay as you throw’ scheme for waste was introduced at the 
same time as supporting home composting and community composting. In 2016 70% of 
the population were either covered by a community composting site or had a composter 
at home. It is estimated that in 2016 over 50% of the population were treating their own 
biowaste by home composting and the decentralized composting facilities managed to 
divers 7436 tonnes of biowaste away from incineration. 201 

Despite being the most densely populated of Europe’s cities, Paris has run a compost 
support program since 2010. Collective compost projects are approved if they have the 
support of at least ten participants and a suitable site. Training is then offered and over 
350 sites have been established. Due to shortages of space these sites currently have 
waiting lists to join. 202 Current figures show 207,935 people in Paris are engaging in 
composting in their own biowaste.203 

197 Piipo, S, and Pongracz, E (2014) Sustainable_bio-waste_strategy_in_Finlan.docx 
198 Helsinki Region Environmental Services Authority HSY Waste management regulations | HSY, accessed 
3 July 2019, https://www.hsy.fi/en/residents/sorting/waste-management-regulations/Pages/default.aspx 
199 Olivier, Stephane, Royne, Veronique, and Rebert, Mylene (2009) Enquête nationale sur la gestion 
domestique des déchets organiques, 2009 
200 Reseau Compost Citoyen (2019) Semaine nationale du compostage de proximité, accessed 28 October 
2019, https://www.semaineducompostage.fr/composter/communication 
201 Zero Waste Europe (2018) The story of Besancon, case study 9, 2018 
202 Paris to Go (2019) How to Compost in Paris 
203 Syctom (2019) jecomposteenville.fr, accessed 28 October 2019, https://www.jecomposteenville.fr/ 

122  

 
 
 
 
 
8.2.2.4 

Portugal  

Launched in May 2018, the Lisbon City Council has begun the first program to support 
home composting in Portugal. Individuals can apply for a compost bin, but need to 
attend a day of training in order to receive their bin. By December 2018, 900 people had 
participated. In addition, the setting up of community compost sites is being supported 
with five currently in operation. 204 

8.2.2.5 

Spain 

Waste management in Spain is managed regionally with large variation in practices. 
Home and community composting is intensively supported in a few regions: 205  

•  The province of Pontevedra (Galicia). 
•  Navarre. 
•  Basque Country. 
•  The province of Valencia.   

In Hernani, Gipuzkoa, Basque country, the community composting system manages 80-
100% of biowaste. There are 35 community composting units serving 700 households 
and a further 700 households are composting their own waste. The community compost 
scheme collects 30.8 tonnes a year, averaging 30kg per person per year. 206 

8.2.2.6  UK 

Starting in 2003, the UK waste NGO WRAP has been working with local authorities to 
support the adoption of home composting through providing subsidised compost 
containers. By 2007 it was reported that 73% of local authorities were distributing 
subsidized bins and accompanying this with information campaigns. 207 More than 
1,700,000 compost bins were supplied by WRAP up to 2007.  

WRAP also reports that 35% of households with a garden compost at home. 208 This 
would indicate that around 8 million households compost. (Total number of UK 
households is 27.2 million, around 87% of which have a garden,209  so, if 35% of these 
compost that is 8,282,400 households that compost – around 8 million). 

204 lisboa a compostar (2018) Câmara Municipal de Lisboa - Lisboa a Compostar | Compostores 
Comunitários, accessed 2 July 2019, https://lisboaacompostar.cm-
lisboa.pt/pls/OKUL/f?p=178:16:1750227251188::NO::: 
205 Vázquez, M.A., and Soto, M. (2017) The efficiency of home composting programmes and compost 
quality, Waste Management, Vol.64, pp.39–50 
206 Global Alliance for Incinerator Alternatives (2012) On-the-Road-to-Zero-Waste.pdf 
207 Mckinley, S., and Williams, I.D. (2007) ASSESSING THE ENVIRONMENTAL IMPACTS OF HOME 
COMPOSTING, p.10 
208 WRAP (2007) Understanding Food Waste, 2007 
209 Buck, D. (2016) Gardens_and_health.pdf, 2016, 
https://www.kingsfund.org.uk/sites/default/files/field/field_publication_file/Gardens_and_health.pdf 

123 

 
 
 
 
 
Community composting is less well developed than in some of the other European 
countries. 210 A 2007 survey identified 84 organisations involved in collecting/receiving 
and composting material at 121 sites and processing approximately 20,500 tonnes of 
material per annum. For the majority of these (60%) composting is an activity that links 
social and environmental objectives. Composting is carried out alongside non-waste 
activities such as running community gardens, city farms, local food production, and 
services for adults with special needs.  

There is no way of knowing the quality of management of the home composters, but 
given that training is required before setting up a community compost site it can be 
presumed that these sites are being managed optimally. Further they have space for 
multiple piles so are more likely to be able to create batch piles.  

8.2.3 

Comparing National Advice on Compost Management 

Composting advice is available from range of sources including NGO’s, National 
Government funded waste organisations, city authorities, waste management 
companies, and compost enthusiasts. This report compares the advice of the National 
Government funded bodies in the UK, 211  France 212 and Belgium, 213 but relies on Lisbon 
City Chamber advice for Portugal,214 a Waste Management Company publication for 
Finland,215 and an NGO publication for Spain. 216 All of these sources describe the 
practices needed to achieve a well-managed pile, but there is no way of verifying if the 
advice of these organisations represents actual practice in the country concerned. 

A key difference in the advice given regards the suitability of meat and fish as material to 
be included in the compost. Belgium, UK and Portugal recommend not including it while 
France, Finland and Spain support its inclusion. The Spanish advice goes as far as to say 
the inclusion of protein rich food is necessary to raise the temperature of the compost217 

210 Slater, R. (2007) Community Composting Activity in the UK - 2006, Report for The Open University, 
2007, ⬚http://oro.open.ac.uk/10289/1/cc_report_Final.pdf⬚ 
211 WRAP Recycle Now How to compost.pdf 
212 Reseau Compost Citoyen (2019) Semaine nationale du compostage de proximité, accessed 28 October 
2019, https://www.semaineducompostage.fr/composter/communication 
213 Brussels Environment (2016) Composter pour réduire ses déchets: Guide pratique, p.30 
214 Lisboa Camara Municipal (2018) Guia Pratico de Compostagem 
215 Paijat-Hame Waste Management (2015) Kompostointiopas_2015_pienennetty_ID_31440.pdf, accessed 
28 October 2019, 
http://www.pienennabioberttaa.fi/images/Kompostointiopas_2015_pienennetty_ID_31440.pdf 
216 Zero Waste Europe (2019) Community Composting: A Practical Guide for Local Management of 
Biowaste Zero Waste Europe Guides/01, 2019, https://zerowasteeurope.eu/wp-
content/uploads/edd/2019/04/zero_waste_europe_fertile_auro_community_composting_guide_april_20
19.pdf 
217 Zero Waste Europe (2019) Community Composting: A Practical Guide for Local Management of 
Biowaste Zero Waste Europe Guides/01, 2019, https://zerowasteeurope.eu/wp-
content/uploads/edd/2019/04/zero_waste_europe_fertile_auro_community_composting_guide_april_20
19.pdf 

124  

 
 
 
 
 
—although it is worth pointing out there is no specific evidence for this and the 
implication would be that garden waste or food waste from vegetarian households 
would lead to a dysfunctional composting process which is evidently not the case. Small 
variations in practice are found in the suggested ratio of greens to browns, and in the 
frequency of turning the pile. These are unlikely to result in significant changes to the 
outcome of the compost, though interesting to note that the Finnish advice proclaims 
that turning is not required (which strictly, it isn’t, but is still best practice).  

The Spanish and Belgian advice recommend having multiple containers to allow turning 
of the compost and maturation of the compost. This is good practice but easier for 
community composting sites than home composting. The Portuguese advice pamphlet 
describes the batch method where the composting material is layered up in one go and 
then left. This is perhaps misleading for a home composter who is new to composting 
and not aware that they can also build their pile gradually. The other three publications 
simplify the instructions and do not offer suggestions on whether to add-as-you-go or 
build the pile in one go (batch method).  

Overall, the national differences in composting advice do not seem to be significant 
enough to lead to the adoption of different practices in the relevant countries. If 
followed, the advice given should lead to a well-managed pile in all cases.  

There is a marked lack of advice to consumers on how to handle plastic waste in home 
composting. in some cases, this is because the document predates the prevalence of 
compostable plastics.  Of the sources considered for this report only the French network 
‘Reseau Compost Citoyen’ offers advice on compostable plastics and composting. They 
present a comprehensive factsheet online discussing compostable bags and other 
compostable materials such as tableware. 218 This advice shows the OK HOME compost 
logo and states that materials with this logo can “theoretically be composted in a 
domestic composter”. It states that after 6 months 90% of the bag must be able to pass 
through a 2mm sieve, giving some indication to the consumer of what they can expect in 
what time frame, whilst also warning that these items can take longer than expected to 
‘disappear’. It is suggested that other materials such as plates and cutlery are 
fragmented before being added to the compost and it also makes the point that 
products labelled as ‘compostable’ are not suitable for vermicomposting.  

8.2.4 

Key Conclusions    

Key Conclusions – Comparing Home Composting across six EU countries 

218 Reseau Compost Citoyen (2019) Semaine nationale du compostage de proximité, accessed 28 October 
2019, https://www.semaineducompostage.fr/composter/communication 

125 

 
 
 
 
 
 
A number of Member States have been promoting home composting over the past 20 
years though the current extent of home composting is difficult to ascertain as there is 
little incentive to monitor the practice beyond the impact of particular promotional 
schemes.  Typically, a compost promotion project includes subsidised containers with 
some form of knowledge provision or advice scheme.  

Existing biowaste management 

•  Waste that is made from organic matter (putrescibles) comprises between 35-40% 

of Municipal Solid Waste (MSW) in EU Member States.  

•  Within the capitals of the countries compared biowaste capture rates vary from 

0.2% to 42.7% indicating the different levels of maturity of the waste management 
systems.  

•  Biowaste collection, when averaged across 28 EU capitals, is reported to be 19.6 
kg/cap per annum, which is considerably less than the estimated potential 
diversion of biowaste from municipal collection into home composting - 150 
kg/hhld/yr.  A successful community composting scheme in Galicia, Spain collects 
around 30kg/cap/yr.   

National advice on compost management   

•  National level composting advice is not always clear in what method it is 

describing.  

•  Half the countries considered recommend including meat and fish waste, the other 

half strongly suggest not to.   

•  There are wide and varying sources of advice in each country and there is little 

reason to believe that the advice of the National organisations represents actual 
practice in the country concerned.  

•  Overall, the national differences in composting advice do not seem to be significant 
enough to lead to the adoption of different practices in the relevant countries. If 
followed, the advice given should lead to a well-managed pile in all cases.  

•  Only one of the sources of advice compared gave guidance to consumers on how 

what to expect from composting plastics labelled as ‘compostable’. It indicates that 
there is likely to be a difference in ‘theoretical performance’ of the materials with 
actual performance.  

8.3 

Studying the Conditions Found in Home 
Composting and their Effect on the Biodegradation 
of Plastics 

In order to understand the potential biodegradation of plastics in a home composting 
system it is necessary to explore what is known about the biotic and abiotic conditions 
present in such systems (see Figure 24). The biodegradation process of polymers is 
affected by two main types of factors – exposure conditions and polymer characteristics, 
though these interact in several ways. The polymer characteristics determine whether 

126  

 
 
 
 
the initial degradation from polymer to polymer fragments is largely chemical or 
microbial, however the abiotic conditions set the parameters within which this can 
occur. Polymer characteristics also affect the accessibility of the polymer to 
microorganisms and the studies which have looked at this are summarised in Section 
8.3.4. 

Figure 24: Factors affecting biodegradation 

Source: Adapted from Kijchavengkul T and Auras R. 2008219 

8.3.1 

Biotic Exposure Conditions in Home Composting 

The biotic conditions refer to the variation in microorganisms present and the way in 
which they consume waste material. Microbes feed on the sugars within the chemical 
structure of plastics, generating heat, carbon dioxide, water by-products.  
In a home compost pile the food waste and garden waste added will already bring 
microbes to the pile where they can multiply. Further microbes are brought in via macro-
organisms such as ants, beetles, centipedes, worms, flies, millipedes, slugs, snails, spiders 
and woodlice who all find their way into home compost. It is generally the case that 
microbial levels in in both a well-managed and an add-as-you-go pile are sufficient for 
composting, and the abiotic conditions should remain within the parameters needed to 
support the flourishing of these microbes. This is in contrast to soil which can be 

219 Kijchavengkul, T. and Auras, R. Compostability of polymers, Polym. Int, Vol.57, No.6, pp.793–804 

127 

 
 
 
 
 
 
deficient in microbes.220 In a well-managed pile that reaches temperatures over 45°C for 
a sustained period a particular group of microbes (thermophilic bacteria) will flourish, 
accelerating the composting process.  
The enzymes that microbes produce can be specific in what they can digest, with some 
polymers only being broken down by certain microbes. In most cases however the 
plastic has to be broken down chemically before microbes can digest the smaller 
particles. This initial breakdown happens in different ways depending on the 
characteristics of the polymer, but in many cases needs the presence of water to allow 
the hydrolysation of certain bonds in the polymer.  

8.3.2 

Abiotic Conditions in Home Composting  

Abiotic conditions impact on the composting process through their effect on microbes, 
and they vary significantly according to how the compost is managed. The main variables 
are temperature, moisture, pH and carbon/nitrogen ratio.  

In a well-managed pile, the abiotic conditions resemble these shown in Figure 25. The 
Carbon/Nitrogen ratio fall over time, the ammonium (NH4) levels also fall whilst pH 
levels rise to a plateau around pH8. Four temperature phases are discernible: 

1)  The mesophilic phase – mesophilic bacteria proliferate as they use carbon in the 
waste combined with oxygen to produce carbon dioxide and energy. The organic 
matter begins to be broken down and the temperature of the compost rises to 
around 45°C. 

2)  The thermophilic phase – as the temperature exceeds around 45°C mesophilic 
bacteria are inhibited and thermophilic bacteria take over. Temperatures can 
reach 70°C in this stage.   

3)  The cooling phase – other organisms such as fungi further break down coarser 

organic material over a period of months.  

4)  The curing phase – This stage is again important in producing safe compost as 
many human pathogens have a limited period of viability in compost soil.  

In add-as-you-go home composting, the phases are less distinct and, in some systems, 
temperatures never reach those expected for the thermophilic phase (>45°C) for 
sufficiently long enough to allow the flourishing of thermophilic bacteria. This is why 
home composting is sometimes referred to as a form of ‘cold-composting’ and 
consequently the breakdown of organic matter is much slower, though the exact process 
is less well understood than for hot composting 

When characterising the conditions in home compost systems it is necessary to consider 
the profiles of variables over the duration of the composting period, rather than 

220 Wierckx, N., Narancic, T., Eberlein, C., et al. (2018) Plastic Biodegradation: Challenges and 
Opportunities, in Steffan, R., (ed.), Consequences of Microbial Interactions with Hydrocarbons, Oils, and 
Lipids: Biodegradation and Bioremediation (2018) Cham: Springer International Publishing, pp.1–29 

128  

 
 
 
 
 
absolute levels. This makes it harder to simulate a home composting environment in a 
laboratory setting.  

Figure 25: Conditions within a compost pile over duration of composting 
process, 

Source: Fischer and Glazer 2012221 

8.3.3 

Evidence of Range of Conditions in Home Composting 

To determine the range of variation in composting conditions in actual home composting 
settings a detailed review of eight scientific papers exploring home composting practices 
has been conducted. The academic studies took detailed measurements of abiotic 
conditions during the entire composting process. Two papers were included from 
Argentina and Brazil as they extend the range of ambient temperatures which is of 
relevance to the extremes of climatic conditions found in Northern and Southern 
Europe. This report compares these with a study commissioned by the French 
Environment & Energy Management Agency (ADEME) in 2019,222 which is the most 

221 Fischer, D., and Glaser, B. (2012) Synergisms between Compost and Biochar for Sustainable Soil 
Amelioration, in Kumar, S., (ed.), Management of Organic Waste (1 February 2012) InTech 
222 Dewolfs, P., Feix, I., Genty, A., et al. (2019) Biodégradabilité En Compostage Domestique Et Industriel 
Des Sacs Plastiques Biodégradables En Compostage Domestique (Norme Nf T 51-800) Et Des Sacs En 
Papier, p.35 

129 

 
 
 
 
 
 
recent and detailed study of the biodegradability of plastics in home composting 
settings. The ADEME study did not however record all the variables that the academic 
studies measured, but is useful in looking at the temperature profile.  

Studies included both compost piles managed by the researcher and closely monitored 
home composting piles managed by householders. The studies primarily used closed 
containers, with one study also comparing open composting. Table 19 outlines the range 
of conditions and practices covered in the literature review. A full overview of the papers 
considered can be found in Appendix A.5.1. This demonstrates that in all of the key 
variables identified previously, there is a substantial range which provides a good 
indicator of possible conditions and practices.  

Table 19: Range of practices covered in home composting studies 

Practice variable 

Range 

Countries covered 

France, Spain, Italy, Sweden, Denmark, Germany, UK, 
Argentina, Brazil 

Ambient temperature range 

- 15°C to 36°C 

Time period of study 

60 days to 13 months 

Container capacity 

40L to 500L 

Feeding regime 

kitchen waste, some included meat and dairy, different 
bulking agents 

Weekly weight of feed 

1.61kg to 49kg 

Mixing regime 

no mixing to weekly 

Ratio of waste to bulking agent 

1:0 to 23:1 

Table 20 summarises the range of abiotic conditions across the studies. Though it was 
not possible to ascertain whether the compost management in these studies fitted the 
‘well-managed’ or ‘basic’ management patterns it is useful in providing a broad 
indication of the range of conditions likely to occur across both management styles.  

The following are the key observations from these studies in relation to the: 

•  Ambient temperature has a large effect on the process of composting, through its 
impact on microbial activity. However, once activity starts the pile will begin to 
heat up and this process is influenced more by management practices such as the 
pattern of feeding and mixing, rather than ambient temperature levels.  
In the studies assessed, ‘cold composting’ was the most common result and 
where higher temperatures were reached this was only sustained for a couple of 
days.  

• 

130  

 
 
 
•  The carbon/nitrogen balance is important, particularly in the cold composting 
conditions of many home composting systems. This is regulated by feeding the 
right balance of ‘green’ and ‘brown’ materials which requires some degree of 
knowledge and understanding.  

•  Moisture level is influential, but it is relatively easier to achieve an acceptable 

level through appropriate management practices. 

Table 20: Range of abiotic conditions found in home composting studies 

Abiotic condition 

Temperature 

Moisture  

Carbon/Nitrogen ratio 

pH level 

Range in home composting identified 

Temperatures within pile ranged from 5-70°C 

Moisture values ranged from 22% to 85% 

C/N ratio 10-66 

pH range 5.9-9.28 

8.3.4 

Evidence for the Behaviour of Plastics Under Home 
Composting Conditions  

There is a paucity of evidence on the behaviour of plastics under home composting 
conditions. The 2019 ADEME study goes some way to fill this gap and given its 
significance, the findings will be discussed first, followed by a review of earlier academic 
studies that have tested compostable plastics under home composting conditions. 

8.3.4.1 

The 2019 ADEME study 

This study, commissioned by ADEME, tested two types of plastic bag, and two types of 
paper bag, comparing their biodegradation in a variety of different home composting 
conditions. Disintegration was assessed visually and biodegradation was assessed using 
Transmission Electron Microscopy (TEM) that can create a visual image of the molecular 
structure of the material and microbial activity. The home composting process was 
carefully designed to follow the requirements of the French standard for home 
composting NF T 51-800 as far as possible. The materials tested were; 

•  Bag X – 90% PBAT, 9% PLA, 1% green dye 
•  Bag Y – 70% PBAT, 30% starch 

131 

 
 
 
 
 
The authors sought to compare the effects of various home composting practices on the 
biodegradation and fragmentation of the plastic bags. The treatment practices 
compared included; 

regular mixing of the compost 

• 
•  doubling up the bags (one inside another) 
•  placing the bag in the compost filled (with kitchen waste) or empty 
•  composting in a container compared with a pile in open air 
•  adding the material into the compost pile in winter compared with spring – the 

test conditions that began in the winter ran for 18 months, the ones that started 
in the springtime ran for 12 months.  

The practices that were common to all treatment conditions reflect those identified in 
the present study as a ‘well managed’ pile with some key differences that may affect the 
biological processes: 

•  A container was used in all treatments (but one), but the container size was 800L 

(almost 1 cubic meter) which is more than double that typically used in a 
domestic situation. A larger volume of material will support the development of 
higher temperatures so may result in faster biodegradation rates.  

•  The composition of material was a 1:1 mix of green (kitchen waste) to brown 

material (shredded garden waste), and the kitchen waste included meat and fish 
waste as is the practice in France.  

•  Regular mixing was performed - weekly for the first month, then monthly. 

However, the mixing process involved removal of all the material, mixing it then 
replacing it, which is unlikely to be undertaken in domestic situations and may 
improve the conditions for biodegradation.  

•  Lastly, the pile was constructed at the start of the test but no new material was 
added after this. In domestic situations the regular addition of organic waste is 
more common. This would also negate some of the benefit of regular mixing as 
new material would not need to be redistributed around the pile. 

The ways in which this study deviates from domestic conditions are likely to produce an 
environment that is more favourable for biodegradation. In this case the results can be 
viewed as a ‘best case’ scenario - indicating that biodegradation should proceed faster 
than the ‘typical’ approach to home composting that would be expected.  

Overall, the study reported incomplete biodegradation of both the two materials tested 
over the 18 months duration (Bag X – 90% PBAT, 9% PLA, 1% green dye, Bag Y – 70% 
PBAT, 30% starch). Fragments of Bag X under 1mm in size were more frequently 
observed in the final compost than fragments of bag Y, suggesting a lower rate of 
biodegradation. Transmission Electron Microscopy (TEM) revealed that Bag X was being 
degraded from within its structure as bacterial activity was observed in the internal 
layers of the plastic. Bag Y was only being broken down on its surface but it is not clear 
of the link between this observation and the different rates of biodegradation. The 
analysis did not give a lot of weight to comparing the performances of the different 
plastic materials as it seems the main focus of the study was to compare the effects of 

132  

 
 
 
different composting behaviours on the biodegradation of plastics. The paper bags 
showed complete disintegration in all the testing conditions.  

The results of the visual inspection of the fragments left in the compost are recreated in 
Table 21 which show that the only testing condition that showed very little residual 
material was that started in springtime, using a single layer of bag, which was deposited 
full, and with regular mixing of the compost. However, the authors concluded that 
“whatever the practice adopted in home composting; it is likely that there will still be 
visible fragments of the plastics that are deemed ‘biodegradable’ after 12 months.” 
These results suggest that these materials would not pass the disintegration test 
included in the country standards for compostable plastics that require 90% of the 
fragments to pass through a sieve of 2mm within 6 months. While most of the tests 
show pieces over 2mm it is not clear from the way that the results are recorded what 
percentage of the material is of this size.  

This is problematic, as the message for consumers is complex. The presence of visible 
fragments of material is likely to raise doubts with the consumer as to whether the 
product has biodegraded sufficiently. The study conducted a range of tests on the 
ecotoxicity and quality of the final compost and go on to state that consumers should be 
‘warned’ that the presence of this material does not affect the quality of compost and 
that the materials used will degrade further in the soil at an undefined time scale. They 
also found that there were no agronomic benefits to including the plastic at this 
concentration of 1% as the quality of the compost was not enhanced in any way. 

Table 21: Frequency of observed fragments remaining at end of test period 

Bag 
full/empty 
Full 
Empty 
Full  
Empty 
Full 
Empty 

single 
single  
double  
double  
double  
double  

single 

Empty 

single 

Full 

Size of fragment 

5-
20mm 
+ 
0 
+ 
+ 
+ 
0 

+ 

0 

2-
5mm 
0 
+ 
+ 
++ 
+ 
+ 

1-
2mm 
0 
+ 
0 
++ 
+ 
+ 

0-
1mm* 
3 
24 
5 
21 
16 
6 

++ 

++ 

27 

0 

0 

3 

>20mm 

0 
++ 
+ 
+ 
++ 
++ 

+ 

0 

Duration  

Mixing 

Thickness 

Yes 
Yes 
Yes 
Yes 
No 
No 

Yes 

Yes 

18  months – 
Closed Pile  

18 months -
Open Pile 
12 months – 
Spring start 

Notes:  

+ = 1-10 fragments observed  

++= more than 10 fragments observed.  

* fragments of this size were observed using a magnifying glass and individually counted. 

133 

 
 
 
  
  
  
  
Source: Adapted from table 38 in DeWolfs et al.223 

The findings of the study are also useful in evidencing how certain behavioural practices 
affect the composting process: 

•  Mixing of the compost was found to promote higher temperatures in the 

compost. Where mixing was not undertaken, a lower temperature rise was 
observed compared with piles that were mixed, resulting in a slowing down of 
the composting process in all testing conditions.  

•  Placing the bags into the compost when ‘filled’ with kitchen waste improves the 
biodegradation process. It was recorded that the empty bags fragment more 
slowly and the authors link this to the observation that the filled bags were more 
likely to be pierced manually with a fork during the mixing process, whereas 
empty bags were less likely to be caught on the fork. The authors suggest no 
specific reason why piercing the bag would make a difference—it would 
introduce minima extra surface area. A more logical explanation may be that the 
filled bags have more surface area in contact with the waste and a loose bag may 
stick to itself and effectively loose surface area. 

•  Using a container for composting supports the composting process by 

maintaining the temperature of the compost and the activity level of the 
microbial populations. In this study lower levels of bacterial activity were 
observed using TEM when composting in the open air and plastic fragments from 
the bags were still visible after 18 months.  

•  Starting the composting process in the springtime achieves greater 

fragmentation of the plastic materials within 12 months, compared with the 
compost piles that were begun in the winter.  

The authors’ final conclusion is that the study results “invalidate” the French standard by 
demonstrating that in home conditions more time is needed for biodegradation than is 
currently allowed in the test. They also suggest that the testing conditions in the 
standard should be reconsidered to match the most common home composting 
conditions or those described in the ADEME composting guidelines. These findings will 
be revisited in the discussion on differences between composting standards and practice 
in section 8.5.  

223 Dewolfs, P., Feix, I., Genty, A., et al. (2019) Biodégradabilité En Compostage Domestique Et Industriel 
Des Sacs Plastiques Biodégradables En Compostage Domestique (Norme Nf T 51-800) Et Des Sacs En 
Papier, p.35 

134  

 
 
 
 
 
 
 
8.3.4.2 

Earlier studies testing the biodegradability of plastics in home 
composting 

There are a number of earlier studies that claim to report on the biodegradability of 
plastics under ‘natural conditions’, 224 and yet the majority of these rely on the ISO 
laboratory tests for biodegradation such as ISO 14851, ISO 14855 and even the soil test 
ISO 17566. The scientific literature on biodegradation of plastics is also of limited value 
as it cannot keep pace with the continually evolving development of new plastic 
compounds and blends. Many of the peer reviewed studies of a few years ago are 
testing products that have been superseded by newer compounds.  

With these caveats in mind, this report has sought out studies that have actually 
explored biodegradation of plastics in real life home composting systems. These are 
detailed in Table 31 and Table 32 in Appendix 5. The usefulness of these are limited by 
methodological issues and choice of material to be tested. Firstly, three of these studies 
lasted less than 12 weeks which is understood to be insufficient for home composting to 
be complete unless it is carefully managed in warm conditions. In these studies, the 
compost heap was not managed during the study but left undisturbed.  

Song’s (2009)225 UK study is methodologically robust, and uses 160L compost containers 
prepared by following typical advice given to a home composter. Control containers 
were set up in the same way and all containers were ‘turned’ monthly at which time 
samples were taken for analysis. The study ran for 6 months. The results show that PLA, 
and starch/PCL blends all had a negligible mass loss of <5%. Starch based polymers and 
plant fibre-based silvergrass were the two substances that showed mass loss of around 
80%. Although mass loss is not a direct measurement of biodegradation, it provides an 
indicator of the relative performance of materials in this regard. 

Another study, this time conducted in Germany in 2004 compared open air composting 
and home composting. Unfortunately, the home composting trials were impeded by the 
participants failing to follow the instructions, and the results were extremely varied so 
the author recommended they were indicative only. The composting trials monitored by 
the author found that only the starch-based products showed complete degradation. 

A test in Greece simulated home composting over 11 months. A 100L container 
(containing a sheep manure/sawdust ratio of 5:1) was used with ambient temperatures 
of 5-17°C and humidity of between 45-60% w/w. Internal temperatures reached above 
35°C for 4 days in the first week. The PLA film samples showed very little disintegration 
over the 7 weeks of the composting test, after which point the authors deemed that the 
compost had passed the ‘active’ phase, although this is a much shorter period than 

224 Emadian, S.M., Onay, T.T., and Demirel, B. (2017) Biodegradation of bioplastics in natural 
environments, Waste Management, Vol.59, pp.526–536 
225 Song, J.H., Murphy, R.J., Narayan, R., and Davies, G.B.H. (2009) Biodegradable and compostable 
alternatives to conventional plastics, Philosophical Transactions of the Royal Society B: Biological Sciences, 
Vol.364, No.1526, pp.2127–2139 

135 

 
 
 
 
 
typically found in home composting. The results indicate  that PLA will not disintegrate 
sufficiently fast in domestic composting piles since the minimum required conditions are 
typically not met. 226 

PLA has hydrolysable functional groups in its main chain (ester bonds). It has been found 
that the hydrolysis of these ester bonds is the main route of PLA degradation, and that a 
temperature of 60°C is needed for this to occur. 227 This high temperature is closely 
related to the glass transition temperature (Tg) of PLA due to its high molecular weight. 
When a temperature of 60°C is present water can diffuse through the polymer of PLA 
and bulk erosion occurs as the polymer starts to degrade through its cross section. This 
breaks it into smaller units which diffuse out of the polymer bulk to the surface where 
they are consumed by microorganisms.  

Experimental studies have simulated the ‘ideal conditions’ for PLA breakdown reporting 
a range of results. Between 2006 and 2014 eight laboratory studies used an inoculum 
that included compost and were kept at a minimum of 58°C for 28 days. The 
biodegradation, as measured by CO2 production or weight loss, ranged from 13% to 
100% showing that even in ‘ideal conditions’ total biodegradation of PLA is hard to 
achieve.228 

PHA is one plastic that is thought to be more suitable for home composting. There are 
more than 150 PHA monomers, with a great diversity in material properties. Their 
crystallinity ranges from 30% to 70%, and melting temperature ranges from 50°C to 
180°C.229 In contrast to PLA, the primary degradation of PHA occurs at its surface where 
it is attacked by various enzymes which are secreted by microorganisms. 230 A key group 
of enzymes are the depolymerases but different microorganisms produce different 
enzymes and can degrade different types of PHA depending on their internal structure. 
The enzyme specificity of certain polymers is currently being explored in a number of 
studies, but the prevalence of these enzymes in home compost has yet to be identified. 
Temperature again affects the biodegradation process with an increased rate of 

226 Rudnik, E., and Briassoulis, D. (2011) Degradation Behaviour of Poly(lactic Acid) Films and Fibres in Soil 
Under Mediterranean Field Conditions and Laboratory Simulations Testing, Industrial Crops and Products, 
Vol.33, No.3, pp.648–658 
227 Agarwal, M., Koelling, K.W., and Chalmers, J.J. (1998) Characterization of the Degradation of Polylactic 
Acid Polymer in a Solid Substrate Environment, Biotechnology Progress, Vol.14, No.3, pp.517–526 
228 Emadian, S.M., Onay, T.T., and Demirel, B. (2017) Biodegradation of bioplastics in natural 
environments, Waste Management, Vol.59, pp.526–536 
229 Wierckx, N., Narancic, T., Eberlein, C., et al. (2018) Plastic Biodegradation: Challenges and 
Opportunities, in Steffan, R., (ed.), Consequences of Microbial Interactions with Hydrocarbons, Oils, and 
Lipids: Biodegradation and Bioremediation (2018) Cham: Springer International Publishing, pp.1–29 
230 Wierckx, N., Narancic, T., Eberlein, C., et al. (2018) Plastic Biodegradation: Challenges and 
Opportunities, in Steffan, R., (ed.), Consequences of Microbial Interactions with Hydrocarbons, Oils, and 
Lipids: Biodegradation and Bioremediation (2018) Cham: Springer International Publishing, pp.1–29 

136  

 
 
 
 
 
biodegradation of PCL, PHB and PHBV reported at 46°C than 24°C when incubated in 
compost mixtures. 231 

Studies of PHA degradation in real-life conditions at low temperatures have shown 
reported biodegradation rates of 35-48% in soil.232 233 One study found that a 
degradation rate of 90% was achievable when the PHA was blended with rice husks in 
the ratio of 60:40 suggesting that further research into the effect of blends on plastics 
biodegradability is needed. The microbial specificity of certain plastics also limits their 
biodegradation in home composting settings. 

The main conclusions that can be drawn from the current limited research is that PLA 
will not fully biodegrade in home composting, as it needs temperatures above 60°C 
before biodegradation is initiated. There is evidence that PHA, particularly when 
blended, with starch compounds, will biodegrade to some extent under low temperature 
conditions, however there has been no direct testing of this in home composting trials.  
The only materials that have shown high degree of biodegradation in home composting 
studies are the starch-based products, but the limited evidence base means that no firm 
conclusions can be drawn at this stage. 

8.3.5 

Key Conclusions    

Key Conclusions – Conditions in home composting affecting biodegradation of plastics 

In order to understand the potential biodegradation of plastics in a home composting 
system it is necessary to explore what is known about the biotic and abiotic conditions 
present in such systems. The biodegradation process of polymers is affected by two 
main types of factors – exposure conditions and polymer characteristics, though these 
interact in several ways. The polymer characteristics which determine whether the 
initial degradation from polymer to polymer fragments is largely chemical or microbial, 
however the exposure conditions set the parameters within which this can occur.  
Polymer characteristics also affect which microbes are most active in the mineralisation 
stage. 

231 Lotto, N.T., Calil, M.R., Guedes, C.G.F., and Rosa, D.S. (2004) The effect of temperature on the 
biodegradation test, Materials Science and Engineering: C, Vol.24, No.5, pp.659–662 
232 Gómez, E.F., and Michel, F.C. (2013) Biodegradability of conventional and bio-based plastics and natural 
fiber composites during composting, anaerobic digestion and long-term soil incubation, Polymer 
Degradation and Stability, Vol.98, No.12, pp.2583–2591 
233 Wu, C.-S. (2014) Preparation and Characterization of Polyhydroxyalkanoate Bioplastic-Based Green 
Renewable Composites from Rice Husk, Journal of Polymers and the Environment, Vol.22, No.3, pp.384–
392 

137 

 
 
 
 
 
 
 
 
In terms of the biotic exposure conditions using fresh garden waste in a home compost 
pile ensures that microbial levels in both a well-managed and an add-as-you-go pile are 
sufficient for composting. This is in contrast to soil which can be deficient in microbes.  
In a well-managed pile that reaches temperatures over 45°C for a sustained period a 
particular group of microbes (thermophilic bacteria) flourish, which accelerates the 
composting process. 

In terms of the abiotic exposure conditions, these important in how they affect the 
health of the microbial population.  Ambient temperature has a large effect on the 
process of composting, through its impact on microbial activity. However, once activity 
starts the pile will begin to heat up and this process is influenced more by management 
practices such as the pattern of feeding and mixing, rather than ambient temperature 
levels. The carbon/nitrogen balance is important, particularly in the cold composting 
conditions of many home composting systems. This is regulated by feeding the right 
balance of ‘green’ and ‘brown’ materials which requires some degree of knowledge and 
understanding. Moisture level is influential, but it is relatively easier to achieve an 
acceptable level through appropriate management practices. 

There is a lack of robust studies that test how plastics behave under home composting 
conditions. This report identified 6 studies that attempted to measure biodegradation 
of plastics in home composting conditions, but they are limited in their usefulness, 
mostly due to methodological weakness in study design such as shortness of testing 
period. In addition, a number of studies claim to report on the biodegradability of 
plastics under ‘natural conditions’, yet are of little relevance to this study as they rely 
on the ISO laboratory tests for biodegradation rather than testing within an actual 
home compost system.  

Given the low temperature conditions of many home composting systems PLA is not 
home compostable.  Other plastics (PHA, polyesters and blends) show some degree of 
chemical biodegradation at lower temperatures according to their polymer 
characteristics, but there has been no direct testing of their biodegradation in home 
composting systems. The microbial specificity of certain plastics also limits their 
biodegradation in home composting settings.  

A 2019 ADEME study from France provides useful evidence of the behaviour of 
compostable food waste bags in home composting conditions and is the most 
comprehensive study of its kind. The two bag types— PBAT/Starch and PBAT/PLA 
blends—were added to the compost at a concentration of 1%. The use of a very large 
1sqm pile that was created at the beginning (rather than continuously added to) meant 
that the study reflects conditions that are far more optimal that may be found in 
reality; despite this, the study found that: 

• 

• 

incomplete biodegradation (with visible fragments) both bags was reported 
after 18 months;  
fragments of plastic material are likely to be still present in the compost after 18 
months; 

138  

 
 
 
 
• 

there were no ecotoxicity concerns from the resulting compost, but neither 
were there any agronomic benefits from including the plastic material; and, 
•  paper bags equivalents were shown to biodegrade in a much shorter timeframe 

with no visible residues. 

Behavioural factors were also found to be a significant factor in the speed of the 
biodegradation process with the following found to speed up the process: 

•  Depositing the biowaste bag full, rather than empty 
•  Regular mixing of the pile 
•  Starting the pile in springtime not winter  

8.4 

Standards and Certifications for Home Composting 
of Plastics 

Standards for compostable products currently exist only for industrial composting at a 
European level (EN 13432 and EN 14995). There are no European (CEN), international 
(ISO) or American (ASTM) standards for home composting to date though a draft 
standard has been written by CEN specific to carrier bags: “Requirements and test 
scheme for carrier bags suitable for treatment in well-managed home composting 
installations.” This section will analyse the different standards by looking in detail at the 
testing criteria on which they are based.  

8.4.1 

Specifications of Test Methods 

The suite of ISO tests are the building blocks of the country level and EU level standards. 
The tests define in detail the testing procedures for biodegradation, disintegration and 
toxicity effects. Tests differ in the choice of inoculum (microbially active medium e.g. 
soil, compost etc.) and the measurement methods for recording the biodegradation and 
disintegration levels. (e.g. ISO 14851 – oxygen demand and ISO 14852 – evolved carbon 
dioxide). Table 31 and Table 32 in Appendix 5 detail the current biodegradation and 
disintegration tests.  

Biodegradation is thought of as a property of a material, but it is also a property of a 
system; the conditions of the system determining whether the material will biodegrade. 
234 The purpose of lab testing is to show the inherent nature of the material to 
biodegrade under a given set of conditions which is defined in ISO 14855 as a: 

234 Renewable lube (2019) Understanding Biobased/Biodegradable and the Industry’s Standardized Tests 
and Definitions, accessed 28 October 2019, 
http://renewablelube.com/files/4514/4734/8222/standardized.pdf 

139 

 
 
 
 
 
 
“breakdown of an organic compound by microorganisms in the presence of oxygen 
into carbon dioxide, water and mineral salts of any other elements present 
(mineralization) plus new biomass.”  

The test measures the carbon dioxide evolved and compares this with the theoretical 
maximum amount of carbon dioxide that the material could produce. This is also 
compared to a cellulose reference material tested under the same conditions for which 
the test is deemed invalid if the reference material doesn’t reach certain levels of 
biodegradation.  

The most commonly used test for biodegradation is ISO 14855 (Determination of the 
ultimate aerobic biodegradability of plastic materials under controlled composting 
conditions). The test simulates intensive aerobic composting conditions as is found in 
industrial composting facilities. The test material is mixed with a stabilised, mature 
compost derived from the organic fraction of municipal solid waste (the inoculum). The 
mixture is incubated at a constant temperature of 58°C ± 2°C until a plateau phase of 
biodegradation is recorded, which should be no more than 6 months.  

The type of inoculum used in a test will impact on the biodegradation process. ISO 14855 
states that: 

“Well aerated compost from a properly operating aerobic composting plant shall be 
used as the inoculum…It is recommended that compost from a plant composting the 
organic fraction of solid municipal waste be used in order to ensure sufficient 
diversity of microorganisms. The age of the compost should preferably be between 2 
and 4 months.” 

The age of the compost is important here; as discussed in Section 4.2.1 the maturity of 
the compost dictates the level of biological activity present. In this case, compost of 2-4 
months in age is still very biologically active and would be considered as ‘fresh compost’ 
under the German Rottegrad system. In using ISO 14855 it has been found that using the 
specified inoculum can result in the release of extra CO2, confusing the results as CO2 
production is the key indicator of biodegradability. This is known as the ‘priming effect.’ 
235 A 2018 revision to ISO 14855 introduced an alternative test method to remove this 
problem by using a solid mineral medium such as vermiculite inoculated with 
thermophilic microorganisms obtained from compost. 
Certain substances will not be suitable for testing with ISO 14855, particularly colouring 
inks, additives or colourants. In these cases, the alternative tests ISO 14851 and 14852 
have been designed which test within an aqueous medium. The inoculum is derived from 
activated sludge, compost or soil. Biodegradation is measured either through the 
analysis of evolved carbon dioxide (ISO 14852) or through the consumption of oxygen 
(ISO 14851).   

235 Bellia, G., Tosin, M., and Degli Innocenti, F. (2000) Test method of composting in vermiculite is 
unaffected by the priming effect, Polymer Degradation and Stability - POLYM DEGRAD STABIL, Vol.69, 
pp.113–120 

140  

 
 
 
 
 
ISO 17556 is another biodegradation test that can be used for some plastic materials but 
it uses a soil inoculum and measures biodegradation by the amount of oxygen consumed 
rather than by the amount of evolved carbon. Using soil means that the inoculum is 
likely to be less biologically active than a mature compost, but as the soil can be taken 
from anywhere, this is difficult to verify. 

Disintegration of plastics are tested using ISO 16929 and ISO 20200. ISO 16929 takes 
pieces of the sample material that are 5cm x 5cm (or 10cm x 10cm for films) and places 
them in a pilot scale compost bin of minimum volume 140L. The compost bin is filled 
with a homogenous biowaste of the same age and origin with the addition of 10-60% 
bulking agent. The compost is turned weekly during the first 4 weeks of the test, then 
fortnightly until the end of the test. (12 weeks in total) The mixture is then passed 
through a 10mm sieve followed by a 2mm sieve to pick out remaining particles of the 
test material. These are visually inspected. ISO 20200 differs in that it uses a laboratory 
scale test with a synthetic solid waste inoculated with mature compost. The degree of 
disintegration is calculated quantitatively by comparing the initial dry mass of the 
material with the dry mass of residual material that didn’t pass through the sieve—this 
particular task requires a high level of training and skill to accurately identity fragments 
within the compost.   

8.4.2 

Country Level Standards 

Australia is the only non-European country to have produced a home composting 
standard (AS 5810-2010) and they describe the challenges in developing this:  

“Home composting systems vary considerably in their design, construction and 
operation; hence their performance also varies considerably compared to 
commercial composting facilities. Consequently, this Standard, in comparison to AS 
4736 [for industrial composting], uses lower temperatures in test environments and 
a longer test duration, to account for such variations in home composting 
performance.” 

Within Europe, France, Italy and Belgium are the only countries to have developed their 
own standards. The Belgian standard is called a decree yet it has the same legal standing 
as the others.236 Table 22 shows the requirements of these standards and how the 
testing regimes within them make use of the suite of ISO tests. The table also includes 
the draft CEN for carrier bags in home composting.  

In the key aspects the Australian, French and Belgian standards are in broad agreement, 
being largely based on EN 13432 with the following adaptations.  

•  Biodegradation: Temperature restricted to 20-30 oC, time for reaching 90% 

biodegradation is extended to 12 months 

236 Le Ministre du Climat et de l’Energie, and P. MAGNETTE (2008) Belgian Official Gazette - 24.10.2008 - 
MONITEUR BELGE 56651 

141 

 
 
 
 
 
•  Disintegration: Time for reaching 90% <2mm is extended to 6 months 
•  Ecotoxicity: Limits on heavy metals and plant germination testing 

The Italian Standard differs slightly in its requirements, in part because it is not strictly 
speaking a home-composting standard, rather it serves to certify biodegradable plastics 
at ambient temperatures. It specifies; 

•  Biodegradation:  

o  that the biodegradation test takes place in soil rather than compost; ISO 

17556 

o  a tighter temperature range but still within the boundaries of the other 

standards (21-28°C rather than 20-30°C) 

o  a second stage of testing if 90% biodegradation is not reached in 12 

months. The sample can be tested using the same test method with the 
industrial composting threshold which has lower requirements (i.e. at 
58oc for 6 months); 

•  Disintegration: no test specified 
•  Ecotoxicity: the requirements are stronger as it specifies the use of an earthworm 

survival test 

In specifying the use of ISO 17556 (Determination of the ultimate aerobic 
biodegradability of plastic materials in soil) in the Italian standard this is in some ways a 
stricter test as soil is a less biologically active medium than compost so biodegradation is 
likely to be slower. This may be why the Italian standard allows for a secondary stage of 
testing using the industrial composting test if the initial soil test only demonstrated 
biodegradation of between 60-90%.  

However, this seems to allow a loop hole for some products to pass through as a 
material that is proven to be industrial compostable only has to reach 60% 
biodegradation in 12 months in soil conditions.  It is not clear whether this is an 
intentional weakening of the standard or an oversight. Certainly, without using the same 
compost laboratory test as the other country standards it is difficult to draw a direct 
comparison of stringency.  

The Australian and Italian standards are the only ones that require ecotoxicity testing on 
earthworms rather than the more basic germination tests that are required in EN 13432. 
Notably the French standard states that this test is “…not considered to be a 
distinguishing criterion”, suggesting that a plastic could still be classified as ‘home 
compostable’ even if it failed the ecotoxicity test.  
It is unclear why the French standard takes this position and from a precautionary 
principle perspective is could be argued that reducing the risk of any ecotoxicological 
impacts should be a priority for any such standard. It may be that low concentrations of 
compostable plastics in home compost pose a relatively low risk, but low concentrations 
cannot be assumed especially if products using these materials become more available—
appropriate testing should remove the risk at any concentration level.  

142  

 
 
 
All standards require tight limits on heavy metals in the materials to be tested, with 
France also limiting Cobalt. The French standard also has several other prerequisites, 
including the following: 

“If a plastic product is made up of different components, some of which are 
compostable by home compostable while others are not, the product itself shall not 
be identified as "suitable for home composting".” 

“If a plastic product is printed, it may be designated as "suitable for home 
composting" only if it has been assessed taking into account the inks used.” 

These requirements highlight the importance that the entire product (including inks) is 
home compostable to reduce the risk of non-compostable materials being placed in 
home composting.   
The Belgian decree is the only one that specifically states that the standard does not 
apply to ‘worm composting’—all of the other standards, whether they include a worm 
test or not, do not differentiate between or specify which kind of composting system the 
requirements are set for. This could be an issue in the future if indoor composting 
becomes more common.  

143 

 
 
 
 
Table 22: Home Compostable Plastic Standards and certifications   

Orange Text = weaker requirement, Green text = stronger requirement 

Standard 

FRANCE:  T 51-800. Plastics — 
Specifications for plastics suitable for 
home composting 

Limitation 
of heavy 
metals 

<5% non-
bio-
degradable 
substances? 

As for 
EN13432 
also Cobalt 

Allowed 

Biodegradation 
Tests  

Pass at:   

>90% 
degradation in 
12 months 

Dis-
integration 
tests  

Pass at:   

90% <2mm in 
6 months 

Ecotoxicity tests 

ISO 14855 and ISO 
14851/52 

But temp restricted to 20-
30°C and duration 
lengthened to 12 months  

Yes 

Yes 

ISO 16929 but 
at 20-30°C, 6 
months 

As for French 
Standard 

Yes 

Yes 

BELGIUM: Product standards for 
compostable and biodegradable 
materials 

As for 
EN13432  

Allowed 

As for French standard with 
addition of ISO 17556 (soil) 

ITALY: UNI 11183. Biodegradable 
plastics at ambient temperature 

As for 
EN13432  

Unclear 

As for French standard with 
addition of ISO 17556 (soil) 

But at 21-28°C  

If rate is 60-
90% then use 
14855 at 58°C 

None 

None 

AUSTRALIA: AS 5810—2010 
Biodegradable plastics suitable for 
home composting 

DRAFT CEN: Packaging — 
Requirements and test scheme for 
carrier bags suitable for treatment in 
well-managed home composting 
installations 

As for 
EN13432  

Allowed 

As for French standard 

CEN/TR 
13695-2; 

Allowed 

As for French standard with 
addition of ISO 17556 (soil) 

Yes 

Yes 

ISO 20200 at 
20-30°C, 6 
months 

IN DRAFT 

20-30°C, 6 
months  

Yes 

Yes 

144  

Aligned to EN13432 
(germination rate) 

As for French 
Standard 

UNI 10780 
(germination rate) 
ISO 11268 
(earthworm) 

Aligned to EN13432 
(germination rate) 
ASTM E1676 
(earthworm) 

EN ISO 11269-2 – 
plants 
EN ISO 11268-1 – 
earthworms – acute 
and chronic effects 
ISO 15685 - bacteria 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
8.4.3 

Draft European CEN Standard for Home Composting of 
Plastic Carrier Bags 

There are two new forthcoming CEN standards that are in the process of being agreed 
with a view to being published in 2020:  

•  EN 17427:  Packaging — Requirements and test scheme for carrier bags suitable 

for treatment in well-managed home composting installations  

•  EN 17428:  Packaging — Determination of the degree of disintegration under 

simulated home composting conditions  

The aim of EN 17427 is to move beyond the current reliance on EN 13432 as a 
benchmark for plastic compostability and define “the characteristics carrier bags must 
own in order to display biodegradation and disintegration behaviour compatible with 
well-managed home composting installations.” Central to this is the definition of a well-
managed home composting installation. This can raise potential issues as the definition 
of a well-managed home composting system does not acknowledge that many 
successful home composters will be using a more minimal system; the distinction 
between a well-managed pile and a minimally-managed pile is not clearly addressed in 
any current standard and is mentioned only in passing in the draft CEN standard.  

A key area in which EN 17427 moves beyond its predecessors is in defining the 
characterisation of carrier bags that are to be tested. The maximum concentration of 
regulated heavy metals follows the same limits as EN 13432 but in addition per- and 
poly-fluorinated substances (PFCs) are not permitted to be intentionally added to the 
material of the bag. Similarly, substances of very high concern (SoVHC) cannot be 
intentionally added and must not exceed a concentration of 0.1%. Substances hazardous 
to the environment shall be identified and assessed according to CEN/TR 13695-2. 237  

The biodegradability criteria broadly follow those adopted by existing country standards 
in specifying that the temperature during testing should be restricted to 25°C ± 5°C and 
testing should last for up to 12 months. The biodegradation criteria are further 
strengthened by stipulating that any organic constituent present in more than 1% of dry 
mass of the bag needs to also be tested for biodegradability. Such constituents cannot 
exceed 15% in total. This is a very important addition as there are unconfirmed reports 
(from multiple reliable and independent sources that cannot be named) of 
manufacturers using the current threshold of 90% measured biodegradation in EN 13432 
to include up to 10% non-biodegradable materials in order to achieve superior 
mechanical properties whilst lowering costs. This new requirement effectively prohibits 
this ‘loop hole’. 

Ecotoxicity tests are included for negative effects on plant growth and germination (as 
for EN13432), but with new requirements for tests on the effects on earthworms, and on 

237 CEN (2004) CEN_TR_13695-2{2004}_(E).pdf 

145 

 
 
 
 
 
bacteria through a nitrification inhibition test. The inclusion of tests on ecotoxicity are 
important to ensure that the compost produced in a home setting containing 
biodegraded plastic is not harmful to the natural environment in unforeseen ways. The 
addition of the test for adverse effects on earthworms represents a more stringent 
testing requirement and brings ecotoxicity testing in line with EN 17033 for 
biodegradable mulch films.  

The new disintegration test being developed (EN 17428) alongside, differs from earlier 
disintegration tests as it attempts to define a laboratory scale test that simulates aerobic 
home composting conditions, to replace the pilot scale composting specified in ISO 
16929 which used a 140L bin. The new test specifies that the container (composting 
reactor) should be 5-10L in size and the test material should be cut to between 
2.5x2.5cm and 5x5cm in size. The test does allow for alternative testing ‘in situ’ but does 
not currently define a standard method for field testing under home composting 
conditions and in practice it is unlikely this will be an attractive option for cost and 
practicality reasons. 

Limiting the scope of the draft CEN to carrier bags also demonstrates the trend to 
produce product specific standards that help reduce the occurrence of unintended 
consequences (e.g. certifying plastic bottles). However, this does presuppose that it is 
acceptable that carrier bags, as a product, can and should be placed in home composting 
if certified. 

8.4.4 

Certifications 

There are two main industry bodies certifying products as suitable for home composting: 
TUV Austria and Din Certco.  

The Din Certco DIN-Geprüft Home Compostable label and certification can be used for 
any product that passes either the Australian or France standards.  

TUV OK compost HOME currently has 787 certificates issued for products passing its 
home composting tests. 238 This certification and associated label is not linked to other 
home composting standards but uses EN 13432 as the basis but with their own 
variations deemed appropriate for home composting: 

•  Biodegradation: Temperature restricted to 20-30 oC, time for reaching 90% 

biodegradation is extended to 12 months 

•  Disintegration: Time for reaching 90% <2mm is extended to 6 months 

TUV OK compost HOME certification does not include all of the additional elements that 
have been identified in the draft CEN standard and therefore it is assessed to be weaker 
(in the same way the country level standards are) with regard to the disintegration test, 
the ‘loop hole’ for non-biodegradable materials and ecotoxicity tests.  

238 TUV Austria (2019) Certified Products, accessed 29 October 2019, http://www.tuv-at.be/green-
marks/certified-products/ 

146  

 
 
 
 
 
8.4.5 

Key Conclusions  

Key Conclusions – Standards and Certifications for Home Composting 

Specifications of Test Methods 

The suite of ISO tests are the building blocks of the country level and EU level 
standards. The tests define in detail the testing procedures for biodegradation, 
disintegration and toxicity effects. Tests differ in the choice of inoculum (microbially 
active medium) and the measurement methods for recording the biodegradation and 
disintegration levels.   

•  The choice of inoculum is important in testing biodegradation processes. The 
primary test for biodegradation ISO 14855 uses an inoculum derived from 
industrial compost but the maturity of this can affect results 

•  The European CEN standards reference the use of these tests but also stipulate 

what test result indicates a valid result  

Country Level Standards 

National standards for home composting have been are currently available in France, 
Belgium, Italy and Australia. There are no European (CEN), international (ISO) or 
American (ASTM) standards for home composting to date. 

In the following key aspects all of standards are in broad agreement: 

•  Testing temperature: 20-30oC 
•  Biodegradation threshold: 90% in 12 months 
•  Disintegration threshold: 90% <2mm in 6 months 
•  Ecotoxicity: Tests are generally (with the exception of Australia and Italy) not 

stricter than for EN 13432 and do not include any testing to determine toxicity 
to invertebrates such as worms. 

Industry certifications, TUV OK compost HOME and the Din Certco DIN-Geprüft Home 
Compostable, also follow the same requirements as country standards.  

Draft European CEN Standard for Home Composting of Plastic Carrier Bags 
The European Committee for Standardization (CEN) is also developing its own Standard 
which aims to build on the current country standards. The Standard is currently in draft 
form, but its scope is narrower in that it is only applicable to plastic carrier bags at this 
stage— this recognises the increasing need to develop product specific standards for 
biodegradation, but it is yet to be determined whether the implicit promotion of this 
particular application is justified. 
The current draft is stricter that current Standards in the following areas:  

•  Characterisation – restrictions on Substances of Very High Concern, substances 

hazardous to the environment and per and poly-fluorinated substances.  

147 

 
 
 
 
 
•  Biodegradation - any organic constituent present in more than 1% of dry mass 

of the bag also needs to be tested and pass for biodegradability. Such 
constituents cannot exceed 15% in total.  

•  Disintegration – a new test is introduced (and accompanying CEN standard) for 

laboratory scale simulation of the aerobic home composting process 

•  Ecotoxicity - Tests are now included for effects on earthworms, and possible 

effects on bacteria through a nitrification inhibition test. 

•  Ecotoxicity - Tests are included for negative effects on plant growth (as for 

EN13432), earthworms, and possible effects on bacteria through a nitrification 
inhibition test. 

8.5 

Comparison Between Standards and Actual Home 
Composting Conditions 

The draft CEN standard for home composting of carrier bags has gone some way to 
match testing conditions with those found in home composting systems. It is also the 
strongest requirements of any standard to date and, if introduced, is likely to become 
the de facto standard in the EU for compostable carrier bags. For this reason, the focus 
of this section is primarily on the draft CEN standard. 

8.5.1 

Differences Between Home Composting Conditions and Test 
Conditions 

The testing conditions need to be limited in order to facilitate the measurement of 
biodegradation in a scientific, replicable, manner. The tests do however try to 
approximate the conditions in typical home composting systems and in some key areas 
there is still room for discussion around whether the testing conditions are sufficiently 
replicating the home environment.  

The most important aspect that should be considered in the differences between testing 
and actual conditions in home composting are: 

1)  Duration. The duration of all the home composting tests is 12 months which is 
comparable with the length of time that home composters should expect their 
compost to be ready for use if they are adopting a basic management practice 
resulting in cold composting (as indicated earlier in Table 16). If they manage the 
compost efficiently it could be complete in several months. The key here is that 
the plastics in a household composter should compost at the same rate (or 
faster) as the rest of the waste in the compost pile—as the testing is always 
verified in comparison to cellulose which is itself a more readily biodegradable 
substance than much of what ends up in a home composter. In very cold 
climates, composters who let their compost go dormant over winter (i.e. do not 
actively manage it) will already know and expect that the composting process 
may need two summer cycles to mature. A compostable plastic being treated in 
such a home compost system could also take that long but is still keeping pace 

148  

 
 
 
 
with the rest of the biowaste and therefore the expectations of the householder. 
The results of the ADEME study show that it is possible that fragments of plastic 
material will remain in the compost after 12 months, even when the rest of the 
organic material becomes compost.  

2)  Temperature. Temperature is closely related to duration. The draft CEN standard 
and the country standards restrict the temperature of the testing environment to 
20°- 30°C which is to reflect the conditions that low temperature mesophilic 
bacteria thrive in. This recognises that a lower test temperature will only reduce 
bacterial activity, not stop it. Across the home composting studies identified for 
this report it was observed that during the biologically active phase of the 
composting process it is the microbial action that determines temperatures 
within the compost, not the ambient temperature, and higher temperatures 
(thermophilic) can be reached. After this initial phase the compost temperature 
closely follows the ambient temperature levels within a few degrees which is 
usually a satisfactory temperature range for mesophilic bacteria to be active and 
biodegradation to finalise. With the results of the ADEME study showing that 
visible fragments remain even after 12 months, reducing testing temperature to 
reflect sub optimal conditions (in the range of 15-25oC) should be something 
that is considered. Of equal importance is that consumer expectations are 
aligned with the outcomes i.e. if they live in colder climates, full biodegradation 
may take longer (for all materials in the compost, not just plastics). 

3)  Inoculum. The laboratory scale test relies on the use of an inoculum made from 
industrially produced compost matured up to 4 months. Although this inoculum 
is not directly representative of the home compost environment, it presents a 
less active microbial environment than would be found in real life home compost 
with fresh matter. In this way, it can be considered a stronger test compared with 
using fresh compost or even many types of soil which can be highly biologically 
active.  
However, the matter is further complicated by the requirement in testing 
conditions for the new disintegration testing standard (prEN 17428) that the 
inoculum material (mature compost) is to be sieved to fragments between 5mm 
and 10mm. The authors of the ADEME study point out that this increases the 
contact surface between the testing material and the inoculum, optimising the 
conditions for biodegradation. In home composting the base material will never 
be sifted in this way and the fragments will be much larger.   

4)  Form of the testing material. The disintegration testing standard (prEN 17428) 
specify that the material should be reduced in size to between 2.5 cm × 2.5 cm 
and 5 cm × 5 cm. When in home composting the materials will be in their full final 
product form. This can raise many issues—for example, bags may be deposited 
tied up and closed, full or empty. These all affect the speed of the biodegradation 
process.  

149 

 
 
 
 
8.5.2 

Defining the Scope of Home Composting Practices for which 
Standards are Valid 

The actual performance of home compostable plastics is greatly influenced by several 
factors, many of which are behavioural. These include: 

•  Behavioural variation in practice between countries 

o  Cultural differences in practice due to climatic factors  
o  cultural differences in acceptability of including meat and fish waste 
•  Variation in quality of practice (maintaining a ‘well-managed’ pile vs a ‘basic’ pile 

vs dumping of organic waste with little management)  

•  The increasing prevalence of other practices that are referred to as ‘home 

composting’ which will not provide the same abiotic conditions for 
biodegradation and disintegration (Vermicomposting and Bokashi – fermenting).  

•  How the product is presented into the compost pile (e.g. closing a bag prior to 

composting) 

These behavioural issues all add to the variation of conditions likely to exist in home 
composting systems. Although these factors clearly sit beyond the responsibility of the 
standard setting bodies, the variation in outcome that they bring could seriously 
undermine consumer trust in the certification/labelling process if products that are 
labelled as home compostable do not meet expectations.  

One of the potential reasons why there may be a discrepancy between tested products 
biodegradability in the laboratory and in a home setting could be because of a lack of 
clarity in defining the home composting system that the tests are valid for. To this end 
the draft CEN standard defines the scope of the test as applicable to “a well-managed 
home compost system”. The document defines ‘well-managed’ home composting as a 
“home composting practice which meets the minimum required conditions to convert 
biowaste into compost” 239. Annex E of the standard goes on to offer guidelines for 
‘optimal’ composting:  

Optimal composting can be achieved by ensuring: 

•  sufficient air and moisture are present in the rotting heap, 
• 

roughly textured compost raw materials (e.g. branches) are mechanically 
shredded before composting, and   
the composition of the compost raw materials fulfils the nutritional requirements 
of the microorganisms. 

• 

Later in the text it also states that  

•  The rotting material should feel moist but not wet. 

239 P8 CEN (2019) CEN-TC261-SC4-
WG2_N0296_Home_compostable_bags_Text_submitted_to_enquiry_clean_version.pdf 

150  

 
 
 
 
 
 
• 

In order to ensure sufficient air, the compost heap might need to be turned 
manually or aerated by other means. 

These guidelines, while covering the main points of this report’s definition of a ‘well-
managed’ pile (see Table 16) appear to conflate the ideal management practices that a 
home composter needs to carry out with the description of conditions that these 
practices will encourage. Furthermore, the guidelines acknowledge that there are two 
possible routes to successful home composting, but the differences are oversimplified by 
aligning batch composting with a hot composting process and add-as-you-go 
composting with a cold composting process. This is inconsistent with the conclusions of 
the research for the current study which finds that add-as-you-go composting can also 
produce a hot process if managed correctly, as is regularly demonstrated in the success 
of community composting.  

8.5.3 

Key Conclusions    

Key Conclusions - Comparison Between Standards and Actual Home Composting 
Conditions 

Whilst biodegradation Standards are always aimed at testing for ‘inherent 
biodegradability’, this concept has less credibility when applied to environmental 
conditions that are more influenced by local climate and microbial life. At very least it is 
important to ascertain whether the timescales in the Standards (12 months) are 
realistic and what might influence this. This will help to demine whether Standard is fit 
for purpose and how this can be communicated to end-users in order to manage their 
expectations. 
The main ways that home composting conditions differ to test conditions are:  

1)  Duration – The results of the ADEME study show that that fragments of plastic 
material can remain in the compost after 12 months, even when the rest of the 
organic material becomes compost.  

1)  Temperature – It is clear that the testing temperatures do not reflect actual real 

life conditions. Lower ambient temperatures (i.e. <20oC) will see slower 
biodegradation taking place. The effects should be explored of changing the 
testing temperature to something that mirrors the conditions in a temperate 
climate, but still allowing for microbial activity to occur i.e. not lower than 10oC. 

2)  Inoculum- The tests use a mature compost that is likely to be less biologically 
active than fresh garden waste that a householder will use—i.e. the test is 
harder to pass. However, the test inoculum is sieved, which may speed up the 
biodegradation process in comparison to a home environment. 

3)  Form of the testing material – materials tested in the form of smaller samples 

may perform differently when composted in their final product form.  

There is also some disparity between standard testing regimes, real-life studies and the 
actual practice conducted by home composters. The latter has not been studied in any 
great detail and yet studies and lab testing assume a ‘well-managed’ practice is being 
undertaken. Given that individual practices have a large bearing on the effectiveness of 

151 

 
 
 
composting, this is an assumption that will likely mean that at least some of the home 
compostable plastics will not perform as intended in real-life.  

8.6 

Recommendations to Reconcile Theory and Practice 

Having analysed the differences between home composting and the current standards, 
three approaches are recommended for addressing discrepancies between existing 
frameworks and conditions to be found in practice: 

•  Further validation testing in home composting conditions 
•  Refine the wording of the draft CEN standard on home composting 
•  Develop clear communication with the consumer 

Further Validation Testing in Home Composting Conditions 

This  research  has  identified  that  the  actual  ranges  of  abiotic  conditions  within  home 
composting systems are wider that in test conditions.  
As a way of strengthening the validity of the tests some products that currently pass 
existing tests could be subjected to further testing under less optimal conditions to see 
how this affects the biodegradation and disintegration processes. This would not need to 
be done for each product as part of the test standard, but would be a valuable validation 
exercise. See Table 23 for examples of where further testing may be warranted, although 
it is likely that temperature will have the biggest impact and therefore this parameter 
should be prioritised.  
Additionally, the ADEME study revealed that even in a well-managed home compost pile 
it is possible that visually identifiable fragments of material are likely to be present in the 
compost after a year. Although it was established that this does not raise any ecotoxicity 
concerns, consumers need to be reassured that these fragments will continue to 
biodegrade once the compost is used on the soil. The study concludes: 

“It also seems appropriate to warn individuals that the presence of pieces of bags at 
in the final compost is possible but that it does not affect the quality of the compost 
and that the materials will degrade in the soil at an undefined time scale.” Translated 
from French 

“An undefined timescale” may not be acceptable and therefore verification of this 
should be undertaken to determine whether this is the case. There appears to be no 
particular merit in adding an additional test to the standards, but conducting further 
experiments on the remaining fragments to determine the fate once added to a soil 
environment would mean the assertion from the ADEME study could be validated. 

152  

 
 
 
 
 
 
 
Table 23: Potential areas of further testing to strengthen validity of 
certification    

Testing conditions 
 (Draft CEN drawing on 
ISO 14855) 

Temperature 25°C ±5° 

Duration 12 months for 
biodegradation 

Range in home composting studies 
identified 

Satisfactory 
equivalence? 

Spring to Autumn ambient 
temperatures; most likely to be in the 
range of 10 - 20°C 

Further testing 
advised 

3-12 months 

Yes 

pH 7-8 

pH range 5.9-9.28 

C/N ratio 10-40 

C/N ratio 10-66 

Moisture maintained 
around 50% 

Moisture values ranged from 22% 
to 85% 

Further testing 
advised 

Further testing 
advised 

Further testing 
advised 

Refine the Wording of the Draft CEN Standard on Home Composting   

Another approach to ensuring the replicability of test results in the real world is to more 
clearly define the home composting system that should produce the same conditions as 
the test regime. 

It is recommended that the CEN standard describes more clearly the add-as-you-go 
method with the management appropriate to maintaining a healthy compost pile, whilst 
making explicit that this is likely to be a ‘cold composting’ process. If the test results are 
valid in this context then the material should perform even better in a hot composting 
process.  

Greater clarity would be welcomed in describing the conditions expected in the home 
compost system, and also clearly listing the management method needed to achieve 
this. This should include both a description of the range of abiotic conditions for which 
the test is deemed reliable (temperature, duration, pH, moisture), and related to this a 
set of practices which will ensure these conditions. It is also important to make the 
distinction between best practice and a minimal practice that can be undertaken to 
achieve an effective composting process. 

National level guidance could then follow the wording of this standard and in this way 
greater consistency in practice may be achieved across different EU countries. Regional 
variations in practice should still be encouraged where they are adaptations to climate 
or cultural preferences. Promoting community compost schemes is another way of 
supporting the spread of best practice as the knowledge of composting is condensed in 

153 

 
 
 
 
 
the community ‘master composters’ who can support each other in their knowledge 
development. 

Clear Communication with the Consumer 

However, if the testing and labelling is refined, there will be a need for effective 
communication with the consumer so that their expectations are in line with the 
applicability of the test.  

Labelling should give the consumer an expectation of a time frame for the composting of 
the plastic material, which could be described relative to what they currently know of as 
a typical time frame in their own context. i.e. if in very cold climates it usually takes more 
than a full year for food waste to compost, this is also to be expected for plastic products 
labelled as compostable. Harmonising at the EU level would therefore be problematic. 

Another area where clarity is needed is in distinguishing between traditional home 
composting practices and novel indoor composting practices that are increasingly called 
‘composting’ but involve a very different biological process that is unlikely to biodegrade 
plastics. These include vermicomposting and Bokashi (fermentation).  

Finally, for home composting labelling to function well it will need to be accompanied by 
a strong—possibly region specific—communication programme. Ultimately the 
responsibility for achieving this should not be the placed solely on the certification 
bodies, but in collaboration with other levels of government, in particular national and 
local.  

8.6.1 

Home Composting of Plastics as Part of the Circular 
Economy 

Home composting as a means of treating domestically produced biowaste brings 
ecological benefit because it eliminates related GHG emissions from fuel used to run 
vehicles/machinery for collection and transport, thus also bringing economic benefit of 
saved collection and transport costs of the waste. It also offers a means of improving soil 
quality without the need for chemicals (for those that have gardens), and at the same 
time encourages local responsibility for waste. Home composting of plastics will only 
marginally add to this potential benefit through avoiding transport costs and the 
associated reduction in GHG emissions. It will however bring a range of complications to 
the process, at least initially as consumers have to learn how to process this new 
category of waste. There also appears to be no evidence to suggest that the material 
itself provides any specific benefits to the home compost. 

Perhaps the relatively small benefit from labelling more products as home compostable 
could be increased if this is accompanied by a greater promotion of home composting 
through education and support to those wishing to learn how to manage their compost 
but there is a relatively high likelihood that this will not reach all the relevant households 
and it cannot be taken for granted that this approach will be applied in a homogenous 
way across cities, regions and countries. This is problematic if one considers that once on 
the market such products can be sold widely.  This may be problematic given the 
difficulties in monitoring home composting in terms of practice, quantities of waste 

154  

 
 
 
processed and outputs. Furthermore, measuring the input of the home composting 
process in line with the measurement method required to calculate recycling of other 
packaging would likely be almost impossible. Community scale composting is however a 
more viable option as a local waste management tool.  

Table 24 shows how home composting can be viewed differently in the context of 
criteria setting for beneficial use. Fewer criteria are needed as the emphasis changes to 
what most benefits the householder. For example, increasing the capture of biowaste is 
not an imperative for the householder (they have no targets to meet); although from a 
public policy perspective it is still important to divert organic matter from residual waste 
streams. However, as separate collection is implemented over the next three years, this 
will be less of an issue and the focus should be on which applications there is justification 
for home compostable plastics over industrially compostable plastics. 

What is also important, is that householders do not accidentally put conventional or 
industrially compostable plastic in a home composter through confusion. Arguably this 
confusion only exists because of compostable plastics—very few home composters 
would knowingly put conventional plastic in their pile and they would soon see the 
consequences of their mistake. Because of this, the applications are considerably 
narrowed, so as to avoid this confusion. In this case only biowaste bags, fruit labels and 
tea bags are recommended—the latter two are likely to end up in home composting 
anyway, and it is only recently that public attention has been drawn towards the 
somewhat disguised plastic content of teabags. Compostable coffee pods are only 
recommended if no other material alternatives are available on the market. 

With regard to the prerequisites identified in Section 7.2 for industrial composting, the 
requirement for infrastructure is not necessary (although home composters will 
obviously need a compost pile set up), however the following would still apply: 

1)  Products in their entirety must meet EN or local Standards for composting of 
packaging or plastic products – i.e. compostable products should not be 
comprised of components that do not meet the standards 

2)  The term ’biodegradable’ is not used on the product or any marketing 

communication associated with it. 

3)  The correct waste management route is clearly identifiable for the end 

consumer/user and this is communicated effectively on the product/ packaging 

It is also likely given the performance of plastic films in testing, that all of the rigid 
packaging in the example products list would not pass the relevant testing especially if it 
is made from PLA. Reusing carrier bags or vegetable bags as caddy liners for collecting 
biowaste for home composting may be a viable option, but there is still a danger of 
confusion leading to PE bags being used. Clear messaging may negate this somewhat, 
and bags have a large area to provide the appropriate messaging. Unfortunately, the 
increased use of industrially compostable bags creates another layer of confusion.  
As previously identified (Section 5.1), the French approach to this is to make sure all 
compostable products are also home compostable, therefore the consumer does not 
need to make this distinction. There is some merit in the approach of reducing 

155 

 
 
 
complexity although it may result in some unintended consequences; as identified, some 
materials such as PLA are inherently unsuitable for home composting and are therefore 
unlikely to pass the French Standard for this. Many materials that do pass home 
composting tests use thinner gauges than for industrial composting – this could restrict 
applications that may require thicker material for functionality. Similarly, rigid products 
(bottles, etc.) are also unlikely to be pass the test although this study has already shown 
that rigid plastic products are mostly unsuitable as an application of compostable 
plastics. As this amendment has only just been passed, the exact implications are not yet 
known, however. 

Table 24: Criteria Testing for Home Compostable Plastics (5= completely 
true, 1= completely untrue, lowest weighted score possible = 12, highest = 60) 

Example products 

Not 
recyclable 
or could not 
have been 
designed 
for reuse 

Weighting>> 

Carrier bags used in supermarkets 
Biowaste bags as liners for indoor 
caddy 
Clothing packaging bags e.g. for shirts   

Pre-packed fresh fruit bags  

Trays used for fast food 

Rigid Fast food Containers 
Single use paper cups with plastic 
liner 
Supermarket vegetable bags 

Coffee capsules/pods 
Coffee capsules/pods (alternatives 
banned) 

3 
2 

5 

2 

3 

2 

2 

2 

4 

2 

2 

Single Use Bottle 

Fruit Labels 

Tea Bags 

Benchmarks 

1 

5 

5 

Reduces the 
contamina-
tion of 
compost with 
non-
compostable 
plastics 
4 
2 
3 

Does not 
lead to 
increasing 
contamina-
tion 
(consumer 
confusion) 
5 
2 
4 

1 
2 
1 
1 
1 

2 
1 
3 

1 
5 
5 

1 
2 
1 
1 
1 

2 
1 
5 

1 
3 
3 

Wtd 
Score 

% of 
Max 
Score 

24 
47 

15 
27 
15 
15 
15 

30 
15 
43 

12 
50 
50 

25% 
73% 

6% 
31% 
6% 
6% 
6% 

38% 
6% 
65% 

0% 
79% 
79% 

8.6.2 

Key Conclusions    

Key Conclusions – Recommendations to reconcile theory and practice 

Reconciling theory and practice matters for two reasons. Firstly, a consumer who puts a 
plastic product labelled as suitable for home composting will expect to see that product 
disappear into the compost at the same speed as the rest of the material. If there is a 
clear discrepancy here then the trust in the labelling process will be undermined. 

156  

 
 
 
 
 
Secondly, any loophole in the testing procedure opens the way for exploitation of the 
labelling process by manufacturers who seek to bring to the market new products as 
compostable without concern for the end result. 

 This report makes three recommendations for approaches to address the discrepancies 
between existing frameworks and conditions to be found in practice. 

1.  Further Validation Testing in Home Composting Conditions 

As a way of strengthening the validity of the tests some products that currently pass 
existing tests may need to be further tested under less optimal conditions to see how 
this affects the biodegradation and disintegration processes. This would not need to be 
done for each product but would be a valuable validation exercise and may lead to 
changes in the testing regime for associated Standards. 
IN the same way, that residual microplastics are a concern in industrial composting the 
same is true for home composting. Additional testing of materials using soil as an 
inoculum would ensure that were compost to be used with fragments of plastic 
material remaining, consumers could be confident that the fragments would continue 
to biodegrade once used on the soil.  

2.  Refine the wording of the draft CEN standard on home composting   

This report recommends that the CEN standard describes more clearly the add-as-you-
go method whilst making explicit that this is likely to be a ‘cold composting’ process.  
This should include both a description of the range of abiotic conditions for which the 
test is deemed reliable (temperature, duration, pH, moisture), and related to this a set 
of practices which will ensure these conditions.  

3.   Clearer communication with the consumer 

Inevitably, however the testing and labelling is refined, there will be a need for effective 
communication with the consumer so that their expectations are in line with the 
applicability of the test and the quality of the compost is not undermined. 

•  Labelling should give the consumer an expectation of a time frame for the 

composting of the plastic material, which could be described relative to what 
they currently know of as a typical time frame in their own context. i.e. if in very 
cold climates it usually takes more than a full year for food waste to compost, 
this is also to be expected for plastic products labelled as compostable.  
It should be made clear that novel indoor composting practices are not suitable 
for the treatment of ‘compostable’ plastics.  

• 

•  Finally, for home composting labelling to function well it will need to be 
accompanied by a strong—possibly region specific—communication 
programme. Ultimately the responsibility for achieving this should not be placed 
solely on the certification bodies, but in collaboration with other levels of 
government, in particular national and local.  

157 

 
 
 
 
 
GETTING IN TOUCH WITH THE EU 

In person 

All over the European Union there are hundreds of Europe Direct information centres. 
You can find the address of the centre nearest you at: https://europa.eu/european-
union/contact_en 

On the phone or by email 

Europe Direct is a service that answers your questions about the European Union. 
You can contact this service: 

- by Freephone: 00 800 6 7 8 9 10 11 (certain operators may charge for these calls), 

- at the following standard number: +32 22999696, or 

- by email via: https://europa.eu/european-union/contact_en  

FINDING INFORMATION ABOUT THE EU 

Online 

Information about the European Union in all the official languages of the EU is 
available on the Europa website at: https://europa.eu/european-union/index_en 

EU publications 

You can download or order free and priced EU publications from: 

https://publications.europa.eu/en/publications. Multiple copies of free publications 
may be obtained by contacting Europe Direct or your local information centre (see 
https://europa.eu/european-union/contact_en ). 

EU law and related documents 

For access to legal information from the EU, including all EU law since 1952 in all the 
official language versions, go to EUR-Lex at: http://eur-lex.europa.eu  

Open data from the EU 

The EU Open Data Portal (http://data.europa.eu/euodp/en) provides access to 
datasets from the EU. Data can be downloaded and reused for free, for both 
commercial and non-commercial purposes. 

158  

 
 
 
 
 
 
 
 
 
 
 
 
 
 
Relevance of Biodegradable 
and Compostable Consumer 
Plastic Products and 
Packaging in a Circular 
Economy - APPENDICES 
For the European Commission DG 

Environment. Project conducted 

under Framework Contract No 

ENV.B.3/FRA/2017/005 

March – 2020 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Relevance of Biodegradable and 
Compostable Consumer Plastic 
Products and Packaging in a 
Circular Economy 

Appendices 

Simon Hann 

Rosy Scholes 

Star Molteno 

Mark Hilton 

Enzo Favoino 

Line Geest Jakobsen   

25th March 2020 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Report for European Commission, DG Environment 

Prepared by Simon Hann 

Approved by  

…………………………………………………. 

Mark Hilton 

(Project Director) 

Eunomia Research & Consulting Ltd 
37 Queen Square 
Bristol 
BS1 4QS 

United Kingdom 

Tel: +44 (0)117 9172250 
Fax: +44 (0)8717 142942 

Web: www.eunomia.co.uk 

Disclaimer 

Eunomia Research & Consulting has taken due care in the preparation of this report to 
ensure that all facts and analysis presented are as accurate as possible within the 
scope of the project. However no guarantee is provided in respect of the information 
presented, and Eunomia Research & Consulting is not responsible for decisions or 
actions taken on the basis of the content of this report. 

 
 
 
 
 
 
 
 
 
 
 
 
Contents 

APPENDICES ................................................................................................................. 6 

A.1.0 Biodegradable Plastics Market Additional Information ........................................... 7 

A.2.0 Coverage Assessment of Product Labelling Analysis ............................................. 11 

A.3.0 Compost Quality ..................................................................................................... 12 

A.4.0 Criteria Development ............................................................................................. 13 

A.5.0 Home Composting Additional Information ............................................................ 19 

A.6.0 Research and Knowledge Gaps .............................................................................. 30 

A.7.0 Stakeholder Engagement ....................................................................................... 31 

A.8.0 Stakeholder Workshops ......................................................................................... 34 

v 

 
 
 
 
 
 
APPENDICES 

6 

 
 
 
 
 
 
 
A.1.0  Biodegradable Plastics Market 

Additional Information 

A.1.1  Types of Certified Product 

It was found that TUV Austria certify approximately 1,400 products1, and DIN Certco 
have certified products for around 300 companies2. Due to the better granularity of the 
data available, the following section looks at products certified by TUV Austria; by end 
product type. As TUV Austria hold a significantly larger market share of biodegradable 
certifications, it is expected that this is representative of the certified market as a 
whole—this also provides an indication of the overall share of the market for each 
product group as one would expect that more certifications would be present for 
products that have a larger market share as these markets present greater 
opportunities. It should be noted that TUV Austria currently certify 995 (69%) products 
for industrial composting, 442 (30%) for home composting, 13 for soil biodegradability, 1 
for fresh water biodegradability and none for marine biodegradability (although it 
certifies 17 raw materials). Of the thirteen soil biodegradable products, ten are 
agricultural mulch films and the other three are unknown packaging or miscellaneous. Of 
the bags for the collection of organic waste, 36% are certified as home compostable. Of 
the certified shopping bags, 32% are certified as home compostable.  

1 TUV Austria: Certified Products, accessed 25 June 2019, http://www.tuv-at.be/certified-products/ 
2 DIN CERTCO - Companies with certified / registered products for ‘Products made of compostable 
materials’, accessed 25 June 2019, 
https://www.dincertco.tuv.com/search/companies_with_product?locale=en&starting_letters=A&title_id=
85 

7 

 
 
 
 
 
Figure 1: Share of TUV Austria certifications that are for flexible or rigid 
products 

As shown in Figure 1, 82% of products certifications are for flexible plastic, with 14% rigid 
plastic and the remaining 4% unknown.  

Figure 2 shows the share of TUV Austria certifications within catering and packaging by 
end product type (the two largest sectors after bags). This gives an indication of the 
number of certified products on the market. As shown, flexible packaging takes a large 
proportion of this, at 37%.  

Figure 2: Share of TUV Austria certifications for catering and packaging, by 
end product type 

8 

Rigid14%Flexible82%Unknown4%19%11%7%10%4%11%37%1%Trays & PlatesCupsCutleryCoffee pads, filters &capsulesOtherRigid packaging (food andnon-food)Flexible packaging (foodand non-food)Other 
 
 
 
 
 
 
A.1.2  Size of the European Market until 2029 - BAU 

A.1.2.1  Method 

Modelling has been undertaken to estimate the quantity of biodegradable plastics on 
the market within Europe. The data available for this modelling is very limited, as it is a 
relatively new research area. Assumptions have been made to make the modelling 
possible; limitations of the analysis are discussed in section A.1.2.3.  

The model uses the global market value in 2016, the growth rate between 2017 and 
2018 as reported by European Bioplastics3 and the European market share in 2016 to see 
how the market value in Europe until 2029 could look in a business as usual (BAU) 
scenario assuming no specific changes to the current policy framework. This scenario is 
therefore not necessarily a prediction of how the market is likely to look in the future. 

•  The global market value in 2015 was reported to be $2.1 billion4; 
•  Growth at 3.05% (as between 2017 and 2018); and 
•  The European market share in 2016 was reported to be 35-40%5. 

Key assumptions were as follows: 

1)  The compound annual growth rate (CAGR) value remains constant between 2014 

and 2029; and 

2)  Europe consistently holds 35-40% of the market over the aforementioned period. 

A.1.2.2  Results - BAU 

A scenario for the value and size of the biodegradable plastics market until 2029 is as 
shown in Figure 3. As shown, this analysis demonstrates that the European market could 
reach a value of roughly €1 billion by 2029 in a BAU scenario. This would have significant 
implications for the bio-economy in Europe. In this BAU scenario, it is calculated that the 
quantity of scope biodegradable plastics on the market could reach over 360 ktonnes by 
2029; almost twice what is currently on the market from the estimates made for this 
study. It is clear that there are also many additional variables that will affect the market 
and therefore, this scenario should not be considered a forecast of the likely market. 

3 European Bioplastics (2018) Bioplastics Facts and Figures 2018 
4 Biodegradable plastics - Global Market Outlook (2016-2022), accessed 17 May 2019, 
https://www.strategymrc.com/report/biodegradable-plastics-market 
5 Biodegradable plastics - Global Market Outlook (2016-2022), accessed 17 May 2019, 
https://www.strategymrc.com/report/biodegradable-plastics-market 

9 

 
 
 
 
 
 
Figure 3: Value and Size of the Biodegradable Plastics Market in Europe, 
2014 to 2029 

A.1.2.3 

Limitations 

This analysis shows enormous growth to 2029 in the business as usual scenario; a result 
that should be treated with caution. Although this scenario is based on the data 
available, this result has many limitations and is not necessarily a prediction of how the 
market will look in the future.  

The assumption that Europe consistently holds 35-40% of the market over this period is 
unlikely to be the case, as it has been said that the European market is seeing the most 
growth for biodegradable plastics.6 As this relative growth has not been quantified, it is 
difficult to project how this may influence absolute quantities on the European market. 

It has also been assumed that the growth of the biodegradable plastics production 
capacity increases at a rate of 3%. This figure is based on the change in production 
between 2017 and 2018, and although it has been confirmed by stakeholders, it is not 
definitely representative of the growth of the market as a whole. It is a very limited data 
period to use to project for the following ten years, and there are bound to be 
fluctuations in the market.  

6 European Bioplastics (2018) Bioplastics Facts and Figures 2018 

10   

 
 
 
 
 
 
 
The biodegradable plastic production capacity figure used as a starting point for the 
analysis is based on data that is largely variable, as outlined previously the market is 
extremely difficult to trace due to the relative size of businesses consuming these 
biodegradable end products. 

Finally, it is also important to recognise that there are various unpredictable market 
drivers that may have a huge negative or positive effect as outlined in the main report. 

A.2.0  Coverage Assessment of Product 

Labelling Analysis 

The sample by country is shown in Table 1. The labelling assessment is skewed slightly 
towards German products; however, this was not deemed to affect the results – German 
products did not seem to show particularly good or bad practice in comparison to 
products from other nations. 

 The sample by market segment is shown in Table 2. As shown, a large sample of carrier 
bags was assessed, however only a small sample of organic waste bags.  

Table 1: Sample for labelling assessment by country 

Country 

UK 
Italy 
Germany 
France 
Expected on whole European market 
Other 

Table 2: Sample for labelling assessment by market segment 

Market segment 

Packaging  

Carrier bags 
Organic waste bags 
Other 

Agriculture and horticulture 
Consumer goods 
Other 

No. in sample 

10% 
21% 
28% 
14% 
28% 
0% 

No. in sample 

31 
15 
3 
13 
0 
3 
0 

11 

 
 
 
 
 
 
 
A.3.0  Compost Quality 

Table 3: Compost Physical contaminants: maximum allowable 
concentrations in various EU Countries (only thresholds that may concern 
plastics are reported) 

Country 

Impurities 

Mesh size 

Limit values 
(w/w % dry matter) 

>2mm 

>5mm 

>2mm 

<0.5% 
<1% 
<2% 

<0.2% 
<0.4% 
<1% 

<0.5% 

<2% 

<0.5% 

<3% 

<0.3% 

<0.5% 

<0.5% 

<0.5% 

<0.5% 
<0.15% 

<0.5% 
<0.25% 

<0.5% 
<0.3% 

Austria 

Total 
(agriculture) 
(land reclamation) 
(technical use) 

Plastics 
(agriculture) 
(land reclamation) 
(technical use) 

Belgium  

Total  

Czech 
Republic 

Total 

Germany 

Glass + plastics + metals 

Spain 

France 

Ireland 

Italy 

Total  

Plastic films  

Total  

Glass + plastics + metals  

Netherlands  

Total  

Denmark 

United 
Kingdom 

Total 
Plastics 

Total 
(herein included plastics) 

EU Fertilisers 
Regulation  

Glass + plastics + metals 
(any of the foregoing) 

Source: JRC 

12   

 
 
 
 
 
 
 
 
A.4.0  Criteria Development 

A.4.1  Criteria Taken forward 

Criterion 

Proposed 
by 

Detail/Premise 

Can it be measured/ 
defined accurately? 

Is the current Evidence 
Robust? 

Further 
evidence/research  

Effective organic 
waste collection, 
sorting and 
treatment 
infrastructure in 
place that 
accepts 
compostable 
plastic 

FEAD, 
Syctom, 
German 
waste 
associations, 
Suez 

Composters/AD 
operators have 
identified issues such as 
the materials not fully 
biodegrading and 
compostable plastics 
being incompatible with 
machinery   

Yes – Effective 
biodegradation can be 
assessed through 
compositional studies in 
composting plants, but at a 
practical level, if the 
process does not reflect the 
conditions set out in EN 
13432 it is likely to be 

problematic.    

Mixed – some countries (Italy) 
have studied this more than 
others, but evidence is mostly 
anecdotal. It is clear that many 
countries use an AD process 
with no secondary composting 
stage which makes full 
biodegradation challenging.   

Determining whether it is 
beneficial to 
change/improve 
infrastructure to better 
accept compostable plastics 
and how this can be 
financed (potentially 
through EPR)  

13 

 
 
 
Criterion 

Proposed 
by 

Detail/Premise 

Can it be measured/ 
defined accurately? 

Is the current Evidence 
Robust? 

Further 
evidence/research  

The product in 
its entirety must 
meet EN 
Standards for 
composting of 
packaging or 
plastic products 

The correct 
waste 
management 
route is clearly 
identifiable for 
the 
consumer/user 

FEAD 

The requirement to 
meet appropriate EN 
(or country equivalent) 
standards for 
composting in an 
industrial setting. The 
standard includes 
requirement that the 
entire product designed 
to be compostable 
material. 

Yes – the standard(s) 
require specific tests with a 
pass/fail criteria 

Yes – the requirement for a 
test to verify performance is 
undisputed. The nature of 
these tests is sometimes 
questioned. 

There is some merit in 
addressing the discrepancy 
between the standards and 
the typical practice to make 
them more representative  

FEAD, 
Syctom 

Packaging displays clear 
and unambiguous 
instructions that allow 
the householder to 
dispose of correctly in 
the   

Challenging – currently this 
message will be different 
between countries and 
within countries 

The term 
’biodegradable’ 
should not be 
used 

German 
waste 
associations, 
Suez 

Identifies that the term 
is confusing for 
consumers and may 
lead to littering or other 
incorrect disposal. 

Yes – terminology can be 
defined and set as a 
requirement. 

14   

No – there are no significant 
and well documented and 
successful trials. Current 
information is often mixed in 
its message. Labelling schemes 
associated with composting 
test standards are generic and 
non-instructive   

This needs to be 
approached in tandem with 
the waste management 
system. Determining the 
extent to which information 
can be generic will be 
important. 

Limited – evidence for 
consumer behaviour in 
response to terminology is 
lacking. Nevertheless, it is clear 
that current ambiguity will lead 
to confusion.  

Research into consumer 
expectations in relation to 
terminology may help to 
strengthen labelling and 
communication. 

 
 
 
Criterion 

Proposed 
by 

Detail/Premise 

Can it be measured/ 
defined accurately? 

Is the current Evidence 
Robust? 

Further 
evidence/research  

Compostable 
plastic should 
not be mixed 
with other non-
compostable 
materials 

If the use of 
compostable 
plastic reduces 
non-
biodegradable 
plastics in 
organic waste 
collection 

If there is a low 
likelihood of 
item being 
effectively  
recycled 
(recycling 
prioritised over 
composting) 

Project team 

Products containing 
compostable material 
should not contain any 
non-compostable 
material especially if it 
cannot be separated – 
this is already a 
prerequisite of EN 
13432 

Yes – this can be a defined 
rule to back up EN 13432 
unless the standard is 

mandatory.    

Yes - Although this is a 
requirement in EN 13432 it is 
important enough to highlight 
on its own. 

None 

EUBP 

The effect of 
compostable plastics 
reducing contamination 
in compost from 
conventional plastic.  

Challenging – 
Compositional studies in 
composting plants can be 
used, but isolating cause 
and effect is difficult. 

Limited – evidence base is built 
on biowaste bags with no 
other examples of other 
products having the effect.  

Identify and verify 
examples beyond biowaste 
bags where this effect also 
occurs 

EUBP, FEAD 

The notion that 
recycling (mechanical, 
chemical) is more 
beneficial and better 
reflects the principles of 
circular economy than 
composting of plastics 

Challenging – this links to 
ongoing work on defining 
and measuring what can be 
considered ‘recyclable’  

Mixed – LCA results suggest 
that recycling is beneficial, but 
assumptions around the 
benefit gained from recycling 
are often exaggerated  

Whilst virgin material 
replacement recycling can 
be considered circular, 
other less beneficial 
applications (downcycling) 
may be similar to 
composting. Determining 
the cut-off point will be 
important.   

15 

 
 
 
Criterion 

No reusable 
solutions 
available 

Proposed 
by 

Detail/Premise 

Can it be measured/ 
defined accurately? 

Is the current Evidence 
Robust? 

Further 
evidence/research  

EUBP 

A focus on the waste 
hierarchy where reuse 
should be prioritised. 

Challenging – there are 
reusable solutions for 
almost all products 

Yes – Evidence for reuse is 
strong and a key tenet of EU 
waste policy 

Products could be identified 
on a case-by-case basis 
using LCA to determine the 
best option  

Bring 
‘environmental 
benefits’ 

FEAD 

The concept that the 
net environmental 
impact is beneficial 

Yes – through the use of 
LCA this can be achieved, 
but the study should use 
system expansion and/or 
appropriate function unit to 
account for the full life 
cycle including any ‘co-

benefits’   

Mixed – many products appear 
on the market without the 
requirement for and LCA in 
order to exist. This 
requirement should not just be 
for compostable plastic.  

Investigate incorporating 
this into the ‘Essential 
Requirements’ in order to 
subject all packaging to this 
criterion.  

Table 4: Rejected Criteria 

Criterion 

Proposed 
by 

Detail/Premise 

Can it be measured/ 
defined accurately? 

Is the current Evidence 
Robust? 

Reason for 
Removal 

Compostable 
plastics are at 
least partly made 
from renewable 
materials 

German 
waste 
associations 

The proposition that bio-based 
plastic can be the best 
environmental option 
depending upon the lifecycle 
of the product  

Yes – there are several 
methods/labels for verifying 
this. 

Mixed – making plastic from 
biomass is not always 
preferable and not a 
prerequisite for being 
compostable. Conventional 
plastic also does not have this 
requirement imposed. 

The original 
proposition can be 
best incorporated 
into a criterion 
ensuring 
‘environmental 
benefit’ 

16   

 
 
 
 
Criterion 

Proposed 
by 

Detail/Premise 

Can it be measured/ 
defined accurately? 

Is the current Evidence 
Robust? 

Reason for 
Removal 

Use only in 
packaging which 
are ‘rapidly 
consumed’ 

Absence of 
suitable/available 
‘natural’ 
compostable 
materials 

If compostable 
and non-
compostable 
plastics exists 
within the same 
product group  

Syctom 

Possibility of specifying 
material which biodegrades in 
a shorter timeframe as it does 
not require a long shelf-life 

Challenging – defining a 
limit for ‘rapidly consumed’ 
may be difficult   

Project 
team 

The premise that other natural 
material such as paper avoids 
some of the problems 
associated with compostable 
plastic (e.g. will fully 
biodegrade, not leave 
microplastic residue and does 
not confuse consumers)  

Challenging –defining 
whether an alternative is 
‘suitable’ will be open to 
interpretation unless 
specific product groups are 
highlighted.  

Syctom 

In order to reduce consumer 
confusion and the potential to 
normalise putting plastics in 
organic collection.  

Yes – product groups can be 
identified and defined 

Poor - The conditions for 
composting (biodegradation) 
do not generally exist on a 
shop shelf, therefore the 
premise of this criterion may 
be flawed 

Mixed – evidence from LCA is 
often contradictory with 
regard to the (GHG) impacts 
of paper compared with 
alternatives. There is no 
evidence that newspaper is 
problematic (toxic) in 
composting. 

Irrelevant is the 
product already 
meets EN13432 and 
the composting 
process is sufficient. 

Adopting a material 
neutral approach   

Mixed – mostly anecdotal, but 
also it is logical to assume 
identical products that 
require different waste 
streams will cause confusion   

Will be combined 
with – “If the use of 
compostable plastic 
reduces non-
biodegradable plastics 
in organic waste 
collection” 

17 

 
 
 
Criterion 

Proposed 
by 

Detail/Premise 

Can it be measured/ 
defined accurately? 

Is the current Evidence 
Robust? 

Reason for 
Removal 

Compostable 
material is not 
used in products 
that contain or 
come into 
contact with 
human or animal 
waste 

The product is 
contaminated 
with food  

Project 
team 

These sorts of contaminants 
need specialised collection 
and facilities to process – high 
volumes in conventional 
composting may be 
problematic.  

Yes – products can be well 
defined and categorised  

Yes – products such as 
nappies are already used in 
high volumes that could 
significantly change the 
nature of composting and 
affect compost quality (not 
meet standards)   

This can be covered 
by other criteria 
focusing on not 
having detrimental 
effects in composting. 

EUBP 

Food contamination increases 
likelihood that the consumer 
will dispose of it in organic 
waste and reduced ability to 
(mechanically) recycle the 
material.  

Challenging – defining the 
cut-off point where a certain 
level of contamination will 
mean that one material is 
more suitable than another 
is difficult. 

Mixed – as above the link 
between food contamination 
and plastic items being placed 
in organic waste is not fully 

established    

Integrated with other 
criteria 

‘Semi-rigid’ 
compostable 
plastics are only 
suitable for 
‘closed’ systems 

EUBP 

In this context a ‘closed’ 
system is defined as 
application in catering where 
the material is collected and 
processed separately. Rigid or 
‘semi-rigid’ compostable 
plastics will break down 
slower and also may be 
confusing for consumers 
therefore commercial 
applications are potentially 
more suitable.  

18   

Yes – products can be well 
defined and categorised  

Yes – closed systems have 
been demonstrated to work 
as a partnership is formed 
with the waste operator.  

Integrated with other 
criteria 

 
 
 
A.5.0  Home Composting Additional 

Information 

A.5.1  Conditions Found in Home Composting 

A.5.1.1 

Temperature  

Temperature in the home composting system is a key variable with regard to the 
biodegradation of plastics and it is important to understand the relationship between 
the temperature in a compost pile and the ambient temperature.  

The studies analysed have assessed home composting within a range of climatic 
conditions with ambient temperatures ranging from -15°C 7 to 36°C 8. Across the studies 
it is reported that compost temperatures remain consistently higher than ambient 
temperature by few degrees (2-10°C). Figure 4 shows the temperature profile for a 
home composting system that was fed for an initial period of two weeks and then left. It 
can be seen that the temperature in the compost follows ambient temperature closely, 
but in the initial feed stage higher composting temperatures are reached as microbial 
activity intensifies. A similar temperature profile is seen in the ADEME study series 1, 
with the temperatures in the compost pile rising significantly above the ambient 
temperature for the first 3 months, then following ambient levels. (See Figure 5) This is 
the result of the intense microbial activity in this early stage which occurs despite the 
low ambient temperatures of below 5oC which were present at the beginning of the 
study. The temperature profile also shows that after that initial peak of microbial activity 
the compost pile temperature reduces and begins to closely track the ambient 
temperature after around month three as the compost matures. 

In four of the eight studies analysed, cold composting is in evidence with temperatures 
not reaching the 45°C needed for the thermophilic phase. Four of the studies, including 
the ADEME study, reported peak temperatures in excess of 55°C but it is not clear if 
these temperatures were sustained for long enough to allow for a thermophilic phase. 
The low peak temperatures do not seem to have affected the quality of the compost as 
measured in these studies.  

7 Ermolaev, E., Sundberg, C., Pell, M., and Jönsson, H. (2014) Greenhouse gas emissions from home 
composting in practice, Bioresource Technology, Vol.151, pp.174–182 
8 Guidoni, L.L.C., Marques, R.V., Moncks, R.B., Botelho, F.T., da Paz, M.F., Corrêa, L.B., and Corrêa, É.K. 
(2018) Home composting using different ratios of bulking agent to food waste, Journal of Environmental 
Management, Vol.207, pp.141–150 

19 

 
 
 
 
 
Figure 4: Home composting temperature profile - relation to ambient 
temperatures 

Source: Guidoni 2018 

Figure 5: Temperature profile of home composting in ADEME 2019 study 

Source: DeWolfs et al (ADEME) 2019 

20   

 
 
 
 
 
The studies found that larger feeding loads and more frequent feeding raised the peak 
temperatures attained. 9 This would indicate that changes in composting practice can be 
used to balance the differences in ambient temperature across different regions, 
suggesting that even with the extremes of climatic conditions found in Europe home 
composting is a viable means for dealing with organic waste.  

Figure 6 shows a comparison between the temperature profile of a compost system kept 
outdoors on a university campus fed according to a regular regime, with a home 
composting system serving a multi-occupancy house in Italy with an irregular feeding 
regime. 10 The regularly fed pile (left image in figure) shows a classic temperature 
pattern, with a well-defined thermophilic phase, with temperatures above 45°C for 60 
days. A much more varied profile is evident in the irregularly fed pile, illustrating the 
practice of ‘cold composting’ with temperatures closely following ambient temperatures 
and the peak temperature only briefly reaching 37°C. However, this pile still maintains a 
temperature sufficient to allow mesophilic microbial activity (>20oC) for the majority of 
the time.  

Figure 6: Home composting temperature profiles showing variability  

Source: Tatano et al. 2015 

•  Temperature range recorded within compost pile across all studies ranged 

from 5-70°C 

•  Only 4 out of 8 studies showed temperatures reaching above 45°C – 

necessary for thermophilic bacteria to thrive.  

9 Guidoni, L.L.C., Marques, R.V., Moncks, R.B., Botelho, F.T., da Paz, M.F., Corrêa, L.B., and Corrêa, É.K. 
(2018) Home composting using different ratios of bulking agent to food waste, Journal of Environmental 
Management, Vol.207, pp.141–150 
10 Tatàno, F., Pagliaro, G., Di Giovanni, P., Floriani, E., and Mangani, F. (2015) Biowaste home composting: 
Experimental process monitoring and quality control, Waste Management, Vol.38, pp.72–85 

21 

 
 
 
 
 
 
 
A.5.2  Moisture 

Compost needs to remain moist but not overly so. Excessive moisture content can inhibit 
activity of microbes as it can reduce air-filled pores limiting the flow of oxygen that 
microbes depend on. It can also impede the necessary temperature development.11,12 
Equally problematic is a lack of moisture as the microbes will die or go dormant if the 
compost dries out too much.  There is little evidence for what the microbial tolerance 
limits are with regard to moisture.  
Tatano et al studied the moisture profile of four different home composting practices in 
Italy. The study found a gradual decline of moisture which was indicative of the progress 
of the composting practice.13 The starting moisture content differed between practices, 
but followed a similar decline; the authors offer no reason for the observed differences 
between practices. 

•  Most of the studies did not record the moisture levels during the composting 

process, recording only the final moisture content.  

•  This ranged from between 22% to 85%.  

A.5.3  Ratio of Carbon to Nitrogen  

C/N values are determined by the balance of green and brown input materials and 
decline over time as the nitrogen becomes concentrated in the compost. It is difficult for 
a home composter to assess these levels but a foul smell will indicate an imbalance.  

The balance of Carbon to Nitrogen affects the rate of decomposition as the 
microorganisms require the correct proportion of carbon for energy and nitrogen for 
protein production. If there is too much carbon the composting rate will slow and if 
there is too much nitrogen it will be released in the form of ammonia (NH3) – which has 
a distinctive smell and is an indicator of the mix being incorrect. A C:N ratio of 25-30:1 is 
deemed ideal,14 with higher values potentially slowing down the rate of decomposition.   

11 Tatàno, F., Pagliaro, G., Di Giovanni, P., Floriani, E., and Mangani, F. (2015) Biowaste home composting: 
Experimental process monitoring and quality control, Waste Management, Vol.38, pp.72–85 
12 Guidoni, L.L.C., Marques, R.V., Moncks, R.B., Botelho, F.T., da Paz, M.F., Corrêa, L.B., and Corrêa, É.K. 
(2018) Home composting using different ratios of bulking agent to food waste, Journal of Environmental 
Management, Vol.207, pp.141–150 
13 Tatàno, F., Pagliaro, G., Di Giovanni, P., Floriani, E., and Mangani, F. (2015) Biowaste home composting: 
Experimental process monitoring and quality control, Waste Management, Vol.38, pp.72–85 
14 Home Composting Made Easy The Carbon/Nitrogen Ratio, accessed 26 June 2019, 
http://www.homecompostingmadeeasy.com/carbonnitrogenratio.html 

22   

 
 
 
 
 
 
•  Across the studies surveyed C:N ratios ranged from 10:1 to 66:1, though only 

three studies reported on this directly. 

A.5.4  pH value  

The pH level of compost changes as composting proceeds as the organic acids produced 
in early stages become neutralised as the compost matures. Compost organisms can 
grow and multiply within the pH range of 5.5 to 8, 15 Tatano et al tested the pH profile of 
4 home composting conditions using commercial compost standards as the guides to pH 
range. Only one treatment condition showed pH values above 8, indicating that for most 
of the conditions, pH levels were within the bounds of acceptability.16 

•  The final pH levels across these studies ranged from 5.9 to 9.28 

15 pH measurement of compost, accessed 28 June 2019, http://www.carryoncomposting.com/416920214 
16 Tatàno, F., Pagliaro, G., Di Giovanni, P., Floriani, E., and Mangani, F. (2015) Biowaste home composting: 
Experimental process monitoring and quality control, Waste Management, Vol.38, pp.72–85 

23 

 
 
 
 
 
 
 
Table 5: Composting conditions recorded in reviewed studies 

Author, 
date 

Country 

Study 
focus 

Container 
capacity 

Feed 
materials 

Weekly 
weight 
of feed 

Ratio 
of 
green 
to 
brown 

Mixing 
frequency 

Ambient 
temperat
ure range 

Temperat
ure range 
in 
compost 

final 
C:N 
ratio 

final pH 

final 
moisture 
content 

Time 
period 

Andersen,
2011 

Denmark 

greenhouse 
gas emissions 
from home 
compost 

Arigoni, 
2018 

Argentina 

layering 
effects in cold 
climate 

320L 

kitchen 
waste, no 
meat or 
dairy some 
garden 
waste 

500L 

kitchen and 
green waste 
and pine 
shavings 

2.6-3.5kg  

 23:1  

no 
mixing/every 
week/ every 5 
weeks   

0-20°C 

peaked at 
27°C 
Cold 
composting  

15-17:1 

not 
reported 

not 
reported 

1 year 

45kg 

1.5:1 

no 

0-15°C  

5-70°C 

no data 

6.5-8.8  

no data 

8 months 

Ermolaev, 
2014 

Sweden 

greenhouse 
gas emissions 
from home 
compost 

115L to 345L 

 83% food 
waste 

1.61kg to 
4.97kg  
(seasonal 
variation) 

4:1 

range from 
none to  every 
5 days 

-15°C -29°C 

on average 
8°C degrees 
above 
ambient Cold 
composting 

not 
reported 

7.20 

 28% to 85% 

1 year 

Guidoni, 
2018 

Brazil 

green to 
brown ratios 

50L 

food waste 
and rice 
husks 

4kg / 4.6kg 
and 5.1 kg 

30:70, 
50:50 
and 
70:30 

no data 

20-36°C 

20-40.5°C 
Cold 
composting  

66:1  8.21 - 9.28 

43% to 68% 

60 days 

24   

 
 
 
Klauss, 
2004 

Germany  

different 
containers 

500L 

organic 
waste 

Varied 

no data 

no 

12-15°C  

peaked at 
55°C 

not 
reported 

"neutral" 

 22% to 67% 

12 
months 

Lleo, 
2013 

Spain 

Tatano , 
2015 

Italy  

home 
composting 
and 
vermicompost
ing 

in-situ home 
compost and 
simulated 
home 
compost 

300L 

Kitchen 
waste and 
garden 
waste 

300L 

Kitchen 
waste and 
garden 
waste 

6.8kg 

2.47:1 

 mixing when 
feeding 

5-30°C  

peaked at 
55°C  

not 
reported 

5.90 - 8.97 

50.3% 

7 months 

5.5kg 

no data 

no data 

0-28°C 

8-58°C  

averages 
not 
reported.  

averages 
not 
reported.  

averages 
not 
reported.  

7-13 
months 

Vazquez, 
2017 

Spain 

efficiency of 
home 
composting  

340L and 
350L 

food waste 
including 
meat and 
fish 
leftovers 

no data 

no data 

no data 

no data 

7-35°C 
Cold 
composting 

10 to15:1 

no data 

68.1% 

1 year 

25 

 
 
 
 
A.5.5  Home Composting Supplemental Tables 

Table 6: Comparison of national composting advice 

Country 

Organisation 
providing info 

Description of 
Organisation  

Compost method 

Site 

Size of 
container 

Green and 
Brown ratio 

Meat and 
fish?  

Turning? 

How to 
regulate 
moisture 

BEL 

Brussels 
Environment 

Government 
Body  

Multi container 
method 

Easy access, 
semi-shaded, 
flat   

multi 
container or 
200L 

50:50 

No 

Once or twice a 
week  

water as 
needed 

ESP 

Zero Waste 
Europe 

NGO. No 
national level 
organisation. 

Multi container 
method - for 
community 
composting 

close to 
residents 

4 modules to 
allow 
maturation 
phase plus 
storage of 
bulking agent 

no 
specification, 
monitoring 
moisture levels 
is key 

Yes, 
inclusion is a 
benefit 

essential 

squeeze test 

FIN 

FRA 

Päijät-Häme 
Waste 
Management 
Ltd (PHJ) 

Waste 
Management 
company 

ADEME and 
Reseau compost 
citoyen. 

National 
Government 
Body 

Unclear 

Unclear 

Semi shaded, 
flat, easy to 
get to 

200L with 
insulation 

70:30 

Yes 

not needed 

water 
frequently 

Semi-shaded, 
flat and 
drained 

400L 

70:30  
in shared 
composter 
50:50 

Yes 

Yes 

squeeze test 

UK 

WRAP 

National 
Government 
Body 

Unclear 

on soil 

200-300L 

50:50 

No 

Not essential but 
recommended if 
having issues 

squeeze 
test, adjust 
by adding 
more greens 

26   

 
 
 
PRT 

Lisbon city 
chamber 

City Authorities 

Describes batch 
compost method  

Semi-shaded, 
water source 
nearby 

no mention 
but image of 
200L bin 

50:50 

no 

Not mentioned 

squeeze test 

27 

 
 
 
Table 7: ISO tests for biodegradation of plastic materials 

Test number 

Title 

Description and key features 

ISO 14851 

ISO 14852 

Determination of the ultimate aerobic 
biodegradability of plastic material in an 
aqueous medium - Method by measuring the 
oxygen demand in a closed respirometer 

Testing is done in aqueous medium 

Biodegradation measured by consumption of 
Oxygen 

2 months duration 

Determination of the ultimate aerobic 
biodegradability of plastic materials in an 
aqueous medium - Method by analysis of 
evolved carbon dioxide 

ISO 14855-1 

Determination of the ultimate aerobic 
biodegradability and disintegration of plastic 
material under controlled composting 
conditions - Method by analysis of evolved 
carbon dioxide 

Testing is done in aqueous medium 

2 months duration 

Biodegradation measured by analysis of 
evolved carbon dioxide 

Testing using a compost inoculum 

6 months max, 58°±2°C, pH 7.0-8.0, C/N 10-
40 

Biodegradation measured by conversion of 
carbon 

ISO 14855-2  

as above - Part 2: Gravimetric 
measurement of carbon dioxide evolved in a 
laboratory-scale test (ISO 14855-2) 

As for 14855-1 but with different way of 
measuring conversion of carbon 

ISO 17556 

Determination of the ultimate aerobic 
biodegradability in soil by measuring the 
oxygen demand 

Testing using a soil inoculum 

6 months max, 20-28°C 

Biodegradation measured by consumption of 
Oxygen 

Table 8: ISO tests for disintegration of plastic materials  

Test number 

Title 

Description and key features 

ISO 16929 

Determination of the degree of 
disintegration of plastic materials 
under defined composting conditions 
in a pilot-scale test" 

Materials tested in 5x5cm or 10x10cm pieces in pilot 
scale composting using biowaste mixture 

Temp can rise to 65°C naturally, 

12 weeks duration, C/N 20-30, pH >5 

Sample then sieved through 10mm and 2mm sieve 

ISO 20200: 
2015 

Plastics - Determination of the degree 
of disintegration of plastic materials 
under simulated composting 
conditions in a laboratory-scale test" 

Qualitative assessment of disintegration 

58 ±2°C for max 90 days, if not sufficient, then 
continue at room temp for max 90 days 

28   

 
 
 
 
 
 
Table 9: Summary of studies testing plastic biodegradation in home 
composting 

Author, 
date 

Materials tested 

Country 

Duration 
of study 

Reported 
Biodegradation 

Dewolfs et 
al 2019 
(ADEME) 

Bag X – 90% PBAT, 9% 
PLA, 1% green dye 
Bag Y – 70% PBAT, 30% 
starch 

France 

18 
months 

Visual inspection of 
biodegradation using TEM.  
The bag containing 9% PLA (bag 
X) showed a lower 
biodegradation than bag Y 

Adamcova 
et al, 2016 

HDPE mixed with TDPA 
additive/ PE and d2W 
additive  

Czech 
Republic 

12 weeks 

HDPE + TDPA – 0% 
PE + d2w – 0% 

Klauss, 
2004 

Starch based FARD bags  
Starch based TPSS trays  
Mater-BI  
Bioplast GF 102/13  
PLA  

Germany 

52 weeks 

Starch based FARD bags – 
complete degradation in 120 
days 
Starch based TPSS trays – 88-95% 
Mater-BI – 40-77% 
Bioplast GF 102/13 bags – 50-
76% 
PLA - no measurable degradation 

Mater-BI /EPI 

Mauritius 

10 weeks 

Mater-BI – 26.9% 
EPI – 0% 

PLA film 

Greece 

47 weeks 

“Low degree of disintegration” 

Mohee, 
2008 

Rudnik and 
Briassoulis, 
2011 

Song, 2009 

PLA 
PP(A), PP(B), PP(B)+, 
starch/PP, Mater-Bi 

UK 

24 weeks 

Vaverkova, 
2014 

9 plastic bag samples 
that are labelled as 
‘compostable’ 

Czech 
Republic 

12 weeks 

PLA, PP(A), PP(B), PP(B)+, 
starch/PP, Mater-Bi – all had 
negligible mass loss of < 5%  

Visual evaluation of 
disintegration – no changes 
observable except for bag made 
from starch 

29 

 
 
 
 
 
 
 
 
A.6.0  Research and Knowledge Gaps 

The following is a summary of the key knowledge gaps and potential research needs that 
have been identified throughout this study: 

•  Market data by product type and geographic region is generally outdated and 
would benefit from an update to determine where the perceived increase in 
interest in compostable plastics has resulted in market increases in recent years. 

•  Under the Fertiliser Regulation it is clear that fertiliser such contaminated with 

compostable plastics residues could be exported and used in other EU countries. 
The risk of this is not entirely clear for fertiliser from digestate as the Regulation 
stipulates several process types that are suitable (including an option of 
secondary maturation), but these are all focused on eliminating pathogens in the 
digestate and not on successful biodegradation of plastics. Further testing under 
each one of the processes identified in the regulation would be required to verify 
this. 

•  Changing compostable plastic Standards (EN 13432) to reflect all industrial 

composting and AD practises is impractical and therefore it is recommended that 
Member States conduct their own trials to determine whether the Standard is fit 
for the purpose of verifying that compostable plastics perform as required 
(noting that ‘performance’ is a relative term that will be dictated by the local 
process and compost quality requirements). This will help in determining 
whether they should accept compostable plastics or not in their biowaste 
treatment facilities and what changes need to be made to do so in the future (if 
desirable).  

•  Generally, Life Cycle Assessment (LCA) studies are inconclusive and often have 

conflicting results for both comparisons between different compostable 
materials and bio-based or fossil feedstocks. Methodologies for assessing the end 
of life for compostable plastics and the production impacts of bio-based plastics 
require further development to enable accurate and fair comparisons. 

•  As a way of strengthening the validity of the standard tests for home 

compostable plastics, some products that currently pass existing tests may need 
to be further tested under less optimal conditions to see how this affects the 
biodegradation and disintegration processes. This would not need to be done for 
each product, but would be a valuable validation exercise and may lead to 
changes in the testing regime for associated standards. 
In the same way that residual microplastics are a concern in industrial 
composting, the same is true for home composting. Additional testing of 
materials using soil as an inoculum would ensure that were compost to be used 
with fragments of plastic material remaining, consumers could be confident that 
the fragments would continue to biodegrade once used on the soil.  

• 

30   

 
 
 
 
A.7.0  Stakeholder Engagement 

Company 

Method of 
engagement 

Topics discussed 

European 
Bioplastics 

Workshop, 
interview, 
consistent 
engagement 

Nova 
Institute 

Workshop, 
email 
discussions 

BBIA 

Inter
view 

BASF 

Interview, 
workshop 

•  Applications and suitability of compostable 
plastics for applications 

•  Most common applications on the market 
•  Proportion of market that is certified 
•  Past and current quantity of products on the 

global market 

•  Market within Europe 
•  Future quantity of products on the market 

•  Requested images of labels from across 
European market  

•  Applications and suitability of compostable 

plastics for applications 

•  Most common applications on the market 
•  Past and current quantity of products on the 

global market 

•  Future quantity of product son the market 

•  Current market, incl. product types most 

commonly found on the market. 

•  Future market for biodegradable and 
compostable plastics, incl. expected size, type 
of plastics (incl. innovations) and product 
types. 

•  Current market, incl. product types most 

commonly found on the market. 

•  Future market for biodegradable and 
compostable plastics, incl. expected size, type 
of plastics (incl. innovations) and product 
types. 

31 

 
 
 
 
 
•  Current market, incl. product types most 

commonly found on the market. 
•  Future market for biodegradable and 

compostable plastics, incl. expected size, type 
of plastics (incl. innovations) and product 
types. 

•  Labelling and communication on products. 

•  General discussion around certified vs non-
certified products on the market. 

•  Current market, incl. product types most 

commonly found on the market. 

•  Future market for biodegradable and 
compostable plastics, incl. expected size, type 
of plastics (incl. innovations) and product 
types. 

•  Size of the market within Europe. 
•  Most common applications. 
•  Future market for biodegradable and 

compostable plastics, incl. expected size, type 
of plastics (incl. innovations) and product 
types. 

•  Labelling and communication on products 

•  Discussion around number of products 
certified on the market, how certifications are 
audited and what happens with non-
conformances (no numerical data obtained) 

•  Discussion around number of products 
certified on the market, how certifications are 
audited and what happens with non-
conformances (no numerical data obtained) 

•  Requested images of labels from across 
European market 

•  Positions of EU Composting Industry on 

compostable plastics  

•  Possible Concerns on quality of end products  
•  Niche applications (“closed loops”) vs. 

widespread use 

Novamont 

Interview, 
workshop 

Natureworks 

Interview, 
workshop 

Vegware 

Interview 

Workshop, 
email 
discussions 

Workshop, 
email 
discussions 

Workshop, 
email 
discussions 

Interview, 
workshop 

Din Certco 

TUV Austria 

DUH 
Germany 

Marco Ricci
ECN – 
European 
Compost 
Network 

32   

 
 
 
 
•  Use of compostable bags in Copenhagen 
•  Fate of compostable plastics after 

Interview, 

pretreatment  
Influence on compost quality 

• 

•  Trials on compostable plastics in home 
composting systems (not yet available) 

Interview 

•  Fate of compostable plastics during 

composting   

Interview 

Interview 

•  Effects on quality of end product  
•  Acceptance of compostable plastics by site 

managers  

•  Niche applications (“closed loops”) vs. 

widespread use 

•  Maximum acceptable levels of compostable 
plastics in various streams of polymers for 
mechanical recycling 

Interview 

• 

Interaction between operational schemes at 
sorting platforms and presence of compostable 
plastics in various polymers targeted for 
mechanical recycling  

Morten 
Brøgger 
Kristensen
AIKAN 

Isabelle 
Deportes

ADEME 

Alberto 
Confalonieri
CIC 

Chaim 
Gabriel 
Waibel PRE 

Marco 
Alberti, 
Antonio 
Furiano

COREPLA 

Juergen 
Priesters

TOMRA 

Interview 

•  Effect of presence compostable plastics on 

mechanical recycling 

•  Maximum acceptable levels of compostable 
plastics in various streams of polymers for 
mechanical recycling 

• 

Interaction between operational schemes at 
sorting platforms and presence of compostable 
plastics in various polymers targeted for 
mechanical recycling  

•  Potential and evolution of sorting systems vis a 
vis contamination of compostable plastics in 
selected streams for mechanical recycling   

33 

 
 
 
 
 
 
 
 
 
A.8.0  Stakeholder Workshops 

A.8.1  Workshop 1 - 23rd July 2019 

A.8.1.1 

Introduction 

The European Commission, DG Environment, has commissioned a study on the relevance 
of biodegradable and compostable consumer plastic products and packaging within a 
circular economy. The study is in the context of the Commission’s ongoing work related 
to plastics with biodegradable properties. The objectives of this particular study are 
fourfold:  

3)  To provide an overview of the current market and regulatory situation with 

regard to biodegradable/compostable plastic products and packaging, and to 
look at how this may change in the future; 

4)  To assess possible implications of the use of such products in a circular economy 
context, in particular on waste management and in light of conditions found in 
practice in home composting systems across the EU;  

5)  To identify conditions in which the use of such products could possibly be 

beneficial; and 

6)  To compare conditions assumed to be found in home-composting in 

certifications and/or legislation to conditions in practice, and to provide 
recommendations on possible measures to address any discrepancies. 

On the 3rd June the first of two stakeholder workshops planned was carried out. The 
main purpose of this initial workshop was to gather information and facilitate discussion 
between stakeholders with varying viewpoints on biodegradable and compostable 
plastics. The workshop involved representatives from a range of Member States across 
the biodegradable plastic and packaging industries, as well as from the organic waste 
treatment industry, parties involved in certification– see Appendix 8 for the full attendee 
list.    

The following report summarises the key discussions and themes from the workshop. 
The points reflect the various viewpoints that were raised and do not indicate a 
consensus position. The presentation slides from the day have been communicated 
separately.  

This workshop was the first stage of engagement for the project. There will be ongoing 
one-to-one discussions and interviews. Stakeholders were also invited to send position 
papers or further information, or to request a meeting with the project leads. 

34   

 
 
 
 
A.8.1.2  Added value in a circular economy 

Wider added value 

Several areas were identified where compostable plastics could potentially add value 
within a circular economy. Key points are as follows: 

7)  Compostable plastic bags can be used in place of conventional plastic bags for 
organic waste collections. This can reduce the amount of residual conventional 
plastic in compost, and aid with the reduction of microplastics; 

8)  This reduces the need for pre-screening for bags at composting facilities; 
9)  Compostable plastics can be disposed of with other organic waste which may 
otherwise end up in the residual waste stream, thus improving organic waste 
capture rates; 

10) Compostable plastics can be used to reduce the amount of food contamination in 

mechanical recycling; and 

11) The use of compostable plastics could result in better coherence between the 
bioeconomy and circular economyRevenue from packaging EPR schemes could 
for example contribute to the treatment of organic waste. 

The added value of using compostable plastic as a tool to increase the capture rates of 
other organic material, for example organic waste bags boosting food waste recycling 
rates was highlighted. When used correctly, compostable plastics have the capacity to 
divert organic waste away from landfill, where it would otherwise decompose releasing 
methane into the atmosphere (a greenhouse gas). It was however also mentioned that 
biowaste collected in compostable plastic bags rather than in bins could lead to 
greenhouse gas emissions due to fermentation in knotted bags. For this application it 
appears important that local composting operators are supportive of the use of such 
bags for organic waste collection where this is introduced as a solution for organic waste 
collection. It was also pointed out that “brown paper bags”, to some extent an 
alternative, are easily compostable. 

It has been outlined that compostable packaging can reduce microplastics in soil from 
the reduction of residual conventional plastic in compost. Although front-end processing 
often exists for conventional plastic, these processors are not 100% accurate and plastic 
parts as well as microplastics often end up in the resulting compost. It was said that 
compostable plastics have a displacing effect for conventional plastics within organic 
collections. 

Contamination of other waste streams with food is a problem for the mechanical 
recycling industry; it was said at the workshop that using compostable plastic packaging 
and tableware are opportunities to decrease this contamination with food. This could 
potentially save mechanical recyclers both money and time, and allow composters to 
collect this additional organic material. 

It was outlined that, at present, the way EPR schemes across Europe are set up means 
that revenues from such schemes does not contribute towards the treatment of organic 
waste. If these schemes were re-evaluated, the composting industry could potentially 
benefit by receiving much-needed funding to boost organic collections.  

35 

 
 
 
Applications which could be of added value 

As outlined above, a number of stakeholders highlighted the added value of using 
compostables as a tool to increase capture rates of other organic materials. Many of the 
packaging applications that were deemed ‘appropriate’ are with this in mind – i.e. to 
increase the amount and quality of bio-waste as a feedstock for composting  

Nova Institute (Nova) informed the audience that they are about to conduct a study on 
the appropriate applications of biodegradable plastics. This study will not be completed 
within the timeframe of this project; however, Nova have identified 50 applications  
some of which, after further assessment, may ultimately be deemed appropriate 
applications, and this list will be shared with Eunomia. 

European Bioplastics identified the following applications for which they deem industrial 
compostable plastic appropriate: 

12) Thin carrier bags and bio-waste bags 
13) Coffee capsules 
14) Tea bags 
15) Fruit labels 
16) Thin film applications for fruit, vegetables and perishable food products 
17) Food products packaged in laminates 
18) Catering items (plates, cups, cutlery) 

A.8.1.3  Challenges from the use of compostable plastics 

There were several key themes that came up when discussing challenges from 
widespread use of compostable plastics in Europe. 

Biodegradation in practice 

A key concern from several stakeholders was how these products biodegrade in practice. 
It was highlighted that, for both industrial composting and anaerobic digestion, the 
timeframe in test method used in EN 13432 does not reflect the actual process time at 
facilities. There were differing views on how this should be managed. Some parties 
suggested amending the EN 13432 standard to include representative time frames, 
whilst others suggested conditions on the facilities themselves; to include longer 
processing times for industrial composting (thus more mature compost which in itself 
has numerous benefits), or compulsory composting of the digestate output from AD 
facilities. Despite differing opinions on how this should be achieved, there was a 
consensus that test methods should align as much as possible with actual facility 
conditions. 

There was a statement that in relation to compostable plastics ‘100% biodegradation’ is 
not scientifically possible. However, if a product does not ‘fully’ biodegrade, it does not 
necessarily mean that there is microplastic left. Eunomia were pointed to a study 
regarding full biodegradation, and this will subsequently be explored and analysed. 

36   

 
 
 
Suez showed key results from testing of packaging samples from the market with claims 
of compostability and biodegradability. Suez tested the processing of such samples in 
their laboratory, in conditions representative of their actual facility conditions – 
including anaerobic and aerobic composting, and mechanical plastic recycling facilities.  

They found that compostable plastic bags do not degrade entirely in anaerobic 
conditions, and that there is a risk of still finding microplastics in composts and 
digestates after the end of the waste treatment operation. Suez also concluded that the 
standards for compostable plastics do not reflect industrial conditions, including the 
duration, temperature and level of aeration. 

They also found that generally compostable plastics get stuck in rotors and screws in the 
processing equipment, slowing down the process and affecting machinery. As such, the 
waste managers found that it was more effective to screen out the products at the 
beginning of the process and dispose of as residual waste.  

Potential drawbacks in the circular economy context 

Potential drawbacks were highlighted for biodegradable and/or compostable plastics. 
One key issue is that when these plastics are composted, the energy and raw materials 
used for production are mostly lost. They mostly degrade into water and carbon dioxide 
and as such do not add nutritional benefit to the compost. This is a contradiction with 
the circular economy, in which resources should be kept for as long as possible and the 
maximum value should be extracted whilst in use.  

Concerns were also highlighted that the products in which compostable plastics are 
deemed ‘appropriate’ could instead be prevented entirely, following the waste hierarchy 
– for example through the use of reusable alternatives to single use options. Another 
example given was fireworks; it was suggested that instead of replacing the conventional 
plastic in fireworks with biodegradable plastic, the use of fireworks should be prevented, 
and perhaps even banned entirely. A counterargument was that food packaging, for 
example, cannot be prevented entirely and that some packaging actually helps reduce 
food waste.  

Interference with mechanical recycling 

Concerns were raised by some parties about the interference that compostable plastics 
can have on mechanical recycling. It was outlined that flexible compostables can 
interfere with equipment, however it was not established whether this was any more 
than other flexible non-targeted plastics. There were fears that there could be a quality 
decrease of the recyclate output if rigid plastics such as PLA were to go through the 
recycling process without being removed. Eunomia mentioned a study that found that a 
small amount of PLA contamination in dry recycling of PET does not cause issues. 
Another recent study was however mentioned which found that 0,1% PLA is enough to 
declassify PET recyclates. Eunomia will seek to explore this further and compare 
expected quantities to ‘allowed’ contamination rates in the context of the current 
recycling market landscape. 

37 

 
 
 
 
Lack of homogeneity 

One challenge that was presented was the lack of homogeneity in products, an example 
given was an industrially compostable PLA bottle with a conventional plastic PE lid and a 
conventional PET wrapper that had been found on the market. This, inevitably, leads to 
problems in the waste management of these products, as consumers are extremely 
unlikely to separate the three.  

Limited acceptance in composting facilities 

As outlined in section 0, Suez found that compostable plastics are often sorted out at the 
entrance of composting plants as they regularly get stuck in equipment. It was 
highlighted that a facility can decide themselves whether they accept compostable 
plastics, and this varies widely from facility to facility. There is generally low acceptance 
for rigid compostable plastic packaging items, and acceptance is higher for flexible 
packaging including organic waste bags. 

The European Composting Network presented a map – to be finalised – showing the 
acceptance of compostable plastics across Europe. This map shows ‘advanced’, ‘partial’ 
or ‘low’ acceptance levels for compostable plastic for Member States. Eunomia will seek 
to get this map once it is finalised, to influence its guidance for the appropriateness of 
the use of compostables across Europe.  

The DUH presented their 2015/16 survey, in which they found that 80% of the 
composting plants in Germany that responded called all products made from 
biodegradable plastics as “unwanted impurities”. A further 77% of these plants screen 
compostable plastic bags (including organic waste bags) out before the composting 
process. 

A.8.1.4  Consumer information, standards and certification schemes 

Definitions 

Concerns and opportunities regarding consumer information, standards and certification 
schemes were discussed. It was primarily identified that clear definitions are key, and 
that there is no clear definition of home-composting. The standard for home-composting 
that is being developed within CEN refers to a ‘well-managed system’, whereby it is not 
clear what this means and whether it is appropriate to develop a standard which would 
assume conditions which may be unlikely to be found in most cases in practice  

Standards and certifications 

It was highlighted that the communications regarding test methods, standards and 
certifications, and related claims, are extremely difficult for consumers to understand. It 
is also difficult for those working in the industry to understand the methods, standards 
and certification, which often results in further misinformation. European Bioplastics 
agreed to write a short one-page document on the technical content of the standards to 
be made available to the Commission and Eunomia. 

38   

 
 
 
It was identified that there are products on the market, such as PE bags, fraudulently 
using certifications as ‘compostable’. It was made clear that this is not misinformation 
but fraud, and that instances should be reported to certification bodies. The process by 
which certification bodies verify products on the market was discussed. It was explained 
that there is a team monitoring the market to ensure all certified products on the market 
are compliant. 

In regards to home-composting, there is a standard currently being written by industry 
stakeholders for CEN.  It was outlined that an ecotoxicity test method within a home-
composting standard is not possible, as nitrates and worms vary widely across systems, 
amongst other factors. Eunomia will seek to look at the standard that is being developed 
to guide this project.  

Consumer perceptions and labelling 

There were concerns raised about the consumer perception of a product as being home 
compostable if it is industrially compostable and vice versa. Oliver Ehlert from DIN 
CERTCO stated that purely from a standards point of view, a product was not necessarily 
industrially compostable if it was certified home compostable due to the time frames 
involved. It was highlighted that this could be extremely confusing for consumers and 
should be addressed.  

The labelling of products was discussed in detail, and it was agreed by all parties that 
labelling needs to be extremely clear to limit misunderstanding from consumers. There 
needs to be clear directions on which waste stream the product should go in. There 
should be no misleading information such as ‘plastic-free’, or broadly unjustifiable claims 
such as ‘good for the environment’.  

A.8.1.5  Summary of Workshop Themes 

Challenges from the use of compostable plastics in Europe were discussed, however 
various views were presented on how the waste from these products are managed in 
practice. Several accounts were given of the impacts of plastic in industrial composting, 
anaerobic digestion, and mechanical dry recycling streams, and waste managers 
believed that their facilities are not able to process these wastes. Home composting 
facilities were also discussed, and it was highlighted that a definition of home 
composting is required so that stakeholders can discuss the role of compostables within 
home composting environments and their place in the circular economy.  

There was a consensus in the room that no parties felt compostable/biodegradable 
plastics were appropriate in applications where there were existing, functional materials 
which had an appropriate disposal method which is considered better or equivalent in 
the waste hierarchy. However, stakeholders identified some applications where 
compostables appear to be of added value. It was suggested that perhaps compostable 
plastics could replace products which have the tendency to leak into the natural 
environment, or to prevent organic materials from contaminating other streams.  

39 

 
 
 
Benefits of using compostables in certain circumstances were highlighted. A main point 
from a number of attendees was the added value of compostable plastic bags as a tool 
to increase the capture rates of other organic material, for example organic waste bags 
boosting food waste recycling rates. It was highlighted by some stakeholders that – 
when used correctly – compostable plastics have the capacity to divert biowaste from 
landfill, reduce impurities in organic waste and reduce microplastics.   

Some stakeholders suggested that legislation could aid the use of compostable 
packaging in ‘appropriate’ applications. It was also highlighted that education across all 
Member States is necessary if such products are to be used more widely, both at the 
consumer and waste management level.  

Concerns regarding misinformation and fraud were addressed, and this was highlighted 
as a key issue for various points in the chain. In particular, it was agreed that the 
labelling of these products can largely be misleading to consumers and that further 
guidance and legislation is required to ensure this does not continue.  

A.8.1.6  Agenda and attendees 

Agenda 

Agenda Item 

19) Registration and refreshments  

20) Introduction to project from Commission: the background 

context for the study; the Commission’s expectations and 
objectives 

Q&A 

21) Overview of Initial Research Findings  

a.  Data and Trends on current and future market for 
biodegradable/ compostable plastic products and 
packaging - Simon Hann, (Eunomia)  

b.  Compost and Recycling - Enzo Favoino, (SADPM) 

Q&A 

Lunch 

Time 

9:30 

10:00 

10:15 

12:00 

40   

 
 
 
 
Time 

13:00 

14:15 

14:30 

15:30 

Agenda Item 

22) Challenges from the more widespread use of compostable 

plastics in Europe  

a.  Compostable plastics and their impacts in composting in 
Europe - Marco Ricci-Jürgensen (European Compost 
Network) 

b.  Biodegradable plastics in composting – results of survey 

Philipp Sommer (DUH) 

c.  Waste Management Perspective - Nicole Couder (Suez) 

Discussion 

i.  Options for mitigating adverse impacts from compostable 

plastics including adequate disposal. 

Break 

23) Conditions/ applications for which the use of compostable 

products and packaging is of added value in a circular economy 
a.  Kristy-Barbara Lange (European Bioplastics) 
b.  Mariagiovanna Vetere (Natureworks) 

Discussion: 

i.  What could be criteria for identifying products where 

compostable plastics are of added value (e.g. compared to 
making a product/ packaging reusable, recyclable or out of 
an alternative material). 

24) The role of consumer information, standards and certification 
schemes in achieving best possible use of compostable plastics 
a.  Oliver Ehlert (DIN CERTCO) 
b.  Philippe Dewolfs (TÜV Austria) 
c.  Development of a European Standard for Home composting 

Tony Breton (Novamont) 

Discussion: 

i.  Are today’s tests and standards fit for purpose in light of 
conditions to be found in home-composts, industrial 
composting and AD plants? 

ii.  Could better instructions/information/labelling be provided 
to households and waste operators to ensure compostable 
plastic products are managed under optimal conditions?  

25) Closing Remarks and Next Steps 

16:30 

41 

 
 
 
 
 
 
 
 
 
Attendees 

Name 
Kristy-Barbara Lange 
Hasso von Pogrell  
Tony Breton 
Mariagiovanna Vetere 
Steve Dejonghe 
Juli Vol 
Chaim Gabriel Waibel 
Philippe Dewolfs 
Oliver Ehlert 
Katharina Schlegel 
Thomas Grusemann 
Ioana Popescu 
Marco Ricci-Jürgensen 
Erwin Lepoudre  
Philipp Sommer  
Nicole Couder 
Denis Pohl 
Sophie Jenerwein 
Michael Carus  
Simon Hann 
Rosy Scholes 
Enzo Favoino 
Leonardo Mazza 
Bettina Lorz 
Maja Desgrees du Lou 
Werner Bosmans 
Emilien Gasc 
Fleur van Ooststroom Brummel 
Andrea Accorigi 
Hans-Christian Eberl 
Peter Eder 

Organisation 
European Bioplastics 
European Bioplastics 
Novamont 
Natureworks 
Looplife Polymers  
TIPA 
Plastics Recyclers Europe 
TUV Austria 
DIN CERTCO 
BASF 
TUV Rheinland 
ECOS 
European Compost Network 
Kaneka 
Environmental Action Germany (DUH) 
Suez 
Federal Environment Ministry Belgium 
DEKRA 
Nova Institute 
Eunomia Research & Consulting  
Eunomia Research & Consulting  
SADPM 
EU Commission DG ENV 
EU Commission DG ENV 
EU Commission DG ENV 
EU Commission DG ENV 
EU Commission Secretariat General 
EU Commission DG GROW 
EU Commission DG RTD 
EU Commission DG RTD 
EU Commission JRC 

42   

 
 
 
 
A.8.2  Workshop 2 – 22nd October 2019 

A.8.2.1 

Introduction 

The European Commission, DG Environment, has commissioned a study on the relevance 
of biodegradable and compostable consumer plastic products and packaging within a 
circular economy. The study is in the context of the Commission’s ongoing work related 
to plastics with biodegradable properties.  

The objectives of this particular study are to:  

1)  provide an overview of the market and regulatory situation with regard to 

biodegradable/ compostable plastic products and packaging;  

2)  assess possible implications of the use of such products in a circular economy 
context, in particular on waste management and in light of conditions found in 
practice in home composting systems across the EU (in terms of leakage of 
compostable plastics into the open environment and for the quality of the 
compost); and,  

3)  identify conditions/ applications in which biodegradability/ (home) 

compostability of products or packaging could be of added value when compared 
to reuse and other forms of recovery and clarify the basis for establishing such 
conditions/ applications. Identification of relevant benchmarks in relation to the 
“added value”.  

4)  provide an overview of biodegradability criteria set in existing home-

compostability frameworks (standards, legislation, certification schemes)  

5)  assess the practical relevance and limitations of such criteria in light of conditions 

found in practice in home-composting systems across the EU and identify 
possible measures for addressing discrepancies. 

6)  develop related recommendations. 

In support of the overall objectives, a stakeholder workshop was carried out on the 23rd 
October. This was the second of two workshops, and was centred on the following: 

•  Presenting research on the market and possible implications of the use of 

biodegradable / compostable plastic products and packaging within a circular 
economy; 

•  Getting feedback on a preliminary proposal for criteria under which the use of 

such products could be beneficial; and 

•  Discussion of the findings related to the effectiveness of home composting as a 

waste management route for plastics. 

The workshop involved representatives from a range of Member States, industry bodies, 
manufacturers, waste processers and parties involved in testing and certification.  

The following report summarises the key discussions and themes from the workshop. 
The points reflect the various viewpoints that were raised and, unless stated, do not 
indicate a consensus position. The presentation slides from the day have been 
communicated separately.  

43 

 
 
A.8.2.2  Research Findings 

Eunomia presented key findings from the market research and implications of using such 
products. Key topics that were addressed were: 

•  The size of the market and most common applications; 
• 
Issues with labelling / communication of products; 
•  Main concerns about the products from composters; 
•  Main concerns about the products from plastic recyclers; 
•  How compostable packaging fits with recycling targets from the Packaging and 

Packaging Waste Directive (PPWD); and 

•  Risks of littering such products. 

Some of these topics did not promote much new discussion, but can be seen in more 
detail in the accompanying presentation. Discussion was had particularly around 
processing concerns and how these products contribute towards recycling targets. This 
discussion is summarised below. 

Processing Concerns 

It was highlighted that there is a need for detailed waste composition analyses at 
composting facilities, to identify the plastic materials and products that are present in 
compost, both compostable and non-compostable. It would be particularly interesting to 
look at composition in Italy compared to a country with lower use of compostable 
products. 

There was also discussion on how much of contamination in conventional plastic 
recycling is made up of compostable and non-compostable contamination. It was 
presented that studies in Italy show an average compostable plastic contamination rate 
of 0.84% prior to sorting, but it is unclear how much non-compostable contamination 
there is on top of this. 

It was suggested that composters concerns are partly operational and partly perception, 
and that the clear labelling of ‘suitable’ products could mitigate many issues.  

As in the first workshop, it was highlighted that the Extended Producer Responsibility fee 
for compostable products goes towards processing conventional plastics, and this should 
be amended to support the composting of such products. 

Contribution to Recycling Targets 

Article 6a (4) of the PPWD 94/62/EC states that;  

“For the purposes of calculating whether the targets laid down in points (f) to (i) 
of Article 6(1) have been attained, the amount of biodegradable packaging waste 
that enters aerobic or anaerobic treatment may be counted as recycled where 
that treatment generates compost, digestate, or other output with a similar 
quantity of recycled content in relation to input, which is to be used as a recycled 
product, material or substance. Where the output is used on land, Member States 
may count it as recycled only if this use results in benefits to agriculture or 
ecological improvement.” 

44 

 
It is unclear whether the compostable plastics meet these criteria, particularly as the 
terms ‘similar’ and ‘ecological improvement’ are undefined.  

In the workshop, European Bioplastics highlighted that there is no efficiency recycling 
threshold for composting, and that the targets for conventional recycling do not work for 
compostable plastics. It was suggested that these amended to make it possible for 
compostable plastic packaging to contribute to such targets. 

It was decided that whether a product meets the recycling targets should be considered 
at application specific level, as it is easier to quantify for some products over others. 

A.8.2.3  Suitability of Standards  

Concerns were highlighted over whether the time frame used in the EN 13432 standard 
is representative of the actual time frame used in composting facilities. Composting 
facilities typically make the composting stage as short as possible to save resource. This 
is sometimes known as ‘biological drying’ and produces compost that is deemed to be 
unstable and lacks nutritional value. It was said that a clear distinction needs to be made 
between biological drying and proper composting, which products a stable output.  

It was also outlined, however, that many other naturally occurring materials would not 
typically degrade in a short composting process and often have to be re-processed. For 
example, woody materials are often re-processed, sometimes several times.  

It was made clear that the standard is not designed to reflect real life, and aims to show 
inherent industrial compostability – a quality of the material itself. 

The ecotoxicity tests with EN 13432 do not include tests for soil organisms such as 
earthworms, however only test plant germination and growth. An earthworm toxicity 
test is included in the draft home composting standard, and some people think this 
should be added to the EN 13432 industrial composting standard. Several parties also 
thought that a nitrification inhibition test should be included, as in the home composting 
draft. 

Different views were presented on whether EN 13432 should be updated. Key points 
were: 

•  There is no point updating the standard until there is standardisation of the 

composting process or legislation limiting digestate being applied directly to land; 

•  The standard should be updated to include nitrification inhibition and an 

earthworm toxicity test; 

•  The standard should be changed to reflect actual conditions, particularly the 

length of the process; and 

•  The standard should be updated now, in line with Essential Requirements. 

It was highlighted that the standard is due to be reviewed in 2020, and that a mandate 
from the Commission would be necessary to update it. 

45 

 
 
A.8.2.4  Criteria Development 

A key part of this project is to use the research conclusions highlighted in the previous 
sections to help derive a set of criteria that can help to identify beneficial uses of 
compostable plastics in the context of a circular economy. 

Criteria Ranking 

An exercise was undertaken to include the stakeholders in this criterion setting process. 
The criteria presented to the stakeholders had primarily been derived from position 
papers provided for the project, with others being developed by Eunomia.  

The stakeholders were asked to separate the criteria using a tier system, with the 
expectation that a consensus could be built around a core set of criteria. The tier system 
is as follows: 

•  Tier 1 – Highly important criteria as identified through the project research; the 

implication is that all should be met. 

•  Tier 2 – May highlight an important requirement, but the evidence base or the 
ability to measure this does not allow effective criteria to be developed at this 
stage. 

•  Tier 3 – Likely to be low priority aspects with mixed evidence and difficulty 

measuring. 

The stakeholders were also invited to add any additional criteria, or reject any of the 
criteria proposed. 

The stakeholders were split into five mixed groups so that a range of opinions were 
present in each. The results from each group are shown in Table 10. Green cells indicate 
a Tier 1 criterion, yellow cells a Tier 2, red cells a Tier 3, and blank cells are rejected 
criterion.

46 

 
1 

2 

3 

4 

5 

Table 10: Results from the group exercise deciding importance and feasibility of criterion 

Effective organic waste collection, sorting and treatment infrastructure should be in place that accepts 
compostable plastic 

The product is likely to end up in organic waste collection 

The material/product is likely to be contaminated with food  

The product being compostable reduces non-biodegradable plastics in organic waste collections 

‘Semi-rigid’ compostable plastics should only be used in ‘closed’ systems 

Compostable material should not be used in products that contain or come into contact with human or 
animal waste 

There is a low likelihood of item being effectively recycled (recycling prioritised over composting) 

The packaging is ‘rapidly consumed’ 

The co-existence of compostable and non-compostable plastics within the same product group should 
be avoided  

There are no alternative reusable solutions available 

There is an absence of suitable/available ‘natural’ compostable materials 

The products should meet EN Standards 

Compostable plastic should not be mixed with other non-compostable materials 

The product should bring ‘environmental benefits’ 

Compostable plastics are at least partly made from renewable materials 

The correct waste management route is clearly identifiable for the consumer/user 

The term ’biodegradable’ should not be used 

# 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

11 

12 

13 

14 

15 

16 

17 

47 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
There was clearly a majority agreement that the following should be core criteria: 

1)  Effective organic waste collection, sorting and treatment infrastructure that 

accepts compostable plastic should be in place. 

2)  The products should meet EN Standards for composting of packaging or plastic 

products. 

3)  Compostable plastic should not be mixed with other non-compostable materials. 
4)  The correct waste management route should be clearly identifiable for the 

consumer/user. 

5)  The term ’biodegradable’ should not be used. 

Many groups agreed that the criteria ‘product is likely to end up in organic waste 
collection’ was an important criterion, however there is a low possibility of being able to 
measure this.  

The criteria ‘The co-existence of compostable and non-compostable plastics within the 
same product group should be avoided’ was highly divisive, with some groups grouping 
this as a Tier 1 criterion, and others rejecting it entirely.  

The criteria on the product bringing environmental benefits was also highly divisive, 
possibly as it is important but very difficult to measure. 

Several stakeholders highlighted that further clarity is needed on some of the criteria, 
particularly in regards to the wording. It was also highlighted that many of the criteria 
are moving targets, for example the criteria ‘there is a low likelihood of item being 
effectively recycled’ may be true now for a plastic film but could improve with the 
introduction of chemical recycling. 

Decision Tree 

Using these criteria, it is possible to develop a decision-making process that identifies 
where compostable plastics could provide added value.  

The stakeholders were asked to follow this decision tree for common applications to 
address the following questions: 

•  Can the decision tree be used to determine a positive list of applications for 

which the use of compostable plastics should be allowed (or promoted) based on 
their added value (while closing the door to other applications)? 
Is this decision tree approach a useful and effective way to assess (and 
communicate) the pros and cons of designing a given application for composting? 

• 

•  Should trees be different depending on whether one is considering designing a 

• 

product/packaging for industrial or home-composting? 
Is there a benefit of creating categories based on application for the certification 
bodies? 

•  Would certification bodies use such a tool to help them determine suitable 

applications to provide certification for? 

There was a consensus opinion that the decision tree was fairly simple to follow for the 
applications visited and overall useful, however it was mentioned that the tree may not 

48 

 
be appropriate for more complex applications such as multilayer packaging and 
adhesives.  

It was deemed that it would be a useful tool for certification bodies, as they are currently 
having to decide on a product specific basis whether compostable plastic is used suitably 
and certification has been earnt.  

It was not thought that a decision tree was necessary for home composting, rather the 
very few suitable applications could be listed. The consensus position was that the 
decision tree was suitable for industrial compostability only. 

One group asked for a decision box on whether the product is collected with organic 
waste or not, however this would result in the decision tree no longer being material 
neutral but assumes a compostable plastic is used. 

It was also highlighted that ‘unacceptable food waste’ needs further definition, and was 
suggested that a level of contamination may be useful.  

The criteria that the compostability should be effectively communicated to consumers 
was not in the tree. This was due to the fact that Eunomia think this could simply come 
after the decision-making process, however not all stakeholders agreed with this. The 
communication regarding these products will be fundamental to their effectiveness and 
there were suggestions that this should be incorporated into the decision tree.  

It was also stated that it needs to be clear that the waste hierarchy is being followed, for 
example food waste reduction needs to be prioritised over food waste capture.  

It was decided that it should be asked explicitly in the decision tree whether the product 
is banned by law, for example single use cutlery.  

A.8.2.5  Home Composting 

Due to time restrictions, the interactive session on the home composting of plastics did 
not go ahead as planned. Stakeholders were invited to review the information supplied 
in the workshop briefing paper, and send over position statements. 

A brief discussion was had on the merits of home composting plastics. Overall, home 
composting is not being pushed as a suitable waste management solution. Most 
stakeholders agreed with this sentiment, as a circular economy cannot be promoted if 
people are disposing of things in their own garden. It was highlighted that in industrial 
composting, nutrients are effectively recycled into crops – so long as the compost is 
mature. 

As such, it was deemed to not be imperative to discuss with stakeholders what is 
happening in practice in home composting systems compared to certifications, but 
instead why home composting is not deemed a suitable waste disposal method. 

49 

 
 
 
A.8.2.6  Agenda, Attendees and Apologies 

Agenda 

Agenda Item 

1)  Registration and refreshments 

2)  Introduction to project from Commission: the background context 
for the study; the Commission’s expectations and objectives 

Time 

9:30 

10:00 

3)  Presentation – Overview of study and current findings 

10:15 

•  Market – further information building from first workshop 
•  Labelling and Communication 
• 
•  Compostable Packaging Contributing to Recycling Targets 
•  Risks of Littering 

Issues in composting and recycling 

4)  Q&A on current findings 

10:55 

5)  Introduction to criteria setting for beneficial use of compostable 

11:15 

plastics 

Lunch (BU-5 canteen) 

12:00 

6)  Interactive session on criteria setting and the decision process 

13:00 

7)  Summary and feedback of interactive session 

Break 

14:30 

14:45 

8)  Presentation of findings from investigation into home composting 

15:00 

as treatment method for compostable plastics 

9)  Interactive session: Q&A, feedback and discussion on the merits of 

15:45 

home composting of plastics 

10) Closing remarks and next steps 

16:30 

50 

 
 
 
 
 
 
Attendees  

Name 
Kristy-Barbara Lange 
Philippe Dewolfs 
Ioana Popescu 

Steve Dejonghe 
Oliver Ehlert 
Nicole Couder 
Denis Pohl 
Sophie Jenerwein 
Chaim Waibel 
Katharina Schlegel 
Darko Horvat 

Paolo La Scole 
Petr Bažil 
Bruno De Wilde 
Stephan Dreyer 
David Nordqvist 
Lara Dammer 
Merja Saarnilehto 
Anindya Mukerjee 
Pablo Rodriguez Porras 
Simon Hann 
Rosy Scholes 
Leonardo Mazza 
Bettina Lorz 
Maja Desgrees du Lou 
Werner Bosmans 
Silvia Forni 

Organisation 
European Bioplastics 
TUV Austria 
ECOS - European Environmental Citizens 
Organisation for Standardisation 
Looplife Polymers 
DIN CERTCO (TUV Rheinland) 
Suez 
Federal Environment Ministry Belgium 
DEKRA 
Plastics Recyclers Europe (PRE) 
BASF 
Republic of Croatia Ministry of Environment and 
Energy 
Novamont 
Ministry of the Environment, Czech Republic 
OWS Lab and consulting services 
Federal Environment Ministry Germany 
Nestle 
Nova Institute 
Ministry of the Environment, Finland 
GO!PHA 
Ministry for the Ecological Transition - Spain 
Eunomia Research & Consulting  
Eunomia Research & Consulting  
EU Commission DG ENV 
EU Commission DG ENV 
EU Commission DG ENV 
EU Commission DG ENV 
EU Commission DG ENV 

51 

 
 
 
 
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