Umweltbundesamt
Click to enlargeBio-plastics - what are they? Can they be composted – or should they be disposed of in the yellow bin? Can bioplastics rot in the forest? Bio-based and biodegradable plastics raise many questions that we would like to answer in this FAQ.
Bio-based plastics are made entirely or partially from biogenic raw materials (e.g. from corn and sugar cane). Biodegradable plastics, on the other hand, are plastics that decompose under certain conditions, leaving behind mainly carbon dioxide (CO2) and water. Bio-based plastics, on the other hand, can be biodegradable, but often are not, such as bio-based PET. Conversely, biodegradable plastics can be both fossil-based and bio-based.
The raw materials for bio-based plastics are usually provided by plants rich in starch and cellulose, such as corn or miscanthus, but sometimes also oilseeds or wood. Biodegradable plastics can be made from thermoplastic starch, cellulose, degradable polyesters and polylactide (PLA). Polylactide is the polymer of lactic acid, which is also derived from starch or cellulose. Some degradable polyesters are also sometimes made from petroleum. Biodegradable plastics can therefore be bio-based or fossil-based. There are also often mixtures, for example of PLA and degradable polyesters.
Global production capacity for bio-based and biodegradable plastics in 2022 was around 2.22 million tonnes, according to estimates by industry experts. For comparison: In the same year, 390 million tons of conventional plastics were produced. Europe accounts for around 26.5% of the production of bio-based and biodegradable plastics, corresponding to about 588,000 tons. The most common application for bio-based and biodegradable plastics is flexible packaging (bags) (european bioplastics 2022).
That depends. There are bio-based plastics that have the same chemical structure as their fossil-based counterparts, and sorting and recycling are possible using established processes. An example of this are PET bottles partly made of bio-based plastics. They can be recycled together with conventional PET bottles. It is important that the highest possible quality of mechanical recycling takes place, regardless of the raw material source.
According to the current state of practice bio-based plastics, which do not have the same chemical structure as fossil-based plastics, are usually not sorted in sorting plants, even if they could theoretically be sorted. Though many of these plastics are thermoplastic and therefore theoretically mechanical recyclable, the sorting systems for lightweight packaging from the yellow bag / yellow bin are not designed to identify and sort them out. Due to the low volume, it is not economical to sort and recycle these plastics as a separate fraction. Therefore these bio-based plastics, which do not have the same chemical structure as fossil-based plastics, usually end up in energy recovery.
Rather no. We know from comparative life cycle assessments of simple objects and packaging that the environmental impacts do not improve significantly if the raw materials are bio-based instead of fossil-based. The effects tend to shift: while conventional fossil-based plastics release more climate-impacting CO2, the ecological footprint of bio-based plastics shows a higher potential for acidification and eutrophication as well as a higher land requirement for raw material production (GIZ 2021). Since agricultural land is limited worldwide, there can be competition for alternative land uses, especially with food production, nature conservation or the use of biomass for energy. The situation is different when residues, for example from agriculture, are used for the production of bio-based plastics. The use of residues is usually ecologically more advantageous, since no additional land use is required. However, even with residues, there is competition between energetic and material use and use as animal feed.
Bio-based plastics are often only partially bio-based. The bio-based content can be determined experimentally in polymers and in products. The standards CEN/TS 16137 for polymers and EN 16785-1 for products are used as a basis. The proportion is given as a value in percent.
There are polymers that can be produced both bio- and fossil-based and ultimately have the same structure. An example is polyethylene. There are also polymer groups, for example polyamides, which are formed by condensation of different carboxylic acids and amines, which can be both bio- and fossil-based. This can be used to produce plastics that are partly bio-based (and partly fossil-based). There are also plastics that can only be produced bio-based, such as polylactide (PLA). Derivatives of cellulose, such as cellulose acetate and cellulose hydrate, are mostly bio-based and are then chemically modified.
Generally: No. Bio-based plastics are not always biodegradable. Plastic bags that are resistant to biodegradation do not decompose in composting or fermentation and must be sorted out. For operators of composting plants, this is associated with a great deal of effort. Bio-based biowaste collection bags may only be put in the biowaste bin if they are also biodegradable and approved as biowaste collection bags. For this purpose, the bags must be certified according to "Bioabfall-Beutel DINplus" (recognizable by the seedling symbol) and comply with the specifications of the Ordinance on Biowastes Appendix 5. In addition, the municipalities can prohibit the use of these biowaste collection bags, e.g. for technical reasons. Further information on biowaste collection bags can be found in point 3.2.
Yes. Plastic packaging must be disposed of in the yellow bin or the yellow bag. This also applies to bio-based plastic packaging. Under no circumstances may they be placed in the biowaste bin.
Yes. For environmental reasons, plastics should generally be mechanically recycled as a matter of priority. The German Packaging Act also determines quotas for this. In order to achieve these quotas, manufacturers should design their packaging to be as recyclable as possible. The Central Agency Packaging Register offers dual systems and indirectly also manufacturers assistance and orientation in the assessment of recyclability.
Although raw materials obtained from agriculture and forestry are renewable, they are not available in unlimited quantities. In addition, intensive agriculture and forestry have a negative impact on the climate and the environment. Therefore, a sustainable and resource-conserving use of biogenic resources is particularly necessary. The principle of cascade use provides for biogenic resources first to be used materially in durable and repairable products, then to be recycled later, and only finally feeding biogenic material into energy recovery. Bio-based plastics should also follow this principle.
No! Packaging or single-use products made of degradable plastics, such as cups, cutlery and plates do not belong in the biowaste collection. Plastic products and packaging must always be disposed of in the designated waste collection (packaging: yellow bin/yellow bag; other products: Residual waste bin). The reason for the ban is that the collected biowaste is used to produce fertilizer for agriculture or, for example, compost as a basis for potting soil. Plastics, even if they are biodegradable, are not suitable for this purpose. These products made from biodegradable plastics also interfere with the treatment processes in composting plants. They are only partially degraded and contaminate the compost produced.
Yes, if they are approved for this purpose. The requirements for this are described in Annex 1 and Annex 5 of the German Biowaste Ordinance. According to this, a prerequisite for approval as a biowaste collection bag is certification in accordance with "Bioabfall-Beutel DINplus". This certification is based on the requirements of EN 13432 but additionally demands a disintegration of the material within 6 instead of 12 weeks. For consumers, approved biowaste collection bags can be recognized by the area-wide printing of the seedling symbol. The exact requirements for labelling are described in Annex 5 of the Biowaste Ordinance and will be mandatory from November 2023 on with the amendment of the German Biowaste Ordinance (Annex 5 of the Biowaste Ordinance) and shown in the following figure.
A further prerequisite for the permissibility of collection bags made of degradable plastics is that the bags are also approved locally for biowaste collection. The cities and districts have the option of restricting the list of materials permitted under the German Biowaste Ordinance in their waste statutes if this is for example technically necessary. In many statutes, the use of the degradable collection bags is explicitly prohibited because they cause problems in the treatment plants, for instance. Before using the degradable bags, the local separate collection regulations should therefore be observed.
No. The standards for industrial compostability examine degradation under the conditions of a large-scale composting plant. In such composting plants, for example, temperatures of well over 60 °C are reached, which is not usually the case with compost heaps in the garden. Only under these conditions does the microbiological degradation of the bags take place quickly and reliably. Under normal environmental conditions, such as those found in a garden compost pile, degradation takes much longer, leaving residues in the finished compost. However, since degradable plastics do not benefit the compost, they should be disposed of as residual waste.
Collection bags made of degradable plastics enable citizens to collect biowaste separately in a hygienic and convenient way. In contrast to bags made of paper, they are largely tear-resistant and waterproof, which facilitates the transport of organic waste even from multi-storey flats. In several studies, the use of bags made of degradable plastic has led to an increase in the amount of collected biowaste. At the same time, it was possible to reduce the number of incorrect throws, i.e. the introduction of conventional plastic into the organic waste bin.
One disadvantage of degradable bags is that composting and fermentation plants have to separate them to a large extend already in the waste processing (e.g. sieving) together with other interfering materials and disposed of as residual waste. The technology used cannot distinguish between degradable and conventional plastic bags. In addition, there is a danger that citizens will not differentiate sufficiently and also use bags made of conventional plastics as soon as degradable plastic bags are permitted.
In the past, the degradation time specified in the standard was another problem, as the treatment times in today's composting plants are much shorter and the bags did not completely decompose despite being degradable. However, manufacturers have reacted in the meantime and developed material with shorter degradation times. Also, with the standard "Bioabfall-Beutel DINplus" the rotting time was reduced from 12 weeks to 6 weeks. Nevertheless, it is possible that particles, e.g. from knotted bags, can still be found in the finished compost.
Pet litter and faeces should be disposed of as residual waste. Bags made of recycled plastic (bio- or fossil-based) are suitable as collection bags. Cat litter or sand from terrariums and aviaries also does not belong in the compost. Collection bags (incl. contents) must not be left in the environment. Not even if they are biodegradable!
Used flower pots are waste that should be carefully collected, stored and reused or recycled in order to protect the soil. As packaging they should be disposed of in the yellow bin or the yellow bag. As individually purchased items they should be disposed of in the residual waste. Neither biodegradable nor bio-based flower pots should be left in the garden, on green spaces or in open fields. The same applies to agricultural films. To protect resources, we also advise to use flower pots made of recycled material.
Plastic packaging must be disposed of in the yellow bin or the yellow bag. This also applies to packaging made of biodegradable plastics. They must not be placed in the organic waste bin.
Under no circumstances should packaging be disposed of in the environment. According to current knowledge, even the degradation of biodegradable plastics takes several months, depending on the environmental conditions. During this time, waste poses a risk to people and the environment and incurs clean-up costs.
The German Packaging Act establishes product responsibility for packaging waste. This ensures high-quality recycling and the allocation of disposal costs according to the polluter-pays principle. Producers/first distributors of packaging must register in the packaging register LUCID. Producers/first distributors of packaging that typically accumulates as waste at private end consumers must additionally participate with their packaging quantities in a dual system.
The use of biodegradable packaging does not offer any advantages compared to packaging made of conventional or bio-based plastics. Stable and durable material usually has decisive advantages. The repeated use of the material through recycling offers significant ecological advantages over any loss of material through biodegradation. Other critical properties include stability during use and suitability as a food contact material. Biodegradable plastics are easily colonised by degrading microorganisms, which may also contaminate the product or food.
No. Single-use products are short-lived and - unlike reusable products - generate unnecessary waste, whether biodegradable or not. If biodegradable disposable items end up in the environment, this has similar negative consequences as the input of conventional plastics in nature (e.g. fields and meadows), as the items usually hardly degrade at all and only very slowly. Indications of biodegradability can even lead to careless and thoughtless handling of waste. The consequences could be increased littering of the environment, higher demand for cleaning measures and misdirected waste in biowaste bins. Reusable options are always the better choice!
The UBA’s motto, For our environment (“Für Mensch und Umwelt”), sums up our mission pretty well, we feel. In this video we give an insight into our work.
