Environmental Aspects of Biopolymers

Plastics can generally be considered to have a favorable environmental impact due to their lightweight nature, efficient use of resources and energy during production, transport and application, and their high energy potential for thermal recovery after use. Bioplastics have an added advantage of using renewable resources, which can be beneficial in terms of reducing consumption of fossil fuels and CO2 emissions, as well as enabling regional closed-loop management. However, standardized assessment criteria should be used to validate their environmental performance. The compostability of many bioplastics offers an additional advantage, especially in arid zones with a lack of humus, as the resulting compost can be used to improve soil quality. Although many bioplastics are biodegradable, they are not intended to be disposed of in nature and should be recovered in a controlled and eco-efficient manner. European Bioplastics takes a clear anti-littering position.

The Role of Bioplastics in Climate Protection

Manmade influences are today considered to be the main reasons for climate change. Burning of fossil resources increases the levels of CO2 in the atmosphere, which causes an increase in the average temperature (greenhouse effect). Scientists see a distinct connection between CO2 increase in the atmosphere and increasing numbers of thunderstorms, floods, and aridity.

Climate protection is nowadays a central part of environmental policy, due to the fact that climate change can create far-reaching negative consequences. Governments and organizations work against this threat with targeted measures.

The increased use of renewable resources is an important step toward a solution. Life cycle analysis shows that bioplastics enable CO2 savings of 30 to 80% in relation to conventional plastics. This does not apply generally and inevitably it depends on the product and its application. The saving (in the case of the same application) results from the use of renewable resources.

Plastics in general are considered to be “climate-friendly” materials: in comparison with materials such as metal or concrete they can be easily produced, transported, or used without much energy expenditure. In the automotive engineering sector (lightweight construction) or as thermal insulating materials, plastics enable significant “secondary” effects by protecting resources and thus saving CO2 production.

Examples of the successful use of bioplastics exist already: Goodyear’s car tires contain a proportion of starch material, which decreases the tires’ rolling resistance and is therefore also able to reduce fuel consumption.

Life-Cycle Economy

The principle of sustainable development and the lack of landfill capacity in Europe are reasons for the introduction of the closed-loop economy in the European Union. Products have to be produced and used in a manner that conserves resources and have to be recovered after use, if their use cannot be avoided entirely.

Landfill of waste is not allowed anymore, so the question of disposal is already an issue during the development of a product. If easily disposed materials are used for the production, the disposal cost will decrease, and so in consequence will the overall product costs.

According to these guidelines, bioplastics have been developed, with composting considered to be the most cost-effective method of disposal. Only by use of renewable resources can a genuine closed loop be achieved.

Assessments of the impacts of products on the environment require objective and standardized criteria. Life-cycle analyses complying with ISO 14040 are a suitable means of quantifying the impact of products on the environment.

Their primary use in industry is to optimize process-engineering aspects of production with regard to the environment.

Recovery Options

The objective of the EU to close material cycles has led to a different understanding and handling of the term “waste”: “waste” can be regarded as “raw material for new after-life options”. Bioplastics have been designed based on the concept of closed-loop material management, as is found in nature.

Bioplastics can be recovered and recycled like conventional plastics by all available methods: by thermal recovery, back to plastics, or by chemical recovery. Unlike conventional plastics, most bioplastics types can be organically recycled by composting, provided that they comply with EN 13432 criteria.

Diverse investigations and studies show that there is no “best” option in recovery and recycling for plastics. Ecological and economical evaluation results differ regarding different applications of plastics, even if the same resin type is considered.

Composting is a useful and often preferred method for mulch film and bio-waste bags, as well as for gardening articles, which additionally offer shoppers the “second life option” of also serving as organic waste bags. In all these applications, biodegradability represents added value.

Used food packaging can be processed with high eco-efficiency by composting, especially for packing of easily spoiled food with a short shelf-life. Then the packaging can be recovered together with the spoiled content without further treatment. Nevertheless, eco-efficiency is also dependent on the given infrastructure at a place or in a region.

Short characterization of recovery options for bioplastics:

  • Thermal recovery: Use of the high calorimetric value of the substance to produce heat and electricity (legislative criteria have to be met).
  • Organic recycling (composting): The resulting compost is used to improve soil quality and as a replacement for fertilizers.
  • Chemical recycling: This can be an option, especially for polyester types such as PLA or PHA. By chemical treatment the polymer chain can be depolymerized, and the resulting monomers can be purified and polymerized again. Sufficient amounts of source-separated collected plastic waste are a precondition for application of this method. The same arguments apply for recycling back to plastics.

Waste Management and Bioplastics Treatment

Waste management is crucial for the success of bioplastics, particularly in terms of compostable plastic products. The availability of composting infrastructures is vital, and that’s why European Bioplastics advocates for separate collection of organic and residual waste and the establishment of composting sites across Europe. The association welcomes all political initiatives supporting this goal, such as the recent announcement from the German Environmental Ministry, which intends to create a national organic waste recycling strategy.

The strategy will include determining whether organic waste should be dried, burnt, fermented, or composted, or whether it should be processed to create biofuels. The German Federal Government has also begun to implement its organic waste strategy at the European level. Organic waste constitutes around 38% of municipal waste in the EU, equivalent to about 120 million tonnes of organic waste per year, with the potential to provide over 50 million tonnes of compost annually (in EU 25).

One challenge is the European Landfill Directive, which permits burning, treatment in a mechanical biological facility, and mixed composting of organic waste components, thereby making the waste unsuitable for soil improvement. Despite the support from the EU parliament and the “biowaste coalition” (Austria, Belgium, Cyprus, the Czech Republic, Estonia, Hungary, Italy, Portugal, Slovakia, Spain, Romania, and Germany), a dedicated Organic Waste Directive is not yet on the EU Commission’s agenda, as European Bioplastics advocates.

On the other hand, European Bioplastics strongly supports appropriate treatment of bioplastics in view of the quantities of material available. Organization of the best-suited waste-management system is dependent on local infrastructures for collection and recycling, local and regional regulations, the total available volume on the market, and the compositions of waste streams.

This is also a primary reason why conventional packaging is not always treated in the same way across the EU. Most countries have set up systems to recover and to recycle post-consumer plastic bottles. For most other packaging, the results are more fragmented and not always very well developed. In many cases, mixed fractions are being incinerated, and in doing so, (fossil) energy is being recovered.

With both bioplastics and biopackaging in their infancy, the development of the market should not be delayed, even though optimal recovery systems have often not been ascertained by local authorities. The risks associated with existing recovery schemes should be monitored. These will be limited at present, given the relatively small volumes that are currently entering the market. Once volumes reach a critical mass, waste-management systems that make most sense from an environmental and economic point of view can be set up.

Over time, recycling may be the best option for certain bioplastics, especially if a homogenous stream can be organized, like that in place for plastic bottles. The German government acknowledged these considerations in an amendment to its Packaging Ordinance by releasing bioplastic bottles from deposit obligation. The ordinance states that bottles with more than 75 percent RRM content will not be subject to a deposit charge. This exemption postpones the obligation to install recovery systems to a point of time after market introduction.

European Bioplastics is the representative body of the European bioplastics industry. The association comprises companies along the whole value chain of bioplastics: from the agricultural feedstock, chemical, and plastics industries, as well as industrial users and recycling companies. Founded in 1993 as IBAW (interest group biodegradable plastic materials), in 2007 the association represented the interests of 75 member companies. Between 2004 and 2007 the number of members more than doubled. The goals of the association are to shape the political, business, and public landscape for the bioplastics industry.

It is recommended that commercial users or retailers of compostable bioplastic products ask distributors about their product certifications and demand the certification numbers. Even if composting of the product is not intended, certification guarantees high product safety. Certification, moreover, distinguishes between bioplastic and conventional plastic and offers marketing and communication opportunities.

The certification program for compostable plastic products has been set up by experts responsible for waste-management recycling and compost quality assurance.

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