Bioplastic as an alternative?
A fundamental distinction must be made between “organic plastic” and “biodegradable plastic”.Often, but by no means always, organic plastic means both. Bio-based plastic is not automatically biodegradable – while petroleum-based plastic can be degradable. The market share of bioplastics in Europe is currently only around 1%.
From an ecological point of view, bioplastics made from plant material have, at least apparently, essential advantages over conventional plastics. Bio-based plastics do not need fossil raw materials for production but use renewable resources. Different types of plastic (starch, PLA or cellulose-based bioplastics) can be produced from natural materials such as corn, wheat, potatoes, sugar cane, sugar beet, bamboo or wood using various processes. A paper by the Association of Organic Food Manufacturers (AöL) speaks of 20 to 80 per cent emission savings.
The use of food as a raw material for plastic is in direct competition with food production. And valuable areas for growing food are also lost for non-edible plant material. While people are starving in many parts of the world, food and cultivated land are being used for packaging material. In addition, large quantities of fertilizers and pesticides are often used to grow these plants, which pollute the soil and water.
The myth of composting
Biodegradable plastic can call itself “compostable” and, for example, bear the “seedling” logo if it is broken down to 90 per cent into the smallest particles under industrial conditions within a maximum of 90 days. In theory, only CO2 and water may remain after decomposition. After this time, in industrial composting, no more than 10% of the remains may be larger than 2 millimetres.
Unfortunately, this standard is outdated because modern plants only need three to four weeks to turn organic waste into humus. The bioplastic cannot keep up, and plastic scraps remain, making the hummus unusable. Organic recyclable bags are therefore sorted out again before composting. Although there are also certifications for home-compostable plastic products, these are rare, and the European Bioplastics industry seems to be somewhat sceptical about such products.
In principle, fully compostable plastic products – for example, disposable tableware or biodegradable bin bags made of cornstarch – can potentially avoid waste and thus protect the environment. Even if they do end up in nature, they can at least decompose faster and more completely than traditional plastic.
In agriculture and horticulture, naturally rotting bioplastic films can make work more accessible because they do not have to be collected and disposed of at great expense. In practice, however, even biodegradable or compostable plastic products should by no means end up in the environment (or on the compost) – under difficult-to-control conditions, degradation can still take a very long time.
A glimpse of hope
Various research approaches produce bioplastics from organic raw materials that can hardly be used for any other purpose, such as wood or food waste. The idea is very promising, but these materials are still being developed. After all: When it comes to “energy recovery”, i.e. incineration,, bio-based bioplastic is somewhat more climate-friendly than conventional plastic. This is because only as much CO2 is released as was stored in the plant-based starting material – significantly less than with petroleum-based materials.
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