Biodegradability – busting the “eco-packaging” myth

The market for bioplastics looks set to grow in the coming years, and many believe that alternative plant-based plastics will provide the ultimate solution to the reliance on oil-derived plastics.

The so-called recycled or plant-based bottles are nothing more than an analogue of standard plastic bottles made of polyethylene terephthalate, in which thirty percent of the ethanol is replaced by a corresponding amount of plant-derived ethanol. This means that such a bottle can be recycled, even though it is made from plant material; however, it is by no means biodegradable.

There are varieties of biodegradable plastic – Today, the most common plastic is made from polyoxypropionic (polylactic) acid. Polylactic acid derived from corn biomass actually decomposes under certain conditions, turning into water and carbon dioxide. However, high humidity and high temperatures are needed to decompose PLA plastic, which means that a glass or bag of polylactic acid plastic will only decompose XNUMX% in industrial composting conditions, and not in your usual compost heap in your garden. And it will not decompose at all, buried in a landfill, where it will lie for hundreds or thousands of years, like any other piece of plastic garbage. Of course, retailers don’t put this information on their packaging, and consumers mistake them for environmentally friendly products.

If biodegradability is taken out of the discussion, the widespread use of bioplastics could be a great boon. – for many reasons. In the first place is the fact that the resources required for its production are renewable. The crops of corn, sugarcane, algae, and other bioplastic feedstocks are as limitless as the possibilities to cultivate them, and the plastics industry could finally wean itself off fossil hydrocarbons. Growing raw materials also does not lead to an energy imbalance if it is carried out in an environmentally sustainable way, that is, more energy is extracted from the raw materials than it is spent on growing certain crops. If the resulting bioplastic is durable and can be reused, then the whole process is eminently worthwhile.

Coca-Cola’s “vegetable bottles” are a good example of how bioplastics can be produced within the right infrastructure. Because these bottles are still technically polyoxypropion, they can be recycled regularly, allowing the complex polymers to be preserved rather than thrown into a landfill where they are useless and will rot forever. Assuming that it is possible to improve the existing recycling infrastructure by replacing virgin plastics with durable bioplastics, the overall need for virgin polymers could be significantly reduced.

Bioplastics creates new challenges that we must take into account as we move forward. First, an attempt to completely replace oil-derived plastics with plant-based bioplastics would require tens of millions of additional hectares of agricultural land. Until we colonize another habitable planet with arable land, or reduce (significantly) our consumption of plastic, such a task will require a reduction in the area of ​​cultivated land that is already being cultivated for the purpose of producing food. The need for more space may even be a catalyst for further deforestation or forest fragmentation, especially in a region of tropical forests such as South America that is already at risk.

Even if all the above problems were not relevant, then we still do not have an adequate infrastructure for processing large volumes of bioplastics. For example, if a polyoxypropion bottle or container ends up in a consumer’s trash can, it can contaminate the recycle stream and render the damaged plastic useless. In addition, recyclable bioplastics remain a fantasy these days—we don’t currently have large-scale or standardized bioplastic recovery systems.

Bioplastic has the potential to become a truly sustainable replacement for petroleum-derived plastics, but only if we act appropriately. Even if we could limit deforestation and fragmentation, minimize the impact of food production, and develop recycling infrastructures, the only way bioplastic could be a truly sustainable (and long-term) alternative to oil-based plastics is if the level of consumption decreases significantly. As for biodegradable plastic, it will never be the final solution, despite claims from some companies to the contrary, no matter how efficiently this material degrades in the compost heap. Only in a limited segment of the market, say, in developing countries with a large number of organic landfills, biodegradable plastic makes sense (and then in the short term).

The category of “biodegradability” is an important aspect of this whole discussion.

For conscientious consumers, understanding the true meaning of “biodegradability” is critical, because only it allows them to buy environmentally friendly products and adequately decide what to do with garbage. Needless to say, manufacturers, marketers and advertisers have distorted the facts.

biodegradability criterion is not so much the source of the material as its composition. Today, the market is dominated by petroleum-derived durable plastics, commonly identified by polymer numbers from 1 to 7. Generally speaking (because each plastic has its own strengths and weaknesses), these plastics are synthesized for their versatility and strength, and also because that they have a high resistance to atmospheric conditions: these qualities are in demand in many products and packaging. The same applies to many of the plant-derived polymers that we also use today.

These desirable characteristics relate to a highly refined plastic, with long, complex polymer chains, that is highly resistant to natural degradation (such as by microorganisms). Since it’s so most of the plastic on the market today is simply not biodegradable, even those types of plastic that are obtained from renewable biomass.

But what about the types of plastic that manufacturers declare biodegradable? This is where most of the misconceptions come in, as claims of biodegradability usually don’t come with precise instructions on how to properly make that plastic biodegradable, nor does it explain how easily that plastic is biodegradable.

For example, polylactic (polylactic) acid is most commonly referred to as a “biodegradable” bioplastic. PLA is derived from corn, so it can be concluded that it decomposes just as easily as corn stalks if left in the field. Obviously, this is not the case – just exposed to high temperature and humidity (as in industrial composting conditions), it will decompose soon enough for the whole process to be justified. This simply won’t happen in a normal compost heap.

Bioplastics are often associated with biodegradability simply because they are derived from renewable biomass. In fact, most of the “green” plastic on the market is not rapidly biodegradable. For the most part, they require processing in industrial environments where temperature, humidity, and exposure to ultraviolet light can be tightly controlled. Even under these conditions, some types of biodegradable plastic can take up to a year to be completely recycled.

To be clear, for the most part, the types of plastic currently available on the market are not biodegradable. To be eligible for this name, the product must be able to decompose naturally through the action of micro-organisms. Some petroleum polymers can be combined with biodegradable additives or other materials to speed up the degradation process, but they represent a small segment of the global market. Hydrocarbon-derived plastic does not exist in nature, and there are no micro-organisms naturally predisposed to aid in its degradation process (without the aid of additives).

Even if the biodegradability of bioplastics would not be a problem, our current recycling, composting and waste collection infrastructure cannot handle the large amount of biodegradable plastic. By not (seriously) increasing our ability to recycle biodegradable polymers and biodegradable/compostable material, we will simply be producing more trash for our landfills and incinerators.

When all of the above is implemented, only then will biodegradable plastic make sense – in very limited and short-term circumstances. The reason is simple: why waste energy and resources producing highly purified biodegradable plastic polymers, only to sacrifice them completely later – through composting or natural biodegradation? As a short-term strategy to reduce waste in markets like Hindustan, it makes some sense. It doesn’t make sense as a long-term strategy to overcome the planet’s detrimental dependence on oil-derived plastics.

From the above, it can be concluded that biodegradable plastic, the “eco-packaging” material, is not a completely sustainable alternative, although it is often advertised as such. Moreover, the production of packaging products from biodegradable plastic is associated with additional environmental pollution.


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