vendredi 10 avril 2009

Bioplastics: Concerns and Responses

London Bio Packaging (LBR) believes that bio based plastics are the most environmentally friendly materials available and play an important role in creating a more sustainable society.
Recently some have challenged whether bio-plastics are actually environmentally friendly. London Bio Packaging raises these issues and responds to them.

The Concern: Bio-plastics do not break down in landfill and if they do they create methane.

LBP Response:

In the UK the majority of landfill sites are now containment sites. This means that the landfill is lined and leachate and gas that is produced is collected. Bio-plastics will break down into compost in as little as eight weeks in an industrial composting facility. There are currently over 100 composting facilities in the UK and many more are being planned and built. Anaerobic digestion (an in vessel form of composting) takes what is apparently a waste product (such as post use food and bio packaging) and turns it into two useful commodities: compost and energy!

It should also be remembered that the problems of landfill apply to other wastes such as conventional plastics.

Mostly conventional plastics are sent to landfill because very few forms other than bottles can be recycled in the UK.

London Bio Packaging has developed its own closed loop composting system whereby bio packaging and food waste is collected and taken to a composting facility. All that is left at the end of the closed loop process is compost that farmers use to fertilize fields. (The fields could then grow more crops to make packaging!)

One key environmental benefit of using bio-plastics is they have a lower carbon footprint thus helping to combat climate change. Bio-plastic (PLA) emits 0.75 kilos of carbon dioxide per kilo of resin as compared with conventional plastic (PET), which emits 3.4 kilos of carbon dioxide per kilo. So bio-plastic emits 77 percent less carbon dioxide. This is not just a marginal difference but a hugely important step in fighting climate change!

The Concern: Bio-plastics use crops that would otherwise be used for food.

LBP Response:

The amount of corn used worldwide for bio-plastics in 2007 was about 250,000 tonnes. In 2007 the US alone produced 332 million tonnes of corn (in addition the US grew numerous other food crops including sorgum grain - 12.8 million tonnes, rice - 10 million tonnes and soybean - 70 million tonnes).

The percentage of US food production that would be used for worldwide bio-plastics production is 0.0005 percent. This does not take into account all the other food produced worldwide. This cannot be considered to have an effect on food scarcity, especially when compared to bio-fuels which used approximately 18 percent of US grain production in 2008. The raw material for bio-plastic production is plant starch. With technological developments, soon the starch will be taken from any biomass or crop waste and not the crop parts used in food production.

The Concern: If bio-plastics are sent to recycling facilities they will contaminate the waste stream.

LBP Response:

Currently bio-polymers account for a small percentage of overall conventional plastics use. As such they currently have little affect oil based plastic recycling.

Other polymers, i.e. PP or PVC, are already in widespread use and can also contaminate recycled PET plastic waste streams, so this is not something unique to bio-polymers. It is also possible to separate bio-plastics from the waste stream in the same way as other materials. More modern sorting/recycling facilities already have the ability to do this, but it may require investment in infrastructure in some recycling facilities.

But, the future always requires investment! Otherwise we will be stuck using oil, emitting lots of carbon and sending waste to landfill. The environmental costs of not developing sustainable materials and processes will outweigh the investment in bio-polymers.

The government must lead on putting in place the infrastructure for dealing with bio-plastics and compostable waste. There are vested interests in both the packaging industry and waste management organisations to focus on oil based plastics and diverting waste from landfill at the expense of real sustainable materials and solutions.

The Concern: Degradable plastics break down into tiny pieces which pollute the environment.
LBP Response:

Yes degradable plastics (also called oxy degradable plastics) have even more negative environmental impacts than conventional oil based plastics! Degradable plastics are different from biodegradable plant-based plastics (bio-plastics). They are conventional oil based plastics with additives that break them down into tiny pieces.

Degradable plastics do not have the renewable resource and low carbon benefits that plant based bio-plastics have, but also when they break down into tiny pieces, they pollute the environment. Research suggests the tiny pieces spread through the eco system and act as transporters for nasty chemicals such as DDT.

The concern: Recycled plastics are preferable to bio-plastics.

LBP Response:

Recycled plastics are a strong environmental option where good infrastructure for recycling exists (such as with bottles) or where bio-plastic applications are not currently suitable (i.e. some microwaveable packaging). Recycled plastics (like rPET) provide many environmental benefits over conventional virgin plastics and LBP does offer rPET products. However, recycled plastics are not ideal and not a long term solution. They still rely on a large percentage of oil (about 50 percent recycled is a standard maximum). Oil is unsustainable and sooner or later will run out! Importantly the carbon emissions associated with recycled plastic production are higher than bio-polymers.

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