Two cups of latteI see more and more places getting cups, or bags, or other containers made from ‘bio plastic’. This is the material many companies are using, to remove plastic from tea bags. Compostable is good, if you DO compost them. But I’ve read people saying “it’s just as bad as plastic!” So I thought I’d dig a little deeper.

Researching PLA

The most common one is Polylactic Acid (PLA) or “Corn Plastic”. Generally made from maize in the US (the same crop that might be turned into food, fed to cows or turned into bio fuels) and hence probably genetically modified. It is also made from tapioca or sugar cane elsewhere in the world. PLA was discovered in the 1920s by Wallace Corothers (the scientist who invented nylon) but it hadn’t been successfully commercialised on a large scale.

Read the difference between biodegradable, compostable, and degradable. Materials that are compostable require heat, moisture, and certain microbes.

The pros are:

  • it comes from a renewable source instead of oil, so is ‘carbon neutral’
  • it is commercially compostable and then breaks down into harmless natural materials
  • it doesn’t produce toxic fumes if incinerated (burning plastic is carcinogenic)
  • it is ‘bio compatible’, ie suitable for medical implants that are absorbed

The cons of ‘corn plastics’ include:

  • most will not break down in a home compost, only industrial (there are not many in the US)
  • it requires industrial-sized fields, competing with food crops for land
  • if not composted or burnt, it will collect as rubbish in the sea, and affect wildlife the same way as plastic
  • it can not be recycled with plastics – if it gets into the plastic recycling stream, it will contaminate the load
  • if it goes into landfill, it won’t have the conditions to degrade properly and will produce methane (like food does)

“There has been an increase in availability of home compostable plastics. However a recent survey by Business Waste revealed that 97% of UK households DO NOT compost. You can read the article HERE.” [quote from 1.]

What about paper and card?

One particularly helpful quote I found is is:

Paper is biodegradable AND recyclable.
Plastic is biodegradable OR recyclable.

“Paper can degrade in any environment. Obviously paper will last for years if stored in dry conditions away from sunlight. But in the unfortunate event of paper being discarded in the open environment, buried or dropped in the sea, then it will naturally degrade and be absorbed harmlessly into the local eco-system.” [quote from 1.]

My thoughts in summary

Always, whenever possible, go for REUSABLE rather than disposable. There is too much rubbish in the world, we don’t need to add to it.

If disposable is needed, paper is better than bio-degradable plastics, in situations where it can be used, because it will always degrade harmlessly, eventually – even in the sea. If coated, go for bio plastic or wax.

Paper-based coffee cups can’t go into most paper/card recycling because of the film lining. If the lining is bio plastic, ask your council if they’ll take them in the composting, otherwise they have to go in the black bin. However, they will break down sooner and more harmlessly than any plastic.

Food packaging such as pizza boxes can be paper or card, but these need to be composted or black-binned, they can’t be recycled because of the residual grease. Bio plastics will cause the same problems in landfill as ordinary plastics, so best avoid.

NEVER mix the two kinds of plastic, there is no way for the processors to tell them apart either visually or mechanically, and a whole load could end up in landfill rather than risk processing a mixed load.

It seems to me that tea bags are quite a sensible use for PLA (until they come up with something better). It will degrade *eventually* (presumably assisted by the presence of damp tea leaves) – and harmlessly. They will rot down eventually even in a home compost heap. But best when added to food waste for industrial composting, and this isn’t available everywhere. Alternatively find a local route for anaerobic digestion (eg a farm) to make electricity, if your council doesn’t do local composting.

Compostable food waste bags are a logical route for food waste being composted. You can also line your caddy with newspaper (or bought paper liners), which can be readily composted by the council or at home. Bio plastic does have issues with other uses, like the new trend for biodegradable carrier bags. In a landfill environment, they can produce methane, but if incinerated (as many councils do) they are better normal plastic.

Plastic cutlery is not recyclable. The tougher ones can be reused extensively so if you’ve got some collect it up again for washing. Wooden cutlery is gaining in popularity. It can’t be reused, but be sure to collect it up to go into the garden waste collection.

Wherever possible, avoid disposable things which are a waste of our limited resources. And if unavoidable, choose paper-based or wood-based options especially if they will end up in the bin anyway.

Some of my sources:

  1. Which is more eco-friendly…paper, or biodegradable plastic?
  2. Are biodegradable plastics eco-friendly?
  3. Microplastics in the Environment – discusses the source of microplastics, the effects they have on living things, and potential solutions.
  4. The Environmental Impact of Corn-Based Plastics
    How does corn-based plastic stand up against its petroleum based counterpart?
  5. The Pros and Cons of Polylactic Acid (PLA) Bioplastic, the “Corn Plastics” 
  6. Pros and Cons of PLA: Corn-Based Plastic
  7. The Difference Between Biodegradable, Degradable and Compostable
    Includes Zero Waste tips for commercial kitchens
  8. Teabags: Is there plastic in yours?
    This BBC article considers bio plastic to be still basically plastic
  9. Polylactic acid or polylactide (PLA)