Eco-Friendly Gifts Blog: What's the Difference Between 'Biodegradable' and 'Compostable'?
Two of the buzzwords being used by seemingly every fast food / coffee chain currently: 'biodegradable' and 'compostable'.
With advertisements promising 'biodegradable cups' and 'compostable packaging' being thrown around, let's slow down and investigate what these words really mean.
Are they really as good as they sound?
The answer is a bit more complicated than you might think.
Definitions of 'Biodegradable' and 'Compostable'
Let's give the definitive versions of what each word means, so no one's time is wasted scrolling endlessly through a blog you, sort of, only want to half read. (We get that).
If a material is biodegradable, it will:
"Break down into biomass, CO2 and water, with the aid of microorganisms".
If a material is compostable, it will:
"Biodegrade to form compost, within set conditions, within a set time frame".
Why do Consumers Value Biodegradability and Compostability?
Most of the consumer demand for biodegradable and compostable items and packaging, is coming from the dislike of conventional plastic.
Plastic pollution is now so far widespread, it's being found in our drinking water, our food, and on top of mountains. Such is the shock at the scale of plastic pollution, and the damage it's causing, that consumers now want to move away from conventional plastic.
Including us, there is now a mass movement to crack down on plastic, and to clean up what plastic is on our planet today.
Conventional plastic has a few different problems that have resulted in environmental catastrophe the world over.
Conventional plastic doesn't biodegrade, it just breaks down into smaller and smaller pieces of plastic.
Pieces of plastic that are less than 5mm in all dimensions are what's known as microplastics. Microplastics can either be primary, or secondary.
Primary microplastics are created as such; microfibers from clothing, and microbeads, are two of the most commonly used primary microplastics.
Secondary microplastics are microplastics formed as a result of larger pieces of plastic breaking down. Water bottles, disposable plastic cups and plastic straws are just a few items that can form microplastics.
When microplastics enter the marine environment, things start to get really nasty.
Microplastics in the Marine Food Chain
Entering at the lower rungs, if not the bottom, of the marine food chain, microplastics are consumed by small creatures. Zooplankton are common examples of an entity at the bottom of the marine food chain, so let's use zooplankton as the example.
Microplastics, whether primary or secondary, are consumed by zooplankton. These zooplankton are then consumed by a predator the next trophic level up.
A trophic level is effectively a step in the marine food chain. The predator consumes the zooplankton, along with all the microplastic inside it. This process of transferring microplastics between prey and predator, is what's known as the trophic transfer of microplastics.
This process continues again and again, until the plastic accumulates in larger predators.
Unsurprisingly, but disturbingly, humans have now been confirmed to have plastic in their faeces also. We are, rather grimily, eating our own plastic waste inadvertently.
Plastic Pollution is Dangerous for Marine Wildlife
Plastic pollution on the primary scale is also a huge problem that is causing mass damage to our marine wildlife. Species are being wiped out from consuming plastic, which scientists have now partially discovered the reason for.
Seabirds and other marine species hunt krill. Krill, in turn, consume algae. When algae breaks down in our oceans, it releases a smelly gas: dimethyl sulfide.
Seabirds and other predators, have learned correctly that this smell equates to there being a large amount of krill present (who are feeding on the algae).
Unfortunately, floating plastic debris creates the perfect environment for algae to thrive.
As a consequence, the seabirds and other predators who hunt krill are now consuming plastic instead.
This can be lethal, for various reasons including but not limited to suffocation, internal bleeding from consuming plastic and inadvertent starvation. This last way is what we consider to be the saddest.
It's due to the predators thinking they are full with the food they need, but they are just full of plastic instead. This effectively means they are starving to death without knowing it.
Turtles experience a 22% chance of death by consuming one piece of plastic. This rises sharply to 50% when they consume 14 pieces or more. With over an estimated 8 million tonnes of plastic waste entering our oceans every year, it's no wonder that there is a rise in dwindling marine populations.
What has Biodegradability got to do with Plastic Pollution then?
The solution being presented by a material being biodegradable is simple. The material will biodegrade harmlessly, leaving no chance of wildlife getting injured or worse, from consuming the material.
However, it's not so simple.
Let's get into specifics. A usual material that disposable cups are made from, is PET, or Polyethylene Terephthalate. As it's a conventional plastic, it is non biodegradable, and also made from fossil fuels.
New plastics are being invented that are made from biobased, renewable raw materials such as cornstarch. These plastics are called bioplastics. Some bioplastics are also fully biodegradable. An example of a biodegradable bioplastic made from renewable resources is called PLA, or polylactic acid.
We love PLA!
However, just because it's classified as biodegradable does not mean it will break down in the natural environment anytime soon, whether it be on land or in ocean.
Think back to the definition. PLA is classed as biodegradable because it can break down into biomass, CO2 and water, with the aid of microorganisms. This is correct, PLA can do all of those things.
What's missing is the time frame. PLA could still break down into biomass, CO2 and water, but it could take 1,000 years. This key fact is what's missing from advertisers who call their coffee cups 'biodegradable'. Have you ever seen an advert saying:
"This cup is 100% biodegradable, but it's not guaranteed to break down in landfill, oceans or in the natural environment. In fact, it might take this 100% biodegradable cup 1,000 years to break down. But it's still biodegradable".
Let us know if you do!
So how do you make sure it will biodegrade within a short time frame?
This where composability comes into play.
Biodegradable vs Compostable
If that PLA cup is also compostable, like our ones, they will biodegrade within a set time frame, under set conditions, to form compost. Another slight porkie pie from advertisers, using the word 'compostable' is slightly misleading, because there are two types of composting: home and industrial.
Home composting is what we typically think of when we talk about composting. Putting food waste into the compost bin in your garden, if you have one. If not, allotments have them, as well as home composters for flats and apartments.
If you see an item with the logo below on the packaging, it means it is ok to compost it at home.
Most organic foods should compost at home with a well managed compost heap. Typical timelines for composting apple cores and bananas are around a month. For composting orange peels, it should completely biodegrade in six months.
Home compost heaps typically have temperatures of around 20-30 degrees celsius, although this varies hugely with many factors including location and time of year etc.
The PLA cups we were talking about earlier are not home compostable, they are what's known as 'industrially compostable'. If you were to put a compostable PLA cup into a home compost setting, there is no guarantee it will biodegrade within the set time frame for home composting.
So what's this industrial composting?
Industrial composting takes place in industrial composting plants. In these compost processing plants, there are higher temperatures along with controlled factors including moisture, and nitrogen ratio.
PLA cups need industrial composting to break down within the set time frame.
So how do you access industrial composting?
We have developed a free post back scheme, LFHP Zero, for any compostable goods processed from us. We guarantee that anything sent back to us will be fully composted, with zero waste going to landfill.
We have partnered up with an industrial composting partner, to ensure that they process compostable waste in their industrial composting plant.
It's really that simple - just send your used compostable waste back to us, and we will do the rest. Zero waste, zero problems.
You can find out if an item is industrially compostable, if the logos below are on the items or their packaging. The one on the left is what's known as the 'seedling' logo.
Below, we have compiled an infographic of the main differences between industrial composting, and home composting.
Are all Bioplastics Biodegradable?
No, not all bioplastics are biodegradable. Below is a chart showing the different types of bioplastic, as well as conventional plastic.
Let's start with our favourite type of bioplastic: biobased biodegradable bioplastics.
These bioplastics are made from renewable biobased resources, and can biodegrade (in some cases be composted, like PLA) as well. This group is, in our opinion, the most sustainable and environmentally friendly option. Theoretically, it's the only group that can readily form a circular production, use and disposal process.
The group to the left are biobased non biodegradable bioplastics. These bioplastics are produced from biobased renewable resources, but cannot biodegrade.
The group on the bottom right of the graph are fossil based biodegradable bioplastics. These are bioplastics that are produced from non-renewable fossil fuels such as petroleum, but they can biodegrade.
Finally, we get to conventional plastic. This group is produced from non-renewable fossil based resources, and also cannot biodegrade. As mentioned before, this is the group of plastics that are responsible for a large part of the plastic pollution crisis.
What's the difference?
After reading this blog, we hope you now have a good understanding of what 'biodegradable' and 'compostable' really mean.
Make sure to know what any adverts promising green concepts actually are saying, as often they can be misleading.
We are constantly looking at the latest developments concerning plastic pollution, and all the alternatives that are being developed to fight it.
Who knows, if you're reading this 100 years in the future, hopefully plastic pollution will be a thing of the past!
Let's hope so.
Environmentally Friendly Gifts
Our collection of environmentally friendly gifts covers celebratory gifts, as well as a few different niches.
We have environmentally friendly gifts in the form of festival survival kits, gifts for students and picnic hampers.
You can read more about compostable bioplastics by subscribing to our email list at the bottom of the page.