Biodegradable and Compostable Concept

What does biodegradable and compostable actually mean?

03 Apr 2023

When considering environmentally friendly choices, it's important to understand the meaning behind terms like ‘biodegradable’ and ‘compostable’. While these terms are often used interchangeably to describe materials that can break down over time, there are subtle differences between them. First, let’s answer the question: which is better, a biodegradable product or one that is compostable? The short answer is that the compostable product is the better choice. A product marketed as natural and biodegradable - like plastic garbage bags made from sugar cane - may be neither; especially if it ends up in a landfill where pretty much nothing ever biodegrades.

Composting Soil

What makes something biodegradable?

One way to define whether something is biodegradable is if, after some metabolic or enzymatic processes, the molecular structure of that thing can be broken down. It means that microorganisms, such as bacteria or fungi, can metabolize the material and convert it into simpler substances. There is no limit on the length of the process or what’s left after completion. The time frame for biodegradation can last from several days to millions of years.

Dinosaurs are biodegradable. Yet, we still run across their bones from time to time. Is it any surprise then that when archaeologists tunnel through landfills (talk about a field of study with some job security) they often uncover 50-year-old newspapers that look hot off the press and even guacamole still good enough to eat.

Just because something can biodegrade, it doesn’t mean that it actually will in a reasonable amount of time.

Does biodegradable mean environmentally friendly?

The term "biodegradable" can be misleading, as it suggests that a product will naturally break down and be environmentally friendly. It is true that most things, especially newspapers and guacamole, if left out in the open will biodegrade over time. The sun and weather will break down newspapers and a tribe of wild nacho chips would finish off the guac.

Plastic Pollution - Plastic Bottle Left on the Ground

But even if left out in the open, things that are supposedly “biodegradable” may not do much degrading. “Biodegradable” plastic bags are often touted as an eco-friendly solution to the blight of plastic pollution and waste. But check this out, even after three whole years in the ocean, scientists have found that bags billed as biodegradable can still hold a load of groceries. This raises some questions about the efficacy of these so-called biodegradable products and highlights the ambiguity of the term.

Biodegradable is definitely a nebulous marketing term with plenty of wiggle room. Something can sound eco-friendly without having to be verifiably proven to be less harmful to the planet.

In short, biodegradable products are like herbal supplements - they haven't been rigorously tested to do what they are purported to.

Plant Seedling

What is compostable?

If you live someplace where leaves fall off trees you may have started a compost pile at some point in your life. Many people keep special bins for yard and food waste that are perfectly suited to break down organic matter and turn it into rich soil that's good for plants. Under normal conditions, it takes about 6 to 12 months to turn leaves into compost.

In theory, compostable products behave in the same way. They are designed to undergo a similar process, breaking down into organic matter that can contribute to the production of compost. However, not all compostable products will compost in a backyard compost pile. Some may require specific conditions or facilities, such as industrial composting facilities, to properly decompose.

FACT: to be labelled compostable, no toxic materials can persist after an item has been broken down. Objects labelled biodegradable do not have this requirement.

If you're interested, you can check out our guide to composting with the Eden Project's Catherine Cutler.

What makes a product compostable?

For a product to be termed “compostable” certain legal obligations have to be met. This is usually a recipe for the type of material. It dictates the duration of time needed to decompose and the specific conditions needed for decomposition to take place. One example is ASTM D6868, it’s the recipe that packaging designed to be composted (including plastic-coated paper and board) should comply with if it wants to display that certification.

Compostable products are better for the environment, right?

Yes, and no- it depends. Some “compostable” things might not compost the way you think (remember that guacamole?). As already mentioned, sometimes the composting recipe has requirements that only exist in industrial composting facilities.

Let’s look at leaves again. In some places, municipalities collect bagged-up leaves. The leaves are transported to compost facilities where they are composted on an almost industrial scale (for leaves at least). These leaves receive more attention than the average backyard compost heap and since the process is more controlled, it will produce a more consistent result.

Similarly, many compostable products - like the majority of bioplastics - are engineered to biodegrade or be compostable in a managed process dedicated to that kind of compostable waste.

This has led to confusion but things are getting better. In the EU, products can be labelled OK Compost Home (like compostable wheat straws, bamboo straws) or OK Compost; the latter designating that the product needs a commercial or municipal composting facility to break down.

Compostable and Biodegradable Bamboo Straws
Biodegradable and Compostable Wheat Straws

Are compostable plastics recyclable?

Yes, but. Oftentimes bioplastics can’t be recycled with other plastics — they can ruin batches of recyclable plastic, degrading the product until it becomes unusable.

Are compostable plastics better for the environment?

Again, it depends. Ethylene, the raw material for all packaging plastics, is derived from either natural gas or crude oil. These carbon sources took millions of years to accumulate and are not renewable. Producing and refining ethylene requires massive amounts of energy which could be better used elsewhere.

Using plants as a carbon source for bioplastics is much more sustainable when compared with petroleum or natural gas. Plant-based plastics can be carbon-negative, meaning they help reduce greenhouse gas emissions.  This is a massive improvement, however, they still need to be collected and recycled properly to maximise their environmental benefits.

But plastic is still plastic.

Plastic Bottles in a Bag Ready for Recycling

Plastic pollution whether it’s bags in trees, or microplastics in water and food, is still pollution no matter the ultimate source, and can cause a lot of damage to ecosystems and even us. Learn more about how plastic can harm people through its toxic chemicals and long-lasting environmental impact.

Ultimately, it's essential to remember that regardless of whether a product is biodegradable or compostable, reducing overall waste and not using plastic whenever possible is the best way forward if we want to mitigate our environmental impact.

Dispose of things in the right place

The deep, anoxic waters of the Black Sea have perfectly preserved wooden ships that sunk millennia ago. Banana peels locked in landfills last for decades. Bottles turn into sea glass in 20 to 30 years. Trees turn into petroleum after several million. The time something takes to break down and what is left behind depends on a lot of different things.

If there’s no catalyst to start the change - air, microbes, temperature, etc. - or if something is disposed of in the wrong place, even things made from natural materials can persist in the environment.

Make LESS trash

If you’d like to minimise your waste and adopt more sustainable practices, there are several strategies that can help. One of the key principles is to try to make LESS trash in the first place. This can be achieved through recycling (check out The Importance of Recycling or Benefits of Recycling), upcycling (12 Inspiring Upcycling Projects to Try Today or The Ultimate Guide to Upcycling), embracing circular fashion and composting (8 Benefits of Composting).

Upcycling Project With Plastic Bottles

For things you do buy, look for alternatives to plastic and choose products made from recognizable materials with minimal packaging. Opting for reusable items such as stainless steel water bottles, reusable bamboo cutlery, cloth shopping bags, and glass food containers can significantly reduce our reliance on single-use plastic and contribute to a more sustainable lifestyle.

For more info on what to look out for, check out our guide to products you might think are compostable but aren't.

Biodegradable Bamboo Cutlery Set
Reusable Water Bottle Eco-Friendly Alternative to Plastic

Beware of greenwashing: don't fall for false claims

When it comes to more eco-friendly alternatives like biodegradable or compostable products, it's also important to be mindful of greenwashing. This term refers to the deceptive practices used by some companies to make their products appear more environmentally friendly than they actually are. Many products labelled as biodegradable or compostable may not live up to their claims, leading to consumer confusion and potential harm to the environment. It's important to look beyond buzzwords and marketing claims and dig deeper to verify the authenticity of a product's environmental credentials.

Reliable certifications and transparent information about a product's lifecycle can help in discerning genuine eco-friendly options from greenwashing attempts. The good news is there's a reliable way to spot businesses that genuinely care about the planet: the highly respected B Corp certification. When you look for companies with B Corp certification, you can feel confident that they've been thoroughly evaluated to meet the toughest sustainability standards.

Circular Mobile Cases

The compostable mobile case

When we designed our circular mobile cases we made sure that, if you don't want to send them back to us to be recycled, then they can be composted and safely returned to the biosphere from which they came (they're made with plants, you know).

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