Are Biodegradable Garbage Bags Really Biodegradable?

Recently I’ve been trying to focus on de-cluttering my home and whilst we must all aim to reuse and repurpose there were items that just weren’t fit for a new life. Having bought some biodegradable rubbish bags from a local store, when I took the first one out I wondered whether biodegradable garbage bags really biodegradable. So I did some research.

Biodegradable garbage bags are biodegradable however they need specific environmental conditions to degrade quickly. These conditions are rarely seen in the natural environment and so most biodegradable plastic bags that are discarded will not degrade for years to come.

So let’s get into the detail of what I discovered but before we do if you are interested in compostable garden waste bags then you may want to read my article “Compostable Bags for the Green Bin – Should You Use Them?” next.

What is the Difference Between Degradable, Biodegradable and Compostable Bags

The first thing I found was that there are a few different types of garbage bags that could be suitable, compostable, biodegradable, and then there’s degradable. But which one of these trash bags should you choose?

1. Degradable Bags

Although the word degradable seems like it should be good for the environment we should try to avoid degradable plastic bags wherever possible.

These types of plastic bags do degrade and so when we think about bags staying around for hundreds of years, with the right treatment and conditions degradable bags will actually break down.

However, the issue here is that they break down into hundreds if not thousands of small pieces of plastic which we now refer to as microplastics.

There’s a huge amount of information on the internet about microplastics so I won’t go into detail here but needless to say that once consumed, they are incredibly dangerous to all types of animals. Now seen across the world, microplastics are passed from animal to animal through the natural food chain where microplastics have even been found in humans.

Best to avoid these types of bags but if you can’t don’t just discard them thinking they will degrade, make sure they are properly disposed of.

2. Biodegradable Bags

From their name, Biodegradable plastic bags sound great however there are a few things we should know before we start to use them.

Biodegradable plastic bags are generally made from plant-based material such as corn or wheat starch and they have specific additives added to promote the discarded bag to break down.

So although these bags will break down much quicker than degradable plastic bags one of the key issues is that to do so they need to be exposed to specific environmental conditions. High temperature, UV and oxygen are the main ones all of which may not necessarily exist where the bag is discarded.

This is the reason they can’t biodegrade fully and so using biodegradable trash bags isn’t perfect.

3. Compostable Bags

Made from 100% organic material such as plant starch these types of plastic bags do not leave behind any hazardous byproducts. All the material in the bag will simply return to the earth however there are still issues with compostable waste bags.

The main problem with some compostable plastic bags is that as with biodegradable plastic bags they need certain environmental conditions for the composting process to occur.

For some bags, this means that you cannot simply toss the plastic bag onto your compost heap at home unless they are specifically made for home composting.

If the compostable plastic bags you buy are not suitable for home composting then they would need to go to a special council compositing site of which there aren’t that many.

Degradable vs Biodegradable vs Compostable Garbage Bags – Which is best?

Out of the three options, compostable bags are the best. They are constructed of nutrient-rich components that, when broken down, leave nothing but natural material behind.

They also biodegrade at a faster pace, leaving no evidence behind however you do need to check that you can responsibly dispose of them either at home or at your local recycling facility.

Overall, they are far more environmentally friendly than standard polyethene.

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How Long Does it Take for a Biodegradable Plastic Bag to Decompose?

We do need to be careful using the term “biodegradable” as it can be misleading. You’d imagine that once such bags are discarded, they magically degrade spontaneously with nothing left behind, right?

Sadly this is not the case.

The truth is that biodegradable plastics require extremely high temperatures and humid conditions to decompose. With this in mind, it is extremely rare, if not impossible to occur in the natural environment where most bags are discarded.

Under the correct conditions, biodegradable bags can degrade completely in 3-6 months however the conditions required can only really be achieved in a manufactured way.

For the breakdown process to begin, the temperature must be above 50°C, which in the natural world is rare to occur even in the hottest of countries and is definitely not possible in our oceans.

The process also requires UV exposure, again difficult in the Nordics where sunlight in winter months only appears for a couple of hours a day.

One key point is that biodegradable plastic bags are not recyclable so they end up buried in landfills which ultimately means that they are very unlikely to see any sunlight again.

So, how long does a biodegradable bag take to degrade?

Well, it depends on so many factors but my guess is that it’s still a very long time indeed.

Are Biodegradable Garbage Bags Environmentally Friendly?

Given the research and information I’ve gathered over the last week or so, I would say they are not eco-friendly even though retailers are hailing them as a success.

Researchers at the University of Plymouth (the most famous research, cited by many sources I have read) in the United Kingdom recently examined five different types of plastic carrier bags, including two types of oxo-biodegradable bags, one biodegradable garbage bag, one compostable bag, and a typical high-density polyethylene plastic bag.

Here is a video clip from the University of Plymouth.

They discovered no clear evidence that bioplastic bags, including biodegradable and compostable bags, provide an environmental advantage over conventional plastics because they have been shown to linger in the environment for an extended period of time.

Furthermore, experts expressed worry that biodegradable plastic bags, in particular, could be fragmented into microplastics, having the same environmental impact as typical single-use plastic bags – partially decomposed compostable or biodegradable bags could be consumed by animals and enter the food chain, offering certain health hazards.

Greenpeace and the Environmental Investigation Agency (EIA) have recently issued a stern warning against the use of biodegradable and compostable plastics, calling them a false solution.

They point out that the vast bulk of bioplastics come from agricultural feedstock, which competes with food crops. As a result, bioplastic endangers food security, contributes to biodiversity loss, and increases agricultural emissions.

Here is the Greenpeace article – “Biodegradable Plastics: Breaking Down the Facts“

Rather than opting for a dubious solution, Greenpeace and the EIA strongly advise focusing on reduction and reuse.

To be fair, even though all three of these are better than the plastic bags of old I couldn’t agree more.

Common FAQs

Do Compostable Bags Break Down in Landfills?

Compostable bags have a hard time breaking down in landfills. Even though the bag material is made from 100% organic material such as plant starch, oxygen and sunlight are essential to make this process happen both of which are not usually present in landfills.

In my opinion, compostable bags are not a solution to waste management on their own.

They are best disposed of in composting facilities or home composting systems, where they can be properly managed to facilitate decomposition and produce nutrient-rich compost.

That said, reducing the use of plastic bags and opting for reusable alternatives is a more environmentally friendly choice.

What is an Eco-Friendly Alternative to Trash Bags?

To help with my green recycling and as part of my research, I decided to look if other people had found interesting alternatives to using trash bags.

An eco-friendly alternative to traditional plastic trash bags is to use biodegradable or compostable bags specifically designed for waste disposal. These bags are typically made from plant-based materials, such as cornstarch or other renewable resources, which break down more readily in composting or landfill environments compared to conventional plastic bags. However, as mentioned earlier, it’s important to note that even biodegradable or compostable bags may not effectively break down in a landfill due to the lack of suitable conditions.

Here are a few options for eco-friendly trash bag alternatives:

1. Biodegradable Bags: Look for bags labelled as “biodegradable” or “oxo-biodegradable.” These bags are designed to break down into smaller pieces over time, although the process may take longer in landfills.
2. Compostable Bags: Choose bags labelled as “compostable” that meet recognized standards such as ASTM D6400 or EN 13432. These bags are specifically designed to decompose in composting environments.
3. Paper Bags: Consider using paper bags for collecting non-hazardous waste. They are made from a renewable resource, can be easily recycled, and have a lower environmental impact compared to plastic.
4. Reusable Containers: Instead of using bags at all, you can opt for reusable containers or bins for waste disposal. This approach eliminates the need for single-use bags altogether.

Remember, regardless of the alternative you choose, it’s essential to properly dispose of waste and bags according to local regulations.

Recycling, composting, and waste segregation practices can further enhance your efforts to reduce environmental impact.

Can You Put Bin Liners in Recycling?

As a general rule, you should not put bin liners in recycling and instead, simply place all your recycling loose in the recycling bin itself. You may be tempted to use plastic garbage bags as you would with general waste however black plastic garbage bags aren’t biodegradable.

Remember, it’s crucial to follow your local recycling guidelines near your home to ensure proper waste management.

If your area does not have recycling programs for plastic bags, it is generally best to reduce their use and opt for reusable alternatives or appropriate disposal methods, such as waste-to-energy facilities or landfill disposal, if necessary.

Are Black Garbage Bags Biodegradable?

Most common black garbage bags are not biodegradable as they are made from low-density polyethylene (LDPE) which is a type of plastic that cannot biodegrade in typical landfill environments. It is of course possible for manufacturers of biodegradable bags to make them in black so checking the labelling is important.

Are Biodegradable Trash Bags Recyclable?

Whilst biodegradable trash bags are better for the environment it is not advisable to put them in your recycling bin as they can contaminate the recycling process and the whole batch might need to be sent to landfill. It is better to throw your recycling products directly into the bin itself.

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