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How Long Does It Take to Degrade Plastic Waste in a Landfill?

Plastic waste issues are becoming more and more prevalent in recent history. This is best

illustrated by the statistic that only one ton is recycled for every 10 tons of plastic thrown

away. That means we're left with 4.9 billion tons of plastic that have been sent to a landfill or

natural environments.

Many people brush off this fact due to the concept that all plastic is degradable. But did you

know that, subject to the plastic, it can take hundreds of years to decompose?

Here’s how long popular plastic products take to decompose:

Traditional Plastics

Traditional plastics are still used in many products, such as plastic water bottles. These plastics

include the likes of PET (polyethylene terephthalate). However, these plastics do not quickly

decompose or biodegrade. PET is made with chemicals that bacteria can’t consume to

decompose the product.

Instead of bacteria decomposing traditional plastics, UV radiation from the sun does the trick.

But this can take hundreds of years; one study reports that plastic bottles take up to 450 years

to decompose in a landfill. Even after this decomposition, they leave debris known as

‘microplastics’ which can kill marine life and devastate the climate.

Biodegradable Plastics

Biodegradable plastic waste can be completely broken down by bacteria, making them faster at

decomposing than traditional plastics. These plastics include polyhydroxyalkanoate (PHA) and

polylactic acid (PLA), which are specifically designed to break down naturally.

Bacteria can decompose these plastics because they are generally made from more natural

materials. For instance, PLA is made from plant materials such as corn sugar, potatoes, and

sugar cane.

Given the right composting conditions, biodegradable plastics take three to six months to

decompose, which is much faster and more sustainable than traditional plastics! However, the

story does not end there.

Biodegradable plastics can only be degraded in industrial environments. You can't just chuck

them in the garden and hope for the best! There needs to be specific infrastructure to facilitate

the complex process of biodegrading these plastics, which is why they should always be

separated when thrown away, so they don't accidentally end up in a landfill!


Although some consider plastics to be relatively sustainable, the truth of the matter is complex.

While all plastic is biodegradable to some degree, this doesn't make it completely sustainable.

As we have established, traditional plastics take hundreds of years to biodegrade and leave

microplastics that can contaminate local habitats. In the process, these kill off wildlife due to the

chemicals involved in their production.

On the other hand, biodegradable plastics are designed to be broken down by bacteria, which

means that they can decompose in months! However, for biodegradable plastics to decompose

properly, they need to be in the right conditions! Therefore, industrial facilities deal with the

degradation process of biodegradable plastics.

So, next time you buy a plastic product, be sure to purchase biodegradable plastics whenever

possible. When throwing away your biodegradable plastics, make sure to separate them from

the regular plastics so that they won't just go to a landfill and will decompose properly!

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