Biodegradable vs Compostable: What is the difference?

It is not difficult to come across the terms "Biodegradable" and "Compostable" these days. More and more companies are claiming that their products are either Biodegradable or Compostable. If you are not familiar with these terms, I hope my article will help you!


Biodegradable


According to scientists, biodegradable means when an item can be broken down into much smaller pieces by bacteria, fungi or microbes to be reabsorbed by the surrounding environment, without creating any pollution to the environment. For example, plant-based products can break down into CO2, water, and some naturally occurring minerals, without any toxins. However, some products that are so called biodegradable actually break down into harmful chemicals that can damage the soil.

biodegradable plastic bag
Is biodegradable plastic bag the perfect solution? (source: Unsplash)

Different products biodegrade at different rates. Some take only few days, some could take up to 1 million years! For the biodegrading process, microorganisms need light, water and oxygen. Temperature is also one of the key factors, as in warmer conditions, microorganisms reproduce much faster.

Vegetables

5 days - 1 month

Paper

2 - 5 months

Cotton T-shirt

6 months

Orange peels

6 months

Tree leaves

1 year

Wool socks

1 - 5 years

Plastic-coated paper milk cartons

5 years

Leather shoes

25 - 40 years

Nylon fabric

30 - 40 years

Tin cans

50 - 100 years

Aluminium cans

80 - 100 years

Glass bottles

1 million years

Styrofoam cup

500 years to forever

Plastic bags

500 years to forever

Biodegradable plastic was first discovered in 1926 by a French researcher, Maurice Lemoigne, and it has become increasingly popular these years. However, according to James and Morton, biodegradable plastic generates the most methane, followed by office paper, food waste, newspaper when they are in an average landfill. Hence, biodegradable plastics are not the ideal answer as an eco-friendly alternative to conventional plastic. Researchers from the University of Plymouth found out that biodegradable plastic bags were barely damaged and still remained their strengths after 3 years being buried in the soil or left in the sea water, which means don't get yourself GREENWASHED, biodegradable plastic bags are not that great!


Compostable


Compostable items are technically biodegradable, but they must be in a compost environment. According to the ASTM, compostables are those that undergo degradation by biological processes during composting to yield carbon dioxide, water, inorganic compounds and biomass at a consistent rate with other compostable materials, leaving no visible, distinguishable or toxic residue. The typical time in a right setting environment is usually within 90 days.

landfill
The landfill's condition is so important! (source: Unsplash)

Unlike biodegradable products, after the composting process, compostable products like food scraps, leaves, etc. turn into organic matters or humus, leaving no plastics or chemicals of concerns.


In short, anything that is compostable is biodegradable, but, biodegradable does not always mean compostable.


So next time you go shopping, make sure you choose the right products, and read the label carefully!


Love,

Tram Anh



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