Biodegradability

We see the term ‘biodegradable’ on some products that we buy, such as washing powders and shampoo, but what does it actually mean?

Biodegradable washing products

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Some consumer products use biodegradability as a selling point.

Rights: Ecostore

The ‘degradable’ part of the word simply means that the product is able to break down into smaller compounds and eventually into very simple compounds such as carbon dioxide, water and oxygen.

The ‘bio’ part of the word means that the process is helped along with biological organisms, such as fungi and bacteria, which digest the material.

So a ‘biodegradable’ object is one that will break down quickly and safely into harmless compounds by using the action of microorganisms.

Composting is another name for biodegrading.

Rotting apple core

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This apple core is starting to biodegrade. This rotting process is helped by the action of bacteria and fungi. These microorganisms break down the apple core into simple nutrients.

Rights: Image licenced through 123RF.com

When a leaf falls off a tree onto the ground, it will rot away until nothing visible is left – this is biodegradation at work. Fungi and bacteria break up the leaf into smaller and smaller parts and eventually into carbon dioxide, oxygen and other important elements that have helped make up the leaf, such as phosphate and nitrogen. These simple elements are harmless in the environment and can actually be beneficial, as it enables the tree to get back some nutrients. This is why people often collect and compost their biodegradable waste and later, when the material has broken down, put it on to the garden to act as fertiliser.

So what makes a product ‘biodegradable’? Any material that comes from nature will be able to return to nature provided that it hasn’t been changed too much by man-made processing. For example, we all know that an apple core is capable of biodegrading even if we accidentally leave it in our school bag, but what about a T-shirt? A T-shirt is made from cotton, which is from a plant, but it has been processed by spinning the thread and weaving the cloth – but because it is still basically from a plant, it will break down, though not as quickly as it would had the fibre been left on the plant.

Any plant-based, animal-based or natural mineral-based product has the capability to biodegrade, but they will biodegrade at different rates depending on the original material and how much it has been processed.

Products made from man-made compounds formulated in a laboratory are in combinations that do not exist in nature and therefore microorganisms are not able to break them down.

Find out how and innovative New Zealand company, Potatopak, use waste potato starch to make biodegradable disposable plates and trays.