What is the difference between compostable and biodegradable?

What is the difference between compostable and biodegradable?

You’ve heard about climate change and its effect on the environment but you’ve never taken it seriously until now. You’ve conducted your research and have identified a lack of proper waste management as one of its causes. This has spurred you into taking proactive measures to help the environment. The question on your mind right now is ‘What is the difference between compostable and biodegradable?’ ‘What items are compostable and what items are biodegradable?’ And then there’s recycling too.

While we are doing our best to help the environment, it can be a bit confusing to distinguish between what items are biodegradable and compostable but it isn’t as difficult as it seems.  Both processes involve the decomposition of products into the soil but while all compostable items are biodegradable, not all biodegradable materials are compostable.

Still, confused? Not to worry. This blog post will explain in detail the difference between these two words that have come to be wrongly used interchangeably. By the end of this article, you will be able to clearly distinguish between biodegradables and compostables. You will also gain further insight into what recycling entails and what should go into your recycling bin.


What does compostable mean?

Etymologically, the word compost is related to the French word ‘compote’ which means ‘stewed fruits, fruit preserved in syrup.’The etymological root of both words – ‘compost’ and ‘compote’– go back to the word ‘composita’a Latin word which means ‘placed together.’

In clearer terms, composting is the process of breaking down a product into natural elements in a compost environment. The American Society for Testing and Materials (ASTM) defines compostables as anything that undergoes degradation as a result of biological processes during composting to yield water, CO2, biomass and inorganic products at a rate consistent with other compostable materials and more importantly, leaves no visible, distinguishable toxic residue.

In composting, organic waste is taken and allowed to decompose thereby creating fertilizer for the soil. However, they must be placed in the right conditions if they are to break down. Unlike biodegradable products, compostable products will break down in three months or less if managed properly. They, however, require human management to undergo this process successfully.

During composting, millions of tiny microbes consume organic materials and transform the waste into compost.

What does biodegradable mean?

The word which dates back from 1962 consists of 3 words “bio”, “degrade”, and “able”. “Bio” which means life, “degrade” meaning to disintegrate, and “able” meaning that it can happen. When put together, it simply means “susceptible to disintegration/ decomposition by living organisms(bacteria, algae, and fungi)”

The American Society for Testing and Materials (ASTM) defines biodegradables as anything that undergoes degradation resulting from the action of naturally occurring microorganisms such as bacteria, fungi, and algae.

In clearer terms, biodegradables are products that can be broken down into water vapor, carbon dioxide (or methane) and biomass naturally.

For biodegradation to occur, certain conditions (sufficient heat and moisture) must be present. In the absence of any of the above, it may take very long to decompose. For example, if the environment is too cold, it would not decompose.

Biodegradation is a process that largely depends on conditions such as temperature, presence of microorganisms, location, and humidity of the environment (garden compost, soil, industrial composting material, water, etc.) Its application and the material itself may also influence the process and its outcome.

What is the difference between compostable and biodegradable?

So now you know what these terms mean, but you still can’t tell the difference between compostable and biodegradable. Not to worry, we would take you through the differences between these two terms

While all compostable items are biodegradable, not all biodegradable material is compostable. Before a biodegradable material can be referred to as compostable, it must break down in a single composting cycle and must reach specific standards regarding disintegration, toxicity and both chemical and physical effects on the resulting compost. If a biodegradable material fails to break down in a single composting cycle and doesn’t reach the specific standards of disintegration, it cannot be referred to as a compostable.

Unlike compostables, biodegradables are subject to certain environmental factors and the absence of such conditions may interfere with the process of decomposition

While both products will break down and return to the soil, the key difference lies with the duration, that is, how long it would take before it completely disappears. Compostables will take about 3 months or less to break down completely despite environmental factors. By contrast, plant-based plastics that have been labeled as biodegradable may take as long as regular plastic to break down if the right environmental factors are absent.

Unlike biodegradables, compostable leave no toxic residue

Another key difference between biodegradable and compostable is that one leaves no toxic residue and the other may leave toxic waste behind. When compostables break down, it goes back into the soil and enriches it. Its end products are beneficial. It fertilizes and improves the soil’s health. Some biodegradables, on the other hand, may take several years to break down completely, leaving toxic waste behind. In fact, some never break down completely.

Types of compostable items

What items can go into my compost pile?

Before an item can be considered to be compostable, it must be broken down within 90 days. It must also pass ecotoxicity tests. More importantly, it must possess nutritive elements that would prove beneficial to the soil.

Some examples of compostable items are disposable products such as spoons, paper ice cream cups, dishes, cutlery, and even take-out boxes.

The majority of compostable products are produced in PLA(polylactic acid plastic.) They are made from polymer, which is derived from corn starch. However, in order for PLA to break down, it requires sufficient moisture and heat and must undergo a process known as hydrolyzing. This process is only possible in industrial composting systems and cannot be done at home.

Berry cartons, coffee filters, pizza boxes, tea bags, grass clippings, color newspaper, lettuce, potato peels, banana peels, avocado skins, black and white newspaper, printer paper, vegetable animal manure, sawdust, corn stalks, disease-free yard waste, twigs, dry pasta, hair, human or otherwise, pine needles, nutshells, toothpicks, wine corks, wood chips, old string & twine made of natural fabrics, pits from mangos, avocados, peaches, plums, pine cones, tissues, cotton balls, and paper toweling, sheets, used clothes, and towels, made from natural fabrics — cotton, silk, bamboo linen, and wool can all compostable and can go into your compost bin.

Types of biodegradable items

Almost all products can be broken down. The difference is in the duration. Some may take a few months and others may take several years. All products listed under compostable items are biodegradable.

In addition plant products like rubber, human and animal excreta, leaves, paper, cotton, wool, kitchen waste, dead remains of living organisms, agricultural waste, weed seed, tampons, diapers, treated sawdust, cheese, citrus peels, large branches, walnuts, pasta, coal ash, colored paper, dead plants, tea, coffee bags, onions, sticky labels on fruits and vegetables, dyed paper, cooking oil, coal fire ash, coated or glossy paper, raspberry & blackberry brambles, long twigs or big branches, pet droppings, especially cats & dogs, animal products, including bones, milk, fish skins, butter, meat, etc. are all biodegradable.

How is recycling different from composting and biodegradation?

So you know the difference between compostable and biodegradable but still can’t tell if it is the same as recycling? Not to worry, it is quite easy to differentiate between the three processes.

Like I mentioned earlier, both compostable and biodegradable materials have to undergo decomposition. They have to be broken down into the soil.

By contrast, recycling doesn’t need to undergo any decomposition into the soil nor does it add any beneficial nutrients to the soil. It simply is a process that converts used materials into something new. It is an efficient way to keep products away from landfills. But not all products can be recycled. In fact, there are limits to the number of times some materials can be recycled. For example, standard paper and plastics can only be recycled a few times before they become unusable, whereas metal, aluminum, and glass can be recycled endlessly.

Types of recyclable items

Newspaper, magazines, glossy ads, paperclips, staples, telephone books, tin cans (labels can be left on), corrugated cardboard, aluminum cans, tissue boxes, cereal boxes, metal hangers, paper towels, toilet paper rolls, junk mail, irons, toasters, coffee makers, kitchen mixers, pots and pans, office paper, wrapping paper are recyclable and should go into the recycle bin.

Plastics like soda bottles, milk jugs, water bottles, juice bottles, laundry detergent bottles, and any natural colored or clear plastic containers can also be recycled.

Can my biodegradable and compostable plastics be recycled?

No, biodegradable and compostable plastics cannot be recycled and should not be thrown into the recycling bin. They can contaminate the recycling process if placed in a recycling bin. With the development of technology, compostable and biodegradable solutions that can also be recycled may be created in the near future.

Leave nothing but footprints, take nothing but photographs.