By Oliver Berger –

We see them everywhere. Utensils, stir sticks, disposable cups, plates, plastic bags, and even six-pack rings labelled compostable, biodegradable, earth-friendly, photo-degradable… what does all of this mean?

Photo: Oliver Berger holding a compostable bag at the compost station at the Potato House. Photo: Lisa Bland
Oliver Berger holding a compostable bag at the compost station at the Potato House. Photo: Lisa Bland

From a scientific stand point, I have discovered it is important to be aware that the terms “biodegradable,” “compostable,” and “disintegration” are not the same. The key differences between these terms are time and end result.

For biodegradation and disintegration, there is no time reference needed for decomposition or the type of physical and chemical qualities of the end product produced through decomposition. Biodegradation requires the action of naturally occurring microorganisms and the process for disintegration does not. This means that the itemis simply broken down into smaller pieces of the original material, whatever that may be.

There are two basic classes of biodegradable plastics. Bioplastics, whose components are made up of renewable raw materials like starch (eg. corn, tapioca, potato), soy, lactic acid, cellulose, etc. These materials are converted into a polymer, which gives the bioplastic product its strength. The important thing to remember about bioplastics is that they must be composted properly. An industrial or commercial composing process is required to maintain proper moisture and temperature levels to assure the process is completed with accuracy.

The other class of biodegradable plastics contains components that are made up of petrochemicals containing biodegradable additives which enhance in the decomposition process. These fall into the disintegration category, or ‘photo-degradable,’ as you might read. Potentially, plastic breaking down into smaller pieces of plastic.

If these ‘biodegradable plastics’ end up in landfills they can take about as long as regular plastics to decompose. Recycling is also not an option for these plastics; small amounts can contaminate processing batches and it costs recycling centers money and efficiency to sort them out.

In contrast, I most often found the term “compostable” means that the material is capable of undergoing biological decomposition within a specific time period. The results are the material is visually indistinguishable in the finished compost, being broken down into carbon dioxide, water, inorganic compounds, and biomass only, and without exceeding any regulated toxicity levels.

Canada uses the standards developed by the International Organization for Standardization (ISO). The ISO’s definition of compostable plastic is “plastic that undergoes degradation by biological processes during composting to yield CO2, water, inorganic compounds, and biomass at a rate consistent with other known compostable materials and leave no visible, distinguishable or toxic residue.”

On the flipside ISO also lists, “ ‘biodegradable during composting’ as synonymous with ‘compostable’ (see definition of “compostable plastic”).”

So, is the ISO saying there is no difference between the words ‘biodegradable’ and ‘compostable’?

I am thoroughly researching this and I am still finding variations in the way people or organizations perceive these words. Marketing also uses these words to catch our attention, and there are no clear regulations to do so otherwise. It is misleading.

My answer to you is this: as you would read the ingredients of a granola bar to decide whether you want to put them into your body, so should you find out the contents of any packaging or products you’re using before you put them into the earth.

However, with these new technologies, larger municipalities can divert significant quantities of waste from overburdened landfills since the entire waste stream could potentially be biodegradable. For us in the Cariboo-Chilcotin, with our backyard composters, recycling stations, and landfills, we must consider our options differently.

If I had to use a take away container from the local food truck I would either choose a recyclable plastic container or some sort of all-paper plate or napkin, which I could compost easily. Bring your own plate and utensils with you and carry your own reusable mug. It is still the more sustainable option.

Consider also the time, energy, and space needed to grow the completely edible foods that are used in the production process of these bioplastics. Is it a wise choice to be making packaging out of food when there are people in this world with no food to eat?

It is also important to note, there are now certified compostable resins available in the market derived from petroleum and the field of compostable plastics is constantly evolving. Does this mean we should change our thinking and get used to bits of petro products in our gardens? I know is hard to keep up so as always contact me or our local waste-wise specialists with any questions regarding the impact of your leftovers.

Oliver has a 35-year degree in life, starting out in the Spokin Lake area, spending adolescence in Williams Lake, and then venturing throughout the world on a quest of always learning new things. His priorities include dedication to and education about waste management.


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