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Zero Waste Question? Ask Marianne and Sonja - Edition #14

Sustainability consultants Marianne and Sonja answer your questions on zero waste initiatives at health authority–owned hospital and residential care sites.

Missed previous editions?

We post the question and answer series with photos and posters on BC Green Care.

What is the difference between biodegradable and compostable?​

All compostable items are biodegradable, but not all biodegradable items are compostable. Confused yet? Let's look closer.

What does “biodegradable" mean?

Biodegradable materials break down and decompose to carbon dioxide, water, biomass, methane, and mineral salts, depending on the specific material and environmental conditions. All materials are biodegradable given enough time, even those that pollute. Natural materials, like plant fibres, tend to degrade a lot faster than human-made materials, like plastics. 

The environment that the biodegradable item is located in can speed up or slow down degradation. We often think of biodegradable materials breaking down in landfills, but this isn't always the case. Landfills tend to have few microorganisms and very little oxygen, making biodegradation an extremely slow process, even for organic matter, which can take decades.

What does “compostable" mean?

Only some biodegradable materials are compostable. Compostable materials are made of organic matter that breaks down to form compost. Compost benefits soil by adding nutrients, microorganisms, and structure. 

Oxygen and microorganisms, like bacteria and fungi, play an important role in breaking down organic materials to form compost. In optimum conditions, such as dedicated composting facilities, compostable materials break down very quickly—in weeks and months. 

Unlike a number of biodegradable materials, compostable materials do not leave metal residues or introduce harmful materials to the environment. Examples of compostable materials include food scraps and coffee grounds, garden trimmings, and, in some cases, wet or food-soiled paper.

How do I ensure an item is compostable?

Labels can be confusing, especially those that mark items as biodegradable or compostable “where facilities exist." 

Instead of relying on labels, identify compostable products by looking for items made entirely from natural (not human-made) materials—devoid of plastics or waxes. 

If the item is made with a mix of natural and human-made materials, the item must be placed in the garbage.

Where can I compost the item?

Cafeterias and kitchens and some staff areas collect organics for composting. Staff areas that collect organics are currently responsible for maintaining the bin and disposing the contents.

If your staff area needs compost collection, contact your Support Services Manager via Housekeeping.

photo: Food scraps are an example of an organic material that breaks down to form compost