What does the term ‘biodegradable’ mean?
It refers to the ability of a material to be broken down by natural microorganisms (bacteria, fungi, algae, etc.). During this process, biodegradable materials are transformed into elements such as water, CO2 and biomass.
In theory, any organic material is biodegradable over time. However, this degradation can take months or even years, depending on environmental conditions.
What factors influence biodegradation?
Biodegradability: environmental conditions
Biodegradability depends on factors such as:
- temperature
- humidity
- presence of oxygen
- microbial activity
For example, a biodegradable material may break down more quickly in a warm, ventilated and humid environment such as industrial compost.
Decomposition time
Although products are biodegradable, there is no specific requirement as to how long they should take to break down completely. Some products may take months to degrade under ideal conditions, while others may persist for years.
The time factor becomes a key detail.
Biodegradable products and their final residues
The other crucial point is that not all biodegradable materials are transformed into completely non-toxic products. It is possible for residues or micro-particles to persist, particularly with certain bioplastics which, although ‘biodegradable’, can leave fragments in the environment.
What does the term “compostable” mean?
This term refers to a material’s ability to:
- degrade in a defined period of time and under specific conditions
- transform into nutrient-rich compost
- leave no toxic residues
N.B. The standards for compostable products are much stricter than those for biodegradable materials. They specify degradation times, precise environmental conditions and the absence of harmful substances in their residues.
What are the characteristics of compostable materials?
Composting standards
A compostable product must meet very specific standards, such as EN 13432 in Europe or ASTM D6400 in the United States. These require the material to decompose in an industrial composting environment in less than six months. In addition, the compost collected must be free of toxic substances and be capable of improving soil quality.
Compostable materials: industrial vs domestic
Different materials can be composted in different ways. A distinction needs to be made between products that can be composted under industrial conditions and those that can be broken down in domestic composters. Industrial composting requires very high temperatures (around 55-60°C) and specific control of humidity and oxygen. Plastics designed to be composted in these facilities do not break down adequately in domestic compost…
More or less rapid decomposition
Unlike biodegradable products, compostable products must break down within a few months and under specific composting conditions.This guarantees a relatively short life cycle and reduces the accumulation of waste.
Compostable or biodegradable: the key differences
| Biodégradable | Compostable | |
|---|---|---|
| Degradation conditions | Decomposition in various environments, but the process can be very slow (humidity, heat, oxygen). | They require specific conditions (industrial or domestic composting) to decompose quickly and efficiently. |
| Decomposition time | The degradation time is not predetermined and can vary considerably depending on conditions. N.B. Some biodegradable plastics can take years to decompose. | Designed to decompose in a few months in industrial compost, in accordance with international standards. |
| Final residues | Biodegradable products can leave behind residue, such as microplastics or toxic substances, and have a negative impact on the environment. | Compostable products must break down into non-toxic materials (water, CO2, biomass) without leaving behind hazardous residue. |
Focus on bioplastics: compostable or biodegradable?
Bioplastics can be designed to be biodegradable, compostable or non-degradable, depending on their chemical composition and intended application. The distinction lies in the conditions and time required for these materials to break down completely. To make the right choice between compostable or biodegradable bioplastics, it’s essential to understand these differences!
Good to know: PHA is the only natural polymer that is 100% biosourced and 100% compostable. It degrades in just a few weeks, even up to 86% in seawater, without leaving any harmful residue.
Compostable products – subject to standards – break down in controlled environments and leave no toxic residue. Biodegradable products can decompose under a variety of conditions, but with varying timescales and results. For companies, this choice will have repercussions not only on their carbon footprint, but also on their communication strategy. So, are you ready to adopt different types of bioplastics to reduce your ecological footprint?
