Biodegradable and compostable packaging are not interchangeable. Dr Carol Kilcullen-Lawrence, the national president of the Australia Institute of Packaging (AIP) explains why.
Compostable and biodegradable – two terms that are often used interchangeably, but in reality actually mean very different things.
In light of the recent Australian Environment Ministers announcement that 100 per cent of packaging in Australia will be reusable, recyclable or compostable by 2025 we need to better understand how we can really achieve this and how different this target is compared to the packaging waste streams that are in place today.
The first step is to understand the difference between compostable and biodegradable packaging.
Everything will degrade over time but true biodegradation occurs through a biochemical process, with the aid of enzymes produced by naturally occurring microorganisms, both in the presence and absence of oxygen i.e. aerobic or anaerobic, without leaving behind any toxins, yielding only carbon dioxide, water and humus or biomass.
Biodegradable packaging is either completely or partially derived from a renewable source – like paper or starch – or, if it is petroleum based, is specifically engineered with the aid of additives, to decompose in the natural environment. Such additives change the chemical composition of the plastic.
While this does not affect its manufacturing, use or shelf life, such that it differs functionally from other plastics, it is significant at the end of life.
A biodegradable plastic will be considered a contaminant in the plastics recycling stream, as on being exposed to moisture and appropriate microorganisms, the biodegradation process will commence.
Compostable packaging has an organic origin, like sugar cane, bamboo or paper, and can broadly be classified into two types:
1. one that which will compost in a home compost; and
2. one that requires an industrial compost facility.
Industrial composting can cope with a wider range of compostable products as it involves pre-processing – where materials are ground and chipped down into smaller pieces, and in addition, industrial composting provides the higher temperatures needed for more efficient break down.
Home composting takes place at much lower temperatures and over an extended time frame, which can typically go up to a year, compared to a matter of weeks for industrial composting. And what people and organisations need to realise is that there is a different set of standards for materials suitable for home composting, which is governed by Vincotte a Belgium-based certification organisation.
While not currently available in all regions of Australia, industrial composting facilities are becoming increasingly widespread with many more councils and private companies providing bins where food scraps and compostable packaging can be disposed of within existing green waste collection services.
Known as FOGO, participating councils are considering potentially reducing landfill collections to fortnightly, allowing FOGO collections to become weekly. However, most councils also know that there will need to be significant consumer education to ensure the right types of compostable and biodegradable packaging are disposed of in such services.
One of the ideal situations to utilise compostable and biodegradable packaging is at public events where the inputs to the waste stream can be controlled by those at the arenas.
In such situations if all food packaging is manufactured from compostable organic sources and biodegradable plastics, then disposal facilities that capture this with the food waste will allow the packaging to be industrially composted together.
This is an ideal solution as many types of biodegradable and compostable packaging cannot be recycled, hence cannot be placed in kerbside recycling. It would be impossible for a consumer to identify the difference between a biodegradable PLA plastic container with a visually identical petroleum-based polymer one.
The move to biodegradable or compostable packaging is real, and with a 2025 target, now is the time to identify not only the most suitable sustainable solutions to suit each product, but to also ensure that the packaging waste streams have the capabilities to manage this change.