By now, you would have noticed an increase in light plastic-like carrier bags on supermarket shelves. Most conventional light plastic packaging – for groceries, dry cleaning, bread, frozen food bags, newspapers, and garbage – is low-density polyethylene (LDPE), made from synthetic polymers, and comes almost entirely from non-renewable fossil fuels. These plastics, when not responsibly managed, cause great harm to the natural environment.
Most South African consumers have very limited awareness and understanding of what ‘biodegradable’ and ‘compostable’ mean and what is required for responsible post-consumer management
Along with the understanding that there is an urgent need to move away from a fossil fuel-based economy comes an increased demand for compostable bags, biodegradable, bio-plastic bags, and even dissolvable bags. While these are exciting new developments, we should take time to understand them and how to manage them at end-of-use.
South African scientist and plastics expert at The Moss Group, Rob van Hille, says that, “Most South African consumers have very limited awareness and understanding of what ‘biodegradable’ and ‘compostable’ mean and what is required for responsible post-consumer management.”
Rob is concerned that the absence of effective education and awareness can create the misconception that biodegradable materials decompose rapidly in the environment, which can potentially exacerbate the litter problem.
According to a review of biodegradable and compostable packaging prepared by The Moss Group, “There is currently very limited separation, collection, and processing infrastructure to support the responsible post-consumer management of packaging made from biodegradable and compostable materials.”
Let’s unpack the different types of plastic-like bags:
Biodegradable bags
The first thing to understand is that everything is technically biodegradable: it will biodegrade through biological activity. This means it will be broken down and consumed by bacteria and fungi, although for conventional plastics this may take many decades.
A plastic bag labelled as biodegradable should biodegrade within a reasonable time frame but the labelling on these bags usually doesn’t offer the time and conditions under which the bag biodegrades. We are left wondering whether these bags can biodegrade in the ocean or the environment. “Biodegradable” is a vague and unhelpful term.
- Raw materials: Renewable raw materials (biomass) or fossil fuels
- Recyclable: No
- Compostable: Not necessarily. And if they do, they do not necessarily convert into good quality compost
Bio-based plastics
Bio-based plastic are plastics where the initial raw material is a biological material, such as corn or sugarcane, rather than fossil resources. The polymers are identical to fossil fuel-based polymers and can be recycled with conventional plastics. According to Fashion for Good, fully bio-based plastics generally have a lower carbon footprint when compared to fossil-based plastics.
- Raw materials: Sugar cane / corn ethanol
- Recyclable: Yes
- Compostable: No
Compostable bags
Ideally, compostable bags degrade by natural processes and turn into new, biological materials again. Compostable bags can be made from various raw materials, including fossil fuel resources. They are compostable under various conditions, either in a home compost heap or an industrial one.
If a compostable bag ends up in the ocean, in the open environment, or a landfill and not in the correct composting environment, it may well not degrade for months or years. If compostable bags end up in conventional plastic recycling streams, they can disrupt the recycling process.
To avoid these unintentional consequences, compostable bags need to be directed to the appropriate composting facility, either a home composting system or an industrial composting facility at a temperature at which they will decompose.
It is for these reasons that good labelling and certification are important for compostable bags. Fashion for Good recommends looking for (home or industrial) composability and marine degradability certifications for confidence in compostable or marine degradable properties.
The best thing you can do with the compostable bag is put your food scraps into it and put them into your compost heap, says Rob.
- Raw materials: Food crops / organic waste / wood pulp and / or fossil fuel resources
- Recyclable: No
- Compostable: Depending on specific coatings and finishes used
Dissolvable bags
Dissolvable bags currently on the market are made from polyvinylalcohol (PVA or PVOH), a fossil fuel-based polymer that can dissolve in water under certain conditions, usually hot water. PVA is used as a film for dishwasher tablets and medicinal pill coverings.
While these bags dissolve, they do not meet the requirements for composability. Because they disappear so quickly in hot water, there isn’t an end-of-life plan for them which is problematic as they are not contributing to the circular economy. Resources are wasted. Rob Hille says scientists are picking up a lot of PVA in water streams. “It’s a solution that looks good, because you can make it disappear, but its environmental credentials are questionable,” says Rob.
- Raw materials: Fossil fuel resources
- Recyclable: No
- Compostable: No
What else should you consider?
Greenhouse gas emissions
All these options come with trade-offs and the environmental impact of each differs. Fashion for Good reports that bio-based plastic options have the lowest in greenhouse gas emissions, while PVA has the highest. Compostable plastics, although more difficult to assess due to the blends of bio-based and petroleum-based plastics used, are generally quite good.
Certifications
Ensure that the plastic-like bags you choose are certified. According to the Consumer Goods Council of South Africa, these are the most recognised certification bodies.
The way forward
Before buying your packaging, be sure that the material has been assessed fully in all relevant environments and then appropriately labelled.
Then check in your area if the infrastructure exists for the collection and recycling of a particular material. If you choose compostables, be clear about whether you can compost the packaging at home, and if not, can you get it to an industrial composting facility?
We need more regulation. Currently, there is no EPR legislation guiding manufacturers and retailers in the most responsible type of packaging. Government, consumers, and the media need to work together to support and disseminate information about these alternative plastic bags.
If a retailer or brand is going to offer compostable bags to consumers they should include instructions for correct disposal and management.
Rob recommends that the potential for developing local capacity for the production of bio-based polymers and biodegradable and compostable materials should continuously be assessed.
In conclusion
Remember that what we are trying to achieve in a circular and sustainable economy is to reduce the use of raw materials, eliminate toxins, reuse products for as long as possible, and then finally ensure the collection of waste and for products to be designed so that they can be fully recycled and remanufactured into new products.
In the meantime, we should all continue to try our best to reduce, reuse and rethink our use of plastic. This will bring us closer to a circular economy, in which we reuse and recycle far more products. When possible, refuse to use or purchase it from the get-go!
- Cover image: Photo by Karolina Grabowska on Pexels
- As part of our #PlasticFreeMzansi campaign, and using the Dirty Dozen, we have created a game to help you distinguish which common plastic waste items can be recycled and which cannot. Play it here.
